Physical activity in adolescence and smoking in young adulthood: a prospective twin cohort study.

Aims  To control for familial confounds, we studied the association between adolescent physical activity and later smoking in twin siblings discordant for their baseline physical activity. Design and measurements  In this prospective population-based twin study, we asked whether persistent physical activity/inactivity in adolescence (assessed at 16, 17 and 18.5 years) predicted questionnaire-reported daily smoking at ages 22–27. Twins who, on the three baseline questionnaires, consistently reported frequent leisure physical activity (more than three times weekly) were classified as persistent exercisers, those who exercised less than three times monthly were called persistently inactive, ot…

Leisure-Time Physical Activity and Academic Performance : Cross-Lagged Associations from Adolescence to Young Adulthood

AbstractPhysical activity and academic performance are positively associated, but the direction of the association is poorly understood. This longitudinal study examined the direction and magnitude of the associations between leisure-time physical activity and academic performance throughout adolescence and young adulthood. The participants were Finnish twins (from 2,859 to 4,190 individuals/study wave) and their families. In a cross-lagged path model, higher academic performance at ages 12, 14 and 17 predicted higher leisure-time physical activity at subsequent time-points (standardized path coefficient at age 14: 0.07 (p < 0.001), age 17: 0.12 (p < 0.001) and age 24: 0.06 (p < 0.…

Long-term leisure time physical activity and properties of bone: A twin study

Effects of physical activity on bone properties, when controlled for genetic effects, are not fully understood. We aimed to study the association between long-term leisure time physical activity (LTPA) and bone properties using twin pairs known to be discordant for leisure time physical activity for at least 30 yr. Volumetric BMD and geometric properties were measured at the tibia shaft and distal end using pQCT in 16 middle-aged (50-74 yr) same-sex twin pairs (seven monozygotic [MZ] and nine dizygotic [DZ] pairs) selected from a population-based cohort. Paired differences between active and inactive co-twins were studied. Active members of MZ twin pairs had larger cortical bone cross-secti…

Genetic and Environmental Effects on Telomere Length and Lung Function: A Twin Study.

Background The purpose of the study was to estimate the heritability of leukocyte telomere length (LTL) and lung function and to examine whether LTL and lung function share genetic or environmental effects in common. Methods 386 monozygotic and dizygotic Finnish twin sisters (age 68.4±3.4 years) were included. Relative LTL was determined from peripheral blood DNA by qPCR. Lung function measures of FEV1, FVC, FEV1/FVC, and PEF were derived from spirometry. Genetic modeling was performed with MPlus statistical software. Results Univariate analysis revealed that in LTL, 62% (95% confidence interval 50-72) of the variance was explained by additive genetic and 38% (28-50) by unique environmental…

Genome-wide association studies identify 137 genetic loci for DNA methylation biomarkers of aging

Abstract Background Biological aging estimators derived from DNA methylation data are heritable and correlate with morbidity and mortality. Consequently, identification of genetic and environmental contributors to the variation in these measures in populations has become a major goal in the field. Results Leveraging DNA methylation and SNP data from more than 40,000 individuals, we identify 137 genome-wide significant loci, of which 113 are novel, from genome-wide association study (GWAS) meta-analyses of four epigenetic clocks and epigenetic surrogate markers for granulocyte proportions and plasminogen activator inhibitor 1 levels, respectively. We find evidence for shared genetic loci ass…

Older women's personal goals and exercise activity: an 8-year follow-up.

This study investigated the associations of personal goals with exercise activity, as well as the relationships between exercise-related and other personal goals, among older women. Both cross-sectional and longitudinal designs were used with a sample of 308 women ages 66–79 at baseline. Women who reported exercise-related personal goals were 4 times as likely to report high exercise activity at baseline than those who did not report exercise-related goals. Longitudinal results were parallel. Goals related to cultural activities, as well as to busying oneself around the home, coincided with exercise-related goals, whereas goals related to own and other people’s health and independent living…

Hormone replacement therapy enhances IGF-1 signaling in skeletal muscle by diminishing miR-182 and miR-223 expressions : a study on postmenopausal monozygotic twin pairs

MiRNAs are fine-tuning modifiers of skeletal muscle regulation, but knowledge of their hormonal control is lacking. We used a co-twin case-control study design, that is, monozygotic postmenopausal twin pairs discordant for estrogen-based hormone replacement therapy (HRT) to explore estrogen-dependent skeletal muscle regulation via miRNAs. MiRNA profiles were determined from vastus lateralis muscle of nine healthy 54-62-years-old monozygotic female twin pairs discordant for HRT (median 7 years). MCF-7 cells, human myoblast cultures and mouse muscle experiments were used to confirm estrogen's causal role on the expression of specific miRNAs, their target mRNAs and proteins and finally the act…

Peer reports of adaptive behavior in twins and singletons: is twinship a risk or an advantage?

We compared twins to their gender-matched singleton classmates in peer-assessed behavioral adjustment. Our samples include 1874 11- to 12-year-old Finnish twins (687 monozygotic, MZ; 610 same-sex dizygotic, SSDZ; 577 opposite-sex dizygotic, OSDZ) and their 23,200 non-twin classmates. Data were collected using a 30-item Multidimensional Peer Nomination Inventory containing three factors and their subscales. We found twin-singleton differences: classmates rated twin girls and boys higher than gender-matched singletons in Adaptive Behaviors (constructive, compliant, and socially active behavior), and those effects were particularly evident among OSDZ twins for assessments of social interaction…

Associations between long-term physical activity, waist circumference and weight gain: a 30-year longitudinal twin study.

Background and objective: Physical activity level and obesity are both partly determined by genes and childhood environment. To determine the associations between long-term leisure-time physical activity, weight gain and waist circumference and whether these are independent of genes and childhood effects. Design and subjects: The study design is a 30-year follow-up twin study in Finland. For this study, 146 twin pairs were comprehensively identified from the large Finnish Twin Cohort. These twin pairs were discordant for both intensity and volume of leisure physical activity in 1975 and 1981 and were healthy in 1981. At follow-up in 2005, both members of 89 pairs were alive and participated…

A genome-wide association study of monozygotic twin-pairs suggests a locus related to variability of serum high-density lipoprotein cholesterol

Serum lipid levels have been associated with cardiovascular diseases, metabolic syndrome and type II diabetes (Kannel et al., 1961; Miller & Miller, 1975; Pilia et al., 2006). Variation in lipids levels is highly influenced by heritable factors (Friedlander et al., 1997) and 95 loci have already been associated with levels of high density lipoprotein (HDL) cholesterol, low density lipoprotein (LDL) cholesterol, triglycerides (TG) and total cholesterol (TC) in numerous study samples and replicated in various populations using genome-wide approaches (Aulchenko et al., 2008; Kathiresan et al., 2008; Kooner et al., 2008; Teslovich et al., 2010; Willer et al., 2008). However, the genetic associa…

Muscle cross-sectional area and structural bone strength share genetic and environmental effects in older women

The purpose of this study was to estimate to what extent muscle cross-sectional area of the lower leg (mCSA) and tibial structural strength are influenced by common and trait-specific genetic and environmental factors. pQCT scans were obtained from both members of 102 monozygotic (MZ) and 113 dizygotic (DZ) 63- to 76-yr-old female twin pairs to estimate the mCSA of the lower leg, structural bending strength of the tibial shaft (BSIbend), and compressive strength of the distal tibia (BSIcomp). Quantitative genetic models were used to decompose the phenotypic variances into common and trait-specific additive genetic (A), shared environmental (C), and individual environmental (E) effects. The …

Genome-wide association study identifies five loci associated with lung function

Pulmonary function measures are heritable traits that predict morbidity and mortality and define chronic obstructive pulmonary disease (COPD). We tested genome-wide association with forced expiratory volume in 1 s (FEV(1)) and the ratio of FEV(1) to forced vital capacity (FVC) in the SpiroMeta consortium (n = 20,288 individuals of European ancestry). We conducted a meta-analysis of top signals with data from direct genotyping (n < or = 32,184 additional individuals) and in silico summary association data from the CHARGE Consortium (n = 21,209) and the Health 2000 survey (n < or = 883). We confirmed the reported locus at 4q31 and identified associations with FEV(1) or FEV(1)/FVC and co…

Shared Genetic and Environmental Effects on Strength and Power in Older Female Twins

Purpose: This study examined the relative contribution of genetic and environmental effects on maximal leg extensor power and also investigated whether leg extensor power and maximum voluntary isometric knee extensor strength share a genetic component. Methods: Muscle functions were measured as part of the Finnish Twin Study on Aging in 101 monozygotic (MZ) and 116 dizygotic (DZ) female twin pairs aged 63–76 yr. Leg extensor power was measured using the Nottingham Leg Extensor Power Rig and maximum voluntary isometric knee extensor strength using an adjustable dynamometer chair. The analyses were carried out using the maximum likelihood method in Mx-program on the raw data set. Results: A b…

Genetic association study of childhood aggression across raters, instruments, and age

AbstractChildhood aggressive behavior (AGG) has a substantial heritability of around 50%. Here we present a genome-wide association meta-analysis (GWAMA) of childhood AGG, in which all phenotype measures across childhood ages from multiple assessors were included. We analyzed phenotype assessments for a total of 328 935 observations from 87 485 children aged between 1.5 and 18 years, while accounting for sample overlap. We also meta-analyzed within subsets of the data, i.e., within rater, instrument and age. SNP-heritability for the overall meta-analysis (AGGoverall) was 3.31% (SE = 0.0038). We found no genome-wide significant SNPs for AGGoverall. The gene-based analysis returned three sign…

Contribution of genetic and environmental factors to individual differences in maximal walking speed with and without second task in older women

Background. Among older people, distraction while walking may increase the risk of falls. Factors underlying individual differences in dual tasking are not fully understood. Our aim was to study the effect of a second task on maximal walking speed and to examine whether individual differences in walking speed measured with and without a second task are accounted for by genetic and environmental influences shared across tasks or specific to each task. Methods. The data were collected from the 101 monozygotic and 116 dizygotic twin pairs aged 63–76 years recruited from the Finnish Twin Cohort. Maximal walking speed (MWS) over 10 m was measured on a laboratory corridor and timed with photocell…

Childhood aggression and the co-occurrence of behavioural and emotional problems: results across ages 3–16 years from multiple raters in six cohorts in the EU-ACTION project

Childhood aggression and its resulting consequences inflict a huge burden on affected children, their relatives, teachers, peers and society as a whole. Aggression during childhood rarely occurs in isolation and is correlated with other symptoms of childhood psychopathology. In this paper, we aim to describe and improve the understanding of the co-occurrence of aggression with other forms of childhood psychopathology. We focus on the co-occurrence of aggression and other childhood behavioural and emotional problems, including other externalising problems, attention problems and anxiety-depression. The data were brought together within the EU-ACTION (Aggression in Children: unravelling gene-…

Mobility and muscle strength in male former elite endurance and power athletes aged 66−91 years

The aim of this cross-sectional study was to compare mobility and muscle strength in male former elite endurance and power athletes aged 66-91 years (n = 150; 50 men in both former elite athlete groups and in their control group). Agility, dynamic balance, walking speed, chair stand, self-rated balance confidence (ABC-scale), jumping height, and handgrip strength were assessed. Former elite power athletes had better agility performance time than the controls (age- and body mass index, BMI-adjusted mean difference -3.6 s; 95% CI -6.3, -0.8). Adjustment for current leisure time physical activity (LTPA) and prevalence of diseases made this difference non-significant (P = 0.214). The subjects i…

Long-Term Physical Activity May Modify Brain Structure and Function: Studies in Young Healthy Twins

Background: Physical activity (PA) is said to be beneficial to many bodily functions. However, the effects of PA in the brain are still inadequately known. The authors aimed to uncover possible brain modulation linked with PA. Here, they combine 4 of their studies with monozygotic twins, who were within-pair discordant in PA for a minimum of 1 year. Methods: The authors performed brain imaging, brain electrophysiology, and cardiovascular and body composition assessments, and collected questionnaire-based data. The present synopsis elucidates the differences associated with differing PA history in conditions without genetic variability. They present new structural and electrophysiological re…

The difference in risk of chronic pulmonary disease morbidity and mortality between former elite athletes and ordinary men in Finland.

The impact of a history of competitive sports on later smoking behaviour and occurrence of chronic pulmonary diseases is poorly known. We investigated how a history of elite level sports predicted later pulmonary disease morbidity and mortality. Chronic pulmonary disease incidence was assessed from national hospital and cause-of-death registers from 1970 to 2015 among Finnish male former elite athletes (n = 2078) and matched controls (n = 1453) alive in 1970 (mean age 45.0 years). Hazard ratios (HRs) were calculated by Cox proportional hazards model. In 1985, cohort members reported on their smoking habits, engagement in physical activity/sports and physician-diagnosed chronic diseases. The…

Associations between sports participation, cardiorespiratory fitness, and adiposity in young adult twins.

Exercise behavior, cardiorespiratory fitness, and obesity are strongly influenced by genetic factors. By studying young adult twins, we examined to what extent these interrelated traits have shared genetic and environmental etiologies. We studied 304 twin individuals selected from the population-based FinnTwin16 study. Physical activity was assessed with the Baecke questionnaire, yielding three indexes: sport index, leisure-time index, and work index. In this study, we focused on sport index, which describes sports participation. Body composition was determined using dual-energy X-ray absorptiometry and cardiorespiratory fitness using a bicycle ergometer exercise test with gas exchange ana…

Menopause and adipose tissue: miR-19a-3p is sensitive to hormonal replacement

Tissue-specific effects of 17 beta-estradiol are delivered via both estrogen receptors and microRNAs (miRs). Menopause is known to affect the whole-body fat distribution in women. This investigation aimed at identifying menopause-and hormone replacement therapy (HRT)-associated miR profiles and miR targets in subcutaneous abdominal adipose tissue and serum from the same women. A discovery phase using array technology was performed in 13 women, including monozygotic twin pairs discordant for HRT and premenopausal young controls. Seven miRs, expressed in both adipose tissue and serum, were selected for validation phase in 34 women from a different cohort. An age/menopause-related increase of …

The heritability of depressive symptoms: multiple informants and multiple measures

Background: Earlier research suggests large rater differences in heritability estimates of children's depressive symptoms in the context of significant age and sex-limitation effects. Methods: With data from an ongoing, population-based twin-family study, we estimated genetic and environmental influences on children's depression with models allowing for sex-specific effects. Our assessments of twins included self-reports and ratings made by their classmate peers, their parents and their teachers, allowing estimates of genetic and environmental effects with data from different informants. Model-fitting used maximum likelihood estimation of log-transformed data from a sample of 1,366 11- and …

Longitudinal heritability of childhood aggression

The genetic and environmental contributions to the variation and longitudinal stability in childhood aggressive behavior were assessed in two large twin cohorts, the Netherlands Twin Register (NTR), and the Twins Early Development Study (TEDS; United Kingdom). In NTR, maternal ratings on aggression from the Child Behavior Checklist (CBCL) were available for 10,765 twin pairs at age 7, for 8,557 twin pairs at age 9/10, and for 7,176 twin pairs at age 12. In TEDS, parental ratings of conduct disorder from the Strength and Difficulty Questionnaire (SDQ) were available for 6,897 twin pairs at age 7, for 3,028 twin pairs at age 9 and for 5,716 twin pairs at age 12. In both studies, stability and…

Hearing as a Predictor of Falls and Postural Balance in Older Female Twins

BACKGROUND: The purpose of the present study was to examine, first, whether hearing acuity predicts falls and whether the potential association is explained by postural balance and, second, to examine whether shared genetic or environmental effects underlie these associations. METHODS: Hearing was measured using a clinical audiometer as a part of the Finnish Twin Study on Aging in 103 monozygotic and 114 dizygotic female twin pairs aged 63-76 years. Postural balance was indicated as a center of pressure (COP) movement in semitandem stance, and participants filled in a fall-calendar daily for an average of 345 days after the baseline. RESULTS: Mean hearing acuity (better ear hearing threshol…

Genetic effects in common on maximal walking speed and muscle performance in older women

The purpose was to examine whether maximal walking speed, maximal isometric knee extensor strength, and leg extensor power share genetic or environmental effects in common. The data was collected from 103 monozygotic and 114 dizygotic female twin pairs aged 63–76 years. Maximal walking speed over 10 m was measured in the laboratory corridor using photocells for timing. Isometric knee extensor strength and leg extensor power were measured using an adjustable dynamometer. The genetic models showed that strength, power, and walking speed had a genetic effect in common which accounted for 52% of the variance in strength, 36% in power, and 34% in walking speed. Strength and power had a non-share…

Catechol-O-Methyltransferase Gene Polymorphism Is Associated with Skeletal Muscle Properties in Older Women Alone and Together with Physical Activity

BackgroundMuscle strength declines on average by one percent annually from midlife on. In postmenopausal women this decrement coincides with a rapid decline in estrogen production. The genetics underlying the effects of estrogen on skeletal muscle remains unclear. In the present study, we examined whether polymorphisms within COMT and ESR1 are associated with muscle properties and assessed their interaction and their combined effects with physical activity.Methodology/principal findingsA cross-sectional data analysis was conducted with 434 63-76-year-old women from the population-based Finnish Twin Study on Aging. Body anthropometry, muscle cross-sectional area (mCSA), isometric hand grip a…

Walking Ability and All-Cause Mortality in Older Women

In this study self-reported ability to walk 2 km and six-minute walking test (6MWT) performance were examined as predictors of all-cause mortality in 434 women, aged 63-76 years. The primary outcome measure was all-cause mortality (follow-up: 8 years). Predictors were self-reported difficulties in walking 2 km and 6-min walking distance tertiles of ≤495, 496-560 and ≥561 m, and no test result due to refusal by the physician to grant permission to perform the test or participant's inability or unwillingness to perform the test. During the follow-up, 39 participants died. Participants reporting minor (age- and body mass index-adjusted hazard ratio 2.53, 95% confidence interval 1.12-5.69) or m…

Hormone therapy is associated with better body composition and adipokine/glucose profiles

Objective: The aim of this study was to evaluate the possibility of preventing the metabolic health consequences of postmenopausal hypogonadism with the use of long-term hormone therapy (HT). Methods: We used a monozygotic co-twin control design including 10 twin pairs (aged 56-62 y) discordant for HT (duration of HT, 2-10 y). In addition, 14 premenopausal women (aged 29-35 y) who did not use HT were studied to evaluate the differences in metabolic health between the premenopausal and postmenopausal states. Body composition was determined, and waist-to-hip ratio was used as an estimate for fat distribution. Serum sex steroids, sex hormone-binding globulin, and serum lipid and glucose profil…

Physical Activity and Academic Performance: Genetic and Environmental Associations

Introduction Physical activity and academic performance are believed to be associated. Though both traits are partially heritable, it remains unclear whether these traits also share a genetic and/or environmental background in common. We aimed to examine to what extent leisure time physical activity and academic performance share genetic and environmental effects from early adolescence to young adulthood. Methods Participants were Finnish twins (2543-2693 individuals/study wave) who reported their leisure-time physical activity at ages 12, 14, 17, and 24 yr. Academic performance was assessed with teacher-reported grade point averages at ages 12 and 14 yr and by self-reported educational lev…

Disc degeneration and bone density in monozygotic twins discordant for insulin-dependent diabetes mellitus

The effects of insulin-dependent diabetes mellitus on bone density and connective tissue degeneration have theoretical interest and practical relevance. Several experimental studies in animals have demonstrated the harmful effects of insulin deficiency on connective tissues. However, clinical studies in humans have produced somewhat contradictory results, most likely due to difficulties controlling for general degeneration and factors associated with diabetes. In nine pairs of monozygotic twins discordant for insulin-dependent diabetes mellitus, we compared femoral and lumbar bone mineral density (assessed by dual-energy x-ray absorptiometry) and spinal degeneration (assessed by magnetic re…

Physical Activity in Adolescence as a Predictor of Alcohol and Illicit Drug Use in Early Adulthood: A Longitudinal Population-Based Twin Study

AbstractWe investigated prospectively whether physical activity level in adolescence predicts use of alcohol and illicit drugs in early adulthood. We studied 4,240 individual twins (1,870 twin pairs). We classified those who consistently reported frequent leisure physical activity at ages 16, 17 and 181/2 as persistent exercisers, those exercising less than three times monthly as persistently inactive, and all others as occasional exercisers. To control for familial confounds, within-family analyses compared activity-substance use associations in co-twins discordant for baseline physical activity. Individual-based analyses showed no clear association between baseline physical activity and s…

Leisure activity patterns and their associations with overweight: A prospective study among adolescents

We examined longitudinal associations between individual leisure activities (television viewing, video viewing, computer games, listening to music, board games, musical instrument playing, reading, arts, crafts, socializing, clubs or scouts, sports, outdoor activities) and being overweight using logistic regression and latent class analysis in a cohort of Finnish twins responding to self-report questionnaires at 11–12 (N = 5184), 14, and 17 years. We also studied activity patterns (“Active and sociable”, “Active but less sociable”, “Passive but sociable”, “Passive and solitary”) thought to represent different lifestyles. Among boys, activity patterns did not predict becoming overweight, but…

If you drink, don't smoke : Joint associations between risky health behaviors and labor market outcomes

This paper examines the links between risky health behaviors and labor market success. We provide new evidence on the joint relationships between the most prominent forms of risky health behavior - alcohol consumption, smoking and physical inactivity - and long-term labor market outcomes. We use twin data for Finnish men and women linked to register-based individual information on earnings and labor market attachment. The twin data allow us to account for shared family and environmental factors and to measure risky health behaviors in 1975 and 1981. The long-term labor market outcomes were measured in adulthood as an average over the period 1990-2009. The sample sizes are 2156 and 2498 twin…

Mobility Limitation and Changes in Personal Goals Among Older Women.

