We found no differences in model effects when controlling for the PC1 scale or when we restricted models to only those with PC1-identified European ancestry; that is, we found little evidence for population stratification in either case. Additionally, given the correlation between GABRA2 genotype and gender, we also ran TVEM analyses controlling for Gender, Gender x GABRA2 TT, and Gender x Intervention age-varying interaction effects. Our pattern of results was replicated, suggesting that our G x I results are robust to gender differences.
