genomic control (GC) in the Stage 1 analysis (i.e. divided by the median of all χ2 statistics for each study) to eliminate any remaining over dispersion before combining the GWAS in the meta-analysis. In Stage 1, we conducted a fixed effect meta-analysis using the inverse variance weighted method implemented in the program METAL5. We performed a second GC correction of the Stage 1 meta-analysis results (lambda = 1.136) before selecting SNPs for follow-up.