Objectives. Several theoretical viewpoints suggest that older adults need to modify their personal goals in the face of functional decline. The aim of this study was to investigate longitudinally the association of mobility limitation with changes in personal goals among older women. Method. Eight-year follow-up of 205 women aged 66–78 years at baseline. Results. Health-related goals were the most common at both measurements. Goals related to independent living almost doubled and goals related to exercise and to cultural activities substantially decreased during the follow-up. Higher age decreased the likelihood for engaging in new goals related to cultural activities and disengaging from g…

Additional file 4 of Genome-wide association studies identify 137 genetic loci for DNA methylation biomarkers of aging

Additional file 4. Assessment of genomic inflation and heterogeneity.

Hormone Replacement Therapy Associated White Blood Cell DNA Methylation and Gene Expression are Associated With Within-Pair Differences of Body Adiposity and Bone Mass.

The loss of estrogen during menopause causes changes in the female body, with wide-ranging effects on health. Estrogen-containing hormone replacement therapy (HRT) leads to a relief of typical menopausal symptoms, benefits bone and muscle health, and is associated with tissue-specific gene expression profiles. As gene expression is controlled by epigenetic factors (including DNA methylation), many of which are environmentally sensitive, it is plausible that at least part of the HRT-associated gene expression is due to changes in DNA methylation profile. We investigated genome-wide DNA methylation and gene expression patterns of white blood cells (WBCs) and their associations with body compo…

Genetic effects on life-space mobility in older women.

Heritability of Intraocular Pressure in Older Female Twins

Purpose To examine the heritability of intraocular pressure (IOP) among older women not diagnosed as having glaucoma. Design Cross-sectional twin study. Participants 94 monozygotic (MZ) and 96 dizygotic (DZ) female twin pairs aged 63–76 years and not diagnosed as having glaucoma. Methods Intraocular pressure was measured using a noncontact tonometer. The contributions of genetic and environmental factors to individual differences in IOP were estimated by applying an independent pathway model to twin data. Main Outcome Measures Contribution of genetic and environmental effects to the variation in IOP among MZ and DZ twins. Results Mean IOP of the study population was 14.1 mmHg (± standard de…

Heritability of Lung Function: A Twin Study Among Never-Smoking Elderly Women

Most studies on lung function heritability have been conducted in smokers and non-smokers using cross-sectional study design. Smoking patterns may, however, confound the contribution of genetic factors. We investigated heritability of forced expiratory volume in one second (FEV1), forced vital capacity (FVC), and FEV1/FVC ratio longitudinally, excluding the effects of smoking. A sample of never smoking female twins (n = 374), aged 63–76 at baseline, answered health questionnaires and attended spirometry in years 2000 and 2003. Bivariate structural equation modeling, restricted to adequate spirometry performances (baseline n = 339, follow-up n = 252), was used to estimate genetic and environ…

Inattentiveness, parental smoking and adolescent smoking initiation

Aims  To examine how adolescents’ inattentive behaviour, together with parental smoking patterns, predicts smoking initiation by age 14. Design, settings  A prospective, longitudinal study: baseline at ages 11–12, follow-up at age 14. A population-based sample of Finnish twins, born 1983–1987, with parents and classroom teachers as additional informants. Two groups were formed, allocating the co-twins of each family into separate groups: the study sample and a replication sample. Participants  Twin individuals (n = 4552), aged 11–12 at baseline and 14 (average 14.04 years) at follow-up. Measurements  At baseline, inattentiveness was assessed with the Multidimensional Peer Nomination Invento…

Dementia in former amateur and professional contact sports participants : population-based cohort study, systematic review, and meta-analysis

Background Although there is growing evidence that former professional athletes from sports characterised by repetitive head impact subsequently experience an elevated risk of dementia, the occurrence of this disorder in retired amateurs, who represent a larger population, is uncertain. The present meta-analysis integrates new results from individual-participant analyses of a cohort study of former amateur contact sports participants into a systematic review of existing studies of retired professionals and amateurs. Methods The cohort study comprised 2005 male retired amateur athletes who had competed internationally for Finland (1920–1965) and a general population comparison group of 1386 …

Branched-Chain Amino Acid Levels Are Related with Surrogates of Disturbed Lipid Metabolism among Older Men.

Aims/hypothesis: Existing studies suggest that decreased branched-chain amino acid (BCAA) catabolism and thus elevated levels in blood are associated with metabolic disturbances. Based on such information, we have developed a hypothesis how BCAA degradation mechanistically connects to tricarboxylic acid cycle, intramyocellular lipid storage, and oxidation, thus allowing more efficient mitochondrial energy production from lipids as well as providing better metabolic health. We analyzed whether data from aged Finnish men are in line with our mechanistic hypothesis linking BCAA catabolism and metabolic disturbances. Methods: Older Finnish men enriched with individuals having been athletes in y…

Genetic contribution to the relationship between personality and depressive symptoms among older women.

BackgroundPrior studies suggest that certain types of personality are at higher risk for developing depressive disorders. This study examined the relationship between old age depressive symptoms and two middle-age personality dimensions, neuroticism and extraversion.MethodThe present study is part of the Finnish Twin Study on Aging, where altogether 409 female twins who had completed the Eysenck Personality Inventory at the age of 38–51 years were studied for depressive symptoms 28 years later using Center for the Epidemiologic Studies Depression Scale. Logistic regression analysis suitable for dependent data and univariate and Cholesky models for decomposing the genetic and environmental f…

The role of genetics and environment in lifting force and isometric trunk extensor endurance.

Background and Purpose. Our understanding of what different back performance tests are measuring is limited. The purpose of this study was to investigate the relative contributions of genetics and unique and common environmental factors for 3 tests of back muscle performance in a classic twin analysis. Subjects. The subjects were a population-based sample of 122 monozygotic and 131 dizygotic male twin pairs aged 35 to 69 years (X̄=49.9, SD=7.7). Methods. Variance component analysis was applied to estimate genetic and environmental influences on isokinetic and psychophysical lifting and isometric trunk extensor endurance test performance. The Cholesky decomposition genetic factor model was u…

TRIB1 constitutes a molecular link between regulation of sleep and lipid metabolism in humans.

Epidemiological studies show association between sleep duration and lipid metabolism. In addition, inactivation of circadian genes induces insulin resistance and hyperlipidemia. We hypothesized that sleep length and lipid metabolism are partially controlled by the same genes. We studied the association of total sleep time (TST) with 60 genetic variants that had previously been associated with lipids. The analyses were performed in a Finnish population-based sample (N = 6334) and replicated in 2189 twins. Finally, RNA expression from mononuclear leucocytes was measured in 10 healthy volunteers before and after sleep restriction. The genetic analysis identified two variants near TRIB1 gene th…

ASYMMETRICAL LOWER EXTREMITY POWER DEFICIT AS A RISK FACTOR FOR INJURIOUS FALLS IN HEALTHY OLDER WOMEN

Genetic and environmental influences on pubertal timing assessed by height growth

Secular trends towards earlier puberty, possibly caused by new environmental triggers, provide a basis for periodic evaluation of the influence and interaction of genetic and environmental effects on pubertal timing. In such studies, a practical marker that reflects timing of puberty in both genders needs to be used. We investigated genetic and environmental influences on pubertal timing by using change in the relative height between early and late adolescence (HD:SDS, height difference in standard deviations) as a new marker of pubertal timing. HD:SDS correlated well with age at peak height velocity in a population of men and women with longitudinal growth data. In 2,309 twin girls and 1,8…

A twin study on the heritability of walking ability among older women

BACKGROUND This study examined the role of genetic and environmental factors explaining individual differences in women's walking ability in old age. METHODS A maximal walking speed test over 10 meters and a 6-minute walking endurance test were done under standard conditions among 92 monozygotic and 105 dizygotic pairs of twin sisters reared together, aged 63-75 years. RESULTS The mean maximum walking speed was 1.73 +/- 0.32 m/s and the mean distance covered in the 6-minute walking test was 525.6 +/- 77.3 m. Multivariate genetic modeling showed that a minor part of the variances in walking speed (16%, 95% confidence interval [CI]: 0%-54%) and endurance (20%, 95% CI: 0%-56%) were accounted f…

Genome-wide Association Analysis in Humans Links Nucleotide Metabolism to Leukocyte Telomere Length

Leukocyte telomere length (LTL) is a heritable biomarker of genomic aging. In this study, we perform a genome-wide meta-analysis of LTL by pooling densely genotyped and imputed association results across large-scale European-descent studies including up to 78,592 individuals. We identify 49 genomic regions at a false dicovery rate (FDR) < 0.05 threshold and prioritize genes at 31, with five highlighting nucleotide metabolism as an important regulator of LTL. We report six genome-wide significant loci in or near SENP7, MOB1B, CARMIL1, PRRC2A, TERF2, and RFWD3, and our results support recently identified PARP1, POT1, ATM, and MPHOSPH6 loci. Phenome-wide analyses in >350,000 UK Biobank p…

Genetic and environmental factors affecting self-esteem from age 14 to 17: a longitudinal study of Finnish twins.

ABSTRACTBackgroundWe analysed genetic and environmental influences on self-esteem and its stability in adolescence.MethodFinnish twins born in 1983–1987 were assessed by questionnaire at ages 14 (n=4132 twin individuals) and 17 years (n=3841 twin individuals). Self-esteem was measured using the Rosenberg global self-esteem scale and analyzed using quantitative genetic methods for twin data in the Mx statistical package.ResultsThe heritability of self-esteem was 0·62 [95% confidence interval (CI) 0·56–0·68] in 14-year-old boys and 0·40 (95% CI 0·26–0·54) in 14-year-old girls, while the corresponding estimates at age 17 were 0·48 (95% CI 0·39–0·56) and 0·29 (95% CI 0·11–0·45). Rosenberg self-…

Allelic variants of IL1R1gene associate with severe hand osteoarthritis

Background In search for genes predisposing to osteoarthritis (OA), several genome wide scans have provided evidence for linkage on 2q. In this study we targeted a 470 kb region on 2q11.2 presenting the locus with most evidence for linkage to severe OA of distal interphalangeal joints (DIP) in our genome wide scan families. Methods We genotyped 32 single nucleotide polymorphisms (SNPs) in this 470 kb region comprising six genes belonging to the interleukin 1 superfamily and monitored for association with individual SNPs and SNP haplotypes among severe familial hand OA cases (material extended from our previous linkage study; n = 134), unrelated end-stage bilateral primary knee OA cases (n =…

Cumulative incidence of achilles tendon rupture and tendinopathy in male former elite athletes

To study the cumulative incidence of Achilles tendon rupture and tendinopathy among former top-level athletes.Historical cohort study.Finland.Male former elite athlete cohort members (n = 785; median age, 69 years when responding to the questionnaire; range, 54-97) and their matched controls (n = 416; median age, 68 years; range, 56-94).Questionnaire-reported Achilles tendinopathy and tendon rupture diagnosed by physicians before the age of 45 years and within the subjects' lifetimes.Cumulative incidence of Achilles tendinopathy before the age of 45 was high for middle and long-distance runners (adjusted odds ratio, 31.2 compared with controls; P0.001), and cumulative incidence of Achilles …

Prospective associations of early-onset Axis I disorders with developing eating disorders

Objective: The purpose of this study is to analyze the developmental relationships of adolescent-onset Axis I mental disorders and eating disorders (EDs).Method: One thousand three hundred eighteen adolescent twins born from 1983 to 1987 completed a professionally administered semistructured psychiatric interview at the age of 14 years and a questionnaire follow-up at the age of 17.5 years.Results: Eating disorders at the age of 17.5 years were significantly predicted by major depressive disorder (odds ratio, 5.9; 95% confidence interval, 2.6-15.3) and generalized anxiety disorder (GAD) (odds ratio, 4.7; 95% confidence interval, 1.8-15.6) at the age of 14 years, when baseline EDs were exclu…

A common biological basis of obesity and nicotine addiction

Contains fulltext : 128630.pdf (Publisher’s version ) (Open Access) Smoking influences body weight such that smokers weigh less than non-smokers and smoking cessation often leads to weight increase. The relationship between body weight and smoking is partly explained by the effect of nicotine on appetite and metabolism. However, the brain reward system is involved in the control of the intake of both food and tobacco. We evaluated the effect of single-nucleotide polymorphisms (SNPs) affecting body mass index (BMI) on smoking behavior, and tested the 32 SNPs identified in a meta-analysis for association with two smoking phenotypes, smoking initiation (SI) and the number of cigarettes smoked …

Personal goals and personality traits among young adults: Genetic and environmental effects

To assess genetic and environmental contributions to personal goals, 1279 twins aged 20-26 filled in Personal Project Analysis and NEO-FFI inventories. Personal goals relating to education, the respondent's own family, friends, property, travel and self showed primarily genetic and unique environmental effects, whereas goals related to parents and relatives showed both shared and unique environmental effects. The variation in goals related to health, work, hobbies and life philosophy was attributable to non-shared environmental effects. Openness to experience and personal goals related to family, education and property shared a significant amount of genetic influence. The same was true for …

A Genome-Wide Screen for Interactions Reveals a New Locus on 4p15 Modifying the Effect of Waist-to-Hip Ratio on Total Cholesterol

Recent genome-wide association (GWA) studies described 95 loci controlling serum lipid levels. These common variants explain ∼25% of the heritability of the phenotypes. To date, no unbiased screen for gene–environment interactions for circulating lipids has been reported. We screened for variants that modify the relationship between known epidemiological risk factors and circulating lipid levels in a meta-analysis of genome-wide association (GWA) data from 18 population-based cohorts with European ancestry (maximum N = 32,225). We collected 8 further cohorts (N = 17,102) for replication, and rs6448771 on 4p15 demonstrated genome-wide significant interaction with waist-to-hip-ratio (WHR) on …

Genetic and Environmental Influences Underlying Externalizing Behaviors, Cigarette Smoking and Illicit Drug Use Across Adolescence

We investigated genetic and environmental influences common to adolescent externalizing behavior (at age 12), smoking (at age 14) and initiation of drug use (at age 17) using the FinnTwin12 cohort data. Multivariate Cholesky models were fit to data from 737 monozygotic and 722 dizygotic twin pairs. Heritability of externalizing behavior was 56%, that of smoking initiation/amount 20/32%, and initiation of drug use 27%. In the best-fitting model common environmental influences explained most of the covariance between externalizing behavior and smoking initiation (69%) and amount (77%). Covariance between smoking initiation/amount and drug use was due to additive genetic (42/22%) and common en…

Physical activity and dementia : Long-term follow-up study of adult twins

Introduction. Physical activity is associated with a decreased occurrence of dementia. In twins, we investigated the effect of persistent physical activity in adulthood on mortality due to dementia. Materials and methods. Physical activity was queried in 1975 and 1981 from the members of the older Finnish Twin Cohort (n = 2 1,791), who were aged 24-60 years at the end of 1981. The subjects were divided into three categories according to the persistence of their vigorous physical activity. Dementia deaths were followed up to the end of 2011. Results. During the 29-year follow-up, 353 subjects died of dementia. In individual-based analyses the age-and sex-adjusted hazard ratio (HR) was 0.65 (…

Heritability of refractive astigmatism: a population-based twin study among 63- to 75-year-old female twins.

PURPOSE: To examine the heritability of refractive astigmatism in older women. METHODS: Astigmatism was measured with an autorefractor in 88 monozygotic and 82 dizygotic female twin pairs aged 63 to 75 years. The prevalence and distribution of astigmatism and polar values J0 and J45 were estimated by standard statistical methods. Bivariate maximum likelihood model fitting was used to estimate genetic and environmental variance components using information from both eyes. RESULTS: Mean astigmatism of the more astigmatic eye was 0.93 diopters (D; SD ±0.58). Astigmatism of at least 0.25 D, 0.5 D, 0.75 D, or 1.0 D in either eye was present in 99.7%, 88.5%, 66.5%, and 46.2% of cases, respectivel…

Genetic and Environmental Effects on the Individual Variation and Continuity of Participation in Diverse Physical Activities

INTRODUCTION Participation in diverse physical activities has beneficial health effects. However, little is known on how genetic and environmental factors affect this trait. Thus, we examined to what extent these factors explain participation in diverse leisure-time physical activities from late adolescence to adulthood using a twin study design. METHODS The participants were Finnish twins who reported their participation in diverse leisure-time physical activities at ages 17 (n = 5429) and 34 yr (n = 4246). The number of physical activities engaged in was analyzed using applications of structural linear modeling for twin data. RESULTS On average, the total number of physical activities eng…

Heritability of anterior chamber depth and axial length: a population-based twin study among 66 to 79-year old female twins.

Decreased prevalence of left-handedness among females with male co-twins: Evidence suggesting prenatal testosterone transfer in humans?

Studies of singletons suggest that right-handed individuals may have higher levels of testosterone than do left-handed individuals. Prenatal testosterone levels are hypothesised to be especially related to handedness formation. In humans, female members from opposite-sex twin pairs may experience elevated level of prenatal exposure to testosterone in their intrauterine environment shared with a male. We tested for differences in rates of left-handedness/right-handedness in female twins from same-sex and opposite-sex twin pairs. Our sample consisted of 4736 subjects, about 70% of all Finnish twins born in 1983–1987, with information on measured pregnancy and birth related factors. Circulatin…

Does telomere length predict decline in physical functioning in older twin sisters during an 11-year follow-up?

Background: Leucocyte telomere length (LTL) is known to be associated with mortality, but its association with age-related decline in physical functioning and the development of disability is less clear. This study examined the associations between LTL and physical functioning, and investigated whether LTL predicts level of physical functioning over an 11- year follow-up. Methods: Older mono- (MZ) and dizygotic (DZ) twin sisters (n=386) participated in the study. Relative LTL was measured by qPCR at baseline. Physical functioning was measured by 6-min walking distance and level of physical activity (PA). Walking distance was measured at baseline and at 3-year follow-up. PA was assessed by q…

The Association Between Epigenetic Clocks and Physical Functioning in Older Women: A 3-Year Follow-up

Abstract Background Epigenetic clocks are composite markers developed to predict chronological age or mortality risk from DNA methylation (DNAm) data. The present study investigated the associations between 4 epigenetic clocks (Horvath’s and Hannum’s DNAmAge and DNAm GrimAge and PhenoAge) and physical functioning during a 3-year follow-up. Method We studied 63- to 76-year-old women (N = 413) from the Finnish Twin Study on Aging. DNAm was measured from blood samples at baseline. Age acceleration (AgeAccel), that is, discrepancy between chronological age and DNAm age, was determined as residuals from linear model. Physical functioning was assessed under standardized laboratory conditions at b…

Objectively measured physical activity profile and cognition in Finnish elderly twins

Introduction We studied whether objectively measured physical activity (PA) and sedentary behavior (SB) are associated with cognition in Finnish elderly twins. Methods This cross-sectional study comprised twins born in Finland from 1940 to 1944 in the Older Finnish Twin Cohort (mean age, 72.9 years; 726 persons). From 2014 to 2016, cognition was assessed with a validated telephonic interview, whereas PA was measured with a waist-worn accelerometer. Results In between-family models, SB and light physical activity had significant linear associations with cognition after adjusting for age, sex, wearing time, education level, body mass index, and living condition (SB: β-estimate, −0.21 [95% con…

Meta-analysis of gene-environment-wide association scans accounting for education level identifies additional loci for refractive error

Myopia is the most common human eye disorder and it results from complex genetic and environmental causes. The rapidly increasing prevalence of myopia poses a major public health challenge. Here, the CREAM consortium performs a joint meta-analysis to test single-nucleotide polymorphism (SNP) main effects and SNP × education interaction effects on refractive error in 40,036 adults from 25 studies of European ancestry and 10,315 adults from 9 studies of Asian ancestry. In European ancestry individuals, we identify six novel loci (FAM150B-ACP1, LINC00340, FBN1, DIS3L-MAP2K1, ARID2-SNAT1 and SLC14A2) associated with refractive error. In Asian populations, three genome-wide significant loci AREG…

Short telomere length is associated with impaired cognitive performance in European ancestry cohorts

AbstractThe association between telomere length (TL) dynamics on cognitive performance over the life-course is not well understood. This study meta-analyses observational and causal associations between TL and six cognitive traits, with stratifications on APOE genotype, in a Mendelian Randomization (MR) framework. Twelve European cohorts (N=17 052; mean age=59.2±8.8 years) provided results for associations between qPCR-measured TL (T/S-ratio scale) and general cognitive function, mini-mental state exam (MMSE), processing speed by digit symbol substitution test (DSST), visuospatial functioning, memory and executive functioning (STROOP). In addition, a genetic risk score (GRS) for TL includin…

Telomere Length in Circulating Leukocytes is Associated with Lung Function and Disease

Several clinical studies suggest the involvement of premature ageing processes in chronic obstructive pulmonary disease (COPD). Using an epidemiological approach, we studied whether accelerated ageing indicated by telomere length, a marker of biological age, is associated with COPD and asthma, and whether intrinsic age-related processes contribute to the interindividual variability of lung function. Our meta-analysis of 14 studies included 934 COPD cases with 15 846 controls defined according to the Global Lungs Initiative (GLI) criteria (or 1189 COPD cases according to the Global Initiative for Chronic Obstructive Lung Disease (GOLD) criteria), 2834 asthma cases with 28 195 controls, and s…

Sequence variants at CHRNB3-CHRNA6 and CYP2A6 affect smoking behavior

Contains fulltext : 89305.pdf (Publisher’s version ) (Closed access) Smoking is a common risk factor for many diseases. We conducted genome-wide association meta-analyses for the number of cigarettes smoked per day (CPD) in smokers (n = 31,266) and smoking initiation (n = 46,481) using samples from the ENGAGE Consortium. In a second stage, we tested selected SNPs with in silico replication in the Tobacco and Genetics (TAG) and Glaxo Smith Kline (Ox-GSK) consortia cohorts (n = 45,691 smokers) and assessed some of those in a third sample of European ancestry (n = 9,040). Variants in three genomic regions associated with CPD (P < 5 x 10(-8)), including previously identified SNPs at 15q25 repre…

Heritability of Spherical Equivalent

Purpose To examine the heritability of spherical equivalent (SE) in older women. Design Population-based twin study. Participants Ninety monozygotic (MZ) and 86 dizygotic (DZ) female twin pairs aged 63 to 76 years who were born from 1924 through 1937. Methods Ocular refraction was measured using an autorefractor and controlled by the subjective method. The contributions of genetic and environmental factors to individual differences in SE were estimated by applying an independent pathway model to twin data. Main Outcome Measures Contribution of genetic and environmental effects to the variation in SE. Results Mean SE of the study population was 1.68 (standard deviation, ±1.82) with no differ…

Effects of 32-year leisure time physical activity discordance in twin pairs on health (TWINACTIVE study): aims, design and results for physical fitness.

