Data analysis of the effects of exercise during adolescence and young adulthood on body composition of females

Objectives: While it is generally accepted that exercise can decrease adiposity and improve health, the relationship between physical activity (PA) during childhood/adolescence and corresponding behaviors during young adulthood and their associations with adiposity during young adulthood have not been adequately assessed. Data from the Dietary Intervention Study in Children (DISC) and the DISC06 Follow-Up Study were utilized to investigate associations between PA during late childhood/adolescence and young adulthood with young adult body composition. Methods: Physical activity (MET-hrs/wk in moderate and intense physical activities) was assessed by questionnaire at 5 clinic visits during youth when participants were 7-18 years old and at age 25-29 years. Overall adiposity (primary outcome) and central adiposity (secondary outcome) were assessed at 25-29 years by percent body fat (%fat) and android-to-gynoid (A:G) fat ratio, respectively, measured by whole body dual x-ray absorptiometry (DXA). Analysis was conducted utilizing linear mixed models. Generalized linear latent effects and mixed models also were used to assess associations of the latent variable, childhood PA, with both %fat and A:G fat ratio. Results: PA during young adulthood was significantly inversely associated with %fat during young adulthood ([beta]=-0.17 per 10 MET-hrs/wk, p=0.02). Adjusted for physical activity and other covariates in young adulthood, the latent variable childhood PA was significantly inversely associated with %fat during young adulthood, both with and without adjusting for childhood BMI ([beta]=-0.40 per 10 MET-hrs/wk, p=0.02 ; [beta]=-0.41 per 10 MET-hrs/wk, p=0.02 respectively). No significant associations between PA and A:G fat ratio were observed. Conclusions: Results suggests that PA during adolescence is an important predictor of %fat during young adulthood and may have an impact on reducing the burden of chronic disease later in life due to overweight and obesity. More research must be done to determine the physiological changes responsible for this association.