Department of Radiology and Biomedical Imaging, University of California, San Francisco, CA 94143-0946, USA.
Bone. 2011 Apr 1;48(4):741-7. doi: 10.1016/j.bone.2010.12.004. Epub 2010 Dec 17.
A group of 48 men (22 aged 65-75 years, 26 aged 80-90 years) and 59 women (32 aged 65-75 years, 27 aged 80-90 years) were enrolled in the Age, Gene/Environment Susceptibility-Reykjavik study and imaged with in vivo volumetric Quantitative Computed Tomography (QCT) to investigate the effects of age and sex on femoral neck structure and strength. Femoral neck cross-sectional moment of inertia for bending directions near those of standing and walking (I(AP)), bending strength (M(y)), and axial compressive strength (F(y)) were computed at the location of minimum cross-sectional area (minCSA). Local cortical thickness was computed in the inferior femoral neck based on density profiles extending through the cortex of the minCSA femoral neck section. Multivariate models accounting for height, weight, and age group (younger or older) showed that men had a 46% higher M(y) and a 23% higher F(y) than women, while women had a 13% thicker inferior cortex than men. Cortical thickness in the inferoposterior region of the femoral neck was significantly related to bending and axial strength after adjusting for overall volumetric bone mineral density. Both minCSA and I(AP) were higher in the older, gender-pooled age group, but F(y) and M(y) did not differ between the two age groups. The results suggest that age-related expansion of the femoral neck primarily occurs in the superior and inferior directions and helps maintain homeostasis of femoral neck stiffness and strength. The higher bending strength of the male femoral neck may partly explain why elderly men have a lower risk of hip fracture than elderly women.
一组 48 名男性（22 名年龄 65-75 岁，26 名年龄 80-90 岁）和 59 名女性（32 名年龄 65-75 岁，27 名年龄 80-90 岁）参与了 Age, Gene/Environment Susceptibility-Reykjavik 研究，并通过体内容积定量计算机断层扫描 (QCT) 进行成像，以研究年龄和性别对股骨颈结构和强度的影响。股骨颈弯曲方向（接近站立和行走方向）的横截面转动惯量（I(AP)）、弯曲强度（M(y)）和轴向压缩强度（F(y)）在最小横截面积（minCSA）处计算。基于通过 minCSA 股骨颈截面的皮质密度分布计算下股骨颈的局部皮质厚度。考虑身高、体重和年龄组（年轻或年长）的多变量模型表明，男性的 M(y)比女性高 46%，F(y)比女性高 23%，而女性的下皮质比男性厚 13%。调整总体容积骨矿物质密度后，股骨颈后下区域的皮质厚度与弯曲和轴向强度显著相关。在年龄较大的、性别混合的年龄组中，minCSA 和 I(AP)更高，但两组之间的 F(y)和 M(y)没有差异。研究结果表明，与年龄相关的股骨颈扩张主要发生在上部和下部方向，有助于维持股骨颈刚度和强度的体内平衡。男性股骨颈的较高弯曲强度可能部分解释了为什么老年男性髋部骨折的风险低于老年女性。