AbstractThe physically active lifestyle is associated with low future morbidity and mortality, but the causality between physical activity and health is not always clear. As some inherited biological characteristics and childhood experiences may cause selection bias in observational studies, we sought to take them into account by identifying 16 twin pairs (7 MZ, 9 DZ, mean age 60 years) discordant for leisure time physical activity habits for thirty years. We conducted detailed health-related examinations among these twin pairs. Our main aims were to study the effects of physical activity and genes on fitness and body composition, with special reference to body fat compartments, metabolic s…

Genome-wide association meta-analysis of corneal curvature identifies novel loci and shared genetic influences across axial length and refractive error

Corneal curvature, a highly heritable trait, is a key clinical endophenotype for myopia - a major cause of visual impairment and blindness in the world. Here we present a trans-ethnic meta-analysis of corneal curvature GWAS in 44,042 individuals of Caucasian and Asian with replication in 88,218 UK Biobank data. We identified 47 loci (of which 26 are novel), with population-specific signals as well as shared signals across ethnicities. Some identified variants showed precise scaling in corneal curvature and eye elongation (i.e. axial length) to maintain eyes in emmetropia (i.e. HDAC11/FBLN2 rs2630445, RBP3 rs11204213); others exhibited association with myopia with little pleiotropic effects …

Hormone replacement therapy improves contractile function and myonuclear organization of single muscle fibres from postmenopausal monozygotic female twin pairs

Ageing is associated with a decline in muscle mass and strength leading to increased physical dependency in old age. Postmenopausal women experience a greater decline than men of similar age in parallel with the decrease in female sex steroid hormone production. We recruited six monozygous female twin pairs (55-59 years old) where only one twin pair was on hormone replacement therapy (HRT use = 7.8 ± 4.3 years) to investigate the association of HRT with the cytoplasmic volume supported by individual myonuclei (myonuclear domain (MND) size,) together with specific force at the single fibre level. HRT use was associated with a significantly smaller (∼27%; P < 0.05) mean MND size in muscle fib…

Electrocardiographic Indices of Left Ventricular Hypertrophy and Repolarization Phase Share the Same Genetic Influences: A Twin Study

Background: Both left ventricular hypertrophy (LVH) and repolarization phase (RP) are known to be attributable to genetic influences, but less is known whether they share same genetic influences. The aim of this study was to investigate to what extent individual differences in electrocardiographic (ECG) LVH and RP are explained by genetic and environmental influences and whether these influences are shared between these two traits. Methods: Resting ECG recordings were obtained from 186 monozygotic and 203 dizygotic female twin individuals, aged 63 to 76 years. Latent factors, called LVH and RP, were formed to condense the information obtained from LVH indices (Cornell voltage and Cornell pr…

Muscle Cross-Sectional Area and Structural Bone Strength Share Genetic and Environmental Effects in Older Women

The purpose of this study was to estimate to what extent muscle cross-sectional area of the lower leg (mCSA) and tibial structural strength are influenced by common and trait-specific genetic and environmental factors. pQCT scans were obtained from both members of 102 monozygotic (MZ) and 113 dizygotic (DZ) 63- to 76-yr-old female twin pairs to estimate the mCSA of the lower leg, structural bending strength of the tibial shaft (BSIbend), and compressive strength of the distal tibia (BSIcomp). Quantitative genetic models were used to decompose the phenotypic variances into common and trait-specific additive genetic (A), shared environmental (C), and individual environmental (E) effects. The …

Smoking and long-term labour market outcomes.

Objective To examine the long-term effects of smoking on labour market outcomes using twin data matched to register-based individual information on earnings. Method Twin data for Finnish men born 1945–1957 was used to remove the shared environmental and genetic factors. The results were subjected to extensive robustness testing. Lifetime cigarette consumption was measured by (cumulative) cigarette pack-years in early adulthood. The average of an individual's earnings (and, alternatively, taxable income) was measured over a subsequent 15-year period in later adulthood. Results Smokers have lower long-term income and earnings. For example, controlling for the shared environmental and genetic …

Persistence or Change in Leisure-Time Physical Activity Habits and Waist Gain During Early Adulthood: A Twin-Study

Objective To determine the relationship between persistence or change in leisure‐time physical activity habits and waist gain among young adults. Methods Population‐based cohort study among 3383 Finnish twin individuals (1578 men) from five birth cohorts (1975‐1979), who answered questionnaires at mean ages of 24.4 y (SD 0.9) and 33.9 y (SD 1.2), with reported self‐measured waist circumference. Persistence or change in leisure‐time physical activity habits was defined based on thirds of activity metabolic equivalent h/day during follow‐up (mean 9.5 y; SD 0.7). Results Decreased activity was linked to greater waist gain compared to increased activity (3.6 cm, P < 0.001 for men; 3.1 cm, P < 0…

Liver and pancreatic fat content and metabolism in healthy monozygotic twins with discordant physical activity

Background &amp; Aims: Ectopic fat in muscle and liver is linked to obesity and type 2 diabetes. Recently, pancreatic lipid accumulation has also been associated with beta-cell dysfunction and reduced insulin production, leading to the development of type 2 diabetes. Physical exercise training has been shown to attenuate beta-cell dysfunction in patients, but little is known about its effects on pancreatic and hepatic fat accumulation. In this study, we validated in-vivo proton magnetic resonance spectroscopy ((1)H MRS) in pancreatic fat measurement with biochemical measurements in a pig model. Thereafter, the effects of increased physical activity on the amounts of pancreatic and liver fat…

It does take a village: nonfamilial environments and children's behavior.

Family characteristics influence children's behavioral development, but so do variations in schools, neighborhoods, and communities. We documented extrafamilial environmental effects by fitting maximum likelihood models to questionnaire data collected from double dyads consisting of twins and their classmate controls. The classmate controls in each double dyad were genetic strangers living in separate households, but they shared school, neighborhood, and community environments with their yoked twin pair and with one another. At ages 11 to 12, the control classmates showed significant similarities in religious practices and smoking and drinking patterns, demonstrating that environmental inf…

Harmonization of Neuroticism and Extraversion phenotypes across inventories and cohorts in the Genetics of Personality Consortium:an application of Item Response Theory

Mega- or meta-analytic studies (e.g. genome-wide association studies) are increasingly used in behavior genetics. An issue in such studies is that phenotypes are often measured by different instruments across study cohorts, requiring harmonization of measures so that more powerful fixed effect meta-analyses can be employed. Within the Genetics of Personality Consortium, we demonstrate for two clinically relevant personality traits, Neuroticism and Extraversion, how Item-Response Theory (IRT) can be applied to map item data from different inventories to the same underlying constructs. Personality item data were analyzed in >160,000 individuals from 23 cohorts across Europe, USA and Australia…

Genetic architecture of circulating lipid levels

Serum concentrations of low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), triglycerides (TGs) and total cholesterol (TC) are important heritable risk factors for cardiovascular disease. Although genome-wide association studies (GWASs) of circulating lipid levels have identified numerous loci, a substantial portion of the heritability of these traits remains unexplained. Evidence of unexplained genetic variance can be detected by combining multiple independent markers into additive genetic risk scores. Such polygenic scores, constructed using results from the ENGAGE Consortium GWAS on serum lipids, were applied to predict lipid levels in an independen…

The effects of social anxiety on alcohol and cigarette use across adolescence: Results from a longitudinal twin study in Finland.

Conflicting reports exist on the direction of the relationship between social anxiety (SA) and alcohol/cigarette use (AU/CU) and alcohol/nicotine dependence (AD/ND), with both positive and negative associations reported. A prospective, longitudinal sample of Finnish twins (n = 1,906) was used to test potential explanations for these discrepancies. Specifically, this study used peer, parent, and teacher ratings of SA, and a clinical interview screening item for social anxiety disorder (SAD-Sc) to examine associations between SA and AU/CU and AD/ND from early adolescence into young adulthood. Peer-rated SA was negatively associated with AU, CU, and AD from age 14 through age 22, implying a pr…

The relative roles of intragenic polymorphisms of the vitamin d receptor gene in lumbar spine degeneration and bone density.

Study Design. A retrospective cohort study. Objectives. To compare the magnitudes of the associations of TaqI polymorphisms of the vitamin D receptor gene with bone density and lumbar spine degeneration in the same sample. Summary of Background Data. Vitamin D receptor gene variations are associated with osteoporosis, osteoarthritis, and disc degeneration. Their role in these conditions remains poorly understood. Methods. Bone density of the spine and femur were determined through DEXA, and lumbar disc degeneration was determined from magnetic resonance imaging assessments of signal intensity, disc narrowing, bulging, anular tears, herniations, and osteophytes. Associations between these me…

Genetic architecture of motives for leisure-time physical activity: a twin study

The aim of this study was to estimate the contribution of genetic and environmental influences on motives for engaging in leisure‐time physical activity. The participants were obtained from the FinnTwin16 study. A modified version of the Recreational Exercise Motivation Measure was used to assess the motives for leisure‐time physical activity in 2542 twin individuals (mean age of 34.1 years). Linear structural equation modeling was used to investigate the genetic and environmental influences on motive dimensions. The highest heritability estimates were found for the motive dimensions of “enjoyment” [men 33% (95% CI 23–43%), women 53% (95% CI 45–60%)] and “affiliation” [men 39% (95% CI 0.28–…

Twin studies on the association of physical activity with cognitive and cerebral outcomes

Regular physical activity (PA) offers positive effects on the human body. However, the effects of PA on cognition and in the brain are less clear. In this paper, we narratively review the relationship of PA with cognition and dementia, first from general perspective and then through genetically informed studies on the topic. Then we move on to imaging studies on exercise and brain anatomy first by presenting an overall picture of the topic and then discussing brain imaging studies addressing PA and brain structure in twins in more detailed way. Regarding PA and cognition or dementia, genetically informed studies are uncommon, even though the relationship between PA and cognitive ageing has …

Additional file 3 of Genome-wide association studies identify 137 genetic loci for DNA methylation biomarkers of aging

Additional file 3. Supplementary Figures - Figures S1-S31.

Liikemittarilla mitatun kevyen fyysisen aktiivisuuden ja paikallaanoloajan yhteys itseraportoituihin liikkumisvaikeuksiin suomalaisilla kaksosilla

Personal Goals of Older Female Twins

This study examined genetic and environmental influences on older women’s personal goals by using data from the Finnish Twin Study on Aging. The interview for the personal goals was completed by 67 monozygotic (MZ) pairs and 75 dizygotic (DZ) pairs. The tetrachoric correlations for personal goals related to health and functioning, close relationships, and independent living were higher in MZ than DZ twins, indicating possible genetic influence. The pattern of tetrachoric correlations for personal goals related to cultural activities, care of others, and physical exercise indicated environmental influence. For goals concerning health and functioning, independent living, and close relationsh…

Fear of falling and coexisting sensory difficulties as predictors of mobility decline in older women.

BACKGROUND: Mobility decline, the coexistence of several sensory difficulties and fear of falling (FOF) are all common concerns in older people; however, knowledge about the combined effect of FOF and coexisting sensory difficulties on mobility is lacking. METHODS: Data on self-reported FOF, difficulties in hearing, vision, balance, and walking 2 km were gathered with a structured questionnaire among 434 women aged 63-76 years at baseline and after a 3-year follow-up. Logistic regression models were used for analyses. RESULTS: Every third participant reported difficulties in walking 2 km at baseline. In cross-sectional analysis, the odds ratio for difficulties in walking 2 km was higher amo…

Global gene expression profiles in skeletal muscle of monozygotic female twins discordant for hormone replacement therapy

Aging is accompanied by inexorable loss of muscle tissue. One of the underlying causes for this is the massive change in the hormonal milieu of the body. The role of a female sex steroid – estrogen – in these processes is frequently neglected, although the rapid decline in its production coincides with a steep deterioration in muscle performance. We recruited 54- to 62-year-old monozygotic female twin pairs discordant for postmenopausal hormone replacement therapy (HRT, n = 11 pairs; HRT use 7.3 ± 3.7 years) from the Finnish Twin Cohort to investigate the association of long-term, estrogen-based HRT with skeletal muscle transcriptome. Pathway analysis of muscle transcript profiles revealed …

Do epigenetic clocks provide explanations for sex differences in lifespan? A cross-sectional twin study

ABSTRACTBackgroundThe sex gap in life expectancy has been narrowing in Finland over the past four to five decades; however, on average, women still live longer than men. Epigenetic clocks are markers for biological aging that predict lifespan. In this study, we examined the mediating role of lifestyle factors on the association between sex and biological aging in younger and older adults.MethodsOur sample included same-sex younger and older twins (21-42-y, n = 1110; 50-76-y, n = 763) and younger opposite-sex twins (21-30-y, n = 302). Blood-based DNA methylation (DNAm) was used to compute epigenetic age acceleration by four epigenetic clocks as a measure of biological aging. Path modelling w…

Accumulation of sensory difficulties predicts fear of falling in older women

Objectives: To explore whether the accumulation of sensory difficulties predicts fear of falling (FOF), and whether the traits correlate with each other regardless of familial factors. Methods: Self-reported hearing, vision and balance difficulties, and FOF were assessed using structured questionnaires at the baseline and after a 3-year follow-up in 63- to 76-year-old women (n = 434). Results: Among the women without FOF at baseline (n = 245), 41% reported FOF at follow-up. Increasing numbers of sensory difficulties at baseline predicted higher incidence of FOF. The relationship between accumulated sensory difficulties and FOF was not mediated by familial factors. Discussion: The accumulati…

Drinking, smoking, and educational achievement: Cross-lagged associations from adolescence to adulthood

Background Adolescent substance use is associated with lower educational achievement but the directionality of the association remains uncertain. We analyzed data on drinking, smoking and educational achievement to study the associations between substance use and education from early adolescence to young adulthood. Methods Longitudinal data from four time points (ages 12, 14, 17, and 19–27 years) from a population-based cohort study of Finnish twin individuals were used to estimate bivariate cross-lagged path models for substance use and educational achievement, adjusting for sex, parental covariates, and adolescent externalizing behavior. A total of 4761 individuals (49.4% females) were in…

The Older Finnish Twin Cohort : 45 Years of Follow-up

AbstractThe older Finnish Twin Cohort (FTC) was established in 1974. The baseline survey was in 1975, with two follow-up health surveys in 1981 and 1990. The fourth wave of assessments was done in three parts, with a questionnaire study of twins born during 1945–1957 in 2011–2012, while older twins were interviewed and screened for dementia in two time periods, between 1999 and 2007 for twins born before 1938 and between 2013 and 2017 for twins born in 1938–1944. The content of these wave 4 assessments is described and some initial results are described. In addition, we have invited twin-pairs, based on response to the cohortwide surveys, to participate in detailed in-person studies; these …

Suicide and depression in former contact sports participants: population-based cohort study, systematic review, and meta-analysis

SummaryBackgroundTraumatic brain injury is associated with the future risk of depression and suicide, and this raises the possibility that former participants in sports characterised by low intensity repetitive head impact may also subsequently experience an increased burden of these mental health outcomes. Using new data from a cohort study integrated into a meta-analysis of the current evidence, we compared the occurrence of depression and suicide in former contact sports athletes against general population controls.MethodsThe cohort study comprised 2004 retired male athletes who had competed internationally on an amateur basis for Finland between 1920 and 1965, and 1385 age-equivalent ma…

Leisure-time physical activity and DNA methylation age : a twin study

Background: Epigenetic clocks may increase our understanding on human aging and how genetic and environmental factors regulate an individual aging process. One of the most promising clocks is Horvath’s DNA methylation (DNAm) age. Age acceleration, i.e., discrepancy between DNAm age and chronological age, tells us whether the person is biologically young or old compared to his/her chronological age. Several environmental and lifestyle factors have been shown to affect life span. We investigated genetic and environmental predictors of DNAm age in young and older monozygotic (MZ) and dizygotic (DZ) twins with a focus on leisure time physical activity. Results: Quantitative genetic modeling rev…

Development of a Food-Based Diet Quality Score from a Short FFQ and Associations with Obesity Measures, Eating Styles and Nutrient Intakes in Finnish Twins

We constructed a food-based diet quality score (DQS) and examined its association with obesity measures, eating styles and nutrient intakes. Participants were 3592 individuals (764 dizygotic [DZ] and 430 monozygotic [MZ] twin pairs) from the FinnTwin16 study. The DQS (0&ndash

Polygenic Score for Physical Activity Is Associated with Multiple Common Diseases

Supplemental digital content is available in the text.

Intergenerational continuity in parents’ and adolescents’ externalizing problems: The role of life events and their interaction with GABRA2.

We examine whether parental externalizing behavior has an indirect effect on adolescent externalizing behavior via elevations in life events, and whether this indirect effect is further qualified by an interaction between life events and adolescents’ GABRA2 genotype (rs279871). We use data from 2 samples: the Child Development Project (CDP; n = 324) and FinnTwin12 (n = 802). In CDP, repeated measures of life events, mother-reported adolescent externalizing, and teacher-reported adolescent externalizing were used. In FinnTwin12, life events and externalizing were assessed at age 14. Parental externalizing was indexed by measures of antisocial behavior and alcohol problems or alcohol dependen…

Outdoor and indoor falls as predictors of mobility limitation in older women

Additional file 6 of Genome-wide association studies identify 137 genetic loci for DNA methylation biomarkers of aging

Additional file 6. Review history.

