We used the Add Health “ah_race” variable for self-report ethnicity. This variable includes five categories: White, Black, Native American, Asian and Hispanic. Add Health respondents who self-reported as Hispanic were included in the Hispanic category irrespective of whether they also self-reported as White, Black, etc. Of the 1,886 individuals included in this analysis, there are 917 who self-identify as White, 677 who self-identify as Black, 209 who self-identify as Hispanic, 73 who self-identify as Asian, 8 who self-identify as Native American; 2 individuals have unknown self-identified ethnicity (see table 2). Supplemental figure 3 shows the first 5 principal coordinate (PC) MDS estimates from KING, color-coded by self-identified ancestry. As can be seen in supplemental figure 3A, the first principal coordinate (PC1) distinguishes the European ancestry from African ancestry while the second principal coordinate (PC2) captures variation between European, Asian and to an extent, Hispanic ancestry. In supplemental figure 3B we see variation from Hispanic samples including a small set of self-identified Native American individuals. Supplemental figures 3C and 3D further distinguish between and within self-identified ethnic groups.
