Visceral fat and prevalence of hypertension among African Americans and Hispanic Americans: Findings from the IRAS family study

BACKGROUND We examined the relationship between visceral adipose tissue (VAT), independent of overall adiposity, and prevalent hypertension among adults enrolled in the Insulin Resistance Atherosclerosis (IRAs) Family Study. We also examined the role of insulin sensitivity (S,) upon hypertension. This was a cross-sectional epidemiological study in which African-American and Hispanic-American families were recruited from three clinical sites. The main outcome measure was prevalent hypertension, as defined by standardized protocol. METHODS The relationship between VAT and prevalent hypertension was examined in adjusted marginal models among 1,582 participants. All continuous variables were standardized. RESULTS A significant VAT by gender interaction prompted separate analyses for VAT according to gender. Further adjustment for S, was performed to determine its potential roles in the VAT-hypertension relationship. The mean age (s.d.) of the sample was 41.3 (13.8) years, with a mean body mass index (BMI) (s.d.) of 28.7 (6.0) kg/m(2). Women comprised 58.5% of the sample (N= 925), and Hispanic Americans comprised 69.2% of the sample (N= 1,095). One in five participants (21.2%) had prevalent hypertension. In women,VAT was significantly associated with hypertension, independent of BMI (odds ratio (OR) = 1.49, P = 0.006). African-American women demonstrated increased odds of prevalent hypertension compared to Hispanic-American women (OR = 3.08, P < 0.001). Among men,VAT was not associated with hypertension independent of BMI, and BMI explained a significant amount of the variation in hypertension. CONCLUSIONS A significant relationship may exist between VAT and hypertension among women, but not among men. The relationship between VAT and hypertension in women was not associated with insulin resistance.