Long-term leisure-time physical activity and other health habits as predictors of objectively monitored late-life physical activity – A 40-year twin study

AbstractIMPORTANCEModerate-to-vigorous physical activity (MVPA) in old age is an important indicator of good health and functional capacity enabling independent living.OBJECTIVETo investigate whether physical activity and other health habits at ages 31-48 years predict objectively measured MVPA decades later.DESIGN, SETTING, AND PARTICIPANTSThis prospective twin cohort study in Finland comprised 616 individuals (197 complete twin pairs, including 91 monozygotic pairs, born 1940-1944), who responded to baseline questionnaires in 1975, 1981, and 1990, and participated in accelerometer monitoring at follow-up (mean age, 73 years).EXPOSURESPrimary exposure was long-term leisure-time physical ac…

Fear of falling and coexisting sensory difficulties as predictors of mobility decline in older women

Background. Mobility decline, the coexistence of several sensory difficulties and fear of falling (FOF) are all common concerns in older people; however, knowledge about the combined effect of FOF and coexisting sensory difficulties on mobility is lacking. Methods. Data on self-reported FOF, difficulties in hearing, vision, balance, and walking 2 km were gathered with a structured questionnaire among 434 women aged 63–76 years at baseline and after a 3-year follow-up. Logistic regression models were used for analyses. Results. Every third participant reported difficulties in walking 2 km at baseline. In cross-sectional analysis, the odds ratio for difficulties in walking 2 km was higher amo…

Associations of physical activity, fitness, and body composition with heart rate variability–based indicators of stress and recovery on workdays: a cross-sectional study

Background. The purpose of this study was to investigate how physical activity (PA), cardiorespiratory fitness (CRF), and body composition are associated with heart rate variability (HRV)-based indicators of stress and recovery on workdays. Additionally, we evaluated the association of objectively measured stress with self-reported burnout symptoms. Methods. Participants of this cross-sectional study were 81 healthy males (age range 26–40 y). Stress and recovery on workdays were measured objectively based on HRV recordings. CRF and anthropometry were assessed in laboratory conditions. The level of PA was based on a detailed PA interview (MET index [MET-h/d]) and self-reported activity class…

Genetic effects on life-space mobility in older women

Tobacco, Cannabis, and Other Illicit Drug Use Among Finnish Adolescent Twins: Causal Relationship or Correlated Liabilities?*

Contains fulltext : 90566.pdf (Publisher’s version ) (Open Access) Objective: Among Finnish adolescent twins, we compared (a) a model that describes a direct impact of liability to tobacco use on cannabis and other illicit drug use with (b) a model that included a shared underlying liability for these substances. Furthermore, the extent to which genetic and environmental influences contribute to the covariation between liabilities to use these substances was examined. Method: Tobacco and illicit drug use were assessed at age 17.5 years. Twin data on 3,744 individuals were analyzed using standard biometrical methods. Two alternative multivariate models were fit and compared with Mx, a statis…

Genetic and environmental effects on body mass index during adolescence: a prospective study among Finnish twins

Objective: To study genetic and environmental factors affecting body mass index (BMI) and BMI phenotypic correlations across adolescence. Design: Prospective, population-based, twin cohort study. Participants and methods: We used twin modeling in 2413 monozygotic and same-sex and opposite-sex dizygotic Finnish twin pairs born in 1983–1987 and assessed using self-report questionnaires at 11–12, 14 and 17 years of age. Results: Heritability of BMI was estimated to be 0.58–0.69 among 11–12- and 14-year-old boys and girls, 0.83 among 17-year-old boys and 0.74 among 17-year-old girls. Common environmental effects shared by siblings were 0.15–0.24 among 11–12- and 14-year-old boys and girls but n…

Genome-wide association analysis identifies six new loci associated with forced vital capacity

Forced vital capacity (FVC), a spirometric measure of pulmonary function, reflects lung volume and is used to diagnose and monitor lung diseases. We performed genome-wide association study meta-analysis of FVC in 52,253 individuals from 26 studies and followed up the top associations in 32,917 additional individuals of European ancestry. We found six new regions associated at genome-wide significance (P < 5 × 10−8) with FVC in or near EFEMP1, BMP6, MIR129-2–HSD17B12, PRDM11, WWOX and KCNJ2. Two loci previously associated with spirometric measures (GSTCD and PTCH1) were related to FVC. Newly implicated regions were followed up in samples from African-American, Korean, Chinese and Hispanic in…

The Interplay between Genes and Psychosocial Home Environment on Physical Activity

Introduction Genetic factors contribute to individual differences in physical activity, but it remains uncertain whether the magnitude of the genetic effects is modified by variations in home environments. We aimed to examine to what extent the psychosocial home environment in childhood and adolescence modifies the genetic influences on leisure time physical activity in young adulthood. Methods Participants were Finnish twins (N = 3305) who reported their leisure time physical activity at age 24 yr. The psychosocial home environment was assessed by twins at ages 12, 14, and 17 yr, as well as by their parents when the twins were age 12 yr. Gene–environment interaction modeling was performed …

Does the epigenetic clock GrimAge predict mortality independent of genetic influences : an 18 year follow-up study in older female twin pairs

Background: Epigenetic clocks are based on DNA methylation (DNAm). It has been suggested that these clocks are useable markers of biological aging and premature mortality. Because genetic factors explain variations in both epigenetic aging and mortality, this association could also be explained by shared genetic factors. We investigated the infuence of genetic and lifestyle factors (smoking, alcohol consumption, physical activity, chronic diseases, body mass index) and education on the association of accelerated epigenetic aging with mortality using a longitudinal twin design. Utilizing a publicly available online tool, we calculated the epigenetic age using two epigenetic clocks, Horvath D…

Increased physical activity decreases hepatic free fatty acid uptake: a study in human monozygotic twins

Exercise is considered to be beneficial for free fatty acid (FFA) metabolism, although reports of the effects of increased physical activity on FFA uptake and oxidation in different tissues in vivo in humans have been inconsistent. To investigate the heredity-independent effects of physical activity and fitness on FFA uptake in skeletal muscle, the myocardium, and liver we used positron emission tomography (PET) in nine healthy young male monozygotic twin pairs discordant for physical activity and fitness. The cotwins with higher physical activity constituting the more active group had a similar body mass index but less body fat and 18 +/- 10% higher (P < 0.001) compared to the less active …

Genome-wide association and large-scale follow up identifies 16 new loci influencing lung function

Pulmonary function measures reflect respiratory health and are used in the diagnosis of chronic obstructive pulmonary disease. We tested genome-wide association with forced expiratory volume in 1 second and the ratio of forced expiratory volume in 1 second to forced vital capacity in 48,201 individuals of European ancestry with follow up of the top associations in up to an additional 46,411 individuals. We identified new regions showing association (combined P &lt; 5 x 10(-8)) with pulmonary function in or near MFAP2, TGFB2, HDAC4, RARB, MECOM (also known as EVI1), SPATA9, ARMC2, NCR3, ZKSCAN3, CDC123, C10orf11, LRP1, CCDC38, MMP15, CFDP1 and KCNE2. Identification of these 16 new loci may p…

Depressive Symptoms and Alcohol Use are Genetically and Environmentally Correlated Across Adolescence

Depressive symptoms and alcohol use are frequently positively associated during adolescence. This study aimed to assess the heritability of each phenotype across adolescence; to assess potential shared liabilities; to examine changes in the nature of shared liabilities across adolescence; and to investigate potential causal relationships between depressive symptoms and alcohol use. We studied a longitudinally assessed sample of adolescent Finnish twins (N = 1,282) to test hypotheses about genetic and environmental influences on these phenotypes within and across ages, using data from assessments at ages 12, 14, and 17.5 years. The heritability of depressive symptoms is consistent across ado…

Femininity and Fertility in Sisters with Twin Brothers: Prenatal Androgenization? Cross-Sex Socialization?

Are sisters of twin brothers behaviorally or physiologically masculinized? Prenatal exposure to their brothers' androgens and postnatal socialization experiences unique to girls growing up with twin brothers might influence their attitudes, pubertal development, and reproductive histories. To investigate, we studied age- and cohort-matched samples of Finnish sisters from same-sex and opposite-sex twin pairs. Using data from two ongoing longitudinal studies of consecutive birth cohorts of Finnish twins, we assessed pubertal development at ages 11 and 14 and endorsement of attitudes associated with femininity at age 16. We also studied fertility in Finnish women from same- and opposite-sex t…

Depressive symptoms and career-related goal appraisals: genetic and environmental correlations and interactions.

Abstract: In order to further understand why depressive symptoms are associated with negative goal appraisals, the present study examined the genetic and environmental correlations and interactions between depressive symptoms and career-related goal appraisals. A total of 1,240 Finnish twins aged 21–26 years completed a questionnaire containing items on the appraisal of their career goals along five dimensions: importance, progress, effort, strain, and self-efficacy. In the same questionnaire, the 10-item General Behavior Inven- tory assessed depressive symptoms. Structural equation modeling was used to evaluate the genetic and environmental correlations and gene–environment interactions be…

Genome-wide association and genetic functional studies identify autism susceptibility candidate 2 gene (AUTS2) in the regulation of alcohol consumption

Alcohol consumption is a moderately heritable trait, but the genetic basis in humans is largely unknown, despite its clinical and societal importance. We report a genome-wide association study meta-analysis of ∼2.5 million directly genotyped or imputed SNPs with alcohol consumption (gram per day per kilogram body weight) among 12 population-based samples of European ancestry, comprising 26,316 individuals, with replication genotyping in an additional 21,185 individuals. SNP rs6943555 in autism susceptibility candidate 2 gene ( AUTS2 ) was associated with alcohol consumption at genome-wide significance ( P = 4 × 10 −8 to P = 4 × 10 −9 ). We found a genotype-specific expression of AUTS2 in 9…

Minor depression in adolescence: Phenomenology and clinical correlates

Background Depressions that fail to meet the diagnostic criteria for major depressive disorder (MDD) may be underdiagnosed and undertreated in adolescent population. Traditionally, they are not considered as serious conditions and the phenomenological nature and clinical correlates of these disorders are largely unknown. In the present study, we used a large, representative and age-standardized sample of adolescents to examine the phenomenology and clinical correlates of minor depression, a poorly understood condition included in the category of Depressive Disorder Not Otherwise Specified in Diagnostic and Statistical Manual of Mental Disorders–Fourth Edition–Text Revised (DSM-IV-TR). Metho…

Leisure-time physical activity and high-risk fat: a longitudinal population-based twin study.

Exercise is thought to reduce high-risk body fat, but intervention studies are frequently limited by short follow-ups and observational studies by genetic selection. Therefore, we studied the effects of a physically inactive vs active lifestyle on high-risk (visceral, liver and intramuscular) fat in twin pairs discordant for leisure-time physical activity habits for over 30 years.A longitudinal population-based twin study.Sixteen middle-aged (50-74 years) same-sex twin pairs (seven monozygotic (MZ), nine dizygotic (DZ)) with long-term discordance for physical activity habits were comprehensively identified from the Finnish Twin Cohort (TWINACTIVE study). Discordance was initially defined in…

Associations between self-estimated and measured physical fitness among 40-year-old men and women

The aim was to evaluate whether 40-year-old men and women are able to estimate their level of fitness compared with actual measured physical fitness. Twenty-nine men and 35 women first completed a questionnaire at home and then their physical fitness was measured at laboratory. The index of self-estimated physical fitness was calculated by summing up the scores of self-estimated endurance, strength, speed and flexibility. The index of self-estimated endurance was calculated by summing up the scores of self-estimated endurance and those of the self-estimated distance they could run, cycle, ski and walk. The index of measured physical fitness was calculated by summing up the z-scores of a sub…

Long-term physical activity modulates brain processing of somatosensory stimuli: Evidence from young male twins.

Leisure-time physical activity is a key contributor to physical and mental health. Yet the role of physical activity in modulating cortical function is poorly known. We investigated whether precognitive sensory brain functions are associated with the level of physical activity. Physical activity history (3-yr-LTMET), physiological measures and somatosensory mismatch response (sMMR) in EEG were recorded in 32 young healthy twins. In all participants, 3-yr-LTMET correlated negatively with body fat%, r = −0.77 and positively with VO2max, r = 0.82. The fat% and VO2max differed between 15 physically active and 17 inactive participants. Trend toward larger sMMR was seen in inactive compared to ac…

Early-onset tobacco use and suicide-related behavior – A prospective study from adolescence to young adulthood

Abstract Background Developmental relationships between tobacco use and suicide-related behaviors (SRB) remain unclear. Our objective was to investigate the longitudinal associations of tobacco use in adolescence and SRB in adulthood. Methods Using a prospective design, we examined whether tobacco use in adolescence is associated with SRB (intentional self-injury, suicide ideation) in young adulthood in a population-based sample of 1330 twins (626 males, 704 females). The baseline and follow-up data were collected by professionally administered semi-structured poly-diagnostic interviews at ages 14 and 22, respectively. Results After adjusting for multiple potential confounders, those who re…

Additional file 1 of Blood and skeletal muscle ageing determined by epigenetic clocks and their associations with physical activity and functioning

Additional file 1: Within-pair correlations in age acceleration in blood and in muscle. Additional file 2: Associations between DNAmAge age acceleration estimates and body composition and physical activity in blood. Additional file 3: Sensitivity analyses related to twin pair discordance in body mass index.

Effect of intensive exercise in early adult life on telomere length in later life in men

A career as an elite-class male athlete seems to improve meta-bolic heath in later life and is also associated with longer life expectancy. Telomere length is a biomarker of biological cellu-lar ageing and could thus predict morbidity and mortality. The main aim of this study was to assess the association between vigorous elite-class physical activity during young adulthood on later life leukocyte telomere length (LTL). The study partici-pants consist of former male Finnish elite athletes (n = 392) and their age-matched controls (n = 207). Relative telomere length was determined from peripheral blood leukocytes by quantita-tive real-time polymerase chain reaction. Volume of leisure-time phy…

Chronic diseases and objectively monitored physical activity profile among aged individuals – a cross-sectional twin cohort study

Introduction: High physical activity (PA) at old age indicates good functional capacity enabling independent living. We investigated how different disease conditions are associated with measured PA indicators in old women and men, and whether they recognize this association. Materials and methods: This cross-sectional twin cohort study in Finland comprised 779 individuals (276 complete twin pairs, including 117 monozygotic pairs), who participated in hip-worn accelerometer monitoring of PA and responded to questions on diseases and mobility limitations at mean age of 73 (range 71–75). Results: Of the participants, 23.2% reported having a disease restricting mobility. With sex and age in the…

Leisure-Time and Occupational Physical Activity Associates Differently with Epigenetic Aging

Supplemental digital content is available in the text.

Genetic Influences on Alcohol Use Behaviors Have Diverging Developmental Trajectories: A Prospective Study Among Male and Female Twins

Background Both alcohol-specific genetic factors and genetic factors related to externalizing behavior influence problematic alcohol use. Little is known, however, about the etiologic role of these 2 components of genetic risk on alcohol-related behaviors across development. Prior studies conducted in a male cohort of twins suggest that externalizing genetic factors are important for predicting heavy alcohol use in adolescence, whereas alcohol-specific genetic factors increase in importance during the transition to adulthood. In this report, we studied twin brothers and sisters and brother–sister twin pairs to examine such developmental trajectories and investigate whether sex and cotwin se…

Factors behind Leisure-Time Physical Activity Behavior Based on Finnish Twin Studies : The Role of Genetic and Environmental Influences and the Role of Motives

Different approaches are being taken to clarify the role of various factors in the development of physical activity behaviors. Genetic studies are a new area of physical activity research and also the motives for physical activity have been widely studied. The purpose of this paper is to review the findings emerging from the longitudinal genetic studies on leisure-time physical activity and to evaluate the associations between motivational factors and leisure-time physical activity. The focus is to review recent findings of longitudinal Finnish twin studies. The results of the latest longitudinal Finnish twin studies point to the existence of age-specific genetic and environmental influence…

Interactive effects of internalizing and externalizing problem behaviors on recurrent pain in children

Objective: To examine, in children, relationships between self-reported recurrent pain and emotion regulation indicated by rated internalizing and externalizing problem behaviors and adjustment. Method: Finnish 11-12-year-old schoolchildren (N = 414) completed a questionnaire measuring recurrent pain. Emotion regulation was assessed by a Multidimensional Peer Nomination Inventory, Teacher Rating Form. Relationships between recurrent pain and emotion regulation were examined in logistic regression analyses, after controlling for past injuries and chronic illnesses. Results: Independent of injuries and chronic illnesses, externalizing and internalizing problem behaviors related to recurrent p…

Genetic and environmental influences on longitudinal changes in leisure-time physical activity from adolescence to young adulthood.

The aim of this study was to estimate genetic and environmental influences on the longitudinal evolution of leisure-time physical activity habits from adolescence to young adulthood. Data were gathered at four time points, at mean ages 16.2, 17.1, 18.6, and 24.5 years. At baseline, the sample comprised 5,216 monozygotic and dizygotic twins, born 1975–1979, and, at the last follow-up point, of 4,531 monozygotic and dizygotic twins. Physical activity volume was assessed as frequency of leisure-time physical activity and participants were categorized into three groups: inactive, moderately active, and active. Genetic and environmental influences were estimated using a multivariate, longitudina…

Accumulation of sensory difficulties predicts fear of falling in older women

Objectives: To explore whether the accumulation of sensory difficulties predicts fear of falling (FOF), and whether the traits correlate with each other regardless of familial factors. Methods: Self-reported hearing, vision and balance difficulties, and FOF were assessed using structured questionnaires at the baseline and after a 3-year follow-up in 63- to 76-year-old women ( n = 434). Results: Among the women without FOF at baseline ( n = 245), 41% reported FOF at follow-up. Increasing numbers of sensory difficulties at baseline predicted higher incidence of FOF. The relationship between accumulated sensory difficulties and FOF was not mediated by familial factors. Discussion: The accumul…

Do Epigenetic Clocks Provide Explanations for Sex Differences in Life Span? A Cross-Sectional Twin Study

Abstract Background The sex gap in life expectancy has been narrowing in Finland over the past 4–5 decades; however, on average, women still live longer than men. Epigenetic clocks are markers for biological aging which predict life span. In this study, we examined the mediating role of lifestyle factors on the association between sex and biological aging in younger and older adults. Methods Our sample consists of younger and older twins (21‒42 years, n = 1 477; 50‒76 years, n = 763) including 151 complete younger opposite-sex twin pairs (21‒30 years). Blood-based DNA methylation was used to compute epigenetic age acceleration by 4 epigenetic clocks as a measure of biological aging. Path mo…

Genetic and environmental effects on body mass index during adolescence: a prospective study among Finnish twins

To study genetic and environmental factors affecting body mass index (BMI) and BMI phenotypic correlations across adolescence. Prospective, population-based, twin cohort study. We used twin modeling in 2413 monozygotic and same-sex and opposite-sex dizygotic Finnish twin pairs born in 1983–1987 and assessed using self-report questionnaires at 11–12, 14 and 17 years of age. Heritability of BMI was estimated to be 0.58–0.69 among 11–12- and 14-year-old boys and girls, 0.83 among 17-year-old boys and 0.74 among 17-year-old girls. Common environmental effects shared by siblings were 0.15–0.24 among 11–12- and 14-year-old boys and girls but no longer discernible at 17 years of age. Unique enviro…

Heritability of corneal refraction and corneal astigmatism: a population-based twin study among 66- to 79-year-old female twins.

. Purpose:  To examine the heritability of corneal refraction power (CR) and corneal astigmatism (AST) in older women. Methods:  Corneal refraction and AST were measured by IOL master in 52 monozygotic (MZ) and 47 dizygotic (DZ) female twin pairs aged 66–79 years. The relative contribution of genetic and environmental factors to individual differences in CR was estimated by applying an independent pathway model to the twin data and AST by intraclass correlations (ICC). Results:  For the right eye, mean CR was 44.58 dioptres (D) (standard deviation (SD) ±1.28) When comparing CR of the right and left eye between MZ and DZ, no significant difference was found. Mean AST was 0.77 D (SD ±0.44) wi…

A comprehensive evaluation of potential lung function associated genes in the SpiroMeta general population sample

Lung function measures are heritable traits that predict population morbidity and mortality and are essential for the diagnosis of chronic obstructive pulmonary disease (COPD). Variations in many genes have been reported to affect these traits, but attempts at replication have provided conflicting results. Recently, we undertook a meta-analysis of Genome Wide Association Study (GWAS) results for lung function measures in 20,288 individuals from the general population (the SpiroMeta consortium). OBJECTIVES: To comprehensively analyse previously reported genetic associations with lung function measures, and to investigate whether single nucleotide polymorphisms (SNPs) in these genomic regions…

Additional file 1 of Blood and skeletal muscle ageing determined by epigenetic clocks and their associations with physical activity and functioning

Additional file 1: Within-pair correlations in age acceleration in blood and in muscle. Additional file 2: Associations between DNAmAge age acceleration estimates and body composition and physical activity in blood. Additional file 3: Sensitivity analyses related to twin pair discordance in body mass index.

School fitness tests as predictors of adult health-related fitness.

Relationships between adolescent physical fitness and adult health-related fitness were investigated. Forty-five subjects (20 males, 25 females) participated in physical fitness tests in 1976 and again in 2001. The adolescent physical fitness tests were distance running (2,000 m for boys or 1,500 m for girls), 50 m run, pull-ups (boys) or flexed arm hangs (girls), shuttle run, a 30-sec sit-up test, standing broad jump, hand grip-test, and sit-and-reach test. The adult health-related physical fitness index (APFI), stratified by sex, was formed by summing the z-scores of a bicycle ergometer test, sit-up test, hand-grip test, and sit-and-reach test. Height- and weight-adjusted correlations bet…

Heritability of maximal isometric muscle strength in older female twins.

The purpose of the present study was to examine genetic and environmental effects on maximal isometric handgrip, knee extension, and ankle plantar flexion strength. In addition, we wanted to investigate whether the strength of these three muscle groups shares a genetic component or whether the genetic effect is specific for each muscle group. Muscle strength was measured as part of the Finnish Twin Study on Aging in 97 monozygotic (MZ) and 102 dizygotic (DZ) female twin pairs, aged 63-76 yr. The MZ and DZ individuals did not differ from each other in age, body height, weight, or self-related health. The age-adjusted pairwise (intraclass) correlations of the MZ and DZ twins were, respective…

Motives for physical activity in older men and women : A twin study using accelerometer-measured physical activity

Motives for physical activity may vary considerably by age, sex, and the level of physical activity. We aimed to examine motives for physical activity in older men and women with different physical activity levels as well as whether genetic and/or environmental factors explain those motives. Finnish twins (mean age 72.9 years, 262 full twin pairs) self-reported their motives for physical activity. Time spent on moderate-to-vigorous physical activity was monitored using a hip-worn accelerometer. Comparisons between the different physical activity groups of older twins (n = 764-791/motive dimension) were analyzed using the Wald test, and effect sizes were calculated as Cohen's d. Quantitative…

Genetic and Environmental Effects on Telomere Length and Lung Function : A Twin Study

Background The purpose of the study was to estimate the heritability of leukocyte telomere length (LTL) and lung function and to examine whether LTL and lung function share genetic or environmental effects in common. Methods 386 monozygotic and dizygotic Finnish twin sisters (age 68.4±3.4 years) were included. Relative LTL was determined from peripheral blood DNA by qPCR. Lung function measures of FEV1, FVC, FEV1/FVC, and PEF were derived from spirometry. Genetic modeling was performed with MPlus statistical software. Results Univariate analysis revealed that in LTL, 62% (95% confidence interval 50–72) of the variance was explained by additive genetic and 38% (28–50) by unique environmental…

Hormone replacement therapy improves contractile function and myonuclear organization of single fibres from postmenopausal monozygotic female twin pairs.

