Physical activity attenuates genetic effects on BMI: Results from a study of Chinese adult twins

Early-life residential green spaces and traffic exposure in association with young adult body composition: a longitudinal birth cohort study of twins

BACKGROUND

Globally, the rapid increase of obesity is reaching alarming proportions. A new approach to reduce obesity and its comorbidities involves tackling the built environment. Environmental influences seem to play an important role, but the environmental influences in early life on adult body composition have not been thoroughly investigated. This study seeks to fill the research gap by examining early-life exposure to residential green spaces and traffic exposure in association with body composition among a population of young adult twins.

METHODS

As part of the East Flanders Prospective Twin Survey (EFPTS) cohort, this study included 332 twins. Residential addresses of the mothers at time of birth of the twins were geocoded to determine residential green spaces and traffic exposure. To capture body composition, body mass index, waist-to-hip ratio (WHR), waist circumference, skinfold thickness, leptin levels, and fat percentage were measured at adult age. Linear mixed modelling analyses were conducted to investigate early-life environmental exposures in association with body composition, while accounting for potential confounders. In addition, moderator effects of zygosity/chorionicity, sex and socio-economic status were tested.

RESULTS

Each interquartile range (IQR) increase in distance to highway was found associated with an increase of 1.2% in WHR (95%CI 0.2-2.2%). For landcover of green spaces, each IQR increase was associated with 0.8% increase in WHR (95%CI 0.4-1.3%), 1.4% increase in waist circumference (95%CI 0.5-2.2%), and 2.3% increase in body fat (95%CI 0.2-4.4%). Stratified analyses by zygosity/chorionicity type indicated that in monozygotic monochorionic twins, each IQR increase in land cover of green spaces was associated with 1.3% increase in WHR (95%CI 0.5-2.1%). In monozygotic dichorionic twins, each IQR increase in land cover of green spaces was associated with 1.4% increase in waist-circumference (95%CI 0.6-2.2%).

CONCLUSIONS

The built environment in which mothers reside during pregnancy might play a role on body composition among young adult twins. Our study revealed that based on zygosity/chorionicity type differential effects of prenatal exposure to green spaces on body composition at adult age might exist.

Genetic Pathways Underlying Individual Differences in Regular Physical Activity

Twin and family studies show a strong contribution of genetic factors to physical activity (PA) assessed by either self-report or accelerometers. PA heritability is around 43% across the lifespan. Genome-wide association studies have implied biological pathways related to exercise ability and enjoyment. A polygenic score based on genetic variants influencing PA could help improve the success of intervention programs.

Genetic and Environmental Influences on Vigorous Exercise in South Korean Adolescent and Young Adult Twins

Twin studies of physical exercise for Asian twins are sparse. This study aimed to examine genetic and environmental influences on frequency of vigorous exercise (FVE) in South Korean twins, with a special emphasis on sex effects. Telephone interviews on FVE were administered to 1757 twins (mean age = 19.05 years, SD = 3.01 years). Tetrachoric correlations were significantly different between monozygotic (MZ) and dizygotic (DZ) twins in males (.40 vs. .12), but they were similar in females (.44 vs. .45), suggesting the importance of genetic factors in FVE in males and that of common environmental factors in females. A scalar sex-limitation model incorporating age as a modifier was applied to data. The results revealed that genetic, common and individual environmental influences did not vary significantly with age, but differed across two sexes, confirming twin correlational analyses. In the best-fitting model, additive genetic and individual environmental influences on FVE were, respectively, .35 (95% CI [.26, .39]) and .65 (95% CI [.61, .74]) in males, and common and individual environmental influences were, respectively, .45 (95% CI [.35, .53]) and .55 (95% CI [.47, .65]) in females. These results contrasted starkly with recent findings from a large sample of Chinese adult twins (age >18 years), in which most variance (≥95%) of vigorous physical activity was attributable to common environmental influences in both sexes. Replications in other Asian samples are clearly needed.

