Multifrequency bioelectrical impedance analysis to assess human body composition

Multifrequency bioelectrical impedance analysis (MF-BIA) was validated as a method to predict total body water (TBW), extracellular water (ECW), fat f ree mass (FFM) and fat mass (FM) with other laboratory based methods. Twent y-two healthy adult male volunteers were selected from the staffs of Intern ational Centre for Diarrhoeal Disease Research, Bangladesh (ICDDR,B). Ten m L of deuterium oxide (D2O) along with 1 mL/Kg of 3 g% NaBr solution were gi ven orally to each subject. In order to validate the method, deuterium- and bromide-dilution principles were utilized by using isotope-ratio mass spec trophotometer (IRMS), high performance liquid chromatography (HPLC) and spe ctrophotometer (SP). Data obtained by these methods were compared to assess the accuracy between the methods. The mean+/-SD BMI was 24.2+/-1.7 which i ndicates that the volunteers were not obese or overweight anthrapometricall y. A significant correlation of TEW was observed between MF-BIA and IRMS te chniques (r(2) = 0.44, p<0.001). However, the ECW volume was 7% higher by M F-BIA and 2% by HPLC in relation to the D2O dilution method whereas SP meth od gave the most accurate volume of ECW. The findings of the study indicate that MF-BIA method overestimated ECW although TBW by MF-BIA and IRMS corre lated well. The co-efficient of variation (CV%) of ECW measured by HPLC was 9% and by SP method was 27%, indicating that ECW measured by HPLC was more accurate. In summary it could be concluded that MF-BIA is a rapid and usef ul technique to assess the body composition and its usefulness could be inc reased if ECW measurement by this method is improved further. (C) 1999 Else vier Science Inc.