Lower hypertension prevalence in first-generation African immigrants compared to US-born African Americans

Both genetic and environmental factors have been hypothesized to explain the higher prevalence of hypertension in US African Americans compared to populations still residing in western Africa. Studies of first-generation immigrants can help to identify risk factors for increased chronic disease expression in the developed world. Since we could identify no prior studies of hypertension in African immigrants to the United States, we conducted a cross-sectional survey of African-born and US-born African-American health professionals to compare the two groups for the prevalence of hypertension (blood pressure > or = 140/90 mm Hg or use of antihypertensive medication) and risk factors for hypertension (body mass index, lifestyle factors, and psychosocial variables hypothesized to relate to hypertension). Subjects were registered pharmacists and nurses recruited by mail. For the 182 individuals who completed study measurements (95 US-born and 87 African-born), the unadjusted odds ratio for hypertension associated with birthplace was 2.16 (95% CI = 1.12, 3.98). After adjustment for body mass index and age, the OR for birthplace was 1.92 (95% CI = 0.92, 4.00). No lifestyle or psychosocial variables were associated with hypertension prevalence. We conclude that there is a lower prevalence of hypertension in first-generation African immigrants that cannot be readily explained by the environmental effects measured in this study. Larger scale studies with African immigrants could advance understanding of the causes of the increased hypertension prevalence in US-born African Americans.