Risk of diabetes in relation to fat distribution: the Asian region experience

Abstract

Asians appear to be more susceptible to diabetes, with nearly halfof the global diabetic population being found in China, India,Japan, Bangladesh and Indonesia. This has been attributed to thehigher percentage body fat in Asians, compared to age-, gender-and BMI-matched Caucasians, and a higher visceral fat andvisceral/subcutaneous fat ratio for the same waist circumference(WC). These observations have led to the proposal of Asian-specific cut-off values of BMI and WC, for the definition ofoverweight/obesity and central obesity, respectively. WC or waist-hip-ratio, as a marker of central obesity, predicts the developmentof diabetes in Asians, with a better or additive performance, rela-tive to BMI, a measure of general obesity. Visceral but not subcu-taneous adiposity, as estimated by CT scan, independently predictsincident diabetes, likely consequent to the augmented hepaticinflux of free fatty acids, and more pronounced disturbances inadipokine expression/action which impact on inflammation andinsulin sensitivity, lipid and glucose metabolism. Thus circulatinglevels of adipokines, such as low adiponectin or high TNF-α levels,or inflammatory markers like C-reactive protein, predict the devel-opment of diabetes in Asian populations. Alternately, increasedvisceral adiposity may be another manifestation of ectopic fatdeposition occurring secondary to increased energy storage,adipocyte hypertrophy, adipose tissue dysfunction and inflamma-tion, and insulin resistance, but nonetheless contributing to thevicious cycle. Lifestyle measures to reduce excessive adiposity arejust as effective in reducing diabetes development in Asians, as inthe more obese Caucasian populations.