Comparison of anthropometric and body composition measures as predictors of components of the metabolic syndrome in a clinical setting.

PROBLEM: The use of body mass index (BMI) to assess obesity and health risks has been criticized in scientific and lay publications because of its failure to account for body shape and inability to distinguish fat mass from lean mass. We sought to determine whether other anthropometric measures (waist circumference (WC), waist-to-height ratio (WtH), percent body fat (%BF), fat mass index (FMI), or fat-free mass index (FFMI)) were consistently better predictors of components of the metabolic syndrome than BMI is.

METHODS: Cross-sectional measurements of height, weight, waist circumference and percent body fat were obtained from 12,294 adults who took part in annual physical exams provided by EHE International, Inc. Blood pressure was measured during the exam and HDL, LDL, and fasting glucose were measured from blood samples. Pearson correlations, linear regression, and adjusted Receiver Operator Characteristic (ROC) curves were used to relate each anthropometric measure to each metabolic risk factor.

RESULTS: None of the measures was consistently the strongest predictor. BMI was the strongest predictor of blood pressure, measures related to central adiposity (WC and WtH) performed better at predicting fasting glucose, and all measures were roughly comparable at predicting cholesterol levels. In all, differences in areas under ROC curves were 0.03 or less for all measure/outcome pairs that performed better than BMI.

CONCLUSION: Body mass index is an adequate measure of adiposity for clinical purposes. In the context of lay press critiques of BMI and recommendations for alternative body-size measures, these data support clinicians making recommendations to patients based on BMI measurements.