Assessment of body composition in Sri Lankan children: validation of a bioelectrical impedance prediction equation

• Published in: European journal of clinical nutrition 2008-10, Vol.62 (10), p.1170-1177
• Main Authors: Wickramasinghe, V.P, Lamabadusuriya, S.P, Cleghorn, G.J, Davies, P.S.W
• Format: Article
• Language: English
• Subjects: accuracy; Adipose Tissue - metabolism; Adolescent; Algorithms; Analysis; bioelectrical impedance; Bioelectricity; Biological and medical sciences; Body composition; Body Composition - physiology; Body fat; Body Fat Distribution - methods; Body Height - physiology; Body water; Body Water - metabolism; body weight; Body Weight - physiology; boys; Child; Child, Preschool; Children; Children & youth; Clinical Nutrition; Dilution; Electric Impedance; Epidemiology; equations; Fat-free body mass; Feeding. Feeding behavior; Female; Fundamental and applied biological sciences. Psychology; gender differences; girls; Health aspects; height; Humans; Impedance; Independent variables; Internal Medicine; Isotope dilution method; Male; Mathematical analysis; measurement; Medical sciences; Medicine; Medicine & Public Health; Metabolic Diseases; Minority & ethnic groups; model validation; Multiple regression analysis; Muscle, Skeletal - metabolism; Obesity; Obesity - diagnosis; Obesity - epidemiology; original-article; Population studies; Populations; Predictions; Predictive Value of Tests; Public Health; Reproducibility of Results; Root-mean-square errors; school children; Scientific method; Sensitivity and Specificity; Sri Lanka - epidemiology; Statistical analysis; Statistics; Variance; Vertebrates: anatomy and physiology, studies on body, several organs or systems; Water in the body; Weight
• ISSN: 0954-3007; 1476-5640
• DOI: 10.1038/sj.ejcn.1602835

Objective: To develop bioelectrical impedance analysis (BIA) equations to predict total body water (TBW) and fat-free mass (FFM) of Sri Lankan children. Subjects/Methods: Data were collected from 5- to 15-year-old healthy children. They were randomly assigned to validation (M/F: 105/83) and cross-validation (M/F: 53/41) groups. Height, weight and BIA were measured. TBW was assessed using isotope dilution method (D2O). Multiple regression analysis was used to develop preliminary equations and cross-validated on an independent group. Final prediction equation was constructed combining the two groups and validated by PRESS (prediction of sum of squares) statistics. Impedance index (height2/impedance; cm2 omega), weight and sex code (male=1; female=0) were used as variables. Results: Independent variables of the final prediction equation for TBW were able to predict 86.3% of variance with root means-squared error (RMSE) of 2.1 l. PRESS statistics was 2.1 l with press residuals of 1.2 l. Independent variables were able to predict 86.9% of variance of FFM with RMSE of 2.7 kg. PRESS statistics was 2.8 kg with press residuals of 1.4 kg. Bland Altman technique showed that the majority of the residuals were within mean bias1.96 s.d. Conclusions: Results of this study provide BIA equation for the prediction of TBW and FFM in Sri Lankan children. To the best of our knowledge there are no published BIA prediction equations validated on South Asian populations. Results of this study need to be affirmed by more studies on other closely related populations by using multi-component body composition assessment.