DXA-BASED BONE GEOMETRY AND OSTEOPOROTIC FRACTURE RISK

在美国，每年发生的与年龄相关的骨折超过130万例。 包括大约250,000髋部骨折，550,000 脊椎和手腕的25万块。每年的治疗费用被认为是 超过100亿美元，预计将增长到 接下来的30年。以它们的频率衡量，对质量的影响 在生活和经济成本中，老年人中与年龄相关的骨折是 危机程度的公共卫生问题。在成功范围内 旨在减少其发生率的举措，对 本世纪和下个世纪的卫生资源分配是 令人震惊。减少与年龄有关的疾病患病率的干预措施 骨折必须建立在对骨折病因的良好理解的基础上， 关于证明有效性和成本效益的药剂和方法， 以及诊断、筛查和治疗监测程序。的 适当的准确度、精密度和灵敏度。在这项研究中 计划，我们将继续致力于新密度测量技术的发展 提高诊断灵敏度和预测准确性的工具。我们的 头三年的目标是描述 骨几何特性与密度学特性的关系 用一种新的多扫描双能X射线吸收法(DXA)测定 技术与桡骨远端和近端的骨折载荷 大腿骨。我们发现：1)多扫描DXA参数可以很好地预测 桡骨远端骨折载荷(R2=0.67，p，0.0001)与传统的 桡骨远端骨密度测量无统计学意义(R2=0.07，p.0.1)； MultiScan DXA参数和股骨颈骨密度是良好的预测指标 股骨近端的骨折载荷(R2=0.740，而传统的骨密度 粗隆间部位的测量值不同(r2=0.12，p=0.10)； 3)桡骨远端的断裂载荷不能很好地预测骨折。 臀部负重。这些发现对其使用具有重要的意义。 以及对常规密度测量的解释，提出了进一步的 DXA技术的发展正在升温。在这场竞争性的更新中 我们建议在两个重要方面扩展我们的发现。首先，在 具体目标1和2，我们计划测试DXA的歧视能力 两项病例对照临床研究中的几何变量(一项回顾 对单独资助的瀑布监测中可用的DXA扫描进行审查 自发性髋部骨折患者的研究及新的观察性研究 以及他们的年龄和性别匹配的对照)。第二，在具体目标上 3和4，我们将DXA方法扩展到脊柱，从而 允许进行常规和几何DXA和断裂载荷比较 首次在所有三个骨折高危区域之间制造 在同一具身体标本中。我们期待着自发的研究 骨折在髋关节之间产生更强的密度分离 骨折患者和对照，因为数据不会被 与跌倒严重程度和创伤负荷相关的问题。我们希望 提供(即使对于传统的密度测量)更真实的估计 与日常生活活动相关的骨折危险阈值 从而更好地瞄准面临真正脆弱性风险的候选人 髋部骨折。

Over 1.3 million age-related fractures occur annually in the U.S. including approximately 250,000 fractures of the hip, 550,000 of the spine and 250,000 of the wrist. Annual costs for treatment are thought to exceed $10 billion are expected to grow to more than $30 billion in the next 30 years. As measured by their frequency, influence on quality of life and economic cost, age-related fractures among the elderly are a public health problem of crisis proportions. Within successful initiatives aimed at reducing their incidence, the implications for the allocation of health resources in this and the next century are staggering. Interventions to reduce the prevalence of age-related fractures must be based on a sound understanding of fracture etiology, on agents and approaches of demonstrated efficacy and cost effectiveness, and on diagnostic, screening and therapeutic monitoring procedures. of appropriate accuracy, precision and sensitivity. In this research program, we continue to address the development of new densitometric tools of increased diagnostic sensitivity and predictive accuracy. Our objectives in the first three years were to characterize the relationships between bone geometric and densitometric properties determined by a new multiscan Dual Energy X-Ray Absorptiometry (DXA) technique and bone fracture loads at the distal radius and proximal femur. We showed: 1) multiscan DXA parameters are highly predictive of distal radius fracture loads (r2=0.67,p,0.0001) whereas conventional measures of BMD at the distal radius are not (r2= 0.07, p .0.1);2) multiscan DXA parameters and BMD at the femoral neck are good predictors of fracture load in the proximal femur (r2=0.740 but conventional BMD measures at intertrochanteric sites are not (r2=0.12, p=0.10); and 3)fracture loads at the distal radius are poor predictors of fracture load at the hip. These findings have important implications for the use and interpretation of conventional densitometry an suggest athe further development of DXA techniques are warmed. In this competitive renewal we propose to extend our findings in two significant ways. First, in Specific Aims 1 and 2, we plan to test the discriminatory power of DXA geometric variables in two case-control clinical studies (a retrospective review of available DXA scans from a separately funded falls surveillance study and a new observational study of spontaneous hip fracture patients and their age- and gender-matched controls). Second, in Specific Aims 3 and 4, we will extend our DXA methodology to the spine and thereby allow conventional and geometric DXA and fracture load comparisons to be made for the first time between all three high fracture risk regions within the same cadaveric specimen. We expect the study of spontaneous fracture to yield a much stronger densitometric separation between hip fracture patients and controls since the data will not be confounded by issues related to fall severity and traumatic loading. We hope to provide (even for conventional densitometry) more realistic estimates of the fracture risk threshold associated with activities of daily living and thus better targeting of candidates at risk for true fragility fractures of the hip.