Search results for " Estimating"

A Critical Review of Statistical Methods for Twin Studies Relating Exposure to Early Life Health Conditions

2021

International audience; When investigating disease etiology, twin data provide a unique opportunity to control for confounding and disentangling the role of the human genome and exposome. However, using appropriate statistical methods is fundamental for exploiting such potential. We aimed to critically review the statistical approaches used in twin studies relating exposure to early life health conditions. We searched PubMed, Scopus, Web of Science, and Embase (2011–2021). We identified 32 studies and nine classes of methods. Five were conditional approaches (within-pair analyses): additive-common-erratic (ACE) models (11 studies), generalized linear mixed models (GLMMs, five studies), gene…

Synchrony Analysis of Unipolar Cardiac Mapping during Ventricular Fibrillation

2014

Ventricular Fibrillation (VF) is one of the main causes of death in developed countries. Recent studies have shown that fibrillation have a complex organization scheme. This work uses three measures of synchrony to characterize three groups of rabbit hearts. These groups consist of rabbits trained with physical exercise (N=7), untrained rabbits treated with a drug (N=13) and a control group of untrained rabbits (N=15). Cardiac mapping records were acquired using a 240-electrode array placed on left ventricle of isolated rabbit hearts, and VF was induced pacing at increasing rates. Two acquisitions were performed: maintained perfusion, and ischemic damage produced by an artery ligation. The …

Model averaging estimation of generalized linear models with imputed covariates

2015

a b s t r a c t We address the problem of estimating generalized linear models when some covariate values are missing but imputations are available to fill-in the missing values. This situation generates a bias-precision trade- off in the estimation of the model parameters. Extending the generalized missing-indicator method proposed by Dardanoni et al. (2011) for linear regression, we handle this trade-off as a problem of model uncertainty using Bayesian averaging of classical maximum likelihood estimators (BAML). We also propose a block model averaging strategy that incorporates information on the missing-data patterns and is computationally simple. An empirical application illustrates our…

Using the dglars Package to Estimate a Sparse Generalized Linear Model

2015

dglars is a publicly available R package that implements the method proposed in Augugliaro et al. (J. R. Statist. Soc. B 75(3), 471-498, 2013) developed to study the sparse structure of a generalized linear model (GLM). This method, called dgLARS, is based on a differential geometrical extension of the least angle regression method. The core of the dglars package consists of two algorithms implemented in Fortran 90 to efficiently compute the solution curve. dglars is a publicly available R package that implements the method proposed in Augugliaro et al. (J. R. Statist. Soc. B 75(3), 471-498, 2013) developed to study the sparse structure of a generalized linear model (GLM). This method, call…

Accounting for dispersion and correlation in estimating Safety Performance Functions. An overview starting from a case study

2013

In statistical analysis of crash count data, as well as in estimating Safety Performance Functions (SPFs), the failure of Poisson equidispersion hypothesis and the temporal correlation in annual crash counts must be considered to improve the reliability of estimation of the parameters. After a short discussion on the statistical tools accounting for dispersion and correlation, the paper presents the methodological path followed in estimating a SPF for urban four-leg, signalized intersections. Since the case study exhibited signs of underdispersion, a Conway-Maxwell-Poisson Generalized Linear Model (GLM) was fitted to the data; then a quasi-Poisson model in the framework of Generalized Estim…

Impact of mobility restrictions on active aging; cross-sectional associations and longitudinal changes parallel to COVID-19 restrictions

2021

Background: Meaningful activities can be done in or around home, but opportunities for participation and active aging decrease when moving in smaller areas. Active aging refers to having an active approach to life in line with one's goals, ability and opportunities. In adults over 75 years with different baseline neighborhood mobility levels, we studied active aging scores two years prior to and amid COVID-19, when governments restricted mobility of residents to slow the COVID-19 outbreak. Methods: AGNES cohort data were collected in 2017-2018 and spring 2020. Individuals were queried about their will, ability, and opportunity, and extent of doing 17 activities, and subsequently, item, comp…

2020

Abstract Background and objectives More knowledge is needed of the effectiveness of complex interventions that aim to promote the wellbeing of older people. This study examines the effects of ‘participatory group-based care management’ conducted among community-dwelling older adults living alone in Central and Eastern Finland. The intervention aimed to promote wellbeing and quality of life (QoL) using a needs-based and participatory approach. Methods The study was carried out as a randomized control trial (intervention group n = 185, control group n = 207). In this article, baseline and 6-month follow-up surveys were used. QoL (WHOQOL-Bref instrument), loneliness (Revised UCLA Loneliness Sc…

Life-Space Mobility and Active Aging as Factors Underlying Quality of Life Among Older People Before and During COVID-19 Lockdown in Finland—A Longit…

2020

Abstract Background Social distancing, that is, avoiding places with other people and staying at home, was recommended to prevent viral transmission during the COVID-19 pandemic. Potentially, reduced out-of-home mobility and lower activity levels among older people may lower their quality of life (QOL). We studied cross-sectional and longitudinal associations of and changes in life-space mobility, active aging, and QOL during COVID-19 social distancing compared to 2 years before. Methods Altogether 809 community-living participants initially aged 75, 80, or 85 years of our active aging study (AGNES) conducted in 2017–2018 took part in the current AGNES-COVID-19 survey in May and June 2020. …

Dietary magnesium intake is inversely associated with mortality in adults at high cardiovascular disease risk

2013

The relation between dietary magnesium intake and cardiovascular disease (CVD) or mortality was evaluated in several prospective studies, but few of them have assessed the risk of all-cause mortality, which has never been evaluated in Mediterranean adults at high cardiovascular risk. The aim of this study was to assess the association between magnesium intake and CVD and mortality risk in a Mediterranean population at high cardiovascular risk with high averagemagnesium intake. The present study included 7216 men and women aged 55-80 y fromthe PREDIMED (Prevencíon con Dieta Mediterŕanea) study, a randomized clinical trial. Participants were assigned to 1 of 2 Mediterranean diets (supplemente…

Effects of comprehensive geriatric assessment-based individually targeted interventions on mobility of pre-frail and frail community-dwelling older p…

2014

Aim To assess the effects of comprehensive geriatric assessment (CGA)-based individually targeted interventions on the ability to walk 400 m in pre-frail or frail and non-frail community-dwelling older people. Methods A subgroups analysis of a population-based comparative study, the Geriatric Multidisciplinary Strategy for the Good Care of the Elderly (GeMS) was carried out in the city of Kuopio, Finland, from 2004 to 2007. This study was based on data from 2005 to 2007. The present analysis included 605 community-dwelling older adults aged ≥76 years (mean age 80.9, 70% women), 314 in the intervention and 291 in the control group. Frailty status was assessed in 2005. Mobility was assessed b…