Early high-fat feeding improves histone modifications of skeletal muscle at middle-age in mice

The purpose of the present study was to investigate how the effects of high-fat diet feeding on the skeletal muscle persisted during aging using mice. Post-weaned male mice were fed a high-fat diet between 1- and 3-mo-old followed by return to supply a normal diet until 13-mo-old. Monthly physical tests demonstrated that age-related glucose intolerance that was generally developed after 10-mo-old in the control mice was significantly improved in mice fed a high-fat diet. Interestingly, mRNA expressions of Pdk4, Ucp3, and Zmynd17 were up-regulated by high-fat feeding and persisted in the tibialis anterior muscle until 13-mo-old. At Pdk4 and Ucp3 loci, enhanced distributions of active histone modifications were noted in the high-fat-fed mice at 13-mo-old. In contrast, age-related accumulation of histone variant H3.3 at these loci was suppressed. These results indicated that epigenetic modifications caused by early nutrition mediated the changes in skeletal muscle gene expression during aging.

The Chinese National Twin Registry: A Unique Data Source for Systems Epidemiology of Complex Disease

The Chinese National Twin Registry (CNTR), initiated in 2001, has now become the largest twin registry in Asia. From 2015 to 2018, the CNTR continued to receive Chinese government funding and had recruited 61,566 twin-pairs by 2019 to study twins discordant for specific exposures such as environmental factors, and twins discordant for disease outcomes or measures of morbidity. Omic data, including genetics, genomics, metabolomics, and proteomics, and gut microbiome will be tested. The integration of omics and digital technologies in public health will advance our understanding of precision public health. This review introduces the updates of the CNTR, including study design, sample size, biobank, zygosity assessment, advances in research and future systems epidemiologic research.

The Chinese National Twin Registry: a 'gold mine' for scientific research

The Chinese National Twin Registry (CNTR) currently includes data from 61 566 twin pair from 11 provinces or cities in China. Of these, 31 705, 15 060 and 13 531 pairs are monozygotic, same-sex dizygotic and opposite-sex dizygotic pairs, respectively, determined by opposite sex or intrapair similarity. Since its establishment in 2001, the CNTR has provided an important resource for analysing genetic and environmental influences on chronic diseases especially cardiovascular diseases. Recently, the CNTR has focused on collecting biologic specimens from disease-concordant or disease-discordant twin pairs or from twin pairs reared apart. More than 8000 pairs of these twins have been registered, and blood samples have been collected from more than 1500 pairs. In this review, we summarize the main findings from univariate and multivariate genetic effects analyses, gene-environment interaction studies, omics studies exploring DNA methylation and metabolomic markers associated with phenotypes. There remains further scope for CNTR research and data mining. The plan for future development of the CNTR is described. The CNTR welcomes worldwide collaboration.

5-2-1-0 Lifestyle risk factors predict obesity in Millennials

The Making Effective Nutritional Choices Generation Y (MENU GenY) study is a web-based intervention trial aimed at improving food choices in those aged 21-30 years. We report baseline levels of the 5-2-1-0 healthy lifestyle patterns to predict a body mass index (BMI) ≥30 vs <30 kg m^-2 . Overall, 1674 young adults (69% female) from two large health systems enroled and completed an online survey asking questions about lifestyle habits. A multivariable binary logistic regression model was utilized to predict a BMI ≥30 while controlling for known predictors of obesity. Consuming >3 daily servings of fruits/vegetables (odds ratio, OR = 0.90, 95% confidence interval, CI = 0.81, 0.99), and reporting >2.5 hours/week of vigorous physical activity (OR = 0.93, 95% CI = 0.89-0.96, P < 0.001) was associated with a BMI <30. Conversely, time sitting (OR = 1.07, 95% CI = 1.04, 1.11) and consuming sugar-sweetened beverages (OR = 1.08, 95% CI = 1.00, 1.15) were related to a BMI ≥30. In this cohort of 20-30-year-olds, we observed a consistent relationship between obesity and the 5-2-1-0 healthy lifestyle patterns previously reported among children and adolescents.

