The obesity GRSs were weakly but consistently associated with BMI and the probability of being obese among whites and African Americans, but associations were weaker among African Americans (Figure 1). Among whites, after adjusting for age, sex, and geography, the un-weighted GRS was associated with BMI at r=0.12 and the weighted GRS was associated with BMI at r=0.13 (p<1×10−26 for both). This effect size corresponded to a 0.60 unit increase in BMI per standard-deviation increase in the GRS. For each standard-deviation increase in their un-weighted and weighted GRSs, a white ARIC participant’s risk for obesity increased by 19.35% and 20.51%, respectively (p<1×10−18 for both). Among African Americans, the weighted and un-weighted GRSs were associated with BMI at r=0.05 (p<0.05 for both). For each standard deviation increase in their un-weighted and weighted GRSs, an African American ARIC participant’s risk for obesity increased by 3.54% (p=0.059) and 4.92% (p=0.017), respectively. Results were substantively unchanged when control variables were removed from the models. To determine whether population substructure influenced our estimates of GRS-BMI or GRS-obesity associations, we repeated our analyses of the white
