A comparison of body mass index and waist-to-hip ratio as indicators of hypertension risk in an urban Argentine population: a hospital-based study.

BACKGROUND AND AIM: To examine the relationship between 24-h ambulatory blood pressure monitoring (ABPM) and three commonest anthropometric measurements for obesity [body mass index (BMI), waist circumference (WC) and waist-hip ratio (WHR)] in patients with essential hypertension never treated or after a 3 week placebo period, living in Buenos Aires.

METHODS AND RESULTS: Cross-sectional survey among outpatients at the Hypertension Program of Buenos Aires University Hospital de Clinicas. Three-hundred seventy-seven essential hypertensives, aged 18-86 years, of either sex, were consecutively recruited. All subjects underwent 24 h ABPM performed with a blood pressure (BP) device. The prevalence of overweight-obesity was 56.76% in women and 75.86% in men. High WHR prevalence in non-obese women was 4.5% and 4.1% in non-obese men while high values of WC were observed in 3.0% of non-obese women and in 0% of non-obese men. The two-way ANCOVA showed that in women with high values of WHR, 24 h DBP was higher in those with BMI<25 than in those with BMI> or =25. Those females with a BMI> or =25 had a higher prevalence of top tertile values of PP (> or =68 mmHg) (P<0.05) than non-obese females. Only in women was mean pulse pressure (PP) significantly correlated with age (r=0.38; P<0.0001), WC (r=0.22; P<0.005), WHR (r=0.21, P<0.008), and BMI (r=0.20; P<0.01) while in men there was no significant correlation between variables. Logistic regression showed that the odds of morning blood pressure surge (MBPS) increased with age, central obesity (represented by high WHR and dipper status), while the odds of higher mean PP increased with age and high WHR.

CONCLUSION: These results indicated a high prevalence of overweight-obesity (more than 56% of women and 75% of men) in our hospital-based sample of essential hypertension and that the WHR offers additional information beyond BMI and WC to predict the hypertension risk according to the ABPM.