Optimum Cut-Off Points of Waist Circumference for Identifying Metabolic Syndrome in Shanghai Adults of 35-74 Years of Age

[Objective] To determine the optimum cut-off points of waist circumference(WC) for assessing obesityassociated metabolic syndrome in Shanghai adults of 35-74 years old. [Methods] A cross-sectional study was conducted in Shanghai with a representative sample of 7 414 Chinese adults aged 35-74 years using multistage random sampling technique. The WC levels associated with at least 2 risk factors of metabolic syndrome with proper susceptibility and specificity were identified in the two gender groups. [Results] With waist circumference increasing, the odd ratios(OR) of clustering of risk factors increased significantly, the specificity and positive predictive values of association with≥2 risk factors also elevated, but related sensitivity and negative predictive values were lowered. When the WC levels were ≥85 cm for male and ≥80 cm for female, the sensitivity values of association with ≥2 risk factors were 68.33%(male) and 70.17%(female), while the specificity values were 58.48%(male) and 58.36%(female) respectively. These points showing the shortest distances(0.522 1 for male and 0.512 2 for female) in the receiver operating characteristic curves were elected as the cut-off points for the two gender groups in the studied population. [Conclusion] WC≥85 cm for male and ≥80 cm for female can well reflect the margin of metabolic syndrome associated risk factors cluster, and serve as the optimum cut-off points for identifying obesity-associated metabolic syndrome in the studied residents.