Ageing is associated with a decline in muscle mass and strength leading to increased physical dependency in old age. Postmenopausal women experience a greater decline than men of similar age in parallel with the decrease in female sex steroid hormone production. We recruited six monozygous female twin pairs (55–59 years old) where only one twin pair was on hormone replacement therapy (HRT use = 7.8 ± 4.3 years) to investigate the association of HRT with the cytoplasmic volume supported by individual myonuclei (myonuclear domain (MND) size,) together with specific force at the single fibre level. HRT use was associated with a significantly smaller (∼27%; P < 0.05) mean MND size in muscle fib…

Genetic and environmental influences on hearing at different frequencies separately for the better and worse hearing ear in older women

The purpose of the present study was to examine the relative contribution of genetic and environmental effects on the air-conducted hearing threshold levels at low (0.125-0.5 kHz), mid (1-2 kHz), and high (4-8 kHz) frequencies separately for the better and worse hearing ear in older women. We also examined the distribution of audiogram configurations. Data was analysed using quantitative genetic modelling. As part of the Finnish twin study on aging (FITSA), hearing was measured in 103 monozygotic and 114 dizygotic female twin pairs aged 63-76 years. Approximately every third subject had a flat type, and two-thirds a descending type of audiogram configuration. No significant difference was o…

Lifetime physical activity and cancer incidence—A cohort study of male former elite athletes in Finland

Abstract Objectives Physical activity has been shown to decrease the risk of certain cancers. Objective of this study was to assess the effect of physical activity on cancer incidence in former male athletes in older age. Design A cohort of 2448 elite male athletes and 1712 referents was followed-up for cancer incidence during 1986–2010 through the Finnish Cancer Registry. Methods Standardised incidence ratios were calculated with the general male population as the reference. Self-reported questionnaire-based data on covariates were used in Cox regression analyses comparing the risk of cancer in athletes and referents. Results The overall cancer incidence was lower in athletes than in the g…

Additional file 5 of Genome-wide association studies identify 137 genetic loci for DNA methylation biomarkers of aging

Additional file 5. Colocalization plots.

Power of lower extremities and age were the main determinants on the agility test for adults in a cohort of men aged 66–91 years

Study Design: Cross-sectional study. Objective: To evaluate the relationship between agility and personal factors, muscle strength and power, mobility, self-reported balance and physical activity among older men. Methods: Agility was measured by using the Agility Test for Adults (ATA). We studied 100 Finnish male former elite athletes (endurance n = 50; power n = 50) and 50 matched controls aged 66 to 91 years (mean age 75.5 years). The associations between agility and other variables were similar between three groups; thus, multiple linear regression analyses were done by using the pooled data of the participants. Results: On the basis of multiple linear regression analyses, combination of…

Contribution of genetic and environmental effects to postural balance in older female twins

The aim of the present study was to determine the relative roles of genetic and environmental influences on postural balance in older women. The participants were 97 monozygotic (MZ) and 102 dizygotic (DZ) female twins, aged 64–76 yr. Postural sway was measured during side-by-side stance with eyes open and eyes closed, and during semitandem stance with eyes open on a force platform. Sway data were condensed into four first-order and one second-order latent factors. The second-order factor, named balance, incorporates sway data from multiple tests and thus best describes the phenotype of postural balance. The contribution of genetic and environmental influences on the variability of the lat…

Physical activity and health: Findings from Finnish monozygotic twin pairs discordant for physical activity.

Genetic and early environmental differences including early health habits associate with future health. To provide insight on the causal nature of these associations, monozygotic (MZ) twin pairs discordant for health habits provide an interesting natural experiment. Twin pairs discordant for leisure-time physical activity (LTPA) in early adult life are thus a powerful study design to investigate the associations between long-term LTPA and indicators of health and wellbeing. We have identified 17 LTPA discordant twin pairs from two Finnish twin cohorts and summarize key findings of these studies in this paper. The carefully characterized rare long-term LTPA discordant MZ twin pairs have part…

Aging and serum exomiR content in women-effects of estrogenic hormone replacement therapy.

AbstractExosomes participate in intercellular messaging by transporting bioactive lipid-, protein- and RNA-molecules and -complexes. The contents of the exosomes reflect the physiological status of an individual making exosomes promising targets for biomarker analyses. In the present study we extracted exosome microRNAs (exomiRs) from serum samples of premenopausal women (n = 8) and monozygotic postmenopausal twins (n = 10 female pairs), discordant for the use of estrogenic hormone replacement therapy (HRT), in order to see whether the age or/and the use of HRT associates with exomiR content. A total of 241 exomiRs were detected by next generation sequencing, 10 showing age, 14 HRT and 10 a…

iGEMS : an integrated model for identification of alternative exon usage events

DNA microarrays and RNAseq are complementary methods for studying RNA molecules. Current computational methods to determine alternative exon usage (AEU) using such data require impractical visual inspection and still yield high false-positive rates. Integrated Gene and Exon Model of Splicing (iGEMS) adapts a gene-level residuals model with a gene size adjusted false discovery rate and exon-level analysis to circumvent these limitations. iGEMS was applied to two new DNA microarray datasets, including the high coverage Human Transcriptome Arrays 2.0 and performance was validated using RT-qPCR. First, AEU was studied in adipocytes treated with (n = 9) or without (n = 8) the anti-diabetes drug,…

Leisure-time physical activity and intra-abdominal fat in young adulthood: A monozygotic co-twin control study

Objective To investigate differences in abdominal fat compartments between young adult monozygotic twin pairs discordant for leisure-time physical activity. Methods Ten young adult male monozygotic twin pairs (age range 32-36 years) discordant for leisure-time physical activity during the past 3 years were systematically selected from a population-based Finnish twin cohort. Magnetic resonance image at the level of the L2-L3 intervertebral disc was used to predict intra-abdominal and subcutaneous abdominal fat masses. Dietary intake was assessed with a 4-day food diary. Results Inactive twins had 31% more intra-abdominal fat than their active co-twins (mean difference 0.52 kg, 95% CI 0.12 to…

FinnTwin16 : A Longitudinal Study from Age 16 of a Population-Based Finnish Twin Cohort

The purpose of this review is to provide a detailed and updated description of the FinnTwin16 (FT16) study and its future directions. The Finnish Twin Cohort comprises three different cohorts: the Older Twin Cohort established in the 1970s and the FinnTwin12 and FT16 initiated in the 1990s. FT16 was initiated in 1991 to identify the genetic and environmental precursors of alcoholism, but later the scope of the project expanded to studying the determinants of various health-related behaviors and diseases in different stages of life. The main areas addressed are alcohol use and its consequences, smoking, physical activity, overall physical health, eating behaviors and eating disorders, weight…

Chernobyl exposure as stressor during pregnancy and behaviour in adolescent offspring.

Objective: Research in animals has shown that exposure to stressors during pregnancy is associated with offspring behavioural disorders. We aimed to study the effect of in utero exposure to the Chernobyl disaster in 1986, and maternal anxiety presumably associated with that exposure, on behaviour disorder observed at age 14. Method: Exposed (n = 232) and non-exposed Finnish twins (n = 572) were compared. A semi-structured interview was used to assess lifetime symptoms of depression, generalized anxiety disorder, attention deficit hyperactivity disorder, conduct disorder and oppositional defiant disorder symptoms. Results: Adolescents who were exposed from the second trimester in pregnancy o…

Physical activity in adulthood: genes and mortality.

AbstractObservational studies report a strong inverse relationship between leisure-time physical activity and all-cause mortality. Despite suggestive evidence from population-based associations, scientists have not been able to show a beneficial effect of physical activity on the risk of death in controlled intervention studies among individuals who have been healthy at baseline. On the other hand, high cardiorespiratory fitness is known to be a strong predictor of reduced mortality, even more robust than physical activity level itself. Here, in both animals and/or human twins, we show that the same genetic factors influence physical activity levels, cardiorespiratory fitness and risk of de…

Harmonizing behavioral outcomes across studies, raters, and countries: application to the genetic analysis of aggression in the ACTION Consortium

BACKGROUND: Aggression in children has genetic and environmental causes. Studies of aggression can pool existing datasets to include more complex models of social effects. Such analyses require large datasets with harmonized outcome measures. Here, we made use of a reference panel for phenotype data to harmonize multiple aggression measures in school-aged children to jointly analyze data from five large twin cohorts.METHODS: Individual level aggression data on 86,559 children (42,468 twin pairs) were available in five European twin cohorts measured by different instruments. A phenotypic reference panel was collected which enabled a model-based phenotype harmonization approach. A bi-factor i…

Association study of MMP8 gene in osteoarthritis.

Objectives: Osteoarthritis (OA) is a joint disease common in the elderly. There is a prior functional evidence for different matrix metalloproteinases (MMPs), such as MMP8 and MMP9, having a role in the breakdown of cartilage extracellular matrix in OA. Thus, we analyzed whether the common genetic variants of MMP8 and MMP9 contribute to the risk of OA. Materials and methods: In total, 13 common tagging single-nucleotide polymorphisms (SNPs) were studied in a discovery knee OA cohort of 185 cases and 895 controls. For validation, two knee OA replication cohorts and two hand OA replication cohorts were studied (altogether 1369 OA cases, 4445 controls in the five cohorts). The chi(2) test for …

FinnTwin12 Cohort: An Updated Review

AbstractThis review offers an update on research conducted with FinnTwin12 (FT12), the youngest of the three Finnish Twin Cohorts. FT12 was designed as a two-stage study. In the first stage, we conducted multiwave questionnaire research enrolling all eligible twins born in Finland during 1983–1987 along with their biological parents. In stage 2, we intensively studied a subset of these twins with in-school assessments at age 12 and semistructured poly-diagnostic interviews at age 14. At baseline, parents of intensively studied twins were administered the adult version of the interview. Laboratory studies with repeat interviews, neuropsychological tests, and collection of DNA were made of in…

Leisure-time physical activity and nutrition: a twin study

AbstractObjectiveTo determine the association between long-term leisure-time physical activity/inactivity and eating behaviours in twin pairs discordant for physical activity for 30 years.DesignCo-twin control design with cross-sectional data collection using questionnaire on eating habits and 5 d food diary. Differences in eating behaviours between physically active and inactive co-twins were analysed with pairwise tests.SettingFinland.SubjectsSixteen same-sex twin pairs (seven monozygotic and nine dizygotic, mean age 60 years) discordant for physical activity, selected from the Finnish Twin Cohort on the basis of physical activity discordance for 30 years, blinded to their possible differ…

Additional file 1 of Genome-wide association studies identify 137 genetic loci for DNA methylation biomarkers of aging

Additional file 1. Individual cohort descriptions and acknowledgements.

Electrocardiographic and other clinical correlates of walking ability in older women

Abstract The purpose of this study was to examine how resting electrocardiographic (ECG) and other clinical variables, which can be included in a routine clinical examination, predict walking ability in older women. Three hundred and twenty women (63–75 years) without overt cardiac diseases and apparent mobility limitations were studied. Measurements performed were clinical examination (standard 12-lead resting ECG, assessment of physical activity level, presence of chronic diseases, use of beta-blockers, body mass index (BMI), ability to squat, resting blood pressure) and six-minute walking test. Participants walked 533 ± 75 m in the six-minute walking test. The best electrocardiographic p…

Physical Activity and Academic Performance : Genetic and Environmental Associations

Introduction. Physical activity and academic performance are believed to be associated. Though both traits are partially heritable, it remains unclear whether these traits also share a genetic and/or environmental background in common. We aimed to examine to what extent leisure-time physical activity and academic performance share genetic and environmental effects from early adolescence to young adulthood. Methods. Participants were Finnish twins (2543–2693 individuals/study wave) who reported their leisure-time physical activity at ages 12, 14, 17 and 24. Academic performance was assessed with teacher-reported grade point averages at ages 12 and 14 and by self-reported educational levels a…

Fat oxidation at rest and during exercise in male monozygotic twins

Abstract Purpose We aimed to investigate if hereditary factors, leisure-time physical activity (LTPA) and metabolic health interact with resting fat oxidation (RFO) and peak fat oxidation (PFO) during ergometer cycling. Methods We recruited 23 male monozygotic twin pairs (aged 32–37 years) and determined their RFO and PFO with indirect calorimetry for 21 and 19 twin pairs and for 43 and 41 twin individuals, respectively. Using physical activity interviews and the Baecke questionnaire, we identified 10 twin pairs as LTPA discordant for the past 3 years. Of the twin pairs, 8 pairs participated in both RFO and PFO measurements, and 2 pairs participated in either of the measurements. We quantif…

Force Platform Balance Measures as Predictors of Indoor and Outdoor Falls in Community-Dwelling Women Aged 63-76 Years

Background. Inability to maintain balance while standing increases risk of falls in older people. The present study assessed whether center of pressure (COP) movement measured with force platform technology predicts risk for falls among older people with no manifest deficiency in standing balance. Methods. Participants were 434 community-dwelling women, aged 63-76 years. COP was measured in six stances on a force platform. Following balance tests, participants reported their falls with 12 monthly calendars. Incidence rate ratios (IRR) with 95% confidence intervals (CI) were computed from negative binomial regression models. For the analysis, those with>/=1 fall indoors were coded"indoor fal…

Hip fractures and femoral bone mineral density in male former elite athletes

We studied whether vigorous physical activity in young adulthood is associated with higher femoral bone density and lower risk of hip fracture at older age in men.A cohort of former male elite athletes (n=2147) and matched control subjects (n=1467) were studied for their leisure physical activity, and for fragility fractures at the hip (proximal femur) by Cox regression. Areal bone mineral densities (aBMD) at femoral neck and trochanter region were measured using dual-energy X-ray absorptiometry in a subgroup of the former athletes (n=87; median age 59 years) and in a population-based control group (n=194) and compared by general linear models.After their active sporting careers, the former…

FinnTwin16: A Longitudinal Study from Age 16 of a Population-Based Finnish Twin Cohort

AbstractThe purpose of this review is to provide a detailed and updated description of the FinnTwin16 (FT16) study and its future directions. The Finnish Twin Cohort comprises three different cohorts: the Older Twin Cohort established in the 1970s and the FinnTwin12 and FT16 initiated in the 1990s. FT16 was initiated in 1991 to identify the genetic and environmental precursors of alcoholism, but later the scope of the project expanded to studying the determinants of various health-related behaviors and diseases in different stages of life. The main areas addressed are alcohol use and its consequences, smoking, physical activity, overall physical health, eating behaviors and eating disorders…

Nicotinamide riboside improves muscle mitochondrial biogenesis, satellite cell differentiation, and gut microbiota in a twin study

Nicotinamide adenine dinucleotide (NAD + ) precursor nicotinamide riboside (NR) has emerged as a promising compound to improve obesity-associated mitochondrial dysfunction and metabolic syndrome in mice. However, most short-term clinical trials conducted so far have not reported positive outcomes. Therefore, we aimed to determine whether long-term NR supplementation boosts mitochondrial biogenesis and metabolic health in humans. Twenty body mass index (BMI)–discordant monozygotic twin pairs were supplemented with an escalating dose of NR (250 to 1000 mg/day) for 5 months. NR improved systemic NAD + metabolism, muscle mitochondrial number, myoblast differentiation, and gut microbiota compos…

Additional file 5 of Genome-wide association studies identify 137 genetic loci for DNA methylation biomarkers of aging

Additional file 5. Colocalization plots.

Intramuscular sex steroid hormones are associated with skeletal muscle strength and power in women with different hormonal status

International audience; Estrogen (E2)-responsive peripheral tissues, such as skeletal muscle, may suffer from hormone deficiency after menopause potentially contributing to the aging of muscle. However, recently E2 was shown to be synthesized by muscle and its systemic and intramuscular hormone levels are unequal. The objective of the study was to examine the association between intramuscular steroid hormones and muscle characteristics in premenopausal women (n = 8) and in postmenopausal monozygotic twin sister pairs (n = 16 co-twins from eight pairs) discordant for the use of E2-based hormone replacement. Isometric skeletal muscle strength was assessed by measuring knee extension strength.…

Heredity of interocular similarities in components of refraction: a population-based twin study among 66- to 79-year-old female twins.

Purpose: To examine genetic influences on interocular similarities in ocular refraction and components of refraction among elderly female twins. Methods: Refraction was assessed in 94 monozygotic (MZ) and 74 dizygotic (DZ) female twins aged 66–78 years. Absolute values of interocular differences (Aniso variables) in spherical refraction (SR), refractive astigmatism (AST), spherical equivalent (SE), corneal refractive power (CR), corneal astigmatism (CAST), anterior chamber depth (ACD) and axial length (AL) were calculated. The differences between sisters in each of the Aniso variables were calculated and graded into two categories, best differentiating the groups, here isometropic and aniso…

Self-reported fitness and objectively measured physical activity profile among older adults : a twin study

Abstract Background Maintaining good fitness and good level of physical activity are important factors for maintaining physical independence later in life. The aim was to investigate the relationship between self-reported fitness and objectively measured physical activity and sedentary behavior in the elderly. Methods Same-sex twin pairs born 1940–1944 in Finland were invited to the study. Altogether 787 individuals (mean age 72.9 years), of whom 404 were female, used a hip-worn triaxial accelerometer for at least 4 days and answered a question on perceived fitness. First, individual differences were studied between four fitness categories. Second, pairwise differences were examined among t…

Early adolescent aggression predicts antisocial personality disorder in young adults : a population-based study

Modestly prevalent in the general population (~ 4%), but highly prevalent in prison populations (> 40%), the diagnosis of antisocial personality disorder (ASPD) involves aggression as one of several possible criteria. Using multiple informants, we aimed to determine if general aggression, as well as direct and indirect subtypes, assessed in early adolescence (ages 12, 14) predict young adulthood ASPD in a population-based sample. Using data from a Finnish population-based longitudinal twin cohort study with psychiatric interviews available at age 22 (N = 1347), we obtained DSM-IV-based ASPD diagnoses. Aggression measures from ages 12 (parental and teacher ratings) and 14 (teacher, self, and…

Former male elite athletes have better metabolic health in late life than their controls

Elite-class athletes have longer life expectancy and lower risk for chronic noncommunicable diseases possibly because of physically active and healthier lifestyle. In this study, we assessed former male Finnish elite-class athletes' (n = 392) and their matched controls' (n = 207) body composition, and risk for the metabolic syndrome (MS) and nonalcoholic fatty liver disease (NAFLD) in later life. Compared with the controls, the former athletes had lower body fat percentage (24.8% vs 26.0%, P = 0.021), lower risk for MS [odds ratio (OR) 0.57, 95% confidence interval (CI) 0.40-0.81], and NAFLD (OR 0.61, 95% CI 0.42-0.88). High volume of current leisure-time physical activity (LTPA) was associ…

Parental Socialization and Adolescents' Alcohol Use Behaviors: Predictive Disparities in Parents' Versus Adolescents' Perceptions of the Parenting Environment

Among adolescents, many parenting practices have been associated with the initiation and development of drinking behaviors. However, recent studies suggest discrepancies in parents' and adolescents' perceptions of parenting and their links with adolescent use. In this study, we derive two independent sets of underlying parenting profiles (based on parent and adolescent reported behaviors at age 11–12 years), which were then examined in relation to adolescents' drinking behaviors at ages 14 and 17½. Results indicated that the two sets of profiles accounted for little shared variance, with those based on adolescents' reports being stronger predictors of adolescent drinking. Moreover, comparis…

Anisometropia of ocular refractive and biometric measures among 66- to 79-year-old female twins

Purpose To examine the prevalence of anisometropia of spherical refraction (AnisoSR), astigmatism (AnisoAST) and spherical equivalent (AnisoSE) and their associations with spherical refraction (SR), refractive astigmatism (AST), spherical equivalent (SE) and interocular differences of ocular biometric parameters among elderly female twins. Methods Refraction of 117 monozygotic (MZ) and 116 dizygotic (DZ) female twin subjects aged 66–79 years was assessed with an auto-refractor (Topcon AT) and controlled by subjective refraction. Corneal refraction, anterior chamber depth and axial length were measured with a Zeiss IOL Master. Participants with eyes operated for cataract or glaucoma were exc…

Myocardial and peripheral vascular functional adaptation to exercise training.

Exercise training seems to restore impaired vascular function in both peripheral and myocardial vessels in patients with coronary artery and peripheral vascular disease or in patients with risk factors for these diseases. However, the results on the effects of exercise training on vascular function in apparently healthy subjects are controversial. We studied the effects of long-term volitionally increased physical activity on peripheral and myocardial vascular function in nine young healthy male monozygotic twin pairs discordant for physical activity and fitness. The brothers were divided into more (MAG) and less active groups according to physical activity and fitness. The difference betwe…

Higher aggression is related to poorer academic performance in compulsory education

Background To conduct a comprehensive assessment of the association between aggression and academic performance in compulsory education. Method We studied aggression and academic performance in over 27,000 individuals from four European twin cohorts participating in the ACTION consortium (Aggression in Children: Unraveling gene‐environment interplay to inform Treatment and InterventiON strategies). Individual level data on aggression at ages 7–16 were assessed by three instruments (Achenbach System of Empirically Based Assessment, Multidimensional Peer Nomination Inventory, Strengths and Difficulties Questionnaire) including parental, teacher and self‐reports. Academic performance was measu…

Genetic and Environmental Influences on BMI From Late Childhood to Adolescence are Modified by Parental Education

To investigate how parental education modifies genetic and environmental influences on variation in BMI during adolescence, self-reported BMI at 11-12, 14, and 17 years of age was collected from a population sample of 2,432 complete Finnish twin pairs born in 1983-1987. Based on parental report, twins were divided to those with high (both parents high school graduates), mixed level (one parent a graduate, the other not), and limited (neither parent a graduate) parental education. Genetic and environmental influences on variation in BMI in different education classes were modeled using twin analysis. Heritability of BMI among 11-12-year-olds with high parental education was 85-87% whereas it…

Combination of hormone replacement therapy and high physical activity is associated with differences in Achilles tendon size in monozygotic female twin pairs.

