origin (168 were in the European ancestry and 3 in the African ancestry clusters). We excluded other population groups from the association analysis. Association tests for AA and EA population groups were performed separately. Principal components analysis (PCA) was performed on the 186 AIMs for each population. The first PCA dimension was used in the subsequent association tests as a covariate to correct for the residual population structure. SNPs for which data were available for less than 95% of the subjects, or for which the P value for Hardy–Weinberg equilibrium was less than 10−7, were excluded from further analysis. The minor allele frequency (MAF) of each SNP was calculated within each population in each association test for different traits. SNPs with MAF < 5% in a population were removed from the association tests for the trait in that population.
