Blood pressure control and anthropometric differences in afro-descendants and other ethnic groups in hypertensive Brazilian populations

Abstract

Background: The prevalence of hypertension (HT) and blood pressure (BP) control varies among ethnic-racial groups, but studies on this issue and correlations between BP and body mass index (BMI) in the black Brazilian population are scarce.

Methods: Cross-sectional study in individuals included in the First Brazilian Hypertension Registry. Relationships between variables were analysed by a binary logistic regression analysis.

Results: The study evaluated 2.191 (82.9%) non-Afro-descendant participants and 452 (17.1%) Afro-descendants. The median age was 61.9 years (55.3% women), the BMI was 28.4 kg/m² and the waist circumference (WC) was 93 cm in the former cohort. In the Afro-descendant group, the median age was 62.5 years (57.5% women), the was BMI 29.8 kg/m² and the was WC 98 cm. A significant correlation was identified between BMI and office diastolic BP (DBP) (R = 0.126; p = 0.007) in Afro-descendants. These individuals had 1.40 times the chance of being obese compared to those of other ethnicities (95% CI: 1.14–1.72; p < 0.001). Afro-descendant men had 0.78 times fewer chance of being obese compared to women (95% CI: 0.66–0.90; p = 0.002), and 1.49 times higher chance (95% CI = 1.21–1.82; p < 0.001) of having uncontrolled BP, with no differences with Afro-descendant women (HR 0.91; 95% CI = 0.78–1.07; p < 0.258).

Conclusion: No correlations were found between office BP, BMI and WC, except for a very weak correlation between DBP and BMI in the Brazilian Afro-descendants, although they were 1.40 times more likely to be obese. In contrast, a significant correlation between SBP and BMI was observed in the non-Afro-descendants. Differences in blood pressure control were not identified between the sexes within each group, but only between ethnic groups, with people of African descent having a 1.49 times greater risk of uncontrolled hypertension compared to non-Afro-descendants.