Wells J C K, Fuller N J, Wright A, Fewtrell M S, Cole T J
MRC Childhood Nutrition Research Centre, Institute of Child Health, London WC1N 1EH, UK.
Br J Nutr. 2003 Sep;90(3):699-707. doi: 10.1079/bjn2003930.
The aim of the present study was to evaluate air-displacement plethysmography (ADP) in children aged 5-7 years. Body-composition measurements were obtained by ADP, (2)H dilution and anthropometry in twenty-eight children. Calculation of body volume by ADP was undertaken using adult and children's equations for predicting lung volume and surface area. Fat-free mass (FFM) was calculated using a three-component model. Measured FFM hydration was then compared with values from the reference child. Differences between measured and reference hydration were back-extrapolated, to calculate the error in ADP that would account for any disagreement. Propagation of error was used to distinguish the contributions of methodological precision and biological variability to total hydration variability. The use of children's equations influenced the results for lung volume but not surface area. The mean difference between measured and reference hydration was 0.6 (sd 1.7) % (P<0.10), equivalent to an error in body volume of 0.04 (sd 0.20) litres (P<0.30), and in percentage fat of 0.4 (sd 1.9) (P<0.28). The limits of agreement in individuals could be attributed to methodological precision and biological variability in hydration. It is concluded that accuracy of ADP was high for the whole group, with a mean bias of <0.5 % fat using the three-component model, and after taking into account biological variability in hydration, the limits of agreement were around +/-2 % fat in individuals. Paediatric rather than adult equations for lung volume estimation should be used.
本研究的目的是评估5至7岁儿童的空气置换体积描记法（ADP）。通过ADP、氘稀释法和人体测量法对28名儿童进行身体成分测量。使用成人和儿童预测肺容积和表面积的公式通过ADP计算身体容积。使用三分模型计算去脂体重（FFM）。然后将测量的FFM水合作用与参考儿童的值进行比较。将测量的水合作用与参考水合作用之间的差异进行反向推算，以计算ADP中可解释任何差异的误差。使用误差传播来区分方法精度和生物变异性对总水合作用变异性的贡献。使用儿童公式影响了肺容积的结果，但不影响表面积的结果。测量的水合作用与参考水合作用之间的平均差异为0.6（标准差1.7）%（P<0.10），相当于身体容积误差为0.04（标准差0.20）升（P<0.30），体脂百分比误差为0.4（标准差1.9）（P<0.28）。个体的一致性界限可归因于水合作用的方法精度和生物变异性。得出的结论是，对于整个群体，ADP的准确性较高，使用三分模型时平均偏差<0.5%体脂，并且在考虑水合作用的生物变异性后，个体的一致性界限约为±2%体脂。应使用儿科而非成人公式来估计肺容积。