Estrogen concentration has been suggested to play a role in tendon abnormalities and injury. In physically active postmenopausal women, hormone replacement therapy (HRT) has been suggested to decrease tendon diameter. We hypothesized that HRT use and physical activity are associated with Achilles tendon size and tissue structure. The study applied cotwin analysis of fourteen 54- to 62-yr-old identical female twin pairs with current discordance for HRT use for an average of 7 yr. Achilles tendon thickness and cross-sectional areas were determined by ultrasonography, and tendon structural organization was analyzed from the images using linear discriminant analysis (LDA). Maximal voluntary and…

Physical activity, mood and the functioning of daily living

We studied whether factors related to type of sport participated in as young adults and level of and changes in physical activity later in life predict changes in mood as well as functioning during a 6-year follow-up. A cohort of male Finnish former athletes (N = 504), referents (N = 349) was followed up for changes in physical activity, in relation to subsequent self-reported mood and functioning of daily living in 1985, 1995, and 2001. The mean age of the cohort was 68.6 years in 2001. Multinomial logistic regression analysis was used to assess changes in mood and functioning between 1995 and 2001 in relation to baseline values and changes in exposure variables and covariates. A low level…

Somatosensory Brain Function and Gray Matter Regional Volumes Differ According to Exercise History : Evidence from Monozygotic Twins

Associations between long-term physical activity and cortical function and brain structure are poorly known. Our aim was to assess whether brain functional and/or structural modulation associated with long-term physical activity is detectable using a discordant monozygotic male twin pair design. Nine monozygotic male twin pairs were carefully selected for an intrapair difference in their leisure-time physical activity of at least three years duration (mean age 34 ± 1 years). We registered somatosensory mismatch response (SMMR) in EEG to electrical stimulation of fingers and whole brain MR images. We obtained exercise history and measured physical fitness and body composition. Equivalent ele…

Early-onset depressive disorders predict the use of addictive substances in adolescence: a prospective study of adolescent Finnish twins

Aims  To explore the developmental relationships between early-onset depressive disorders and later use of addictive substances. Design, setting and participants  A sample of 1545 adolescent twins was drawn from a prospective, longitudinal study of Finnish adolescent twins with baseline assessments at age 14 years and follow-up at age 17.5 years. Measurements  At baseline, DSM-IV diagnoses were assessed with a professionally administered adolescent version of Semi-Structured Assessment for Genetics of Alcoholism (C-SSAGA-A). At follow-up, substance use outcomes were assessed via self-reported questionnaire. Findings  Early-onset depressive disorders predicted daily smoking [odds ratio (OR) …

Additional file 6 of Genome-wide association studies identify 137 genetic loci for DNA methylation biomarkers of aging

Additional file 6. Review history.

Genome-wide association studies identify 137 loci for DNA methylation biomarkers of ageing

AbstractBiological ageing estimators derived from DNA methylation (DNAm) data are heritable and correlate with morbidity and mortality. Leveraging DNAm and SNP data from &gt;41,000 individuals, we identify 137 genome-wide significant loci (113 novel) from meta-analyses of four epigenetic clocks and epigenetic surrogate markers for granulocyte proportions and plasminogen activator inhibitor 1 levels, respectively. We report strong genetic correlations with longevity and lifestyle factors such as smoking, education, and obesity. Significant associations are observed in polygenic risk score analysis and to a lesser extent in Mendelian randomization analyses. This study illuminates the genetic …

Body Fat and Mobility Are Explained by Common Genetic and Environmental Influences in Older Women

In older adults, mobility limitations often coexist with overweight or obesity, suggesting that similar factors may underlie both traits. This study examined the extent to which genetic and environmental influences explain the association between adiposity and mobility in older women. Body fat percentage (bioimpedance test), walking speed over 10 m, and distance walked in a 6-min test were evaluated in 92 monozygotic (MZ) and 104 dizygotic (DZ) pairs of twin sisters reared together, aged 63-76 years. Genetic and environmental influences on each trait were estimated using age-adjusted multivariate genetic modeling. The analyses showed that the means (and s.d.) for body fat percentage, walkin…

Minor depression in adolescence: phenomenology and clinical correlates.

Abstract Background Depressions that fail to meet the diagnostic criteria for major depressive disorder (MDD) may be underdiagnosed and undertreated in adolescent population. Traditionally, they are not considered as serious conditions and the phenomenological nature and clinical correlates of these disorders are largely unknown. In the present study, we used a large, representative and age-standardized sample of adolescents to examine the phenomenology and clinical correlates of minor depression, a poorly understood condition included in the category of Depressive Disorder Not Otherwise Specified in Diagnostic and Statistical Manual of Mental Disorders–Fourth Edition–Text Revised (DSM-IV-T…

Long-term Leisure-time Physical Activity and Serum Metabolome

Background— Long-term physical inactivity seems to cause many health problems. We studied whether persistent physical activity compared with inactivity has a global effect on serum metabolome toward reduced cardiometabolic disease risk. Methods and Results— Sixteen same-sex twin pairs (mean age, 60 years) were selected from a cohort of twin pairs on the basis of their &gt;30-year discordance for physical activity. Persistently (≥5 years) active and inactive groups in 3 population-based cohorts (mean ages, 31–52 years) were also studied (1037 age- and sex-matched pairs). Serum metabolome was quantified by nuclear magnetic resonance spectroscopy. We used permutation analysis to estimate the …

Genetics of Perceived Family Interaction From 12 to 17 Years of Age

We analyzed how the effects of genetic and environmental factors on the perceptions of family interaction change from early to late adolescence. The data were collected by postal surveys on Finnish twins (N = 4808) at 12, 14 and 17 years of age and analyzed using genetic twin modeling. Additive genetic factors explained a modest share of the variation in perceived relational support (a2 = 0.30 in boys and 0.18 in girls) and relational tensions (a2 = 0.13 and 0.14, respectively) at 12 years of age, with the proportions becoming larger through 17 years of age (a2 = 0.53 in boys and 0.49 in girls for relational support; a2 = 0.35 in boys and 0.33 in girls for relational tensions). Simultaneous…

Mortality associations with DNA methylation-based biological aging and physical functioning measures across a 20-year follow-up period

Background Measures of biological aging range from DNA methylation (DNAm)-based estimates to measures of physical abilities. The purpose of this study was to compare DNAm- and physical functioning-based measures of biological aging in predicting mortality. Methods We studied 63- to 76-year-old women (N = 395) from the Finnish Twin Study on Aging (FITSA). Participants’ biological age (epigenetic clocks DNAm GrimAge and DunedinPACE) was estimated using blood DNAm data. Tests of physical functioning conducted under standardized laboratory conditions included the Timed Up and Go (TUG) test and 10-m walk test. Mortality hazard ratios (HRs) were calculated per every one standard deviation (SD) in…

Incorporating Functional Genomic Information to Enhance Polygenic Signal and Identify Variants Involved in Gene-by-Environment Interaction for Young Adult Alcohol Problems

BACKGROUND: Characterizing aggregate genetic risk for alcohol misuse and identifying variants involved in gene-by-environment (G × E) interaction effects has so far been a major challenge. We hypothesized that functional genomic information could be used to enhance detection of polygenic signal underlying alcohol misuse and to prioritize identification of single nucleotide polymorphisms (SNPs) most likely to exhibit G × E effects.METHODS: We examined these questions in the young adult FinnTwin12 sample (n = 1,170). We used genomewide association estimates from an independent sample to derive 2 types of polygenic scores for alcohol problems in FinnTwin12. Genomewide polygenic scores included…

Chronic diseases and objectively monitored physical activity profile among aged individuals – a cross-sectional twin cohort study

Introduction: High physical activity (PA) at old age indicates good functional capacity enabling independent living. We investigated how different disease conditions are associated with measured PA indicators in old women and men, and whether they recognize this association. Materials and methods: This cross-sectional twin cohort study in Finland comprised 779 individuals (276 complete twin pairs, including 117 monozygotic pairs), who participated in hip-worn accelerometer monitoring of PA and responded to questions on diseases and mobility limitations at mean age of 73 (range 71–75). Results: Of the participants, 23.2% reported having a disease restricting mobility. With sex and age in the…

Global gene expression profiles in skeletal muscle of monozygotic female twins discordant for hormone replacement therapy

Summary Aging is accompanied by inexorable loss of muscle tissue. One of the underlying causes for this is the massive change in the hormonal milieu of the body. The role of a female sex steroid – estrogen – in these processes is frequently neglected, although the rapid decline in its production coincides with a steep deterioration in muscle performance. We recruited 54- to 62-year-old monozygotic female twin pairs discordant for postmenopausal hormone replacement therapy (HRT, n = 11 pairs; HRT use 7.3 ± 3.7 years) from the Finnish Twin Cohort to investigate the association of long-term, estrogen-based HRT with skeletal muscle transcriptome. Pathway analysis of muscle transcript profiles r…

Sex differences in genetic and environmental effects on aggression

The aim of the present study was to investigate the genetic and environmental factors influencing teacher and parental rated aggression in boys and girls, asking whether the magnitude of these effects is similar across rater and sex. The study is part of an ongoing nationwide twin-family study of behavioral development and health habits carried out in Finland. The sample consisted of 1651 twin pairs (264 monozygotic male, 300 monozygotic female, 292 dizygotic male, 278 dizygotic female, and 517 dizygotic opposite-sex twin pairs), representing subsets of five 11- to 12-year-old twin cohorts (b. 1983-1987). The data were collected using the teacher and parental rating forms of the Multidimens…

Longitudinal associations of high‐volume and vigorous‐intensity exercise with hip fracture risk in men

Maintenance of vigorous exercise habits from young to old age is considered protective against hip fractures, but data on fracture risk in lifelong vigorous exercisers are lacking. This longitudinal cohort study examined the hazard of hip fractures in 1844 male former athletes and 1216 population controls and in relation to exercise volume and intensity in later years. Incident hip fractures after age 50 years were identified from hospital discharge register from 1972 to 2015. Exercise and covariate information was obtained from questionnaires administered in 1985, 1995, 2001, and 2008. Analyses were conducted using extended proportional hazards regression model for time-dependent exposures…

Chronic diseases and objectively monitored physical activity profile among aged individuals – a cross-sectional twin cohort study

Introduction: High physical activity (PA) at old age indicates good functional capacity enabling independent living. We investigated how different disease conditions are associated with measured PA indicators in old women and men, and whether they recognize this association. Materials and methods: This cross-sectional twin cohort study in Finland comprised 779 individuals (276 complete twin pairs, including 117 monozygotic pairs), who participated in hip-worn accelerometer monitoring of PA and responded to questions on diseases and mobility limitations at mean age of 73 (range 71–75). Results: Of the participants, 23.2% reported having a disease restricting mobility. With sex and age in the…

The role of adolescent lifestyle habits in biological aging: A prospective twin study

Adolescence is a stage of fast growth and development. Exposures during puberty can have long-term effects on health in later life. This study aims to investigate the role of adolescent lifestyle in biological aging.The study participants originated from the longitudinal FinnTwin12 study (n = 5114). Adolescent lifestyle-related factors, including body mass index (BMI), leisure-time physical activity, smoking, and alcohol use, were based on self-reports and measured at ages 12, 14, and 17 years. For a subsample, blood-based DNA methylation (DNAm) was used to assess biological aging with six epigenetic aging measures in young adulthood (21-25 years, n = 824). A latent class analysis was condu…

Shared genetic risk between eating disorder- and substance-use-related phenotypes: Evidence from genome-wide association studies

AbstractEating disorders and substance use disorders frequently co-occur. Twin studies reveal shared genetic variance between liabilities to eating disorders and substance use, with the strongest associations between symptoms of bulimia nervosa (BN) and problem alcohol use (genetic correlation [rg], twin-based=0.23-0.53). We estimated the genetic correlation between eating disorder and substance use and disorder phenotypes using data from genome-wide association studies (GWAS). Four eating disorder phenotypes (anorexia nervosa [AN], AN with binge-eating, AN without binge-eating, and a BN factor score), and eight substance-use-related phenotypes (drinks per week, alcohol use disorder [AUD], …

Early maturation and substance use across adolescence and young adulthood: A longitudinal study of Finnish twins.

AbstractEarly maturation, indexed by pubertal development (PD), has been associated with earlier initiation and greater frequency of adolescent substance use, but this relationship may be biased by confounding factors and effects that change across development. Using a population-based Finnish twin sample (N = 3,632 individuals), we conducted twin modeling and multilevel structural equation modeling of the relationship between PD and substance use at ages 12–22. Shared environmental factors contributed to early PD and heavier substance use for females. Biological father absence was associated with early PD for boys but not girls, and did not account for the relationship between PD and subst…

Effect of physical activity on health in twins: a 30-yr longitudinal study.

Purpose: The aim of this study was to investigate whether persistent leisure-time physical activity, adjusted for genetic liability and childhood experiences, protects against chronic diseases, early signs of disability, and loss of life satisfaction. Methods: From 5663 healthy adult twin pairs, we identified 146 pairs who were discordant for both intensity and volume of leisure physical activity in 1975 and 1981. Of them, both members of 95 pairs were alive and participated in our follow-up study in 2005 when chronic diseases (such as diabetes, cardiovascular disease, and osteoarthritis), life satisfaction, and disability were assessed by a structured telephone interview. The mean age of t…

Physical activity, use of alcohol and smoking in middle-aged and aging men. A longitudinal study among Finnish male former athletes and controls

It is not known whether decrease in physical activity (PA) is associated with binge drinking among former athletes. The purpose of this study was to investigate the reciprocal associations between PA and use of alcohol among former athletes and controls at four time points. Furthermore, we examined whether there were longitudinal latent profiles related to use of alcohol, smoking and PA during the follow-up. Finnish male former elite athletes (n = 1633) and matched controls (n = 1099) questionnaire-reported their PA, alcohol consumption and smoking at four time points in 1985, 1995, 2001 and 2008. Former athletes were more physically active and smoked less than controls, but in all profiles…

Genetic influences on resting electrocardiographic variables in older women: a twin study.

Background: Previous studies in young and middle-aged men and women have shown that resting electrocardiographic (ECG) variables are influenced by genetic factors. However, the extent to which resting ECG variables are influenced by genetic factors in older women is unknown. Thus, the aim of this study was to estimate the relative contribution of genetic and environmental influences to individual differences in resting ECG variables among older female twins without overt cardiac diseases. Methods: Resting ECG recordings were obtained from 186 monozygotic and 203 dizygotic twin individuals, aged 63–76 years. Quantitative genetic modeling was used to decompose the phenotypic variance in each …

Changing Environmental Influences on Substance Use Across Development

AbstractIn contrast to many phenotypes that have been studied using twin designs, substance use shows considerable evidence of environmental influence. Accordingly, specifying the relevant environments and understanding the nature of their effects is an important research priority. Twin studies also have demonstrated that the importance of genetic and environmental influences varies across development for a variety of behavioral outcomes, including substance use. Here, we report analyses exploring moderating effects associated with parenting and peer characteristics on adolescent smoking and drinking, measured at ages 14 and 17. We find significant evidence of moderating effects associated …

Chernobyl exposure as stressor during pregnancy and hormone levels in adolescent offspring

Background: Animal research suggests a programming effect of prenatal stress in the fetal period, resulting in disruptions in behavioural and neuromotor development. Physiological changes that mediate these effects include alterations in the hypothalamic-pituitary-adrenal axis and in testosterone levels. This human study focuses on changes related to these physiological systems after prenatal stress exposure. Methods: We examined the potential effect of prenatal stress associated with the Chernobyl disaster in an ongoing genetic epidemiological study in Finland. One birth cohort of twins (n = 121 twin pairs) was exposed in utero to maternal stress, and their saliva cortisol and testosterone…

Genetics of maximal walking speed and skeletal muscle characteristics in older women.

AbstractThe aim of this study was to examine whether maximal walking speed, maximal isometric muscle strength, leg extensor power and lower leg muscle cross-sectional area (CSA) shared a genetic effect in common. In addition, we wanted to identify the chromosomal areas linked to maximal walking speed and these muscle characteristics and also investigate whether maximal walking speed and these three skeletal muscle characteristics are regulated by the same chromosomal areas. We studied 217 monozygotic (MZ) and dizygotic (DZ) female twin pairs aged 66 to 75 years in the Finnish Twin Study on Aging study. The DZ pairs (94) were genotyped for 397 microsatellite markers in 22 autosomes and X-chr…

Meta-analysis of exome array data identifies six novel genetic loci for lung function

Background: Over 90 regions of the genome have been associated with lung function to date, many of which have also been implicated in chronic obstructive pulmonary disease. Methods: We carried out meta-analyses of exome array data and three lung function measures: forced expiratory volume in one second (FEV1), forced vital capacity (FVC) and the ratio of FEV1 to FVC (FEV1/FVC). These analyses by the SpiroMeta and CHARGE consortia included 60,749 individuals of European ancestry from 23 studies, and 7,721 individuals of African Ancestry from 5 studies in the discovery stage, with follow-up in up to 111,556 independent individuals. Results: We identified significant (P&lt;2·8x10-7) associatio…

Prospective relationships of ADHD symptoms with developing substance use in a population-derived sample

BackgroundClinically ascertained reports suggest that boys and girls with attention deficit hyperactivity disorder (ADHD) may differ from each other in their vulnerability to substance use problems.MethodA total of 1545 Finnish adolescents were assessed for DSM-IV-based ADHD symptoms by their parents and classroom teachers using standardized rating scales at age 11–12 years. At age 14, substance use disorders and psychiatric co-morbidity were assessed with the Semi-Structured Assessment for the Genetics of Alcoholism, providing DSM-III-R/DSM-IV diagnoses for Axis I disorders. At age 17.5, substance use was assessed by multi-item questionnaire.ResultsAlthough baseline ADHD symptoms were less…

Physical and psychological functioning of daily living in relation to physical activity. A longitudinal study among former elite male athletes and controls

Background and aims: Physical exercise plays an important role in the prevention and reduction of disabilities in elderly people. The aim of this study was to determine the role of physical activity in the physical and psychological functioning of daily living in a cohort of former elite male athletes representing different sports, and controls of middle and old age. Methods: Subjects were 664 former elite male athletes (mean age 64.4 years) and 500 controls (62.0 years) in middle and old age. Subjects were mailed “Physical activity and health survey” questionnaires in 1985 and 1995. The primary outcomes — the physical and psychological functioning of daily living — were assessed in 1995 us…

Widespread pain among 11-year-old Finnish twin pairs

Objective To examine the prevalence of widespread musculoskeletal pain (WSP) symptoms in 11-year-old Finnish twins and to determine the relative role of genetic and environmental factors in the etiology of WSP. Methods Data on current pain items were collected from 1995 to 1998 from a national sample of Finnish families with 11-year-old twins born between 1984 and 1987. The presence of WSP was determined using a validated questionnaire method. Pairwise similarity was computed for 583 monozygotic (MZ) pairs, 588 same-sex dizygotic (DZ) pairs, and 618 opposite-sex DZ twin pairs. Variance components for genetic and environmental factors were estimated using biometric structural equation modeli…

Longitudinal changes in genetic and environmental influences on older women's walking ability

This study examined the stability and change over time in genetic and environmental influences on walking ability among older women. Maximal walking speed over 10 m and 6-min walking endurance test were measured under standard conditions at baseline and 3 years later. At both times, 63 monozygotic (MZ) and 67 dizygotic (DZ) twin pairs were measured for walking speed and 58 MZ and 56 DZ pairs for walking endurance. Participants were twin sisters reared together and aged 63-75 years at baseline. Genetic and environmental influences were examined using longitudinal genetic modelling. The results showed that walking speed was preserved from baseline to follow-up. Genetic influences on walking s…

Genetic and Environmental Influences on the Relationship Between Aggression and Hyperactivity-impulsivity as Rated by Teachers and Parents

This study examined genetic and environmental contributions to the covariance between aggression and hyperactivity-impulsivity as rated by twins' teachers and parents. Sex-differences in these genetic and environmental contributions and rater bias/sibling interaction effects were of interest as well. Part of an ongoing nation-wide twin-family study of behavioral development and health habits, the sample consisted of 1636 Finnish twin pairs ascertained from five consecutive and complete twin birth cohorts. Data were collected at ages 11-12, using teacher and parental rating forms of the Multidimensional Peer Nomination Inventory. Bivariate analyses were performed using structural equation mo…

Genetic and environmental influences on hearing in older women.

