the index variant was clumped using PRSice-2. PRS was calculated based on effect size (Euesden et al., 2015). To reduce the burden of multiple testing, only variants that had p values <0.05 were included. For SAGE, sex and the same birth cohort as defined in COGA were included as covariates, while for Yale-Penn-AA and OZALC-EA, sex and age were used. The first 3 PCs were also adjusted in AA samples.
