Revised optimal cut-off point of waist circumference for the diagnosis of metabolic syndrome in Japanese women and the influence of height.

Aim: We reevaluated waist circumference as a diagnostic criterion of metabolic syndrome (MetS) in Japanese.
Methods: We enrolled 5,571 subjects (3,148 men and 2,423 women) who had health check-ups in our center. The criterion was reevaluated using the positive predictive value of a receiver-operating characteristics (ROC) curve at 10 different hypothesized lengths of waist circumference with or without a cluster of risk factors. We also drew ROC curves based on the atherosclerotic findings of clinical examinations.
Results: Based on the ROC curves, the optimal waist circumference cut-off was 85 cm in men and 80 cm in women. Using this 80 cm cut-off point in women, misdiagnosis rates of MetS were lowered (-19.1--56.6%) compared to the cut-off point currently in use. Integrating the influence of height, namely by using a waist-to-height(2) ratio, misdiagnosis rates in shorter populations were decreased in both men and women.
Conclusion: These data suggested an optimal waist circumference cut-off to improve the diagnostic probability of MetS in Japanese women of 80 cm, as well as the utility of an easily detected anthropometric index such as a waist-to-height (cm x 100/cm) or waist-to-height(2) (cm x 10,000/cm(2)) ratio, determined as 51 in men and 52 in women, or 30 in men and 33 in women, respectively.