Body composition of children in south-western Nigeria: validation of bio-electrical impedance analysis.

Bio-electrical impedance analysis (BIA) is a non-invasive method of estimating body composition and has the potential to be useful in clinics and for nutrition and health-related research in Africa. We sought to validate BIA for use among a Yoruba population in south-western Nigeria and to use BIA to assess the body composition of a healthy cohort of children. Total body water (TBW) was measured in 92 individuals (53 adults and 39 children) using deuterium dilution; height, weight and resistance were measured by BIA. Multiple regression analysis was used to develop prediction equations for TBW among children only or among all participants. Independent covariates tested in the regression models included the impedance index (height(2)/resistance), weight, age and gender with TBW as the dependent variable. Depending on the model used, between 97% (root MSE=0.7 kg ) and 99% (root MSE=0.7 kg) of the variance observed in TBW could be explained by the impedance index, weight and/or gender; age, however, was not significant in any model. In a separate cohort of 69 children, 5-8 years old, anthropometrics were measured and TBW was estimated using the developed equations. Body composition data are presented by gender and age group. BIA was validated for use among Nigerian children and adults and provides a potentially important tool for research.