Background. This study examined the relative contribution of genetic and environmental effects on the air-conducted hearing threshold level (0.5‐4 kHz) and speech recognition threshold level of the better ear as well as self-reported hearing in older women. Methods. Hearing was measured as a part of the Finnish Twin Study on Aging in 103 monozygotic (MZ) and 114 dizygotic (DZ) female twin pairs aged 63‐76 years. Audiometric measured hearing was tested using standardized methods in soundproof conditions. Self-reported hearing was assessed by a structured question. Quantitative genetic modeling was used for data analyses. Results. No significant differences in age, exposure to noise, hearing-…

Higher Free Fatty Acid Uptake in Visceral Than in Abdominal Subcutaneous Fat Tissue in Men

Visceral adipose tissue has been shown to have high lipolytic activity. The aim of this study was to examine whether free fatty acid (FFA) uptake into visceral adipose tissue is enhanced compared to abdominal subcutaneous tissue in vivo. Abdominal adipose tissue FFA uptake was measured using positron emission tomography (PET) and [F-18]-labeled 6-thia-hepta-decanoic acid ([F-18]FTHA) and fat masses using magnetic resonance imaging (MRI) in 18 healthy young adult males. We found that FFA uptake was 30% higher in visceral compared to subcutaneous adipose tissue (0.0025 +/- 0.0018 vs. 0.0020 +/- 0.0016 mu mol/g/min, P = 0.005). Visceral and subcutaneous adipose tissue FFA uptakes were strongly…

Polygenic score for physical activity provides odds for multiple common diseases

ABSTRACTPurposeIt has been suggested that genetic pleiotropy, in which the same genes affect two or more traits, may partially explain the frequently observed associations between high physical activity (PA) and later reduced morbidity or mortality. However, the evidence about pleiotropy from human studies is limited. This study investigated associations between PA polygenic risk scores (PRSs) and cardiometabolic diseases among the Finnish population.MethodsPRSs for device-measured overall PA were adapted to a FinnGen study cohort of 218,792 individuals with genome-wide genotyping and extensive digital longitudinal health register data. Associations between PA PRS and body mass index (BMI),…

Estrogenic regulation of skeletal muscle proteome : a study of premenopausal women and postmenopausal MZ cotwins discordant for hormonal therapy

Female middle age is characterized by a decline in skeletal muscle mass and performance, predisposing women to sarcopenia, functional limitations, and metabolic dysfunction as they age. Menopausal loss of ovarian function leading to low circulating level of 17b-estradiol has been suggested as a contributing factor to aging-related muscle deterioration. However, the underlying molecular mechanisms remain largely unknown and thus far androgens have been considered as a major anabolic hormone for skeletal muscle. We utilized muscle samples from 24 pre- and postmenopausal women to establish proteome-wide profiles, associated with the difference in age (30–34 years old vs. 54– 62 years old), men…

A longitudinal study on genetic and environmental influences on leisure time physical activity in the Finnish Twin Cohort.

The purpose of this study was to examine changes in the contribution of genetic and environmental influences to leisure time physical activity among male and female twins over a 6-year follow-up. At baseline the sample comprised 4,280 monozygotic and 9,276 dizygotic twin individuals, and at follow-up 4,383 monozygotic and 9,439 dizygotic twin individuals. Participants were aged 18–54 years at baseline. Genetic modeling results showed that genetic influences on leisure time physical activity declined from baseline (44%) to follow-up (34%). Most of the genetic influences identified at baseline were present at followup (rg= 0.72). Specific environmental influences increased from baseline (56%)…

Influence of long-term postmenopausal hormone-replacement therapy on estimated structural bone strength: A study in discordant monozygotic twins

Although postmenopausal hormone-replacement therapy (HRT) is known to prevent fractures, knowledge on the influence of long-term HRT on bone strength and its determinants other than areal bone mineral density is scarce. This study used a genetically controlled design with 24 monozygotic female twin pairs aged 54 to 72 years in which one cotwin was using HRT (mean duration 8 years) and the other had never used HRT. Estimated bone strength, cross-sectional area, volumetric bone mineral density, bone mineral mass, and cross-sectional density and mass distributions were assessed in the tibial shaft, distal tibia, and distal radius with peripheral computed tomography (pQCT). In the tibial shaft,…

Rare variant analyses across multiethnic cohorts identify novel genes for refractive error

Refractive error, measured here as mean spherical equivalent (SER), is a complex eye condition caused by both genetic and environmental factors. Individuals with strong positive or negative values of SER require spectacles or other approaches for vision correction. Common genetic risk factors have been identified by genome-wide association studies (GWAS), but a great part of the refractive error heritability is still missing. Some of this heritability may be explained by rare variants (minor allele frequency [MAF] ≤ 0.01.). We performed multiple gene-based association tests of mean Spherical Equivalent with rare variants in exome array data from the Consortium for Refractive Error and Myopi…

Circulating miR-21, miR-146a and Fas ligand respond to postmenopausal estrogen-based hormone replacement therapy--a study with monozygotic twin pairs.

Biological aging is associated with physiological deteriorations and its’ remodeling, which are partly due to changes in the hormonal profile. MicroRNAs are known to post-transcriptionally regulate various cellular processes associated with cell senescence; differentiation, replication and apoptosis. Measured from the serum, microRNAs have the potential to serve as noninvasive markers for diagnostics/prognostics and therapeutic targets. We analysed the association of estrogen-based hormone replacement therapy (HRT) with selected microRNAs and inflammation markers from the serum, leukocytes and muscle tissue biopsy samples obtained from 54-62 year-old postmenopausal monozygotic twins (n=11 p…

Influence of long-term postmenopausal hormone replacement therapy on estimated structural bone strength: A study in discordant monozygotic twins.

Although postmenopausal hormone-replacement therapy (HRT) is known to prevent fractures, knowledge on the influence of long-term HRT on bone strength and its determinants other than areal bone mineral density is scarce. This study used a genetically controlled design with 24 monozygotic female twin pairs aged 54 to 72 years in which one cotwin was using HRT (mean duration 8 years) and the other had never used HRT. Estimated bone strength, cross-sectional area, volumetric bone mineral density, bone mineral mass, and cross-sectional density and mass distributions were assessed in the tibial shaft, distal tibia, and distal radius with peripheral computed tomography (pQCT). In the tibial shaft,…

The difference in risk of chronic pulmonary disease morbidity and mortality between elite athletes and ordinary men in Finland

Introduction: The impact of a history of competitive sports on later smoking behavior and occurrence of chronic pulmonary diseases is poorly known. We investigated how a history of elite level sports predicted later pulmonary disease morbidity and mortality. Methods: Chronic pulmonary disease incidence were assessed from national hospital and cause-of-death registers from 1970 to 2015 among Finnish male former elite athletes (n=2078) and matched controls (n=1453) alive in 1970 (mean age 45.0 years). Hazard ratios (HRs) were calculated by Cox proportional hazards model. In 1985, cohort members reported on their smoking habits, engagement in physical activity/sports and physician-diagnosed ch…

Genetic Factors and Susceptibility to Falls in Older Women

OBJECTIVES: To determine whether genetic influences account for individual differences in susceptibility to falls in older women. DESIGN: Prospective twin cohort study. SETTING: Research laboratory and residential environment. PARTICIPANTS: Ninety-nine monozygotic (MZ) and 114 dizygotic (DZ) female twin pairs aged 63 to 76 from the Finnish Twin Cohort study. MEASUREMENTS: The participants recorded their falls on a calendar for an average+/-standard deviation of 344+/-41 days. Reported falls were verified via telephone interview, and circumstances, causes, and consequences of the fall were asked about. RESULTS: The total number of falls was 434, of which 188 were injurious; 91 participants h…

The Associations Between Leisure-Time Physical Activity and Academic Performance: A Twin Study

Background: Both genetic and environmental influences have been shown to contribute to the association between physical activity and overall academic performance. The authors examined whether leisure-time physical activity (LTPA) shares genetic and environmental variances between spelling, essay writing, reading aloud, reading comprehension, and mathematics in early adolescence. Moreover, they investigated whether genetic polymorphisms associated with physical activity behavior affect these academic skills. Methods: Participants were 12-year-old Finnish twins (n = 4356–4370 twins/academic skill, 49% girls). Academic skills were assessed by teachers, and LTPA was self-reported. Polygenic sco…

Allostatic Load of Men and Women in Early Middle Age

Abstract. The present longitudinal study investigated three aspects of allostatic load, a long-term negative consequence of physical responses to stress: (1) sex differences in allostatic load in early middle age, (2) associations between career stability history and allostatic load, and (3) relationships between allostatic load and health problems. Participants consisted of 62 men and 55 women from the ongoing Jyväskylä Longitudinal Study of Personality and Social Development, Finland. Allostatic load was the sum of eight parameters (dehydroepiandrosterone-sulfate, 12-h urinary norepinephrine, high-density lipoprotein, triglycerides, glycosylated hemoglobin, systolic and diastolic blood p…

Leisure Time Physical Activity and Sleep Predict Mortality in Men Irrespective of Background in Competitive Sports

Introduction: Physical activity and sleep are closely related behaviors with suggested synergistic influence on cardiovascular health. Physical activity potentially modifies associations between sleep and mortality. Our aim was to study the interrelationships between sleep, leisure-time physical activity (LTPA), a history of sports, and mortality. Methods: A prospective cohort of former elite male athletes (n = 1,028), and age- and region-matched nonathlete men (n = 610) completed a health questionnaire in 1985. Their mortality was followed up until December 31, 2011. Analyses included Cox proportional hazards models with sleep duration and sleep quality as main predictors of all-cause and …

Parenting Mechanisms in Links Between Parents’ and Adolescents’ Alcohol Use Behaviors

Background: Adolescence has been identified as a critical period with regard to the initiation and early escalation of alcohol use. Moreover, research on familial risk and protective processes provides independent support for multiple domains of parental influence on adolescent drinking; including parents' own drinking behaviors, as well as the practices they employ to socialize their children. Despite this prevalence of findings, whether and how these distinct associations are related to one another is still not entirely clear. Methods: The present study used data from 4,731 adolescents and their parents to test the nature of associations between (a) parents' frequencies of alcohol use and…

Genetic and environmental contribution to postural balance of older women in single and dual task situations

Abstract The purpose of the present study was to examine the effect of a second task on postural balance and to determine the role of genetic influences on postural balance when dual tasking among 206 monozygotic and 227 dizygotic female twins, aged 63–76 years. Balance was measured as medio-lateral and antero-posterior velocity of the centre of pressure (COP) (mm/s) and velocity moment (mm2/s) while standing on a force platform. Doing an arithmetic task increased movement of the COP while the hand motor task had no effect on movement of the COP. The genetic contribution to balance in the single task situation was minor (14%, 95% confidence interval, CI: 11–35%) whereas in the dual task sit…

Is diversity of leisure-time sport activities associated with low back and neck–shoulder region pain? A Finnish twin cohort study

This study investigates cross-sectional and longitudinal associations between the diversity of leisure-time sport activities and the frequencies of low back pain (LBP) and neck-shoulder region pain (NSP) in twins, including a cross-sectional within-pair design to adjust for potential familial confounding. Finnish twins born in 1975–79 (FinnTwin16 study) reported participation in leisure-time sport activities at the mean ages of 17 (1992–96) (n = 5096, 54% females) and 34 years (2010−12) (n = 3731, 57% females). Diversity assessed as the number of sport activities was categorized as 1, 2, 3, 4, and ≥ 5, excluding inactive individuals. The frequencies of LBP (n = 3201) and NSP (n = 3207), rep…

Externalizing Behaviors and Cigarette Smoking as Predictors for Use of Illicit Drugs: A Longitudinal Study Among Finnish Adolescent Twins

We examined whether externalizing problem behaviors (hyperactivity–impulsivity, aggressiveness, and inattention) predict illicit drug use independently, or whether their associations with drug use are mediated through cigarette smoking. We used a prospective longitudinal design within theFinnTwin12-17study among Finnish adolescents with baseline at age 12 and follow-up surveys at ages 14 and 17. Path models were conducted withMplusand included 1992 boys and 2123 girls. The outcome was self-reported ever use of cannabis or other illicit drugs at age 17. The predictors were: externalizing behaviors (hyperactivity–impulsivity, aggressiveness, and inattention) assessed by teachers and parents (…

Motor Development and Physical Activity: A Longitudinal Discordant Twin-Pair Study.

ntroduction : Previous longitudinal research suggests that motor proficiency in early life predicts physical activity in adulthood. Familial effects including genetic and environmental factors could explain the association, but no long-term follow-up studies have taken into account potential confounding by genetic and social family background. The present twin study investigated whether childhood motor skill development is associated with leisure-time physical activity levels in adulthood independent of family background. Methods : Altogether, 1550 twin pairs from the FinnTwin12 study and 1752 twin pairs from the FinnTwin16 study were included in the analysis. Childhood motor development wa…

Physical activity and health: Findings from Finnish monozygotic twin pairs discordant for physical activity

AbstractGenetic and early environmental differences including early health habits associate with future health. To provide insight on the causal nature of these associations, monozygotic (MZ) twin pairs discordant for health habits provide an interesting natural experiment. Twin pairs discordant for leisure-time physical activity (LTPA) in early adult life are thus a powerful study design to investigate the associations between long-term LTPA and indicators of health and wellbeing. We have used this study design by identifying 17 LTPA discordant twin pairs from two Finnish twin cohorts and summarize key findings of these studies in this paper. The carefully characterized rare long-term LTPA…

All-cause and disease-specific mortality among male, former elite athletes: an average 50-year follow-up.

Aim To investigate life expectancy and mortality among former elite athletes and controls. Methods HR analysis of cause-specific deaths sourced from the national death registry for former Finnish male endurance, team and power sports athletes (N=2363) and controls (N=1657). The median follow-up time was 50 years. Results Median life expectancy was higher in the endurance (79.1 years, 95% CI 76.6 to 80.6) and team (78.8, 78.1 to 79.8) sports athletes than in controls (72.9, 71.8 to 74.3). Compared to controls, risk for total mortality adjusted for socioeconomic status and birth cohort was lower in the endurance ((HR 0.70, 95% CI 0.61 to 0.79)) and team (0.80, 0.72 to 0.89) sports athletes, a…

Are computer and cell phone use associated with body mass index and overweight? A population study among twin adolescents

Abstract Background Overweight in children and adolescents has reached dimensions of a global epidemic during recent years. Simultaneously, information and communication technology use has rapidly increased. Methods A population-based sample of Finnish twins born in 1983–1987 (N = 4098) was assessed by self-report questionnaires at 17 y during 2000–2005. The association of overweight (defined by Cole's BMI-for-age cut-offs) with computer and cell phone use and ownership was analyzed by logistic regression and their association with BMI by linear regression models. The effect of twinship was taken into account by correcting for clustered sampling of families. All models were adjusted for gen…

Genetic and environmental factors in health-related behaviors: Studies on Finnish twins and twin families

Family, twin and adoption studies have provided evidence for familial and genetic influences on individual differences in disease risk and in human behavior. Attempts to identify individual genes accounting for these differences have not been outstandingly successful to date, and at best, known genes account for only a fraction of the familiality of most traits or diseases. More detailed knowledge of the dynamics of gene action and of specific environmental conditions are needed. Twin and twin-family studies with multiple measurements of risk factors and morbidity over time can permit a much more detailed assessment of the developmental dynamics of disease risk and the unfolding of behavior…

Persistence or change in leisure-time physical activity habits and waist gain during early adulthood: A twin-study

Objective To determine the relationship between persistence or change in leisure-time physical activity habits and waist gain among young adults. Methods Population-based cohort study among 3383 Finnish twin individuals (1578 men) from five birth cohorts (1975-1979), who answered questionnaires at mean ages of 24.4 y (SD 0.9) and 33.9 y (SD 1.2), with reported self-measured waist circumference. Persistence or change in leisure-time physical activity habits was defined based on thirds of activity metabolic equivalent h/day during follow-up (mean 9.5 y; SD 0.7). Results Decreased activity was linked to greater waist gain compared to increased activity (3.6 cm, P < 0.001 for men; 3.1 cm, P < 0…

Midlife Physical Activity and Cognition Later in Life : A Prospective Twin Study

Background: Physical activity has been associated with a reduced risk of cognitive decline but the nature of this association remains obscure. Objective: To study associations between midlife physical activity and cognition in old age for a prospective cohort of Finnish twins. Methods: Physical activity in the Finnish Twin Cohort was assessed using questionnaire responses collected in 1975 and 1981. After a mean follow-up of 25.1 years, the subjects' (n = 3050; mean age 74.2; range 66-97) cognition was evaluated with a validated telephone interview. Both participation in vigorous physical activity, and the volume of physical activity, divided into quintiles, were used as predictors of cogni…

Genetic influences on adult body mass index followed over 29 years and their effects on late-life mobility: a study of twin sisters.

Background: The rise in body mass index (BMI) during adulthood increases the risk for metabolic disorders, functional limitations and disability in old age. This twin study examined prospectively whether genetic and environmental influences on women’s BMI also account for mobility 29 years later. Methods: The sample consisted of 103 monozygotic and 114 dizygotic pairs of twin sisters reared together. Body mass index was initially evaluated in 1975, when the women were aged 42.6±3.4 years, and was followed-up in 1981, 1990, 2001 and 2004. Mobility was evaluated using the standardised 6-minute walking test in 2001, when the women were aged 68.6±3.2 years, and followed-up 3 years later. An inv…

Association between education and future leisure-time physical inactivity: a study of Finnish twins over a 35-year follow-up

Background: Education is associated with health related lifestyle choices including leisure-time physical inactivity. However, the longitudinal associations between education and inactivity merit further studies. We investigated the association between education and leisure-time physical inactivity over a 35-year follow-up with four time points controlling for multiple covariates including familial confounding. Methods: This study of the population-based Finnish Twin Cohort consisted of 5254 twin individuals born in 1945–1957 (59 % women), of which 1604 were complete same-sexed twin pairs. Data on leisure-time physical activity and multiple covariates was available from four surveys conduct…

Role of individual, peer and family factors in the use of cannabis and other illicit drugs: A longitudinal analysis among Finnish adolescent twins

Background: Although use of illicit drugs shows varying degree of heritability, the influence of shared and unique environmental factors predominate among adolescents. We explored factors predicting use of cannabis and other illicit drugs among Finnish adolescent twins. Methods: We used longitudinal data from the FinnTwin 12-17 study with baseline at age 11-12 and follow-up at ages 14 and 171/2, including 4138 individuals. The outcome was self-reported ever use of cannabis or other illicit drugs at age 171/2. The potential predictors were measures reported by the twins, their parents or teachers. As individual factors we tested smoking, alcohol use, behavioral and emotional problems; as pee…

Polygenic Risk Scores and Physical Activity

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Use of Alcohol and Alcohol-related Morbidity in Finnish Former Elite Athletes

Introduction: The effect of a history of competitive sports on later use of alcohol and occurrence of alcohol-related diseases is poorly known. We investigated how a history of elite level sports was associated with alcohol consumption in middle-age and with alcohol-related morbidity and mortality. Methods: The occurrence of alcohol-related diseases and deaths were followed using national registers from 1970 to 2008 among Finnish male former elite athletes (n = 2202) and matched controls (n = 1403) alive in 1970 (mean age = 45.1 yr). Hazard ratios were calculated by Cox proportional hazards model. In 1985, surviving participants questionnaire-reported their alcohol consumption and engagemen…

Leisure activity patterns and their associations with overweight: A prospective study among adolescents

We examined longitudinal associations between individual leisure activities (television viewing, video viewing, computer games, listening to music, board games, musical instrument playing, reading, arts, crafts, socializing, clubs or scouts, sports, outdoor activities) and being overweight using logistic regression and latent class analysis in a cohort of Finnish twins responding to self-report questionnaires at 11–12 (N=5184), 14, and 17 years. We also studied activity patterns (“Active and sociable”, “Active but less sociable”, “Passive but sociable”, “Passive and solitary”) thought to represent different lifestyles. Among boys, activity patterns did not predict becoming overweight, but s…

Leg extension power asymmetry and mobility limitation in healthy older women

Objective To investigate the association of asymmetry in leg extension power (LEP) with walking and standing balance. Design Cross-sectional analysis. Setting Research laboratory. Participants Healthy female twins (N=419), ages 63 to 75 years. Interventions Not applicable. Main Outcome Measures The LEP difference between the stronger and the weaker leg, measured with the Nottingham power rig, was calculated. Ten-meter maximal walking velocity was assessed in a laboratory corridor on a wide (170cm) and narrow (35cm) track, and the ability to maintain tandem stance for 20 seconds was recorded. Results The mean LEP difference ± standard deviation between the legs was 15%±9% (P<.001). Those wit…

Motives for and Barriers to Physical Activity in Twin Pairs Discordant for Leisure Time Physical Activity for 30 Years

Long-term persistent physical activity is important in the prevention of chronic diseases, but a large number of people do not participate in physical activity to obtain health benefits. The purpose of this study was to examine the motives and perceived barriers to long-term engagement in leisure time physical activity. Same-sex twin pairs (N=16, mean age 60) discordant for physical activity over 30 years were identified from the Finnish Twin Cohort. We evaluated participants' physical activity motivation with the 73-item Recreational Exercise Motivation Measure and assessed barriers to physical activity with a 25-item questionnaire. The characteristics of physical activity motivation and p…

Muscle function in monozygotic female twin pairs discordant for hormone replacement therapy

Introduction: Postmenopausal monozygotic twin pairs discordant for hormone replacement therapy (HRT) provide an advantageous study design controlling for genetic background for elucidating the relationships between aging, sex hormone levels, muscle strength, contractile capacity, and fatigability. Methods: Thirteen postmenopausal monozygotic twin pairs discordant for HRT were measured for maximal voluntary torque (MVC) and twitch characteristics using electrical stimulation before and after intermittent dynamic plantarflexor exercise until exhaustion. Results: Peak twitch torque was 32% higher in HRT users than in their non-HRT, genetically identical sisters (P = 0.002), but MVC did not dif…

