Validation of two portable bioelectrical impedance analyses for the assessment of body composition in school age children.
BACKGROUND
Bioelectrical impedance analysis (BIA) is a convenient and child-friendly method for longitudinal analysis of changes in body composition. However, most validation studies of BIA have been performed on adult Caucasians. The present cross-sectional study investigated the validity of two portable BIA devices, the Inbody 230 (BIA8MF) and the Tanita BC-418 (BIA8SF), in healthy Taiwanese children.


METHODS
Children aged 7-12 years (72 boys and 78 girls) were recruited. Body composition was measured by the BIA8SF and the BIA8MF. Dual X-ray absorptiometry (DXA) was used as the reference method.


RESULTS
There were strong linear correlations in body composition measurements between the BIA8SF and DXA and between the BIA8MF and DXA. Both BIAs underestimated fat mass (FM) and percentage body fat (%BF) relative to DXA in both genders The degree of agreement in lean body mass (LBM), FM, and %BF estimates was higher between BIA8MF and DXA than between BIA8SF and DXA. The Lin's concordance correlation coefficient (ρc) for LBM8MF met the criteria of substantial to perfect agreement whereas the ρc for FM8MF met the criteria of fair to substantial agreement. Bland-Altman analysis showed a clinically acceptable agreement between LBM measures by BIA8MF and DXA. The limit of agreement in %BF estimation by BIA and DXA were wide and the errors were clinically important. For the estimation of ALM, BIA8SF and BIA8MF both provided poor accuracy.


CONCLUSIONS
For all children, LBM measures were precise and accurate using the BIA8MF whereas clinically significant errors occurred in FM and %BF estimates. Both BIAs underestimated FM and %BF in children. Thus, the body composition results obtained using the inbuilt equations of the BIA8SF and BIA8MF should be interpreted with caution, and high quality validation studies for specific subgroups of children are required prior to field research.
Department of Diagnostic Radiology, Chang Gung Memorial Hospital, Chiayi, Taiwan.|Department of Nursing, Chang Gung University of Science and Technology, Chiayi Campus, Chiayi, Taiwan.
Li-Wen
LW
Lee
Department of Diagnostic Radiology, Chang Gung Memorial Hospital, Chiayi, Taiwan.|Department of Nursing, Chang Gung University of Science and Technology, Chiayi Campus, Chiayi, Taiwan.
Yu-San
YS
Liao
Sport Science Research Center, National Taiwan University of Sport, Taichung, Taiwan.
Hsueh-Kuan
HK
Lu
Department of Diagnostic Radiology, Chang Gung Memorial Hospital, Chiayi, Taiwan.
Pei-Lin
PL
Hsiao
Department of Physical Education, National Taiwan University of Sport, Taichung, Taiwan.|Department of Cosmetic Application and Management, St. Mary's Junior College of Medicine, Nursing and Management, Yilan, Taiwan.
Yu-Yawn
YY
Chen
Department of Dermatology, Chang Gung Memorial Hospital, Linkou, Taiwan.|Department of Dermatology, Chang Gung Memorial Hospital, Chiayi, Taiwan.|College of Medicine, Chang Gung University, Taoyuan, Taiwan.
Ching-Chi
CC
Chi
Office of Physical Education and Sport, National Chung Hsing University, Taichung, Taiwan.|Research Center, Charder Electronic Co, Ltd, Taichung, Taiwan.
Kuen-Chang
KC
Hsieh
D015502:Absorptiometry, Photon; D001823:Body Composition; D002648:Child; D003430:Cross-Sectional Studies; D017097:Electric Impedance; D005260:Female; D006801:Humans; D008297:Male; D015203:Reproducibility of Results