Background: It is expected that the number of people with diabetes will reach 435 million by 2030. Obesity is considered the most important predictor of type 2 diabetes mellitus (T2DM). We conducted the present study to determine the best usual discriminator indices of obesity to diagnose diabetes mellitus (DM).
Methods: Of 6143 subjects aged 10-90 years from a baseline cohort study, the data of 5772 participants aged >18 years and without history of type 1 diabetes were utilized to analyze in this study. The cohort study was carried out in northern Iran and sampling frame was provided from related local health centers. The capability of obesity indices, including body mass index (BMI), waist circumference (WC), waist-to-hip ratio (WHR), and body adiposity index (BAI), in the discrimination of DM was evaluated. Discriminatory capabilities were evaluated using the receiver operating characteristic (ROC) curve. Logistic regression analysis was performed to determine the strength of association between obesity indices and DM.
Results: The areas under ROC curve of BAI, BMI, WC, and WHR were 0.6244 (0.5918-0.6570), 0.6214 (0.5908-0.6520), 0.6636 (0.6341-0.6930), and 0.7303 (0.7032-0.7575) in men and 0.5961 (0.5674-0.6249), 0.5963 (0.5690-0.6235), 0.6850 (0.6593-0.7108), and 0.7529 (0.7297-0.7761) in women, respectively. In the multivariate model, one unit increase in Z-score of BMI, WC, and WHR increased the chance of DM by 49%, 65%, and 51% in men and by 17%, 51%, and 67% in women, respectively. No association was found between DM and BAI in this model.
Conclusions: While WHR had an appropriate discriminatory capability for T2DM in the population of northern Iran, BAI and BMI did not.