Chilibeck P, Calder A, Sale D G, Webber C
Department of Kinesiology, McMaster University, Hamilton, Ont.
Can Assoc Radiol J. 1994 Aug;45(4):297-302.
The purpose of this investigation was to determine the short-term reproducibility of measurements of whole-body and subregion bone mass and density, as well as body composition, made by dual energy x-ray absorptiometry. Bone mineral content, bone mineral density and body composition were measured on two occasions, 1 to 2 weeks apart, in 21 women (average age, 20.9 [standard deviation 1.6] years). The method errors of the duplicate measurements, expressed as a percentage of the combined mean values from the two sets of measurements (i.e., as a coefficient of variation), for whole-body bone mineral content, bone mineral density, lean tissue mass and fat mass were 1.6%, 1.1%, 1.4% and 1.8% respectively. The method errors for bone mineral density in the hip were 2.2%, 1.1% and 2.5% for the neck, trochanter and Ward's triangle respectively. On the basis of the method errors and the expected treatment effects, the sample sizes needed for intervention trials (e.g., exercise training) were calculated. All of the whole-body and most of the subregion bone mineral density and lean tissue mass measurements made by dual-energy x-ray absorptiometry were sufficient for detecting the small changes (about 2%) expected in trials with 20 subjects, whereas measurements of subregion bone mineral content and fat mass were less precise.
本研究的目的是确定采用双能X线吸收法测量全身及局部骨量、骨密度以及身体成分的短期可重复性。对21名女性（平均年龄20.9[标准差1.6]岁）在间隔1至2周的两个时间点测量了骨矿物质含量、骨矿物质密度和身体成分。重复测量的方法误差，以两组测量合并均值的百分比表示（即变异系数），全身骨矿物质含量、骨矿物质密度、瘦组织质量和脂肪质量的方法误差分别为1.6%、1.1%、1.4%和1.8%。髋部骨矿物质密度在颈部、大转子和Ward三角区的方法误差分别为2.2%、1.1%和2.5%。根据方法误差和预期治疗效果，计算了干预试验（如运动训练）所需的样本量。双能X线吸收法进行的所有全身及大部分局部骨矿物质密度和瘦组织质量测量足以检测20名受试者试验中预期的小变化（约2%），而局部骨矿物质含量和脂肪质量的测量精度较低。
