Waist Body Mass Index Outperforms Other Anthropometric Indicators in Identifying Obesity Using Bioimpedance

Abstract

Background: While the body mass index (BMI) has been widely used to diagnose overweight and obesity, other anthropometric mark-ers, such as waist circumference (WC), waist-to-height ratio (WHtR), among others, have been proposed as alternative diagnostic measures for obesity. The objective was to determine which anthropometric marker has the best diagnostic accuracy for obesity. Methods: This was a diagnostic test study with the primary analysis in workers of an occupational clinic located in Lima, Peru. The percentage of fat measured by bioimpedance was used as the reference test. The WC, BMI, WHtR, tri-ponderal mass index, new BMI, Clinica Universidad de Navarra-Body Adiposity Estimator (CUN-BAE), and waist BMI (wBMI) were evaluated. Receiver operating characteristic (ROC) curve analysis was used as a statistical and graphical method to assess predictive capacity, as well as the area under the curve (AUC) corresponding to each response variable. Sensitivity and specificity, with their 95% confidence intervals (95% CIs), were calculated. Results: In our study on obesity according to the percentage of fat, 780 participants were included. The overall prevalence of obesity was 19.74%. Regarding the diagnostic test analysis, the measure with the highest accuracy in women was wBMI: AUC = 0.783 (95% CI: 0.735-0.830), sensitivity = 71.59% (95% CI: 60.98-80.69), and specificity = 74.54% (95% CI: 69.45-79.18). For men, the measure with the highest accuracy was wBMI: AUC = 0.828 (95% CI: 0.779-0.878), sensitivity = 89.39% (95% CI: 79.36-95.62), and specificity = 58% (95% CI: 52.19-63.65). Conclusions: Our study concludes that wBMI proved to be a superior tool for diagnosing obesity compared to conventional measures such as BMI, WC, WHtR, and other evaluated anthropometric metrics.