Department of Clinical Nutrition at Sahlgrenska University Hospital, Sahlgrenska Academy at University of Gothenburg, SE 40530 Göteborg, Sweden.
Physiol Meas. 2010 Jan;31(1):59-75. doi: 10.1088/0967-3334/31/1/005. Epub 2009 Nov 26.
This study evaluated water compartment assessment by bioelectrical impedance spectroscopy (BIS) by Xitron 4000B in 164 growth hormone-deficient adults on growth hormone replacement therapy, examined the assumed constant body density and gender-specific resistivities in BIS methodology and evaluated a published BMI-adjusted BIS equation. Body composition was measured by BIS, total body potassium (TBK), tritium dilution and dual-energy x-ray absorptiometry (DXA). Tritium dilution and TBK were combined to a reference method for water compartments. Average difference for total body water (TBW) by tritium dilution and by BIS was 0.6 l in women (p > 0.05) and -0.2 l in men (p > 0.05). Average extracellular water (ECW) by the reference method and by BIS differed 1.5 l in women (p < 0.05) and 1.2 l in men (p < 0.05). Average intracellular water (ICW) by the reference method and by BIS differed -0.9 l in women (p < 0.05) and -1.3 l in men (p < 0.05). However, average ECW and ICW could be successfully estimated by BIS with use of unisex resistivity constants that were derived from this population, although with large individual variation. Average individual body density was lower than assumed. Application of individual body density did not improve agreement between methods. BMI-adjusted equations were not fully accurate in this population.
本研究评估了 164 名生长激素缺乏症成年人在生长激素替代治疗中使用 Xitron 4000B 进行生物电阻抗谱（BIS）的水腔评估，检查了 BIS 方法中假定的恒定体密度和性别特异性电阻率，并评估了已发表的 BMI 调整 BIS 方程。身体成分通过 BIS、全身钾（TBK）、氚稀释和双能 X 射线吸收法（DXA）进行测量。氚稀释和 TBK 结合成为水腔的参考方法。用氚稀释和 BIS 测量的总体水（TBW）的平均差异在女性为 0.6 升（p>0.05），在男性为-0.2 升（p>0.05）。用参考方法和 BIS 测量的细胞外液（ECW）的平均差异在女性为 1.5 升（p<0.05），在男性为 1.2 升（p<0.05）。用参考方法和 BIS 测量的细胞内液（ICW）的平均差异在女性为-0.9 升（p<0.05），在男性为-1.3 升（p<0.05）。然而，通过使用从该人群中得出的两性电阻率常数，BIS 可以成功地估计平均 ECW 和 ICW，尽管存在较大的个体差异。平均个体体密度低于假设值。个体体密度的应用并未改善方法之间的一致性。在该人群中，BMI 调整后的方程并不完全准确。
