Body composition measurement in young children using quantitative magnetic resonance: a comparison with air displacement plethysmography

Abstract

Background: Quantitative magnetic resonance (QMR) has been increasingly used to measure human body composition, but its use and validation in children is limited. Objective: We compared body composition measurement by QMR and air displacement plethysmography (ADP) in preschool children from Singapore's multi-ethnic Asian population (n = 152; mean ± SD age: 5.0 ± 0.1 years). Methods: Agreements between QMR-based and ADP-based fat mass and fat mass index (FMI) were assessed using intraclass correlation coefficient (ICC), reduced major axis regression and Bland–Altman plot analyses. Analyses were stratified for the child's sex. Results: Substantial agreement was observed between QMR-based and ADP-based fat mass (ICC: 0.85) and FMI (ICC: 0.82). Reduced major axis regression analysis suggested that QMR measurements were generally lower than ADP measurements. Bland–Altman analysis similarly revealed that QMR-based fat mass were (mean difference [95% limits of agreement]) −0.5 (−2.1 to +1.1) kg lower than ADP-based fat mass and QMR-based FMI were −0.4 (−1.8 to +0.9) kg/m2 lower than ADP-based FMI. Stratification by offspring sex revealed better agreement of QMR and ADP measurements in girls than in boys. Conclusions: QMR-based fat mass and FMI showed substantial agreement with, but was generally lower than, ADP-based measures in young Asian children.