For ALSPAC, phenotypic (including outcome and covariate) and genetic data were available for N=3683 individuals, all of European ancestry. GWAS was run in Plink 1.9 (Chang et al., 2015). For S4S, we included only groups with N>=400 to reduce the likelihood of spurious results, yielding the following sample sizes: African (AFR)=892; American (AMR)=408; and European (EUR)=2356 (total S4S N=3656). The S4S GWAS were run in SNPTest version 2.5.2 (Marchini et al., 2007), separately by ancestry group, as described previously. Results across samples (total N=7339) were meta-analyzed using METAL (Willer et al., 2010), using inverse variance weighting by sample size. Markers with MAF<0.01 within sample/ancestry group and/or INFO<0.5 were excluded from further analysis.
