Impedancemetry vs. anthropometry in the prediction of body adiposity and obesity diagnosis

Abstract

Background and aim:  Many Bioelectrical impedance analysis (BIA)-based parameters require clinical evaluation. This study was performed to evaluate the relationships between some BIA-based parameters and anthropometric parameters for obesity diagnosis. Methodology: A total of 358 male subjects aged from 19-63 were enrolled in a cross sectional study. The anthropometric measures included weight, height, body mass index (BMI), waist circumference, hip circumference and waist hip ratio. InBody 720 was used to calculate the fat mass, fat mass index (FMI), percent body fat, visceral fat area (VFA), and other related measures. Results: Fat mass index had stronger positive correlation with BMI than percent body fat (r=0.9161 vs. r=0.7516, P<0.00001), and VFA was positively correlated with waist circumference (r=0.692, P<0.00001). Kappa analysis showed that BMI was highly related to FMI, especially when using BMI with Asian cutoff values (27.5 kg/m2) (k=0.671 vs. k=0.560, P<0.00001). The ROC curve indicated that FMI was accurate in the diagnosis of obesity (AUC= 0.970). The FMI cutoff value with the best sensitivity and specificity (89% and 95%, respectively) was 9.20 kg/m2. The VFA cut point of the best sensitivity and specificity (81% and 91%, respectively) was 129.45 cm2. Conclusion: FMI is a better predictor of obesity than percent body fat and its cut off point is 9.20 kg/m2. Furthermore, VFA is a good predictor of central obesity, and its cut off point is 129.45 cm2