Waist circumference and BMI cut-off based on 10-year cardiovascular risk: evidence for "central pre-obesity"

The objective was to assess the waist circumference (WC) cut-off point that best identifies a level of 10-year cardiovascular disease (CVD) risk with optimal balance of sensitivity and specificity in Chinese subjects according to their predicted 10-year CVD risk.

A community-based cross-sectional observational study involving 14,919 Hong Kong Chinese subjects. The 10-year CVD risk based on various prediction models was calculated. The projected WC cut-off points were then determined.

There were 4837 (32.4%) men and 10,082 (67.6%) women (mean age +/- standard deviation, 47.3 +/- 13.5 years; age range, 18 to 93 years; median age, 45.0 years). The mean optimal WC or BMI predicting a 15% to 30% 10-year CVD risk were 83 to 88 cm and 25 kg/m(2) for men, and 76 cm and 23 kg/m(2) for women, respectively. With WC >or=90 cm in men and >or=80 cm in women, the likelihood ratio at various WC cut-off points to develop a >or=20% 10-year CVD risk is 1.5 to 2.0 in men and 3.0 in women. The likelihood ratio was 1.5 in men with WC at 84 cm and in women at 70 cm.

Our results agree with the present guidelines on the definition of general and central obesity in Asia-Pacific regions. We propose the creation of an intermediate state of high WC, the "central pre-obesity" for Chinese men with WC >or=84 to 90 cm (>or=33 to 36 inches) and women with WC >or=74 to 80 cm (>or=29 to 32 inches). People with central pre-obesity, similar to those with overweight (BMI >or=23 to 25 kg/m(2)), already have an increased risk of co-morbidities.