Body composition measured by bioelectrical impedance analysis is a viable alternative to magnetic resonance imaging in children with non-alcoholic fatty liver disease.

OBJECTIVE Determine the relationship between BIA and MRI-obtained measures of body composition in children with NAFLD. METHODS Obese youth with NAFLD were included in this study. Patients had both bioelectrical impedance (BIA) and abdominal magnetic resonance imaging (MRI). BIA measured skeletal muscle mass (SMM), appendicular lean mass (ALM), trunk muscle mass (TMM) and percent body fat. MRI measured total psoas muscle surface area (tPMSA) and fat compartments. Univariate analysis described the relationship between BIA and MRI-derived measurements. Multivariable regression analyses built a model with body composition measured via MRI. RESULTS 115 patients (71% male; 33% Hispanic) with median age 14 years were included. There was a strong correlation between tPMSA and SMM, ALM, trunk muscle mass (correlation coefficients [CC]: 0.701, 0.689, 0.708, respectively; all p<0.001). Higher SMM, ALM, and TMM were associated with higher tPMSA. This association remained after controlling for age, sex, ethnicity, Type 2 Diabetes Mellitus (T2DM) status, and Body Mass Index (BMI) z-score. Total fat mass by BIA and MRI-determined total fat area, subcutaneous and intra-peritoneal fat area correlated significantly (CC: 0.813, 0.808, 0.515, respectively; all p<0.001). In univariate regression, higher total fat mass by BIA was associated with increased total fat area and increased fat in each of the four regions measured by MRI. After controlling for confounders, the association between total fat mass by BIA and total fat area by MRI persisted. CONCLUSIONS BIA measures of muscle and fat mass correlate strongly with MRI measures of tPMSA and fat areas in obese children with NAFLD. This article is protected by copyright. All rights reserved.