Fjeld C R, Freundt-Thurne J, Schoeller D A
University of Chicago, Department of Medicine, Illinois.
Pediatr Res. 1990 Jan;27(1):98-102. doi: 10.1203/00006450-199001000-00024.
Total body water (TBW) is an indicator of fat-free mass and thus of nutritional status but cannot be measured readily in children in developing countries who are at greatest risk of becoming malnourished. We therefore developed equations to predict 18O TBW from bioelectrical impedance (Z), wt, and ht in well and malnourished infants and children whom we considered characteristic of children evaluated in nutritional surveillances in Peru. Children 3 to 30 mo of age, whose wt were 3.4 to 14.4 kg, which was -2.8 to +1 SD wt-for-ht, were randomly assigned to group I (n = 30) to develop equations to predict TBW or to group II (n = 14) to cross-validate the predictive equations. Mean TBW measured by 18O dilution was 4.8 +/- 1.2 kg in group I, and 5.6 +/- 1.7 kg in group II. TBW ranged from 57 to 78% of body wt (65 +/- 6%) in group I and from 56 to 80% (64 +/- 6%) in group II, indicating no statistically significant differences in body composition. The following equation was developed and cross-validated: TBW, kg = 0.48 + 0.68 ht2/Z; standard error estimate = 0.36; r = 0.98). A slight improvement was achieved by the addition of body wt (TBW, kg = 0.76 + 0.18 ht2/Z + 0.39 wt; standard error estimate = 0.23; r = 0.99).
总体水含量（TBW）是无脂肪体重的一个指标，因此也是营养状况的指标，但在最易出现营养不良的发展中国家儿童中，却无法轻易测量。因此，我们建立了一些方程，用于根据生物电阻抗（Z）、体重（wt）和身高（ht）来预测秘鲁营养监测中所评估儿童的典型代表——营养良好及营养不良的婴幼儿和儿童的氧-18总体水含量。年龄在3至30个月、体重为3.4至14.4千克（身高别体重在-2.8至+1标准差之间）的儿童被随机分为第一组（n = 30）以建立预测总体水含量的方程，或分为第二组（n = 14）以对预测方程进行交叉验证。第一组中通过氧-18稀释法测得的平均总体水含量为4.8±1.2千克，第二组为5.6±1.7千克。第一组中总体水含量占体重的比例为57%至78%（65±6%），第二组为56%至80%（64±6%），表明身体组成无统计学显著差异。建立并交叉验证了以下方程：总体水含量（千克）= 0.48 + 0.68×身高²/生物电阻抗；估计标准误 = 0.36；r = 0.98）。加入体重后有轻微改进（总体水含量，千克 = 0.76 + 0.18×身高²/生物电阻抗 + 0.39×体重；估计标准误 = 0.23；r = 0.99）。
