BMI or BIA: Is Body Mass Index or Body Fat Mass a Better Predictor of Cardiovascular Risk in Overweight or Obese Children and Adolescents?

BACKGROUND: Body fat (BF) percentiles for German children and adolescents have recently been published. This study aims to evaluate the association between bioelectrical impedance analysis (BIA)-derived BF and cardiovascular risk factors and to investigate whether BF is better suited than BMI in children and adolescents. METHODS: Data of 3,327 children and adolescents (BMI > 90th percentile) were included. Spearman's correlation and receiver operating characteristics (ROCs) were applied determining the associations between BMI or BF and cardiovascular risk factors (hypertension, dyslipidemia, elevated liver enzymes, abnormal carbohydrate metabolism). Area under the curve (AUC) was calculated to predict cardiovascular risk factors. RESULTS: A significant association between both obesity indices and hypertension was present (all p < 0.0001), but the correlation with BMI was stronger (r = 0.22) compared to BF (r = 0.13). There were no differences between BMI and BF regarding their correlation with other cardiovascular risk factors. BF significantly predicted hypertension (AUC = 0.61), decreased HDL-cholesterol (AUC = 0.58), elevated LDL-cholesterol (AUC = 0.59), elevated liver enzymes (AUC = 0.61) (all p < 0.0001), and elevated triglycerides (AUC = 0.57, p < 0.05), but not abnormal carbohydrate metabolism (AUC = 0.54, p = 0.15). For the prediction of cardiovascular risk factors, no significant differences between BMI and BF were observed. CONCLUSION: BIA-derived BF was not superior to BMI to predict cardiovascular risk factors in overweight or obese children and adolescents.