Comparison of waist-to-height ratio and body mass index for prediction of type 2 diabetes mellitus risk in women: Tehran lipid and glucose study

The aim of this study was to determine which indicator of obesity index is the best predictor of type 2 diabetes mellitus in Iranian women. In an urban Iranian population, we examined 2801 females, aged >/= 20 years who were non-diabetic at baseline. Over a median 3.5 year [11months to 6.3y] follow up, we compared the ability of central obesity indicators [waist circumference [WC], waist-to-hip ratio [WHR], waist-to-height ratio [WHtR]] to body mass index [BMI] in the prediction of type 2 diabetes, based on American Diabetes Association 2003 criteria. To estimate odds ratio [OR] of developing diabetes associated with each quartile of anthropometric variables, we used a multivariate model adjusted for age, hypertension, triglycerides, HDL-C, family history of diabetes [model 1] and a full model adjusted for the variables in model [1] plus abnormal glucose tolerance at the baseline [model 2]. Receiver operator characteristic [ROC] analyses were used to determine the predictive power of each indicator in the development of type 2 diabetes, after adjustment for age. During our follow up, 114 individuals developed diabetes [4.1%]. The OR [95% CIs] of developing diabetes increased to 4.8 [2.1-10.9], 6.7 [2.6-17.1], 8.7 [3.0-24.7], 8.0 [3.1-20.6] for the highest quartiles of BMI, WC, WHR and WHtR compared to the lowest quartile in model [1] respectively. In model [2] the ORs [95% CIs] of the fourth quartile of anthropometric variables decreased, compared to value in model [1], but remained significant [BMI: 3.1 [1.3-7.2], WC: 3.1 [1.1-8.3], WHR: 4.0 [1.3-11.8], WHtR: 3.3 [1.2-8.8]]. Compared to BMI, the WHtR had a higher area under ROC curve [0.72 vs 0.69 P < 0.05], while there was no difference between ROCs of BMI and other anthropometric variables In Iranian women, WHtR is a better predictor of type 2 diabetes than BMI