Masuda Takashi, Komiya Shuichi
Department of Child Education, Nakamura-Gakuen Junior College, Japan.
J Physiol Anthropol Appl Human Sci. 2004 Mar;23(2):35-9. doi: 10.2114/jpa.23.35.
Total body water (TBW) measured by isotope dilution techniques can be used to assess body composition safely and accurately in children. Unfortunately, this method is not readily available for most research projects, particularly when working with large groups of people, because the equipment is complicated and highly specialized. Bioelectrical impedance (BI) method is a simple, quick, and inexpensive method for the assessment of total body water (TBW). In Japanese child population, however, a lack of prediction equations is a problem to determine TBW. The purpose of this study was to determine the prediction equation for TBW determination in Japanese children using the isotope dilution technique as the reference method. Seventy Japanese children (39 boys, 31 girls) with ages ranging between 3 and 6 years participated in this study. They were randomly divided into the validation group (26 boys, 20 girls) and cross-validation group (13 boys, 11 girls). In a forward stepwise regression analysis, 96% of the variability in TBW measured by deuterium oxide (D(2)O) dilution could be predicted by the following equation: TBW(kg)=0.149 x Resistance Index (Stature(2)/resistance, cm(2)/Omega)+0.244 x Weight(kg)+0.460 x Age(y)+0.501 x Sex (boy=1, girl=0)+1.628, with a root mean square error (RMSE) of 0.440 kg in the validation group. This equation predicted TBW in the cross-validation group with R(2)=0.946 and a pure error (PE)=0.400 kg TBW. Hence, this equation should be applicable for predicting TBW in Japanese children aged 3-6 y.
通过同位素稀释技术测量的总体水（TBW）可用于安全、准确地评估儿童的身体成分。不幸的是，这种方法对于大多数研究项目来说并不容易获得，特别是在研究大量人群时，因为设备复杂且高度专业化。生物电阻抗（BI）法是一种简单、快速且廉价的评估总体水（TBW）的方法。然而，在日本儿童群体中，缺乏用于确定TBW的预测方程是一个问题。本研究的目的是使用同位素稀释技术作为参考方法，确定日本儿童TBW测定的预测方程。70名年龄在3至6岁之间的日本儿童（39名男孩，31名女孩）参与了本研究。他们被随机分为验证组（26名男孩，20名女孩）和交叉验证组（13名男孩，11名女孩）。在向前逐步回归分析中，通过氧化氘（D₂O）稀释测量的TBW中96%的变异性可由以下方程预测：TBW（kg）=0.149×电阻指数（身高²/电阻，cm²/Ω）+0.244×体重（kg）+0.460×年龄（岁）+0.501×性别（男孩=1，女孩=0）+1.628，验证组的均方根误差（RMSE）为0.440 kg。该方程在交叉验证组中预测TBW时，R² = 0.946，纯误差（PE）= 0.400 kg TBW。因此，该方程应适用于预测3至6岁日本儿童的TBW。
