Comparison of isotope dilution with bioimpedance spectroscopy and anthropometry for assessment of body composition in asymptornatic HIV-infected and HIV-uninfected breastfeeding mothers

Background: The effect of breastfeeding on the nutrition of HIV-infected (HIV+) mothers is unknown. Simple, valid methods are needed for body-composition assessment of HIV+ women. Objective: We compared the ability of bioimpedance spectroscopy (BIS) and anthropornetry with that of isotope dilution ((2)H(2)O) to measure fat-free mass (FFM) and fat mass (FM) in HIV+ and HIV-uninfected (HIV-) breastfeeding South African mothers. Design: Total body water (TBW) content of 68 lactating mothers (20 HIV+, 48 HIV-) was measured 10 wk after delivery by using BIS and (2)H(2)O to measure FFM and FNI. Anthropometric measurements included body mass index (BMI; in kg/m(2)), midupper arm circumference (MUAC), and 4 skinfold thicknesses. Results: TBW, FFM, and FM measurements determined by BIS were correlated with (2)H(2)O measurements in HIV+ (r = 0.664, 0.621, and 0.872, respectively; P < 0.01) and HIV- (r = 0.876, 0.868, and 0.932, respectively; P < 0.001) mothers. TBW measured by BIS was greater than that measured by the (2)H(2)O method in both HIV+ (1.8 L) and HIV - (1.5 L) women; FM or FFM did not differ significantly by method. BMI, MUAC, and all skinfold-thickness measurements correlated strongly (r > 0.62, P < 0.001) with FM measured by (2)H(2)O in both groups. BMI and MUAC correlated (r > 0.64, P < 0.001) with FFM in HIV- mothers but not in HIV+ mothers. Conclusions: In HIV+ and HIV- breastfeeding mothers, BIS provides an estimate of body composition comparable to that obtained with the (2)H(2)O method. BMI and MUAC are useful in predicting FM in both groups but are not valid measures of FFM in HIV+ mothers.