Background: Risk for obesity and associated lifelong health consequences begins early in life. Previous research highlights the importance of genetic and environmental contributions to obesity risk, however most studies involve related children reared together.
Objective: Here we utilize a novel sibling adoption design to independently estimate genetic and environmental contributions to obesity in childhood and describe how these influences vary with age.
Methods: As part of a prospective adoption study, we assessed biological siblings reared apart or together, and
nonbiological siblings reared together, using a variance partitioning model to 10estimate the contributions of genetics and environment to BMI in a large cohort (N =711) during middle childhood and adolescence.
Results: Sixty-three and 31% of total variance in BMI was attributed to genetics and common environment, respectively, in middle childhood sibling pairs (age 5-11.99; p<0.01). We detected no influence of genetics or common environment in older sibling pairs (12-18) or pairs age groups, but home type (adoptive versus birth) was an important predictor of BMI in adolescence.
Conclusions: We observed a strong influence of genetics and common environment on BMI in middle childhood, supporting existing evidence that early interventions at the family level could 19effectively mitigate childhood obesity risk.