among two subgroups characterized as being of either European (74.3%; N = 1,399) or African ancestry (25.7%; N = 485) (refer to the section on GWAS genotyping for more detail). Twenty-one individuals did not cluster with either of the two groups and were excluded from analysis. A subset of the subjects (N = 1,064) had measurements for theta ERO energy available for GWAS analysis (see Figure 2 for overview of research design).
