[The cut-off point of waist circumference for identifying metabolic syndrome in Chinese adults].

OBJECTIVE: Metabolic syndrome has attracted more attention from scientists of related areas due to its association with increased risk of cardiovascular disease and diabetes. The clinical identification criteria for metabolic syndrome issued by ATP III of NECP indicate the enlarged waist as the first component using the cut-offs derived from Caucasians. The purpose of this study is to investigate the appropriate cut-offs of waist circumference for Chinese adults as a component of metabolic syndrome.

METHODS: Database of 13732 Chinese adults with 35 - 59 years from the risk factor survey in 1998 (the 9(th) Five Year National Project on trends and prediction of cardiovascular disease) was used to analyze the ORs of clustering of risk components by different strata of waist circumference. The sensitivity, specificity and distance in ROC curve by different cut-offs of waist circumference for identifying two or more risk components of metabolic syndrome were estimated to find the cut-off point for men and women with the shortest distance in ROC curve.

RESULTS: The ORs of clustering of risk components increased significantly with the size of waist circumference. The waist circumference (>/= 85 cm for men, >/= 80 cm for women) corresponded to the shortest distance in ROC curve, namely, at these cut-offs, the rates of false positive and false negative for identifying clustering of two or more risk components were the minimum.

CONCLUSIONS: If a person had three or more of the following components, metabolic syndrome could be defined: waist circumference >/= 85 cm in men or >/= 80 cm in women, SBP >/= 130 mm Hg or DBP >/= 85 mm Hg, TG >/= 1.69 mmol/L, HDL-C < 1.03 mmol/L and fasting blood glucose >/= 6.1 mmol/L. The prevalence of metabolic syndrome was 19.3% and 13.9% in middle-aged men and women respectively. In these patients the combination of enlarged waist, high blood pressure and high TG was the most frequent. This recommendation need further confirmed in representative sample of Chinese population.