Variation in the Heritability of Child Body Mass Index by Obesogenic Home Environment

Importance

The early obesogenic home environment is consistently identified as a key influence on child weight trajectories, but little research has examined the mechanisms of that influence. Such research is essential for the effective prevention and treatment of overweight and obesity.

Objective

To test behavioral susceptibility theory's hypothesis that the heritability of body mass index (BMI) is higher among children who live in more obesogenic home environments.

Design, Setting, and Participants

This study was a gene-environment interaction twin study that used cross-sectional data from 925 families (1850 twins) in the Gemini cohort (a population-based prospective cohort of twins born in England and Wales between March and December 2007). Data were analyzed from July to October 2013 and in June 2018.

Exposures

Parents completed the Home Environment Interview, a comprehensive measure of the obesogenic home environment in early childhood. Three standardized composite scores were created to capture food, physical activity, and media-related influences in the home; these were summed to create an overall obesogenic risk score. The 4 composite scores were split on the mean, reflecting higher-risk and lower-risk home environments.

Main Outcomes and Measures

Quantitative genetic model fitting was used to estimate heritability of age-adjusted and sex-adjusted BMI (BMI SD score, estimated using British 1990 growth reference data) for children living in lower-risk and higher-risk home environments.

Results

Among 1850 twins (915 [49.5%] male and 935 [50.5%] female; mean [SD] age, 4.1 [0.4] years), the heritability of BMI SD score was significantly higher among children living in overall higher-risk home environments (86%; 95% CI, 68%-89%) compared with those living in overall lower-risk home environments (39%; 95% CI, 21%-57%). The findings were similar when examining the heritability of BMI in the separate food and physical activity environment domains.

Conclusions and Relevance

These findings support the hypothesis that obesity-related genes are more strongly associated with BMI in more obesogenic home environments. Modifying the early home environment to prevent weight gain may be particularly important for children genetically at risk for obesity.

From forensic epigenetics to forensic epigenomics: broadening DNA investigative intelligence

Human genetic variation is a major resource in forensics, but does not allow all forensically relevant questions to be answered. Some questions may instead be addressable via epigenomics, as the epigenome acts as an interphase between the fixed genome and the dynamic environment. We envision future forensic applications of DNA methylation analysis that will broaden DNA-based forensic intelligence. Together with genetic prediction of appearance and biogeographic ancestry, epigenomic lifestyle prediction is expected to increase the ability of police to find unknown perpetrators of crime who are not identifiable using current forensic DNA profiling.

Running training experience attenuates disuse atrophy in fast-twitch skeletal muscles of rats

Responsiveness to physiological stimuli, such as exercise and muscular inactivation, differs in individuals. However, the mechanisms responsible for these individual differences remain poorly understood. We tested whether a prior experience of exercise training affects the responses of skeletal muscles to unloading. Young rats were assigned to perform daily running training with a treadmill for 8 wk. After an additional 8 wk of normal habitation, the rats were hindlimb unloaded by tail suspension for 1 wk. Fast-twitch plantaris, gastrocnemius, and tibialis anterior muscles did not atrophy after unloading in rats with training experience, although soleus muscle lost weight similar to sedentary rats. We also analyzed the transcriptome in plantaris muscle with RNA sequencing followed by hierarchical clustering analysis and found that a subset of genes that were generally upregulated in sedentary rats after unloading were less responsive in rats with training experience. The distribution of histone 3 was diminished at the loci of these genes during the training period. Although the deposition of histone 3 was restored after an additional period of normal habitation, the incorporation of H3.3 variant was promoted in rats with training experience. This remodeling of nucleosomes closely correlated to the conformational changes of chromatin and suppressed gene expression in response to unloading. These results suggest that exercise training stimulated the early turnover of histone components, which may alter the responsiveness of gene transcription to physiological stimuli.NEW & NOTEWORTHY The present study demonstrates that disuse atrophy was suppressed in fast-twitch skeletal muscles of rats with training experience in early life. We also found a subset of genes that were less responsive to unloading in the muscle of rats with training experience. It was further determined that exercise training caused an early turnover of nucleosome components, which may alter the responsiveness of genes to stimulus in later life.