Body composition of Cameroonian lactating women determined by anthropometry, bioelectrical impedance, and deuterium dilution.

OBJECTIVE: This study compared body composition estimates using deuterium dilution, multiple-frequency bioelectrical impedance analysis (BIA), and skinfold thickness techniques in a group of Cameroonian lactating women. METHODS: Body fat, fat-free mass, and total body water in 44 Cameroonian lactating women (2.63 ± 1.31 mo postpartum) were assessed by deuterium dilution, the Siri or black-specific derived Durnin-Womerley equation, and 12 BIA-prediction equations developed in samples of subjects of white, black, black-and-white, or unspecified racial background, respectively. RESULTS: Compared with deuterium dilution, anthropometry and BIA-based predictive equations overestimated body fat by 2.7 to 11.7 kg; thus, fat-free mass and total body water were underestimated. In all cases, the significant biases resulted in large 95% limits of agreement, yielding unacceptable potential bias at the level of the individual. However, the exclusion of suprailiac skinfold in the calculation, yielding to non-significant (P < 0.05) bias, improved the prediction of body composition in Cameroonian lactating women using the Durnin-Womersley and Siri equations. CONCLUSION: It is essential to adjust the Durnin-Womersley equation before using it in the Siri equation for the prediction of body composition in lactating women. Further development and cross-validation of prediction equations from BIA specific to lactating women is needed.

Validity of impedance-based equations for the prediction of total body water as measured by deuterium dilution in Cameroonian HIV-infected patients treated with antiretroviral treatment.

BACKGROUND & AIMS: No information is available on the validity of impedance-based equations for the prediction of body composition in Cameroonian HIV-infected patients treated with antiretroviral drugs. Equations for the prediction of total body water (TBW) have the tendency to be population-specific, and this may be due to biological factors, such as variable body geometry and physiological state. We tested the validity of equations derived from different racial backgrounds for predicting TBW from bioelectrical impedance analysis measurements. METHOD: The TBW content of 56 Cameroonian HIV patients (19 men and 37 women) treated with the first-line ARV regimen was measured by deuterium dilution and compared with those predicted by 12 equations developed respectively in samples of white, black, black and white, or unspecified racial background subjects. RESULTS: Pure errors in predicting TBW showed acceptable value for all the equations tested. Four equations (three from whites and one from blacks and whites) yielded a non-significant bias; however, equation H which presented the narrower 95% confidence interval and the smaller pure error was recommended for the prediction of TBW in Cameroonian HIV-infected patients treated with antiretroviral drugs. In all other cases, we observed either an overestimation or underestimation of TBW with variable bias values. CONCLUSION: The absence of a clear trend in cross-validation among equations according to their origin and the probable effect of physiological state should encourage further exploration of the causes of the lack of validity.