Technological University of Compiegne, Department of Biological Engineering, BP 20529, 60205 Compiegne cedex, France.
Med Eng Phys. 2009 Nov;31(9):1079-86. doi: 10.1016/j.medengphy.2009.07.005. Epub 2009 Aug 4.
Regional body composition measurements may be achieved in a single operation with impedancemeters equipped with four plantar and four hand electrodes. By measuring sequentially the resistances of five current lines connecting the hands and feet and solving a system of five linear equations, it is possible to calculate the resistances of each limb and the trunk. The impedancemeter used in this study was a prototype with four plantar electrodes and four additional contact electrodes for the hands. Its electronic hardware was identical to that of a Tefal commercial foot-to-foot impedancemeter (FFI). The Tefal FFI was used for measuring weight, whole body fat-free mass (FFM) and fat tissue mass (FM). Impedance and DXA measurements were taken sequentially on a 1st cohort of 170 healthy adults, aged from 19 to 75 years, to obtain equations relating appendicular FFM measured by DXA to their resistances, subject weight and height. For appendicular FM, correlations of the body FM measured by the FFI, age and BMI were used. Trunk FFM was obtained by subtracting appendicular FFM from FFM of trunk+limbs obtained by the same method as that for appendicular FFM. For an independent validation, these equations were tested on a 2nd cohort of 87 subjects (18-74 years) who underwent the same impedance and DXA protocol. Comparison of FFM and FM by impedance and by DXA in the limbs and the trunk using paired Student's t-tests, showed that they were not significantly different both in the 1st and validation cohorts. Mean FFM differences between impedance and DXA were -0.018+/-0.48 kg for right arms and -0.039+/-0.85kg for right legs of men in validation cohort. This work confirms that eight contact electrodes bioimpedance can measure appendicular and trunk FFM and FM in good agreement with DXA, at least in a healthy population.
使用配备有四个足底和四个手部电极的阻抗计，可以在一次操作中获得区域性身体成分测量值。通过依次测量连接手部和脚部的五条电流线的电阻，并求解一个五元线性方程组，可以计算出每个肢体和躯干的电阻。本研究中使用的阻抗计是一个带有四个足底电极和四个额外手部接触电极的原型机。其电子硬件与泰福（Tefal）商用的足对足阻抗计（FFI）相同。泰福 FFI 用于测量体重、全身去脂体重（FFM）和脂肪组织质量（FM）。在第一组 170 名健康成年人中，按顺序进行阻抗和 DXA 测量，以获得通过 DXA 测量的四肢 FFM 与其电阻、体重和身高之间的关系方程。对于四肢 FM，使用 FFI 测量的身体 FM 与年龄和 BMI 的相关性。通过从通过相同方法获得的四肢+躯干 FFM 中减去四肢 FFM，来获得躯干 FFM。为了进行独立验证，在第二组 87 名（18-74 岁）接受相同阻抗和 DXA 方案的受试者中测试了这些方程。使用配对学生 t 检验比较了通过阻抗和 DXA 测量的四肢和躯干中的 FFM 和 FM，结果表明在第一组和验证组中它们均无显著差异。验证组中男性右侧手臂和右侧腿部阻抗和 DXA 之间的 FFM 差异平均值分别为-0.018+/-0.48kg 和-0.039+/-0.85kg。这项工作证实，在健康人群中，八个接触电极生物阻抗可以很好地与 DXA 测量四肢和躯干的 FFM 和 FM，至少在健康人群中是这样。
