Education, genetic ancestry, and blood pressure in African Americans and Whites

Abstract

Objectives: We assessed the relative roles of education and genetic ancestry in predicting blood pressure (BP) within African Americans and explored the association between education and BP across racial groups.

Methods: We used t tests and linear regressions to examine the associations of genetic ancestry, estimated from a genomewide set of autosomal markers, and education with BP variation among African Americans in the Family Blood Pressure Program. We also performed linear regressions in self-identified African Americans and Whites to explore the association of education with BP across racial groups.

Results: Education, but not genetic ancestry, significantly predicted BP variation in the African American subsample (b=-0.51 mm Hg per year additional education; P=.001). Although education was inversely associated with BP in the total population, within-group analyses showed that education remained a significant predictor of BP only among the African Americans. We found a significant interaction (b=3.20; P=.006) between education and self-identified race in predicting BP.

Conclusions: Racial disparities in BP may be better explained by differences in education than by genetic ancestry. Future studies of ancestry and disease should include measures of the social environment.

FIGURE 1—

Interaction plots of self-identified race and education: US Family Blood Pressure Program, 1996–2000. Note. AA = African American; SBP = systolic blood pressure. Interaction plots of education × self-identified race, with education divided into less than or equal to a high-school degree, or greater than a high-school degree (a), and separated by gender (b). SBP measures are adjusted for covariates of age, gender, age × gender, and body mass index (defined as weight in kilograms divided by the square of height in meters).