40 research outputs found
FTO genotype and weight loss: systematic review and meta-analysis of 9563 individual participant data from eight randomised controlled trials
Objective
To assess the effect of the FTO genotype on weight loss
after dietary, physical activity, or drug based
interventions in randomised controlled trials.
Design
Systematic review and random effects meta-analysis
of individual participant data from randomised
controlled trials.
Data sources
Ovid Medline, Scopus, Embase, and Cochrane from
inception to November 2015.
Eligibility criteria for study selection
Randomised controlled trials in overweight or obese
adults reporting reduction in body mass index, body
weight, or waist circumference by FTO genotype
(rs9939609 or a proxy) after dietary, physical activity,
or drug based interventions. Gene by treatment
interaction models were fitted to individual participant
data from all studies included in this review, using
allele dose coding for genetic effects and a common
set of covariates. Study level interactions were
combined using random effect models.
Metaregression and subgroup analysis were used to
assess sources of study heterogeneity.
Results
We identified eight eligible randomised controlled trials
for the systematic review and meta-analysis (n=9563).
Overall, differential changes in body mass index, body
weight, and waist circumference in response to weight
loss intervention were not significantly different
between FTO genotypes. Sensitivity analyses indicated
that differential changes in body mass index, body
weight, and waist circumference by FTO genotype did
not differ by intervention type, intervention length,
ethnicity, sample size, sex, and baseline body mass
index and age category.
Conclusions
We have observed that carriage of the FTO minor allele
was not associated with differential change in
adiposity after weight loss interventions. These
findings show that individuals carrying the minor allele
respond equally well to dietary, physical activity, or
drug based weight loss interventions and thus genetic
predisposition to obesity associated with the FTO
minor allele can be at least partly counteracted
through such interventions.
Systematic review registration
PROSPERO CRD42015015969
Diverse aging rates in ectothermic tetrapods provide insights for the evolution of aging and longevity
Comparative studies of mortality in the wild are necessary to understand the evolution of aging; yet, ectothermic tetrapods are underrepresented in this comparative landscape, despite their suitability for testing evolutionary hypotheses. We present a study of aging rates and longevity across wild tetrapod ectotherms, using data from 107 populations (77 species) of nonavian reptiles and amphibians. We test hypotheses of how thermoregulatory mode, environmental temperature, protective phenotypes, and pace of life history contribute to demographic aging. Controlling for phylogeny and body size, ectotherms display a higher diversity of aging rates compared with endotherms and include phylogenetically widespread evidence of negligible aging. Protective phenotypes and life-history strategies further explain macroevolutionary patterns of aging. Analyzing ectothermic tetrapods in a comparative context enhances our understanding of the evolution of aging.Animal science
Genetics in psychosomatic medicine: Research designs and statistical approaches.
It has become increasingly clear that genetic factors influence many of the behaviors and disease endpoints of interest to psychosomatic medicine researchers. There has been increasing interest in incorporating genetic variation markers into psychosomatic research. In this Statistical Corner article, we build on the valuable experiences gained during two workshops for "starters in the field" at the American Psychosomatic Society and the Society for Psychophysiological Research to review two common genetically informative research designs for human studies: twin and genetic association studies. We outline statistical techniques for each and, for genetic association studies, address special topics, including the treatment of race and ethnicity, gene × gene and gene × environment interaction, haplotype analysis, and power and sample size. Finally, we discuss the issue of nonreplication and interpretation of results derived from genetic association studies. We hope this overview of twin and genetic association designs will support and stimulate thoughtful applications of genetic approaches within psychosomatic medicine. Copyright © 2007 by American Psychosomatic Society