Reproducibility of DXA measurements of bone mineral density and body composition in children
Reproducibility of DXA measurements of bone mineral density and body composition in children
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DOI：
10.1007/s00247-008-1067-7
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发表时间：
2009-02-01
影响因子：
2.3
通讯作者：
Webber, Colin E.
中科院分区：
文献类型：
--
作者：
Leonard, Cheryl M.;Roza, Melissa A.;Webber, Colin E.
基于 X 射线的双光子吸收测定法 (DXA) 技术经常用于儿童检测骨量或身体成分的变化。只有超过测量技术产生的不确定性，这种变化才能被认为是真实的。我们的目标有两个：（1）确定儿童脊柱和髋部以及全身骨矿物质密度（BMD）测量的再现性，以及儿童矿物质量、去脂体重和脂肪量的全身测量的再现性； (2) 根据测量的精度估计在检测到 DXA 变量出现统计显着变化之前需要经过的时间间隔。使用 DXA 测量 BMD 和身体成分的技术的再现性在 15 名幼儿（9 名女孩和 6 名男孩）和 17 名年龄较大的儿童（9 名女孩和 8 名男孩）中进行了测量。再现性来自脊柱 BMD、总髋部 BMD、全身 BMD 的 3 次重复测量的标准差(WBBMD)、全身骨矿物质含量 (WBBMC)、瘦体重和脂肪量。脊柱BMD和WBBMD的技术精度优于0.01 g cm(-2)。髋部 BMD 测量的精确度稍差，尤其是年幼的儿童 (0.013 g cm(-2))。对于身体成分变量，年幼儿童的 WBBMC 技术精度为 13 g，去脂体重为 201 g，脂肪质量为 172 g。对于年龄较大的儿童，相应变量的技术精度为 18 克、251 克和 189 克。预测表明，12 个月后，可以确定小于年龄的女孩的 WBBMC 没有正常增加。对于 11 岁以上的男孩，6 个月后应该可以观察到脊柱 BMD 显着增加。对于年龄较小的男孩，必须经过 12 个月以上才能可靠地检测到预期的变化。在就连续测量儿童 BMD 或身体成分之间观察到的差异的显着性做出决定之前所需的时间间隔取决于儿童的年龄。
The technique of X-ray-based dual photon absorptiometry (DXA) is frequently used in children for the detection of changes in bone mass or body composition. Such changes can only be considered real if the uncertainties arising from the measurement technique are exceeded.Our objectives were twofold: (1) to determine the reproducibility of bone mineral density (BMD) measurements in children at the spine and the hip and from the whole body, as well as of whole-body measurements of mineral mass, lean body mass and fat mass in children; and (2) to estimate, from the measured precision, the time interval that needs to elapse before a statistically significant change in a DXA variable can be detected.The reproducibility of techniques for the measurement of BMD and body composition using DXA was measured in 15 young children (9 girls and 6 boys) and 17 older children (9 girls and 8 boys).Reproducibility was derived from the standard deviation of three repeated measurements of spine BMD, total hip BMD, whole-body BMD (WBBMD), whole-body bone mineral content (WBBMC), lean mass and fat mass. Technique precision was better than 0.01 g cm(-2) for spine BMD and for WBBMD. Hip BMD measurements were slightly less precise, particularly in younger children (0.013 g cm(-2)). For body composition variables, technique precision was 13 g for WBBMC, 201 g for lean body mass and 172 g for fat mass in younger children. Technique precision for older children was 18 g, 251 g and 189 g for the corresponding variables. Predictions showed that the absence of a normal increase in WBBMC in a small-for-age girl could be established after 12 months. For spine BMD, a significant increase should be observable after 6 months for boys over the age of 11 years. For younger boys, more than 12 months has to elapse before anticipated changes can be detected with confidence.The time intervals required to elapse before decisions can be made concerning the significance of observed differences between successive measurements of BMD or body composition in children depend upon the age of the child.