Structural adaptation to changing skeletal load in the progression toward hip fragility: The study of osteoporotic fractures
Structural adaptation to changing skeletal load in the progression toward hip fragility: The study of osteoporotic fractures
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DOI：
10.1359/jbmr.2001.16.6.1108
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发表时间：
2001-06-01
影响因子：
6.2
通讯作者：
Cummings, SR
中科院分区：
文献类型：
--
作者：
Beck, TJ;Oreskovic, TL;Cummings, SR
应用结构分析程序对4187例骨质疏松性骨折研究中的老年女性的纵向双能X线骨密度仪(DXA)数据进行了研究。测量横跨股骨颈和股骨近端狭窄区域的横断面几何形状和骨密度。我们假设：骨骼负荷的改变应该刺激截面模数(弯曲强度指数)的适应性增加或减少，并且维度细节将提供对髋关节脆性的洞察。扫描时间点之间类似3.5年的体重变化被用作骨骼负荷变化的主要指标。“静态”体重定义为基线体重的5%以内，而“增重”和“减重”分别指体重增加或减少5%的人。此外，我们使用了脆弱指数来更好地识别那些骨骼负荷发生变化的受试者。如果受试者不能在没有扶手的情况下从椅子上站起五次，就会被归类为虚弱。将体弱和体重减轻(减重)的受试者与不虚弱且保持体重(不变负荷)或增加体重(增加负荷)的受试者进行比较，60%的受试者(n=2559)，不变负荷的受试者颈部骨密度下降，但不同部位的截骨弹性系数没有变化，而截面弹性系数在两个部位均略有增加，增加负荷的受试者(n=580)失去颈部骨密度，但增加了干骨密度；截骨弹性系数在两个部位均显著增加。那些骨骼负荷下降的人(n=105)显示出颈部和骨干的BMD损失最大；颈部的丢失是由骨量丢失和更大的骨膜下膨胀率共同造成的；骨干的BMD下降只是由于更大的骨量丢失造成的，这组人在两个部位的截面弹性也都出现了显著的下降，这些结果支持了这样的观点，即髋关节的机械动态平衡在截面弹性系数中明显，而在骨量或密度方面则不明显，骨骼负荷下降的适应性反应，具有更快的骨膜下扩张和皮质变薄的速度，可能会增加脆性，超出截面弹性系数或骨量单独降低的预期。
Longitudinal dual-energy X-ray absorptiometry (DXA) hip data from 4187 mostly white, elderly women from the Study of Osteoporotic Fractures were studied with a structural analysis program. Cross-sectional geometry and bone mineral density (BMD) were measured in narrow regions across the femoral neck and proximal shaft. We hypothesized that altered: skeletal load should stimulate adaptive increases or decreases in the section modulus (bending strength index) and that dimensional details would provide insight into hip fragility. Weight change in the similar to3.5 years between scan time points was used as the primary indicator of altered skeletal load. "Static") weight was defined as within 5% of baseline weight, whereas "gain" and "loss") were those who gained or lost >5%, respectively. In addition, we used a frailty index to better identify those subjects undergoing changing in skeletal loading. Subjects were classified as frail if unable to rise from a chair five times without using arm support. Subjects who were both frail and lost weight (reduced loading) were compared with those who were not frail and either maintained weight (unchanged loading) or gained weight (increased loading), Sixty percent of subjects (n = 2559),vith unchanged loads lost BMD at the neck but not at the shaft, while section moduli increased slightly at both regions, Subjects with increasing load (n = 580) lost neck BMD but gained shaft BMD; section moduli increased markedly at both locations. Those with declining skeletal loads (n = 105) showed the greatest loss of BMD at both neck and shaft; loss at the neck was caused by both increased loss of bone mass and greater Subperiosteal expansion; loss in shaft BMD decline was only caused by greater loss of bone mass, This group also showed significant declines in section modulus at both sites, These results support the contention that mechanical homeostasis in the hip is evident in section moduli but not in bone mass or density, The adaptive response to declining skeletal loads, with greater rates of subperiosteal expansion and cortical thinning, may increase fragility beyond that expected from the reduction in section modulus or bone mass alone.