Discriminating glucose tolerance status by regions of interest of dual-energy X-ray absorptiometry - Clinical implications of body fat distribution

OBJECTIVE - To determine whether measuring body fat distribution by dual-en ergy X-ray absorptiometry (DEXA) can be used to discriminate glucose tolera nce status. RESEARCH DESIGN AND METHODS - Using a 75-g oral glucose tolerance test, a t otal of 1,015 Chinese subjects (559 men and 456 women) were categorized as having normal glucose tolerance (NGT), impaired glucose tolerance (IGT), or diabetes. Blood pressure and lipid profiles of these subjects were measure d. Waist-to-hip ratio (WHR) and DEXA were used to evaluate the varying patt erns of body fat distribution among the groups, RESULTS - Body fat distribution, as reflected by WHR and the centrality ind ex, showed significant partial correlation coefficients with glycosylated h emoglobin, blood pressure, and lipid profiles in all subjects. After adjust ing for age and BMI, there were significant differences among the three gly cemic groups for all the cardiovascular risk Factors except for total chole sterol level. The diabetic group had a significantly higher WHR and central ity index, but lower femoral fat percentage than the NGT and IGT groups. Th e diabetic group also showed higher abdominal fat percentage than the NGT g roup. Moreover, the IGT group had a higher centrality index than the NGT gr oup. However, no significant differences were found in the percentage of le an tissue mass among the three groups. Using multiple stepwise logistic reg ression models, the centrality index remained a significant factor for disc riminating different glucose tolerance status independent of the percentage total body fat. CONCLUSIONS - Central obesity has shown significant correlation with cardio vascular risk factors among the three different glycemic groups. Centrality index measured by DEXA appears to be the better predictor of glucose intol erance, compared with WHR, abdominal fat, and general obesity (reflected by percentage total body fat or BMI) in a large cohort of the Chinese populat ion.