Biogeographic ancestry, self-identified race, and admixture-phenotype associations in the Heart SCORE Study

Large epidemiologic studies examining differences in cardiovascular disease (CVD) risk factor profiles between European Americans and African Americans have exclusively used self-identified race (SIR) to classify individuals. Recent genetic epidemiology studies of some CVD risk factors have suggested that biogeographic ancestry (BGA) may be a better predictor of CVD risk than SIR. This hypothesis was investigated in 464 African Americans and 771 European Americans enrolled in the Heart Strategies Concentrating on Risk Evaluation (Heart SCORE) Study in March and April 2010. Individual West African and European BGA were ascertained by means of a panel of 1,595 genetic ancestry informative markers. Individual BGA varied significantly among African Americans and to a lesser extent among European Americans. In the total cohort, BGA was not found to be a better predictor of CVD risk factors than SIR. Both measures predicted differences in the presence of the metabolic syndrome, waist circumference, triglycerides, body mass index, very low density lipoprotein cholesterol, lipoprotein A, and systolic and diastolic blood pressure between European Americans and African Americans. These results suggest that for most nongenetic cardiovascular epidemiology studies, SIR is sufficient for predicting CVD risk factor differences between European Americans and African Americans. However, higher body mass index and diastolic blood pressure were significantly associated with West African BGA among African Americans, suggesting that BGA should be considered in genetic cardiovascular epidemiology studies carried out among African Americans.