Cross-calibration of multi-frequency bioelectrical impedance analysis with eight-point tactile electrodes and dual-energy X-ray absorptiometry for assessment of body composition in healthy children aged 6–18 years

Background:  In diagnosis and treatment of obesity, body composition analysis including percent body fat (%BF) is useful in the clinical setting. Because bioelectrical impedance analysis (BIA) could be used quickly, easily and was non-invasive in clinical setting, the purpose of the present study was to evaluate the usefulness of multi-frequency BIA with eight-point tactile electrodes (MF-BIA8; InBody 720, Biospace) compared with dual-energy X-ray absorptiometry (DXA) in healthy children and adolescents.
Methods:  A total of 166 children and adolescents under 18 (male, n  = 86; female, n  = 80) were recruited. Height, weight, body mass index (BMI) and Tanner stage were measured for each subject. The body composition such as fat-free mass (FFM), fat mass (FM), and %BF was measured on BIA and DXA and compared.
Results:  On linear regression analysis, DXA FFM = 1.006(BIA FFM) + 0.554, R ² = 0.99 and the standard error of the estimate (SEE) was 1.16 kg; DXA FM = 0.971(BIA FM) – 0.596, R ² = 0.93; SEE, 1.34 kg; and DXA %BF = 0.940(BIA %BF) – 1.026, R ² = 0.858; SEE, 3.03%. Limit of agreement in FFM, FM, and %BF was 0.7 ± 2.3 kg, −0.9 ± 2.9 kg and –2.2 ± 6.1%, respectively.
Conclusions:  Although the %BF was not interchangeable with DXA, MF-BIA8 (InBody 720; Biospace) could be used to measure body composition of children and adolescents in the clinical field because of its high precision.