Body Mass Index as a Measure of Percentage Body Fat Predictionand Excess Adiposity Diagnosis among Iranian Adolescents

BACKGROUND: Although various anthropometric methods are available for assessing body composition, these have not been compared in Iranian adolescents. The objective of the present study was to compare body mass index (BMI), waist circumference (WC), waist to hip ratio (WHR), waist to height ratio (WHtR) and sum of four skinfolds as predictors of percentage body fat (PBF) and diagnosis of excess adiposity in Iranian adolescents. METHODS: In this cross-sectional study, all anthropometric measurements were made in133 adolescents (65 boys and 68 girls), aged 10–18 years.PBF was determined using the bioelectrical impedance analysis method. Linear regression and receiver operating characteristic (ROC) analysis were used to analyze the data. Potential covariates including sex, age, and pubertal stage were adjusted. RESULTS: R2adj of models for BMI, WC, WHR, WHtR, and skinfolds were 0.67, 0.56, 0.19, 0.56, and 0.56, respectively (P < 0.001). The AUC value of BMI to differentiate between normal and obese adolescents was 0.92 (P < 0.001). The AUC of BMI was significantly higher than those of WC, WHR, and WHtR (P < 0.05). CONCLUSIONS: The performance of BMI is better than other anthropometric indices in predicting PBF and diagnosing excess adiposity in Iranian adolescents.