Ethnic diversity in genetic study cohorts (as is the case for a cohort consisting of US military members or, for that matter, the nation’s population at large) presents both unique challenges and opportunities. On one hand, beyond the mere proportional representation of the diverse US military service men and women, a genetically diverse study sample facilitates identification of trans-ethnic and population-specific causal variants46. On the other hand, genetic predictors trained on a GWAS conducted on a given ancestral group is less predictive in samples from a different ancestral group. As most genetic studies are conducted with European ancestry participants47, the prediction for non-Europeans is more difficult, particularly for African ancestry individuals, as is seen in the present study.
