The analysis was conducted using the 688 890 SNPs that passed quality control filters previously described. The first two components from the MDS analysis identified clearly separated clusters that correlate with self-reported ethnicity identification. The first two MDS components distinguished African American from European American participants and others and the second component distinguished Hispanic and non-Hispanic subjects. To reduce population stratification, we removed all individuals who described themselves as White/Caucasian in the association analyses (n=7). Both components were used to adjust for any remaining population stratification in the association analyses.
