Following study-specific quality control measures (Supplementary Table 2), all contributing GWAS common SNPs were imputed using the HapMap phase II CEU reference panel for European-descent studies37, and CEU+YRI+CHB+JPT HapMap release 22 for the African-American and Hispanic GWAS. Directly genotyped (GWAS and Metabochip) and imputed variants (GWAS only) were then tested for association with the inverse normally transformed BMI residuals using linear regression assuming an additive genetic model. Quality control following study level analyses was conducted following procedures outlined elsewhere38.
