Differences in air displacement plethysmography, bioelectrical impedance analysis and dual‐energy X‐ray absorptiometry for estimating body composition in Chinese children and adolescents

Abstract

This study aimed to compare body composition (BC) measurements obtained by three widely used BC measuring methods, air displacement plethysmography (ADP), bioelectrical impedance analysis (BIA) and dual-energy X-ray absorptiometry (DXA), in Chinese children and adolescents by sex and different BMI categories. Methods: We used three BC measuring methods to evaluate healthy Chinese children and adolescents aged 5-17 years with BMI categories ranging from underweight to obese. Fat mass (FM, kg), fat mass percentage (FMP, %), fat-free mass (FFM, kg) and appendicular skeletal muscle mass (ASM, kg) were measured by DXA, BIA and ADP on the same day within 1 h. Results: A total of 172 Chinese children and adolescents were included in this study. The agreements for FM, FFM and ASM estimated by the three methods were excellent or good at the population level (intraclass correlation coefficient > 0.850, P < 0.05). However, ADP or BIA estimated lower body fat content and higher FFM than DXA (P < 0.001 for all). Moreover, the precise estimates significantly varied across BMI categories. In addition, the limit of agreements was wide, and the differences might not be clinically acceptable at the individual level. Conclusions: Body fat and FFM obtained by the three commonly used methods were highly correlated, but systematically different and influenced by BMI. This study provided a basis for mutual reference of measurements between three widely used methods.

Assessment of Body Fat Percentage in Emirati Females: A Comparative Analysis of BIA vs DXA

“…Variations in BIA results are in uenced by differences in device parameters, including the path of the electrical current, electrode con guration, participant positioning, frequency settings, and speci c equations used (13). Another factor contributing to variability in BIA measurements is its susceptibility to bias in populations with altered hydration levels, such as during fasting, pregnancy, medication intake, and obesity.…”

“…DXA assessments are rapid, noninvasive, and entail minimal inconvenience for patients, further enhancing its appeal in clinical practice and research (12). However, despite its advantages, DXA does have drawbacks, including the requirement for expensive specialized radiology equipment, small radiation exposure, and the need for trained technicians, which may limit its feasibility in routine clinical practice (12,13).…”

“…BIA, a two-compartment model, operates under the assumption of constant FFM density. However, signi cant water uctuations during growth and development can lead to inaccuracies in body composition measurements (13). Other factors including device type, water distribution, hydration status, weight, and height, may increase the risk of inaccurately assessing FFM (6, 16).…”

“…Other factors including device type, water distribution, hydration status, weight, and height, may increase the risk of inaccurately assessing FFM (6, 16). BIA is safe, simple, non-invasive, and cost-effective, making it increasingly popular for evaluating body composition in clinical and research settings (12,13,17,18) It has emerged as a popular alternative to DXA for assessing body composition (9). BIA's advantages, such as portability, affordability, minimal training requirements, and lack of radiation exposure, make it a practical option for assessing body composition in both clinical practice and large-scale epidemiological studies (15,16,(19)(20)(21).…”