Stringent quality control measures were applied to the summary statistics for each GWAS cohort before combining. All files were checked for data integrity and accuracy. SNPs were filtered from further analysis if they met any of the following criteria: imputation quality (INFO/R2) score < 0.6, Hardy-Weinberg equilibrium (HWE) P < 5×10−6, study-specific minor allele frequency (MAF) corresponding to a minor allele count (MAC) < 100, and mismatch of alleles or allele frequency difference greater than 20% from the Haplotype Reference Consortium (HRC) genome reference panel16. Some cohorts used more stringent criteria (see Supplementary Information 1.1). Indels and SNPs that were duplicated, multi-allelic, monomorphic, or ambiguous (A/T or C/G with a MAF >0.4) were also excluded. Visual inspection of the distribution of the summary statistics was completed, and Manhattan plots and QQ plots were created for the cleaned summary statistics from each cohort (Supplementary Figure 1).
