Assessment of body composition in Sri Lankan children: validation of a bioelectrical impedance prediction equation
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Updated: Jul 13, 2026
Assessment of Child Anthropometry in a Large Epidemiologic Study
Published on: February 2, 2017
V P Wickramasinghe1, S P Lamabadusuriya, G J Cleghorn
1Department of Paediatrics, Faculty of Medicine, University of Colombo, Colombo, Sri Lanka.
Insights
New bioelectrical impedance analysis (BIA) equations accurately predict total body water (TBW) and fat-free mass (FFM) in Sri Lankan children. These validated equations offer crucial insights into body composition for this specific population.
Area of Science:
- Human Physiology
- Biomedical Engineering
- Anthropometry
Background:
- Accurate body composition assessment is vital for pediatric health monitoring.
- Existing bioelectrical impedance analysis (BIA) equations may not be universally applicable, especially in diverse ethnic populations.
- There is a need for population-specific BIA equations to reliably estimate total body water (TBW) and fat-free mass (FFM).
Purpose of the Study:
- To develop and validate bioelectrical impedance analysis (BIA) equations for predicting total body water (TBW) and fat-free mass (FFM) in Sri Lankan children.
- To provide a reliable and accessible method for assessing body composition in this demographic.
- To address the lack of validated BIA prediction equations for South Asian populations.
Main Methods:
- Data from 5- to 15-year-old healthy Sri Lankan children were collected.
- Children were divided into validation and cross-validation groups.
- Multiple regression analysis was used, with impedance index, weight, and sex as predictors; TBW was measured using isotope dilution (D2O).
Main Results:
- The final BIA equations predicted 86.3% of TBW variance (RMSE 2.1 L) and 86.9% of FFM variance (RMSE 2.7 kg).
- PRESS statistics confirmed the predictive accuracy for both TBW and FFM.
- Bland Altman analysis indicated good agreement between predicted and measured values.
Conclusions:
- The developed BIA equations are effective for predicting TBW and FFM in Sri Lankan children.
- This study provides the first validated BIA prediction equations for a South Asian population.
- Further validation with multi-component body composition methods in related populations is recommended.
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 (D(2)O). 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 (height(2)/impedance; cm(2)/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 bias+/-1.96 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.
