Appropriate anthropometric indices to identify cardiometabolic risk in South Asians.

BACKGROUND South Asians show an elevated cardiometabolic risk compared to Caucasians. They are clinically metabolically obese but are considered normal weight based on current international cut-off levels of several anthropometric indices. This study has two main objectives: (i) to predict the most sensitive anthropometric measures for commonly studied cardiometabolic risk factors, and (ii) to determine optimal cut-off levels of each of the anthropometric indices in relation to these cardiometabolic risk factors in South Asians. METHODS The study was conducted on a random sample of 1178 adults of 20-80 years of age from an urban population of eastern India. Obesity, as evaluated by standard anthropometric indices of BMI (body mass index), WC (waist circumference), WHpR (waist-to-hip ratio) and WHtR (waist-to-height ratio), was individually correlated with cardiometabolic risk factors. Receiver operating characteristic (ROC) curve analyses were performed which includes: (i) the area under the receiver operating characteristic curve (AUROC) analysis to assess the predictive validity of each cardiometabolic risk factor; and (ii) Youden index to determine optimal cut-off levels of each of the anthropometric indices. RESULTS Overall, AUROC values for WHtR were the highest, but showed variations within the sexes for each of the cardiometabolic risk factors studied. Further, WHpR cut-offs were higher for men (0.93-0.95) than women (0.85-0.88). WC cut-offs were 84.5-89.5 cm in men and 77.5-82.0 cm in women. For both sexes the optimal WHtR cut-off value was 0.51-0.55. The optimal BMI cut-offs were 23.4-24.2 kg/m2 in men and 23.6-25.3 kg/m2 in women. CONCLUSION WHtR may be a better anthropometric marker of cardiometabolic risks in South Asian adults than BMI, WC or WHpR.