Are race differences in the prevalence of hypertension explained by body mass and fat distribution? A survey in a biracial population.

Body mass and body fat distribution are important considerations in the study of hypertension. However, few studies have investigated the relationships with regards to race differences in elevated arterial pressure. A population-based sample of black and white adults was assessed by interview and physical measurement. The prevalence of hypertension (defined as 140/90 mmHg and/or medically treated) was disproportionately higher among blacks than whites. In addition, blacks had a higher prevalence of the more severe hypertension (160/95 mmHg) and hypertension with higher prevalence at earlier ages than whites. Black females had a significantly higher distribution of body mass index (BMI) than white females, while no difference was found in the distributions of males. White males had a higher distribution of waist to hip ratio (WHR) than black males, while black females had the higher values compared to white females. The prevalence of hypertension increased with BMI and WHR. Blacks maintained higher rates of hypertension after controlling for BMI and WHR, however, the margin of difference diminished when BMI and WHR was considered together. The black-white difference in hypertension was not completely explained by BMI and WHR. In addition, the strength of the association of hypertension and body size was different for blacks and whites which suggests possible differences in the mechanisms regulating blood pressure.