Department of Medicine, The University of Melbourne, Western Hospital, Melbourne, Victoria, Australia.
Bone. 2010 Sep;47(3):673-80. doi: 10.1016/j.bone.2010.06.027. Epub 2010 Jun 28.
We have reported previously that long-term participation of weight-bearing exercise is associated with increased QCT-derived cortical bone size and strength in middle-aged and older men, but not whole bone cortical volumetric BMD. However, since bone remodeling and the distribution of loading-induced strains within cortical bone are non-uniform, the aim of this study was to examine the effects of lifetime loading history on cortical bone mass distribution and bone shape in healthy community dwelling middle-aged and older men. We used QCT to assess mid-femur and mid-tibia angular bone mass distribution around its center (polar distribution), the bone density distribution through the cortex (radial distribution), and the ratio between the maximum and minimum moments of inertia (I(max)/I(min) ratio) in 281 men aged 50 to 79 years. Current (>50 years) and past (13-50 years) sport and leisure time activity was assessed by questionnaire to calculate an osteogenic index (OI) during adolescence and adulthood. All men were then categorized into a high (H) or low/non impact (L) group according to their OI scores in each period. Three contrasting groups were then formed to reflect weight-bearing impact categories during adolescence and then adulthood: H-H, H-L and L-L. For polar bone mass distribution, bone deposition in the anterolateral, medial and posterior cortices were 6-10% greater at the mid-femur and 9-24% greater at mid-tibia in men in the highest compared to lowest tertile of lifetime loading (p<0.01-<0.001). When comparing the influence of contrasting loading history during adolescence and adulthood, there was a graded response between the groups in the distribution of bone mass at the anterior-lateral and posterior regions of the mid-tibia (H-H>H-L>L-L). For radial bone density distribution, there were no statistically significant effects of loading at the mid-femur, but a greater lifetime OI was associated with a non-significant 10-15% greater bone density near the endocortical region of the mid-tibia. In conclusion, a greater lifetime loading history was associated with region-specific adaptations in cortical bone density.
我们之前曾报道过，长期进行负重运动与中年和老年男性的 QCT 衍生皮质骨大小和强度增加有关，但与整个骨皮质体积 BMD 无关。然而，由于骨重塑和加载引起的应变在皮质骨内的分布不均匀，因此本研究旨在研究终身负荷史对健康社区居住的中年和老年男性的皮质骨质量分布和骨形状的影响。我们使用 QCT 评估了 281 名 50 至 79 岁男性的股骨中段和胫骨中段围绕其中心的角骨质量分布（极分布）、通过皮质的骨密度分布（径向分布）以及最大和最小转动惯量之比（I(max)/I(min) 比值）。通过问卷评估当前（>50 岁）和过去（13-50 岁）的运动和休闲时间活动，以计算青少年和成年时期的成骨指数（OI）。所有男性随后根据其在每个时期的 OI 评分分为高（H）或低/非冲击（L）组。然后根据青少年和成年时期的负重冲击类别形成三个对比组：H-H、H-L 和 L-L。对于极分布的骨质量，与最低 tertile 相比，最高 tertile 的男性在股骨中段前外侧、内侧和后侧皮质的骨沉积分别增加了 6-10%，在胫骨中段增加了 9-24%（p<0.01-<0.001）。当比较青少年和成年时期对比负荷史的影响时，在前外侧和后外侧区域的骨质量分布中，各组之间存在分级反应（H-H>H-L>L-L）。对于径向骨密度分布，股骨中段的负荷没有统计学上的显著影响，但更大的终生 OI 与胫骨中段内皮质区域的骨密度增加 10-15%相关，但无统计学意义。总之，更大的终生负荷史与皮质骨密度的特定区域适应性有关。
