Impact of body mass index on the predictive ability of body fat distribution for Type 2 diabetes risk in Koreans

Abstract

The optimal anthropometric measure of obesity or body fat distribution that best predicts the risk of Type 2 diabetes in Asians is unclear. Moreover, it has not been determined whether BMI modifies the effect of body fat distribution on diabetes risk in Asians. We analysed the anthropometric and laboratory data of 7658 non-diabetic Korean adults (5061 men and 2597 women, aged 20-79 years) who underwent routine medical check-ups at 5-year intervals. BMI, waist circumference, waist-to-height ratio, and bioelectrical impedance (to calculate fat mass and per cent body fat) were measured at baseline. Of the 7658 participants, 278 subjects (3.6%) developed diabetes over 5 years. Each of the anthropometric measures of general obesity (BMI, fat mass, per cent body fat) and central body fat distribution (waist circumference and waist-to-height ratio) was a good predictor of Type 2 diabetes. However, when the areas under the receiver-operating characteristic curves were compared, BMI (0.697; 95% CI, 0.669-0.725), waist circumference (0.709, 0.682-0.736) and waist-to-height ratio (0.718, 0.692-0.743) were better predictors of diabetes risk than fat mass (0.672, 0.643-0.700) or per cent body fat (0.657, 0.628-0.686). In the low- (< 23 kg/m(2)) and mid- (23-27 kg/m(2)) BMI groups, the addition of waist-to-height ratio or waist circumference to BMI could improve the prediction of diabetes risk. BMI, waist circumference and waist-to-height ratio were good predictors of Type 2 diabetes risk in Koreans. In non-obese or less obese subjects, measures of central body fat distribution can help improve the prediction of Type 2 diabetes risk when added to measures of general obesity.