Study objectives: Brazil has a high admixture of Blacks and Whites, making it possible to compare the prevalence of hypertension among Blacks, Whites, and Mulattos.
Design: A population-based health and nutrition survey was carried out in 1996 in the city of Rio de Janeiro, Brazil. Blood pressure, weight, height, food frequency information, and skin color were obtained from a sample of 2,802 private household residents aged 20 years or older.
Main outcome measure: Hypertension was defined as systolic blood pressure >140 mm Hg and/or diastolic pressure >90 mm Hg or the use of antihypertensive medication.
Results: The prevalence of hypertension among men was 12.0% among Whites, 13.8% among Mulattos, and 14.4% for Blacks. For women, these prevalences were 12.0%, 16.4%, and 20.2%, respectively. After adjustment for age, calcium and salt intake, physical activity level, body mass index, and waist-hip ratio, we observed (among women only) a trend toward increasing prevalence of hypertension with increasing skin darkness. The adjusted odds ratio of hypertension was 1.52 for Mulatto women compared to Whites and 2.27 for Blacks compared to Whites (P<.05). With further adjustment for income, the odds ratios were reduced to 1.30 (95% CI 0.86-1.95) and 1.75 (95% CI 1.04-2.94).
Conclusions: Black women showed increased risk of hypertension independent of socioeconomic factors or overweight status.