Criteria for central obesity in a brazilian population: impact on the metabolic syndrome

Abstract

Objective: To identify and propose the optimal waist circumference cut-off points (WCp) for the diagnosis of central obesity (CO) in a Brazilian population, so as to compare these cut-off points with those recommended by the ATPIII (WC-ATPIII), and to estimate the difference in prevalence rates of metabolic syndrome (MS) using the two criteria. Methods: Cross-sectional study conducted in a population subgroup of 1439 adults in the city of Salvador, Brazil. ROC curves of WC were plotted to identify diabetes mellitus (DM) and obesity. ROC curve sensitivity and specificity values ≥60% and the closest to each other were used to define WCp. The prevalence of MS was estimated using WCp and WC-ATPIII. Results: Eight hundred and twenty nine women comprised 57.7% of the sample. The WCp selected were 84cm for women and 88cm for men. These cut-off points detected DM with a 68.7% and 70% sensitivity, and a 66.2% and 68.3% specificity, respectively. For obesity, sensitivity and specificity were 79.8% and 77.6% in women and 64.3% and 71.6% in men, respectively. Using WC-ATPIII, 88cm (for women) and 102cm (for men), the sensitivity was 53.3% and 26.5%, respectively, to diagnose DM. For obesity, sensitivity was 66.5% (for women) and 28.6% (for men). The prevalence of MS using WCp was 23.7%, 95%CI (21.6 – 25.9), whereas using WC-ATPIII it was 19.0%, 95%CI (17.1- 20.9), 1.2 times higher using WCp. Conclusion: WC-ATPIII were inappropriate and underestimated the prevalence of MS in the population studied, particularly among men. We suggest that the WC cut-off points > 84cm for women and > 88cm for men should be tested in other Brazilian populations.