Air Displacement Plethysmography, Dual-Energy X-ray Absorptiometry, and Total Body Water to Evaluate Body Composition in Preschool-Age Children

Abstract

Anthropometrics and body mass index are only proxies in the evaluation of adiposity in the pediatric population. Air displacement plethysmography technology was not available for children aged 6 months to 9 years until recently. Our study was designed to test the precision of air displacement plethysmography (ADP) in measuring body fat mass in children at ages 3 to 5 years compared with a criterion method, deuterium oxide dilution (D2O), which estimates total body water and a commonly used methodology, dual-energy x-ray absorptiometry (DXA). A prospective, cross-sectional cohort of 66 healthy children (35 girls) was recruited in the central Arkansas region between 2007 and 2009. Weight and height were obtained using standardized procedures. Fat mass (%) was measured using ADP, DXA, and D2O. Concordance correlation coefficient and Bland-Altman plots were used to investigate the precision of the ADP techniques against D2O and DXA in children at ages 3 to 5 years. ADP concordance correlation coefficient for fat mass was weak (0.179) when compared with D2O. Bland-Altman plots revealed a low accuracy and large scatter of ADP fat mass (%) results (mean=−2.5, 95% CI −20.3 to 15.4) compared with D2O. DXA fat mass (%) results were more consistent although DXA systematically overestimated fat mass by 4% to 5% compared with D2O. Compared with D2O, ADP does not accurately assess percent fat mass in children aged 3 to 5 years. Thus, D2O, DXA, or quantitative nuclear magnetic resonance may be considered better options for assessing fat mass in young children.