What is the optimal anthropometric index/ratio associated with two key measures of cardio-metabolic risk associated with hypertension and diabetes?

Few studies have investigated the optimal anthropometric index associated with potential cardio-metabolic risk. Using direct measures of standing height, body mass, and waist circumference, we sought to identify the optimal index for detecting cardio-metabolic risk associated with diabetes and hypertension in a nationally representative sample of US adults. Complete (non-missing) cross-sectional data from 8375 US adults aged 18–80+ years were obtained from the 2015–16 and 2017–March 2020 (pre-pandemic) cycles of the National Health and Nutrition Examination Survey. The cardio-metabolic risk was identified using blood pressure and glycohemoglobin (A1c). Allometric models were used to identify the optimal anthropometric indices associated with cardio-metabolic risk. Receiver operating characteristics curves were used to verify the discriminatory ability of the identified index in comparison with other anthropometric measures. The optimal anthropometric index associated with cardio-metabolic risk was waist circumference divided by body mass to the power of 0.333 (WC/M0.333). The ability for this new index to discriminate those with diabetes (area under the ROC curve: 0.73 [95%CI: 0.71–0.74]) and hypertension (area under the curve: 0.70 [95%CI: 0.69–0.72]) was superior to all other anthropometric measure/indices investigated in this study (body mass index, waist circumference, waist-to-height ratio, and waist/height0.5). We identified WC/M0.333 as the optimal anthropometric index for identifying US adults with hypertension and diabetes. Instead of using body mass index (kg/m2), we recommend using WC/M0.333 in clinical and public health practice to better identify US adults at potential cardio-metabolic risk associated with hypertension and diabetes.