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 free mass (FFM) and fat mass (FM) with other laboratory based methods. Twenty-two healthy adult male volunteers were selected from the staffs of International Centre for Diarrhoeal Disease Research, Bangladesh (ICDDR,B). Ten mL of deuterium oxide (D2O) along with 1 mL/Kg of 3 g% NaBr solution were given orally to each subject. In order to validate the method, deuterium- and bromide-dilution principles were utilized by using isotope-ratio mass spectrophotometer (IRMS), high performance liquid chromatography (HPLC) and spectrophotometer (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 indicates that the volunteers were not obese or overweight anthrapometrically. A significant correlation of TEW was observed between MF-BIA and IRMS techniques (r(2) = 0.44, p<0.001). However, the ECW volume was 7% higher by MF-BIA and 2% by HPLC in relation to the D2O dilution method whereas SP method 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 correlated 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 useful technique to assess the body composition and its usefulness could be increased if ECW measurement by this method is improved further. (C) 1999 Elsevier Science Inc.