Interplay between genetic risk and built neighborhood conditions as predictor of BMI across the transition into adulthood

Objective:We examined BMI development across changes in the built environment during the transition from adolescence to young adulthood and explored the moderating role of genetic risk.Methods:We used longitudinal data from ages 16 to 25 of the TRacking Adolescents’ Individual Lives Survey (TRAILS) that we linked to built environment data for 2006, 2010, and 2016 from the Geoscience and Health Cohort Consortium. We fitted a latent growth model of BMI and examined associations between changes in fast-food restaurant density and walkability with changes in BMI (n=2735) as well as interactions of changes in fast-food restaurant density and walkability with genetic risk (n=1676).Results:Changes in fast-food restaurant density (e.g., Δ 2010-2006: β=-0.04, 95% CI: -0.11 to 0.03) and walkability (e.g., Δ 2010-2006: β=-0.05, 95% CI: -0.14 to 0.05) were not associated with BMI change. Additionally, genetic risk did not moderate these associations.Conclusions:We found limited evidence that moving to fast-food denser or less walkable neighborhoods was associated with BMI development or that genetic risk moderated these associations. Our findings suggest that associations between the built environment and BMI change during the transition into young adulthood are likely small.