Factors behind Leisure-Time Physical Activity Behavior Based on Finnish Twin Studies: The Role of Genetic and Environmental Influences and the Role of Motives

Different approaches are being taken to clarify the role of various factors in the development of physical activity behaviors. Genetic studies are a new area of physical activity research and also the motives for physical activity have been widely studied. The purpose of this paper is to review the findings emerging from the longitudinal genetic studies on leisure-time physical activity and to evaluate the associations between motivational factors and leisure-time physical activity. The focus is to review recent findings of longitudinal Finnish twin studies. The results of the latest longitudinal Finnish twin studies point to the existence of age-specific genetic and environmental influence…

Externalizing Problem Behaviors and Headache: A Follow-up Study of Adolescent Finnish Twins

Objective.To examine the association of teacher- and parent-rated behavior with headache in a prospective follow-up study of adolescent Finnish twins.Methods.Questionnaire data were collected during 1995–2001 from a nationwide sample of Finnish families of 11-year-old twins who were born 1983–1987 (n = 5393) and again at age of 14. Psychological factors were measured by using parents’ and teachers’ ratings of a 37-item multidimensional rating instrument at the ages of 11 and 14.Results.At age 11, headache frequency (5 categories) was associated with total scales of externalizing and internalizing problem behaviors and adaptive behaviors, assessed by parents, but only with externalizing prob…

Leisure-time physical activity and artery lumen diameters: A monozygotic co-twin control study

Exercise is thought to increase the diameter of the conduit arteries supplying the muscles involved. We studied the effects of a physically active vs inactive lifestyle on artery diameters in monozygotic (MZ) twin pairs discordant over 30 years for leisure-time physical activity habits. In a population-based co-twin control study design, six middle-aged (50-65 years) same-sex MZ twin pairs with long-term discordance for physical activity were comprehensively identified from the Finnish Twin Cohort (TWINACTIVE study). Discordance was initially defined in 1975 and the same co-twin remained significantly more active during the 32-year follow-up. The main outcomes were arterial lumen diameters …

Poor vision accompanied with other sensory impairments as a predictor of falls in older women

Objectives:we studied visual acuity (VA) and co-existing hearing impairment and poor standing balance as predictors of falls. Design: prospective study with 1-year follow-up. Setting: research laboratory and residential environment. Participants: 428 women aged 63‐76 years from the Finnish Twin Study on Aging. Measurements: participants were followed up for incidence of falls over 1 year. VA, hearing ability and standing balance were assessed at the baseline. The incidence rate ratios (IRR) for falls were computed using the negative binomial regression model. Results: during the follow-up, 47% of participants experienced a fall. After adjusting for age and interdependence of twin sisters, p…

Chronic diseases and objectively monitored physical activity profile among aged individuals – a cross-sectional twin cohort study

Introduction: High physical activity (PA) at old age indicates good functional capacity enabling independent living. We investigated how different disease conditions are associated with measured PA indicators in old women and men, and whether they recognize this association. Materials and methods: This cross-sectional twin cohort study in Finland comprised 779 individuals (276 complete twin pairs, including 117 monozygotic pairs), who participated in hip-worn accelerometer monitoring of PA and responded to questions on diseases and mobility limitations at mean age of 73 (range 71 to 75). Results: Of the participants, 23.2% reported having a disease restricting mobility. With sex and age in …

Parental monitoring moderates the importance of genetic and environmental influences on adolescent smoking.

Although there is a substantial literature on the role of parenting in adolescent substance use, most parenting effects have been small in magnitude and studied outside the context of genetically informative designs, raising debate and controversy about the influence that parents have on their children (D. C. Rowe, 1994). Using a genetically informative twin-family design, the authors studied the role of parental monitoring on adolescent smoking at age 14. Although monitoring had only small main effects, consistent with the literature, there were dramatic moderation effects associated with parental monitoring: At high levels of parental monitoring, environmental influences were predominant …

The associations of emotion regulation and dysregulation with the metabolic syndrome factor

Abstract Objective Emotion regulation has been associated with good, and dysregulation with poor subjective health; but it is unclear if emotion regulation is related to metabolic syndrome. Methods Associations between the metabolic syndrome factor (systolic and diastolic blood pressure, waist circumference, high-density lipoprotein, triglycerides, and glucose), emotion regulation (the strategies of repair and maintenance, self-perceived emotion regulation) and dysregulation (emotional ambivalence); and subjective health (self-rated health and psychosomatic symptoms) were studied using a structural equation modelling (SEM) approach. The participants (96 women, 85 men) were drawn from the Jy…

Motives for physical activity among active and inactive persons in their mid-30s

The purpose of this study was to examine the motives for leisure-time physical activity among active and inactive men and women in their mid-30s. We used both cross-sectional and longitudinal designs. Altogether, 2308 participants (mean age 33.9 years, 53.4% women) were identified from the population-based FinnTwin16 Cohort. Physically active and inactive individuals were identified on the basis of their leisure-time MET h/day. We evaluated participants' physical activity motivation with a modified version of the Recreational Exercise Motivation Measure. Comparisons between active and inactive individuals were analysed using the Wald test for equality of means, and effect sizes were calcula…

Persistent leisure-time physical activity in adulthood and use of antidepressants : A follow-up study among twins

BACKGROUND: To study whether persistent leisure-time physical activity (PA) during adulthood predicts use of antidepressants later in life. METHODS: The Finnish Twin Cohort comprises same-sex twin pairs born before 1958, of whom 11 325 individuals answered PA questions in 1975, 1981 and 1990 at a mean age of 44 years (range 33-60). PA volume over 15-years was used as the predictor of subsequent use of antidepressants. Antidepressant use (measured as number of purchases) for 1995-2004 were collected from the Finnish Social Insurance Institution (KELA) prescription register. Conditional logistic regression was conducted to calculate odds ratios (OR) with 95% confidence intervals (CI) for the …

Association of education with leisure-time physical inactivity in Finnish twins over 35 years

Physical Activity, Fitness, Glucose Homeostasis, and Brain Morphology in Twins

The main aim of the present study (FITFATTWIN) was to investigate how physical activity level is associated with body composition, glucose homeostasis, and brain morphology in young adult male monozygotic twin pairs discordant for physical activity.From a population-based twin cohort, we systematically selected 10 young adult male monozygotic twin pairs (age range, 32-36 yr) discordant for leisure time physical activity during the past 3 yr. On the basis of interviews, we calculated a mean sum index for leisure time and commuting activity during the past 3 yr (3-yr LTMET index expressed as MET-hours per day). We conducted extensive measurements on body composition (including fat percentage …

Decreased prevalence of left-handedness among females with male co-twins: evidence suggesting prenatal testosterone transfer in humans?

Studies of singletons suggest that right-handed individuals may have higher levels of testosterone than do left-handed individuals. Prenatal testosterone levels are hypothesised to be especially related to handedness formation. In humans, female members from opposite-sex twin pairs may experience elevated level of prenatal exposure to testosterone in their intra-uterine environment shared with a male. We tested for differences in rates of left-handedness/right-handedness in female twins from same-sex and opposite-sex twin pairs. Our sample consisted of 4736 subjects, about 70% of all Finnish twins born in 1983–1987, with information on measured pregnancy and birth related factors. Circulati…

Genetic and Environmental Influence on Structural Strength of Weight-Bearing and Non-Weight-Bearing Bone: A Twin Study

A bivariate genetic analysis among 217 older female twin pairs showed that, although the structural strength of tibia and radius are mainly regulated by same genetic and environmental factors, the tibia is more affected by environment. Introduction: The habitual loading environment of the bone may modulate the relative contribution of genetic and environmental factors to bone structure. The purpose of this study was to estimate the contribution of the common and site-specific genetic and environmental factors to interindividual variation in compressive structural strength of the weight-bearing tibia and non–weight-bearing radius. Materials and Methods: pQCT scans were obtained from both mem…

Cross-sectional associations between the diversity of sport activities and the type of low back pain in adulthood

Leisure-time physical activity has a complex relationship with low back pain (LBP). Thus, we aimed to investigate whether the diversity of sport activities is associated with the type of LBP. In the FinnTwin16 study, 4246 (55% females) Finnish twins at mean age 34.1 years replied to a health behaviour survey in 2010-2012. Based on the participation in different sport activities, we created two measures of diversity: quantity (i.e. the number of sport activities: 1, 2, 3, 4 and >= 5) and quality (i.e. the type of sport activity: endurance, strength, body care, etc.). Based on the frequency, duration and type of LBP, we created three groups: no history of LBP lasting more than one day, radiat…

Postmenopausal hormone replacement therapy modifies skeletal muscle composition and function: a study with monozygotic twin pairs

We investigated whether long-term hormone replacement therapy (HRT) is associated with mobility and lower limb muscle performance and composition in postmenopausal women. Fifteen 54- to 62-yr-old monozygotic female twin pairs discordant for HRT were recruited from the Finnish Twin Cohort. Habitual (HWS) and maximal (MWS) walking speeds over 10 m, thigh muscle composition, lower body muscle power assessed as vertical jumping height, and maximal isometric hand grip and knee extension strengths were measured. Intrapair differences (IPD%) with 95% confidence intervals (CI) were calculated. The mean duration of HRT use was 6.9 ± 4.1 yr. MWS was on average 7% (0.9 to 13.1%, P = 0.019) and muscle…

Childhood Verbal Development and Drinking Behaviors from Adolescence to Young Adulthood: A Discordant Twin-Pair Analysis

BACKGROUND: Studies suggest that better cognitive and verbal abilities in childhood predict earlier experimentation with alcohol and higher levels of drinking in adolescence, whereas poorer ability is related to a higher likelihood of remaining abstinent. Whether individual differences in language development in childhood predict differences in adolescent drinking behaviors has not been studied. METHODS: To address that question, we compared co-twins from twin pairs discordant for their childhood language development and studied associations of parental reports of within-pair differences in age at speaking words, age at learning to read, and expressive language skills during school age with…

Sport disciplines, types of sports, and waist circumference in young adulthood – a population-based twin study

Purpose: The benefits of physical activity (PA) in preventing abdominal obesity are well recognized, but the role of different sport disciplines remains open. We aimed, therefore, to investigate how participation in different sport disciplines, and the number and types of sports engaged in are associated with waist circumference (WC) in young adulthood. Methods: This population-based cohort study comprised 4027 Finnish twin individuals (1874 men), with a mean age of 34 y (32-37), who answered a survey, including self-measured WC. We extracted the number and identified the types (aerobic, power, and mixed) of the different sport disciplines respondents reported participating in. Results: The…

Physical inactivity and obesity: A vicious circle.

OBJECTIVE: Physical activity (PA) begins to decline in adolescence with a concomitant increase in weight. We hypothesized that a vicious circle may arise between decreasing PA and weight gain from adolescence to early adulthood. METHODS AND PROCEDURES: PA and self-perceived physical fitness assessed in adolescents (16-18 years of age) were used to predict the development of obesity (BMI &gt; or =30 kg/m(2)) and abdominal obesity (waist &gt;/=88 cm in females and &gt; or =102 cm in males) at age 25 in 4,240 twin individuals (90% of twins born in Finland, 1975-1979). Ten 25-year-old monozygotic (MZ) twin pairs who were discordant for obesity (with a 16 kg weight difference) were then carefull…

Association Between Long-Term Job Strain and Metabolic Syndrome Factor Across Sex and Occupation

The present study investigated whether long-term job strain increases the prevalence of risk for metabolic syndrome, a cluster of risk factors for cardiovascular diseases, across sex and occupation. The participants (64 men, 62 women) were drawn from the Jyväskylä Longitudinal Study of Personality and Social Development, Finland. Job strain was measured by a combination of high job demands and low job control ( Karasek, 1979 ) at ages 36 and 42. Metabolic syndrome was measured at age 42. The results indicated that both sex and occupational group moderated the association between long-term job strain and the metabolic syndrome factor but in an unexpected way. In women, low long-term job str…

Physical activity, morbidity and mortality in twins: a 24-year prospective follow-up.

The aim of this study was to find out whether persistent leisure-time physical activity, adjusted for genetic liability and childhood experiences, protect against occurrence of specific chronic diseases and all-cause mortality. Study design was a 24-year prospective follow-up after 6-year physical activity discordance in twin pairs. From 5,663 healthy adult twin pairs, 146 pairs (including 29 mozygotic) discordant for both intensity and volume of leisure physical activity at baseline in both 1975 and 1981 were systematically identified. Mortality and occurrence of chronic diseases (diabetes, hypertension, coronary heart disease defined according to reimbursable medication status) were follo…

Mortality and health-related habits in 900 Finnish former elite athletes and their brothers.

BackgroundThere is conflicting evidence on the associations between participation in vigorous sports, health habits, familial factors and subsequent mortality. We investigated all-cause mortality and health-related behaviour among former elite athletes and their brothers.MethodsThe mortality of Finnish male former elite athletes, who had represented Finland between 1920 and 1965 (n=900) and their age-matched brothers (n=900), was followed from the time when athlete started an elite athlete career until 31 December 2015. The age-adjusted HRs were calculated by a paired Cox proportional hazards model. In 2001, surviving participants (n=199 athletes and n=199 age-matched brothers) reported the…

The Relationship Between Sleep Characteristics and Unmet Physical Activity Need in Older Women

Objective: We examined among older women the association of sleep quality, daytime tiredness, and sleep duration with unmet physical activity need, that is, wishing to be more physically active but perceiving no opportunity for it. Method: Cross-sectional logistic regression analyses among women aged 74 to 86 years (Finnish Twin Study on Aging, third wave, n = 302). Results: Thirty-one participants reported unmet physical activity need. Short sleepers had fivefold and long sleepers threefold odds for unmet physical activity need compared with normative sleepers, while for daytime tiredness the odds were double. Presence of daytime tiredness and unmet physical activity coincided with higher…

Genome-wide association analysis identifies six new loci associated with forced vital capacity

Forced vital capacity (FVC), a spirometric measure of pulmonary function, reflects lung volume and is used to diagnose and monitor lung diseases. We performed genome-wide association study meta-analysis of FVC in 52,253 individuals from 26 studies and followed up the top associations in 32,917 additional individuals of European ancestry. We found six new regions associated at genome-wide significance (P &lt;5 x 10(-8)) with FVC in or near EFEMP1, BMP6, MIR129-2-HSD17B12, PRDM11, WWOX and KCNJ2. Two loci previously associated with spirometric measures (GSTCD and PTCH1) were related to FVC. Newly implicated regions were followed up in samples from African-American, Korean, Chinese and Hispani…

Multi-ancestry genome-wide association analyses improve resolution of genes and pathways influencing lung function and chronic obstructive pulmonary disease risk

Funder: British Lung Foundation (BLF); doi: https://doi.org/10.13039/501100000351

Genetic and environmental influences on non-specific neck pain in early adolescence: A classical twin study

Background Prevalence of neck pain has increased among adolescents. The origins of adult chronic neck pain may lie in late childhood, but for early prevention, more information is needed about its aetiology. We investigated the relative roles of genetic and environmental factors in early adolescent neck pain with a classic twin study. Methods Frequency of neck pain was assessed with a validated pain questionnaire in a population-based sample of nearly 1800 pairs of 11–12-year-old Finnish twins. Twin pair similarity for neck pain was quantified by polychoric correlations, and variance components were estimated with biometric structural equation modelling. Results Prevalence of neck pain repo…

Variants associated with HHIP expression have sex-differential effects on lung function

Background: Lung function is highly heritable and differs between the sexes throughout life. However, little is known about sex-differential genetic effects on lung function. We aimed to conduct the first genome-wide genotype-by-sex interaction study on lung function to identify genetic effects that differ between males and females. Methods: We tested for interactions between 7,745,864 variants and sex on spirometry-based measures of lung function in UK Biobank (N=303,612), and sought replication in 75,696 independent individuals from the SpiroMeta consortium. Results: Five independent single-nucleotide polymorphisms (SNPs) showed genome-wide significant (P&lt;5x10-8) interactions with sex …

Leukocyte and Skeletal Muscle Telomere Length and Body Composition in Monozygotic Twin Pairs Discordant for Long-term Hormone Replacement Therapy

Estrogen-based hormone replacement therapy (HRT) may be associated with deceleration of cellular aging. We investigated whether long-term HRT has effects on leukocyte (LTL) or mean and minimum skeletal muscle telomere length (SMTL) in a design that controls for genotype and childhood environment. Associations between telomeres, body composition, and physical performance were also examined. Eleven monozygotic twin pairs (age 57.6 ± 1.8 years) discordant for HRT were studied. Mean duration of HRT use was 7.3 ± 3.7 years in the user sister, while their co-twins had never used HRT. LTL was measured by qPCR and SMTLs by southern blot. Body and muscle composition were estimated by bioimpedance an…

A Polygenic Risk Score for Hand Grip Strength Predicts Muscle Strength and Proximal and Distal Functional Outcomes among Older Women

Purpose Hand grip strength (HGS) is a widely used indicator of overall muscle strength and general health. We computed a polygenic risk score (PRS) for HGS, and examined, whether it predicted muscle strength, functional capacity and disability outcomes. Methods Genome-wide association study summary statistics for HGS from the Pan-UK Biobank was utilized. PRSs were calculated in the Finnish Twin Study on Aging (N = 429 women, 63–76 years). Strength tests included HGS, isometric knee extension, and ankle plantar flexion strength. Functional capacity was examined with the Timed Up and Go, six-minute and 10-meter walk tests, and dual-task tests. Disabilities in the basic (ADL) and instrumental …

Differences in muscle and adipose tissue gene expression and cardio-metabolic risk factors in the members of physical activity discordant twin pairs

High physical activity/aerobic fitness predicts low morbidity and mortality. Our aim was to identify the most up-regulated gene sets related to long-term physical activity vs. inactivity in skeletal muscle and adipose tissues and to obtain further information about their link with cardio-metabolic risk factors. We studied ten same-sex twin pairs (age range 50-74 years) who had been discordant for leisure-time physical activity for 30 years. The examinations included biopsies from m. vastus lateralis and abdominal subcutaneous adipose tissue. RNA was analyzed with the genome-wide Illumina Human WG-6 v3.0 Expression BeadChip. For pathway analysis we used Gene Set Enrichment Analysis utilizing…

Genetic and environmental sources of continuity and change in teacher-rated aggression during early adolescence

Genetic and environmental sources of continuity and change in aggression were studied in a sample of 1,041 twin pairs (364 monozygotic; 348 same-sex dizygotic; and 329 opposite-sex dizygotic) as part of an ongoing, population-based Finnish twin-family study. At ages 12 and 14, the twins' aggression was assessed by their classroom teachers, using a rating form of the Multidimensional Peer Nomination Inventory. Genetic and environmental sources of continuity and change were studied by fitting a longitudinal bivariate Cholesky decomposition model. Longitudinal model-fitting results indicated that both genetic and environmental factors influenced continuity in aggression during this 2-year peri…

Blood and skeletal muscle ageing determined by epigenetic clocks and their associations with physical activity and functioning

AbstractThe aim of this study was to investigate the correspondence of different biological ageing estimates (i.e. epigenetic age) in blood and muscle tissue and their associations with physical activity (PA), physical function and body composition. Two independent cohorts (N = 139 and N = 47) were included, whose age span covered adulthood (23–69 years). Whole blood and m. vastus lateralis samples were collected, and DNA methylation was analysed. Four different DNA methylation age (DNAmAge) estimates were calculated using genome-wide methylation data and publicly available online tools. A novel muscle-specific methylation age was estimated using the R-package ‘MEAT’. PA was measured with q…

Hormone replacement therapy enhances IGF-1 signaling in skeletal muscle by diminishing miR-182 and miR-233 expressions: A study on postmenopausal monozygotic twin pairs

MiRNAs are fine-tuning modifiers of skeletal muscle regulation, but knowledge of their hormonal control is lacking. We used a co-twin case–control study design, that is, monozygotic postmenopausal twin pairs discordant for estrogen-based hormone replacement therapy (HRT) to explore estrogen-dependent skeletal muscle regulation via miRNAs. MiRNA profiles were determined from vastus lateralis muscle of nine healthy 54–62- years-old monozygotic female twin pairs discordant for HRT (median 7 years). MCF-7 cells, human myoblast cultures and mouse muscle experiments were used to confirm estrogen’s causal role on the expression of specific miRNAs, their target mRNAs and proteins and finally the ac…

Additional file 2 of Genome-wide association studies identify 137 genetic loci for DNA methylation biomarkers of aging

Additional file 2. Supplementary Tables -Tables S1-S31.

Additional file 2 of Genome-wide association studies identify 137 genetic loci for DNA methylation biomarkers of aging

Additional file 2. Supplementary Tables -Tables S1-S31.

Are computer and cell phone use associated with body mass index and overweight? A population study among twin adolescents

Background. Overweight in children and adolescents has reached dimensions of a global epidemic during recent years. Simultaneously, information and communication technology use has rapidly increased. Methods. A population-based sample of Finnish twins born in 1983–1987 (N = 4098) was assessed by self-report questionnaires at 17 y during 2000–2005. The association of overweight (defined by Cole's BMI-for-age cut-offs) with computer and cell phone use and ownership was analyzed by logistic regression and their association with BMI by linear regression models. The effect of twinship was taken into account by correcting for clustered sampling of families. All models were adjusted for gender, ph…