Graves James E, Pollock Michael L, Colvin Andrea B, Van Loan Marta, Lohman Timothy G
Center for Exercise Science, University of Florida, Gainesville, Florida 32611.
United States Department of Agriculture, ARS/WHNRC San Francisco, California 94129.
Am J Hum Biol. 1989;1(5):603-611. doi: 10.1002/ajhb.1310010511.
To investigate the influence of different bioelectrical impedance (BI) analyzers on the prediction of body composition from bioelectrical resistive impedance (R), 146 healthy white adults (73 men; 73 women) were studied at two independent laboratories: The University of Florida (UF) and the USDA, San Francisco. Whole body R was measured on each subject with three different BI analyzers. AT UF analyzers were: Valhalla Scientific model 1990-A (VH), RJL Systems model BIA-101 (RJL), and Medi-Fitness model 1000 (MF). At USDA analyzers were: VH, RJL, and Bioelectrical Sciences model 200Z (BES). The largest difference in R (36 ohms, P ⩽ 0.01) was noted between BES and VH at USDA. When applied to current BI prediction equations, the observed differences among analyzers resulted in differences in predicated % fat of up to 6.3% although most comparisons among mean values (79%) showed differences below 3%. Crossvalidation of the selected BI prediction equations with hydrostatistically determines body composition using the different R values revealed total errors of prediction (E) ranging from 3.6 to 9.8% fat. The prediction equations were most accurate when used with data collected on the same instrument that was to used to develop the equation (E = 3.6 to 5.3% fat). These findings indicate that different analyzers can be a significant source of variation when predicting body composition from R. To minimize this source of variation, it is recommended that BI prediction equations be used with the same type of instrument as that with which they were developed.
为研究不同生物电阻抗（BI）分析仪对基于生物电阻抗（R）预测身体成分的影响，在两个独立实验室对146名健康白人成年人（73名男性；73名女性）进行了研究：佛罗里达大学（UF）和美国农业部旧金山研究中心。使用三种不同的BI分析仪对每位受试者测量全身R。在UF使用的分析仪为：瓦尔哈拉科学公司1990 - A型（VH）、RJL系统公司BIA - 101型（RJL）和医学健身公司1000型（MF）。在美国农业部使用的分析仪为：VH、RJL和生物电科学公司200Z型（BES）。在美国农业部，BES和VH之间的R差异最大（36欧姆，P⩽0.01）。当将这些差异应用于当前的BI预测方程时，分析仪之间观察到的差异导致预测体脂百分比的差异高达6.3%，尽管大多数平均值比较（79%）显示差异低于3%。使用不同的R值，通过静水称重法确定身体成分，对所选BI预测方程进行交叉验证，结果显示预测总误差（E）的体脂范围为3.6%至9.8%。当使用与开发方程相同的仪器收集的数据时，预测方程最为准确（E = 3.6%至5.3%体脂）。这些发现表明，在根据R预测身体成分时，不同的分析仪可能是变异的重要来源。为尽量减少这种变异来源，建议使用与开发BI预测方程时相同类型的仪器。
