Anthropometry and body composition in northern Asian Indian patients with type 2 diabetes: Receiver operating characteristics (ROC) curve analysis of body mass index with percentage body fat as standard

Aims: To determine the anthropometric profile and appropriate cut off of body mass index (BMI) to define obesity in Asian Indians with Type 2 diabetes mellitus (T2DM). Methods: Three hundred and eighty T2DM patients (213 males and 167 females) in northern India were subjected to anthropometric and body fat analysis (derived from skinfold thickness). The latter was considered as "standard" for defining obesity. Receiver Operating Characteristics (ROC) curves were drawn for males and females to determine the appropriate limits of BMI to define obesity. Results: Mean values of percentage of body fat (%BF) were 40.2±6.2% and 29.4±7.1% in females and males, respectively. Of particular note, substantial percentage of patients had high values of waist-hip ratio (W-HR) [males >0.95 (53.9%), and females >0.80 (88.6 %)] indicating significant abdominal obesity, and high %BF [males >25% BF (73.2%), females >30% BF (92.2%)] indicating generalized obesity as well. Significantly higher prevalence of obesity was observed in both males (p<0.001) and females (p<0.001) when estimated by %BF (males >25%, females >30%), as compared to BMI (>25 kg/m² in both males and females). ROC curve analysis showed that with %BF taken as the 'standard' for determining obesity, sensitivity and specificity of BMI of >25 kg/m² were low. For BMI >22 kg/m² in males and >23 kg/m² in females, sensitivity increased and there was decrease in overall misclassification. Conclusions: The data of current study suggest strikingly high prevalence of abdominal obesity, and generalized obesity as determined by %BF in T2DM patients, and that cut offs for defining obesity by BMI are lower than the suggested limit of 25 kg/m². Revised definition of obesity using lower cut off of BMI, or based on %BF in northern Asian Indian T2DM patients will lead to a more rational application of dietary restriction, lifestyle measures, and use of metformin.