Lee Warren T K, Cheung Albert Y K, Lau Joseph, Lee Simon K M, Qin Ling, Cheng Jack C Y
Department of Orthopaedics & Traumatology, The Chinese University of Hong Kong, 5/F Clinical Sciences Building, Prince of Wales Hospital, Hong Kong, Shatin, PR China.
J Bone Miner Metab. 2004;22(5):447-55. doi: 10.1007/s00774-004-0506-2.
Evaluation of bone mineral content/bone mass density (BMC/BMD) is important to determine bone mass development among adolescents in health and disease. It is uncertain at which skeletal site BMC/BMD is best predicted by bone mass determinants. On the other hand, intrapersonal BMC/BMD data can be clustered into a composite index score to facilitate correlation and outcome prediction analysis. This study aimed to identify the skeletal site that was best predicted by bone mass determinants and to develop a composite index score based on multisite BMC/BMD values in healthy adolescent girls. Eleven BMD/BMC variables per subject were evaluated by using dual-energy X-ray absorptiometry (DXA) and peripheral quantitative computed tomography (pQCT) in 236 healthy girls aged 12-15 years. Bone mass determinants, namely, weight, height, puberty, dietary calcium, physical activity, and bone turnover markers, were determined. Factor analysis was used to develop composite index scores that summarized characteristics of multisite BMC/BMD. Results showed that lumbar spinal BMD and BMC (by DXA) and tibial integral BMD (by pQCT) were the BMC/BMD sites better predicted by bone mass determinants (R2, 0.57-0.77) in multiple regression analysis. On the other hand, three composite index scores representing areal BMD, areal BMC, and vBMD were derived to summarize the original BMC/BMD values. The composite index scores had similar predicting power (R2, 0.419-0.749) compared to those of original BMC/BMD, indicating that the composite index scores were representative of the original variables. To conclude, lumbar spinal BMD and BMC and tibial integral BMD were the three BMC/BMD variables better predicted by bone mass determinants. This evaluation would help select appropriate skeletal sites as outcome measures for bone mass evaluation in future studies. Also, the development of composite index scores could help reduce the number of variables for correlation and outcome prediction analyses.
评估骨矿物质含量/骨密度（BMC/BMD）对于确定健康和患病青少年的骨量发育非常重要。目前尚不确定在哪个骨骼部位，骨量决定因素能最好地预测BMC/BMD。另一方面，个体内部的BMC/BMD数据可以聚类为一个综合指数分数，以促进相关性和结果预测分析。本研究旨在确定骨量决定因素能最好预测的骨骼部位，并基于健康青春期女孩的多部位BMC/BMD值制定一个综合指数分数。通过双能X线吸收法（DXA）和外周定量计算机断层扫描（pQCT）对236名12至15岁的健康女孩进行评估，每个受试者评估11个BMD/BMC变量。测定骨量决定因素，即体重、身高、青春期、膳食钙、身体活动和骨转换标志物。采用因子分析来制定综合指数分数，以总结多部位BMC/BMD的特征。结果显示，在多元回归分析中，腰椎骨密度和骨矿物质含量（通过DXA测量）以及胫骨整体骨密度（通过pQCT测量）是骨量决定因素能更好预测的BMC/BMD部位（R2，0.57 - 0.77）。另一方面，得出了三个代表面积骨密度、面积骨矿物质含量和体积骨密度 的综合指数分数，以总结原始的BMC/BMD值。与原始BMC/BMD相比，综合指数分数具有相似的预测能力（R2，0.419 - 0.749），这表明综合指数分数代表了原始变量。总之，腰椎骨密度和骨矿物质含量以及胫骨整体骨密度是骨量决定因素能更好预测的三个BMC/BMD变量。这种评估将有助于在未来研究中选择合适的骨骼部位作为骨量评估的结果指标。此外，综合指数分数的制定有助于减少相关性和结果预测分析中的变量数量。
