Genetic bottlenecks, perceived racism, and hypertension risk among AfricanAmericans and first-generation African immigrants

The complexity of factors influencing the development of hypertension (HTN) in African Americans has given rise to theories suggesting that genetic ch anges occurred due to selection pressures/genetic bottleneck effects (ie, c onstriction of existing genetic variability) over the course of the slave t rade. Ninety-nine US-born and 86 African-born health professionals were com pared in a cross-sectional survey examining genetic and psychosocial predic tors of HTN, We examined the distributions of three genetic loci (G-protein , AGT-235, and ACE VD) that have been associated with increased HTN risk, T here were no significant differences between US-born African Americans and African-born immigrants in the studied genetic loci or biological variables (eg, plasma renin and angiotensin converting enzyme activity), except that the AGT-235 homozygous T genotype was somewhat more frequent among African -born participants than US-born African Americans, Only age, body mass inde x, and birthplace consistently demonstrated associations with HTN status, T hus, there was no evidence of a genetic bottleneck in the loci studied, ie, that US-born African Americans have different genotype distributions that increase their risk for HTN. In fact, some of the genotypic distributions e videnced lower frequencies of HTN-related alleles among US-born African Ame ricans, providing evidence of European admixture, The consistent finding th at birthplace (ie, US vs Africa) was associated with HTN, even though it wa s not always significant, suggests potential and unmeasured cultural, lifes tyle, and environmental differences between African immigrants and US-born African Americans that are protective against HTN.