0000000000266069
AUTHOR
Laura E. Gibbons
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…
Differences in psychomotor reaction time in male monozygotic twins discordant for lifetime cigarette smoking.
The effects of long-term cigarette smoking on psychomotor reaction time were investigated among 8 pairs of monozygotic male twins highly discordant for lifetime smoking (means 32.4 versus 0.6 pack-years). The men had no diagnosed cardiovascular disease or other major diseases, musculoskeletal complaints, or vision problems that might interfere with reaction time testing. The twins had similar education, work, and exercise histories; alcohol and coffee consumption and exposure to solvents were examined as possible confounds. Direct comparison of cotwins also controlled for age, genetics, and possible early environmental factors. Simple and choice reaction time were measured in the dominant h…
Differences in hand and foot psychomotor speed among 18 pairs of monozygotic twins discordant for lifelong vehicular driving.
The purpose of this study was to examine driving as a determinant of hand and foot psychomotor reaction times. Visual simple and choice hand and foot psychomotor reaction times were measured. The occupational driving contrast was determined by an interview reviewing every job held during each subject's lifetime. Comparison was made of psychomotor speed among 18 pairs of 39- to 62-year-old monozygotic male twins discordant for lifelong occupational driving. The mean discordance was the equivalent of 16 years of full-time driving. The twins who drove more tended to have slower hand simple and choice reaction times, although only the difference in hand-choice decision time was statistically si…
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…
Comparison of Foot and Hand Reaction Times among Men: A Methodologic Study Using Simple and Multiple-Choice Repeated Measurements
The primary study goal was to compare visual simple and choice reaction times of the hand and foot to assess validity of measurements for evaluating subjects' ability to perform rapid, controlled movements. First, we examined the repeatability ( N = 34) for four different data-sampling methods from a series of 12 trials within sessions and between two test sessions. Simple and choice reaction times with the preferred hand and both feet were then compared among 153 healthy male volunteers aged 35 to 67 years. Pearson correlations for hand and ipsilateral and contralateral foot reaction times on simple and choice tasks (.53 to .80, p<.001) showed that psychomotor foot reaction time is a v…
Correlations of isokinetic and psychophysical back lift and static back extensor endurance tests in men
Isokinetic lift, psychophysical lift, and static back endurance tests are among the most widely used measurements of muscle function for determining risk for, and recovery from, back problems. After determining test repeatability we examined the degree of association between these test measures in 100 men selected to represent a variety of occupations and lifestyles. Isokinetic lifting had low correlations with test results for psychophysical lifting (r = 0.28) and static back endurance (r = 0.24). Static back endurance and psychophysical lift test results were not at all correlated (r = 0.03). RELEVANCE--:Muscle function measurements for back problems are sometimes arbitrarily selected due…
Lumbar Disc Degeneration and Sagittal Flexibility
It is uncertain whether intervertebral disc degeneration is associated with reduced or increased flexibility, although lumbar flexibility is known to reduce with advancing age. This cross-sectional study of 214 middle-aged men attempted to determine the influence on lumbar sagittal flexibility from intervertebral disc degeneration parameters measured from magnetic resonance images (disc height, signal intensity, bulging, osteophytes). Multivariate analyses showed that a reduced extent of lumbar flexibility could be accounted for by the combined effect of decreasing disc height together with increasing age, weight, and back pain frequency. Although it remains possible that single degenerate …
Lifetime exercise and disk degeneration: an MRI study of monozygotic twins.
Participation in some competitive sports has been shown to increase disk degeneration; however, the long-term effects of recreational physical activities are unclear. We investigated the effects of endurance exercise and power sports on disk degeneration in monozygotic male twins with contrasting lifetime exercise histories. The effects of endurance exercise were studied in 22 discordant twin pairs (mean lifetime frequencies of 3.9 vs 1.1 times/wk), and the effects of power sports were investigated in 12 discordant pairs (2,300 vs 200 h of weightlifting). The age range of the twins was from 35 to 69 yr. No differences in MRI findings between co-twins discordant for endurance exercise were f…
The effect of lifelong exercise on psychomotor reaction time: a study of 38 pairs of male monozygotic twins
Purpose: The aim was to study the effect of lifetime physical activity on psychomotor speed. Methods: Foot and dominant hand visual simple and choice psychomotor reaction times were studied among monozygotic twins (38 pairs) aged 35-69, discordant for lifetime exercise histories. Results: There was a trend that some components of psychomotor reaction time were faster for frequent than for occasional exercisers. but the findings were not consistent for the hand and feet. After controlling for occupational physical activity, only choice decision time for the hand (26 ms, P < 0.01) and choice reaction time for the contralateral foot (51 ms, P < 0.05) both remained 7% faster. There was no trend…
The Long-Term Effects of Physical Loading and Exercise Lifestyles on Back-Related Symptoms, Disability, and Spinal Pathology Among Men
Study design Historical cohort, including selected subgroups. Objectives To understand the long-term effects of exercise on back-related outcomes, back pain, sciatica, back-related hospitalizations, pensions, and magnetic resonance imaging findings were studied among former elite athletes. Summary of background data Exercise and sports participation have become increasingly popular, as have recommendations of exercises for back problems, but little is known about their long-term effects. Methods Questionnaires were returned by 937 former elite athletes and 620 control subjects (83% response rate). Identification codes allowed record linkage to hospital discharge and pension registers. Magne…
Magnetic resonance imaging findings and their relationships in the thoracic and lumbar spine. Insights into the etiopathogenesis of spinal degeneration.
Study design Descriptive epidemiologic study about magnetic resonance imaging findings in the spine. Objectives To describe the prevalence of magnetic resonance imaging findings in a general population at spinal levels T6-S1, and to examine the relationships of these findings within each spinal level and between levels. Summary of background data The prevalence of specific findings and the associations between findings and spinal levels can provide general insights into the etiopathogenesis of spinal degeneration. Methods Subjects consisted of 232 men from a population sample (mean age 49.3 years). Signal intensity, disc bulging, disc herniation, and endplate irregularities were among 11 fi…