Deurenberg P, Tagliabue A, Schouten F J
Department of Human Nutrition, Wageningen Agricultural University, The Netherlands.
Br J Nutr. 1995 Mar;73(3):349-58. doi: 10.1079/bjn19950038.
The relationship between total body water (TBW) and extracellular water (ECW), measured by deuterium oxide dilution and bromide dilution respectively, and impedance and impedance index (height2/impedance) at 1, 5, 50 and 100 kHz was studied. After correction for TBW, ECW was correlated only with the impedance index at 1 and 5 kHz. After correction for ECW, TBW was best correlated with the impedance index at 100 kHz. The correlation of body-water compartments with impedance values obtained with modelling programs was lower than with measured impedance values. Prediction formulas for ECW (at 1 and 5 kHz) and TBW (at 50 and 100 kHz) were developed. The prediction errors for ECW and TBW were 1.0 and 1.7 kg respectively (coefficient of variation 5%). The residuals of both ECW and TBW were related to the ECW/TBW value. Application of the prediction formulas in a population, independently measured, revealed a slight overestimation of TBW and ECW, which could be largely explained by differences in the validation group in body-water distribution and in body build. The ratio of impedance at 1 kHz to impedance at 100 kHz was correlated with body-water distribution (ECW/TBW). The relation is however not strong enough to be useful as a predictor. It is concluded that an independent prediction of ECW and TBW, using impedance at low and high frequency respectively, is possible, but that the bias depends on the body-water distribution and body build of the measured subject.
分别采用重水稀释法和溴化物稀释法测量了总体水（TBW）和细胞外水（ECW），并研究了1、5、50和100kHz时的阻抗及阻抗指数（身高²/阻抗）之间的关系。在校正TBW后，ECW仅与1kHz和5kHz时的阻抗指数相关。在校正ECW后，TBW与100kHz时的阻抗指数相关性最佳。人体水分 compartments 与通过建模程序获得的阻抗值之间的相关性低于与实测阻抗值的相关性。建立了ECW（1kHz和5kHz时）和TBW（50kHz和100kHz时）的预测公式。ECW和TBW的预测误差分别为1.0kg和1.7kg（变异系数5%）。ECW和TBW的残差均与ECW/TBW值相关。在一个独立测量的人群中应用预测公式，结果显示TBW和ECW略有高估，这在很大程度上可由验证组在人体水分分布和体型方面的差异来解释。1kHz时的阻抗与100kHz时的阻抗之比与人体水分分布（ECW/TBW）相关。然而，这种关系不够强，不足以用作预测指标。得出的结论是，分别使用低频和高频阻抗对ECW和TBW进行独立预测是可行的，但偏差取决于被测对象的人体水分分布和体型。
