PREDICTION OF TOTAL-BODY WATER IN INDIAN MEN FROM ANTHROPOMETRY AND BIOELECTRICAL-IMPEDANCE USING DEUTERIUM DILUTION AS REFERENCE

Total body water (TBW) obtained by deuterium dilution (TBWD) in 45 adu lt Indian males of low body mass index was compared with values obtain ed from bioelectrical impedance (TBWImp) and two anthropometry-based p rediction equations. Bioelectrical impedance significantly underestima ted TBW when compared with deuterium dilution, by 2.75 SD 2.86 kg. Com parisons of the anthropometry-based prediction equations demonstrated that TBW was overestimated by 0.87 SD 2.49 kg, and 2.47 SD 2.57 kg, re spectively. Since all parameters in the bioelectrical impedance method were standardized, the difference in the values could have been becau se of the equation used. Therefore, a fresh equation for the measureme nt of TBW by the bioelectrical impedance method was derived using the variables of height(2)/impedance and weight. New prediction equations for TBW were also derived based on anthropometric variables of weight and height. Body weight has the greatest influence in the prediction e quations for TBW, and the equation derived was TBW (kg)=0.533 x body w eight (kg) + 3.77, SEE=2.4 kg. Using height(2)/impedance gave the rela tionship: TBW (kg)=0.568 body weight - 0.04 height(2)/impedance + 4.35 , SEE = 1.9 kg.