Burt Lauren A, Hanley David A, Boyd Steven K
Department of Radiology, Cumming School of Medicine, University of Calgary, Calgary, Canada.
McCaig Institute for Bone and Joint Health, University of Calgary, Calgary, Canada.
J Bone Miner Res. 2017 Jul;32(7):1505-1513. doi: 10.1002/jbmr.3129. Epub 2017 Apr 3.
Longitudinal studies assessing age-related changes using high-resolution peripheral quantitative computed tomography (HR-pQCT) provide novel insight compared with cross-sectional analyses. The purpose of this cohort study was 1) to determine individuals' change in HR-pQCT parameters over 5 years relative to least significant change (LSC), and 2) to evaluate if predicted rate of change from cross-sectional data is comparable to actual change from longitudinal investigation. A cohort of 466 (162 male, 304 female) participants completed two HR-pQCT scans with 5 years between assessments. After image registration, standard and cortical morphological analyses were conducted. Rate of bone microarchitectural change was compared between cross-sectional models and actual change calculated from longitudinal analyses. At the young end of the life span, we observed gains in total bone density of +0.2% to +2.9% per year, whereas the older participants (aged >50 years) lost total bone density at a rate of -0.3% to -1.3% per year. Declines in total bone density begin at age 40 years in females and 60 years in males, and significant adaptation was found at both ends of the age spectrum with respect to the LSC. Models predicting rate of change from cross-sectional data were similar to the actual change reported in this longitudinal study for total density and cortical thickness at the radius and cortical density at the tibia, but we found that changes in comparison to our 5-year longitudinal results were often overestimated from cross-sectional data. Studies aimed at observing age-related changes in a normative cohort, especially in a follow-up period of less than 5 years, are better to focus on the tibia rather than the radius because of the increased sensitivity to change at the tibia. © 2017 American Society for Bone and Mineral Research.
与横断面分析相比，使用高分辨率外周定量计算机断层扫描（HR-pQCT）评估年龄相关变化的纵向研究提供了新的见解。这项队列研究的目的是：1）确定个体在5年期间HR-pQCT参数相对于最小有意义变化（LSC）的变化情况；2）评估从横断面数据预测的变化率是否与纵向研究的实际变化相当。466名参与者（162名男性，304名女性）组成的队列完成了两次HR-pQCT扫描，两次扫描间隔5年。在图像配准后，进行了标准和皮质形态学分析。比较了横断面模型与纵向分析计算出的实际变化之间的骨微结构变化率。在寿命的年轻阶段，我们观察到每年总骨密度增加0.2%至2.9%，而年龄较大的参与者（年龄>50岁）每年以-0.3%至-1.3%的速率丢失总骨密度。女性在40岁、男性在60岁时开始出现总骨密度下降，并且在年龄范围的两端相对于LSC都发现了显著的适应性变化。从横断面数据预测变化率的模型与本纵向研究报告的桡骨总密度、皮质厚度以及胫骨皮质密度的实际变化相似，但我们发现，与我们5年纵向结果相比，横断面数据往往高估了变化情况。由于胫骨对变化的敏感性增加，旨在观察正常队列中年龄相关变化的研究，尤其是在随访期少于5年的情况下，最好关注胫骨而非桡骨。© 2017美国骨与矿物质研究学会。
