Hendel H W, Gotfredsen A, Højgaard L, Andersen T, Hilsted J
Department of Endocrinology, Hvidovre Hospital, Copenhagen, Denmark.
Scand J Clin Lab Invest. 1996 Dec;56(8):671-9. doi: 10.3109/00365519609088814.
A total of 16 obese women (body mass index (BMI) 30-43 kg m(-2)) participated in a weight reduction study. Before and after a weight loss of 11.7 +/- 7.4 kg (mean +/- SD), body composition was assessed by dual energy X-ray absorptiometry (DXA), and total body potassium counting (TBK). These measurements were compared with bioimpedance analysis (BIA) by applying 11 predictive BIA equations published in the literature. Predictive equations for the present study population were developed, with the use of fat-free mass (FFM) as assessed by TBK and DXA as references in multiple regression analysis. The results of the BIA equations varied widely; FFM was generally overestimated by BIA as compared with DXA and TBK before and after weight loss. During weight loss, the FFM did not change, as estimated by DXA (1.3 +/- 2.3 kg, p > 0.05) and TBK (0.9 +/- 2.9 kg, p > 0.05). The recorded change in impedance (R) was also insignificant. Three BIA equations from the literature, which were not specific for the degree of obesity in the present study group, predicted changes in FFM (from 0.5 + 3.6 to 2.4 +/- 4.4kg, p > 0.05) that were comparable with those estimated by the reference methods. Eight equations from the literature, which included equations specific for the degree of obesity in the study group, and the group specific equations developed for the present population predicted significant changes in FFM during weight loss (from 2.3 +/- 3.0 to 5.0 +/- 3.0 kg, p < 0.05). We conclude that in obesity most predictive equations are unable to predict static body composition and are not reproducible for individuals over time. However, a significant or insignificant change in R (without accompanying predictive equations) may be used to indicate whether FFM is lost or preserved in groups of obese subjects.
共有16名肥胖女性（体重指数（BMI）为30 - 43 kg/m²）参与了一项减肥研究。在体重减轻11.7±7.4 kg（均值±标准差）前后，通过双能X线吸收法（DXA）和全身钾计数（TBK）评估身体成分。将这些测量结果与应用文献中发表的11个预测性生物电阻抗分析（BIA）方程得出的结果进行比较。利用TBK和DXA评估的去脂体重（FFM）作为多元回归分析中的参考，建立了本研究人群的预测方程。BIA方程的结果差异很大；与减肥前后的DXA和TBK相比，BIA通常高估了FFM。减肥期间，根据DXA估计FFM没有变化（1.3±2.3 kg，p>0.05），根据TBK估计也没有变化（0.9±2.9 kg，p>0.05）。记录的阻抗（R）变化也不显著。文献中的三个BIA方程，并非针对本研究组的肥胖程度，预测的FFM变化（从0.5±3.6至2.4±4.4 kg，p>0.05）与参考方法估计的变化相当。文献中的八个方程，包括针对研究组肥胖程度的方程，以及为本研究人群建立的组特异性方程，预测减肥期间FFM有显著变化（从2.3±3.0至5.0±3.0 kg，p<0.05）。我们得出结论，在肥胖人群中，大多数预测方程无法预测静态身体成分，且随时间推移对个体而言不可重复。然而，R的显著或不显著变化（无伴随预测方程）可用于表明肥胖受试者群体中FFM是减少还是保持。
