Prediction equations for body composition of children and adolescents aged 8-19 years in Uganda using deuterium dilution as the reference technique.

BACKGROUND AND AIMS

Body composition is important as a marker of both current and future health status. Bioelectrical impedance analysis (BIA) is a simple and accurate method for estimating body composition in field, clinical and research settings, if standard protocol procedures are followed. However, BIA requires population-specific equations since applicability of existing equations to diverse populations has been questioned. This study aimed to derive predictive equations for Total Body Water (TBW), Fat Free Mass (FFM) and Fat Mass (FM) determinations with BIA and anthropometric measurements in a population of children and adolescents aged 8-19 years in Uganda.

METHODS

A cross-sectional study was conducted among 203 children and adolescents aged 8-19 years attending schools in Kampala district (also referred to as Kampala city since the city is conterminous with the district), Uganda through a two-stage cluster sample design. Deuterium dilution method (DDM) was used as the reference measure while BIA and anthropometric measures were used to create the new body composition prediction equations through multivariate regression.

RESULTS

The new prediction equations explained 88%, 87% and 71% of the variance in TBW, FFM % and of FM respectively with no statistical shrinkage upon cross-validation. The linear regression models proposed in this study were well adjusted with respect to TBW, FFM and FM. Log of TBW obtained by DDM = 0.0129 × Impedance index + 0.0055 × Age + 0.0049 Waist Circumference + 0.1219Ht + 2.0388. Log of FFM obtained by DDM = 0.0197 × FFM obtained by BIA - 0.0181 sex code - 0.00055 × Impedance + 3.1761. Log of FM obtained by DDM = 0.0634 × FM obtained by BIA - 0.1881 sex code + 0.0252 × Weight + 0.5273.

CONCLUSION

The use of these equations for more accurate body composition assessment may facilitate identification of effective intervention strategies to prevent or combat overweight and obesity among children and adolescents. They may also assist in treatment of conditions where more accurate information on body composition measures is required.