In instances where multiple SNPs acheived genomewide significance (GWS) in the same region, conditional analyses were performed to identify the lead SNP and to test for the presence of any additional independent signal. For each GWS SNP, we tested the association with the phenotype using age, sex, the first 3 PCs, and each of the other SNPs as covariate. The threshold for statistical significance was 5 × 10−8. Analyses were completed in each sample separately, then meta-analyzed.
