Predicting Hip Fracture Using a Biomechanical Approach

描述（由申请人提供）：髋部骨折是老年人致残和死亡的重要原因。诊断骨质疏松和预测骨折风险最常用的工具是用双能x线骨密度仪测量骨密度（BMD）。然而，通过骨密度测试，多达一半的髋部骨折患者没有骨质疏松症；因此，需要其他方法来评估骨折风险。这强调了寻找其他导致骨折风险的因素的重要性，例如股骨粗隆处软组织厚度减少，这会减弱可能导致骨折的坠落力。根据生物力学原理，当施加的力与骨强度的比率（称为“风险因子”）超过1时，就会发生骨折。之前的两项研究考察了风险因素与粗隆软组织厚度的关系，但只有少量髋部骨折，结果也相互矛盾。为了更好地了解与髋部骨折相关的因素，我们建议使用生物力学方法来评估髋部骨折风险，包括在侧身摔倒时髋部所受的估计力以及股骨近端力量。具体目的是研究股骨粗隆软组织厚度对髋部骨折风险的影响，并将其纳入生物力学风险因素模型。我们假设这些因素可以预测髋部骨折，并进一步证明髋部骨折风险因素预测将优于单独的BMD评估和世界卫生组织的FRAX工具。我们将从三个队列（Framingham研究、mro研究、Rancho Bernardo研究）中确定前瞻性髋部骨折病例，并从每个队列中选择最多4名性别和年龄匹配（3年内）的非骨折队列成员作为对照，采用病例队列研究设计以提高效率。2435个人的软组织厚度

DESCRIPTION (provided by applicant): Hip fractures are a significant cause of disability and mortality in older persons. The most common tool for diagnosis of osteoporosis and prediction of fracture risk is bone mineral density (BMD) measured by dual- energy X-ray absorptiometry. Yet, up to half of individuals suffering a hip fracture do not have osteoporosis by BMD testing; thus alternative approaches to fracture risk assessment are needed. This underscores the importance of looking for additional contributors to fracture risk, such as reduced soft tissue thickness at the trochanter, which attenuates the fall forces that may lead to fracture. According to biomechanical principles, when the ratio of applied force to bone strength, (termed the 'Factor-of-Risk'), exceeds one, a fracture will occur. Two previous studies have examined the Factor-of-Risk along with trochanteric soft tissue thickness but had only small numbers of hip fractures, and conflicting results. To better understand the factors associated with hip fracture, we propose to use a biomechanical approach to assess hip fracture risk that includes both estimated forces applied to the hip during a sideways fall as well as the strength of the proximal femur. The specific goal is to investigate the contribution of trochanteric soft tissue thickness t hip fracture risk, and to include this in the biomechanical Factor-of-Risk model. We hypothesize these factors predict hip fracture, and further that the factor-of-risk prediction of hip fracture isk will prove better than BMD assessment alone and better than the World Health Organization FRAX tool. We will identify prospectively ascertained hip fracture cases from three cohorts (Framingham Study, MrOS, Rancho Bernardo Study) and from each cohort also select up to four sex- and age-matched (within 3-years) non-fracture cohort members as controls, using the case-cohort study design to increase efficiency. Soft tissue thickness in 2,435 individuals will be assess on whole body DXA scans obtained at the earliest time in each cohort before any subsequent hip fracture occurred. Relative risks will be assessed as odds ratios using conditional logistic regression. This study has potential to significantly alter the way hip fractue risk is currently being assessed, and thus how patients are selected for drug therapy.