The Proximal Femoral Musculature: A new Risk Factor for Hip Fracture

描述（由申请人提供）：骨质疏松性骨折具有复杂的病因，涉及骨骼脆性、跌倒风险和跌倒后反应受损。目前，定量骨骼评估，如双x线吸收仪（DXA）和定量计算机断层扫描（QCT）作为骨骼强度的替代品，但作为骨折风险替代品的价值有限，因为它们不能提供跌倒等非骨骼风险因素的信息。研究表明，跌倒风险与肌肉力量下降有关，尤其是股骨近端肌肉组织。髋关节的QCT图像提供了关于股骨近端肌肉大小和组成的信息，在不同骨骼部位的研究表明，x射线CT测量的肌肉力量、肌肉大小和衰减之间存在相关性。在我们的实验室中，我们最近表明，将肌肉大小和衰减数据与CT骨骼测量相结合，可以显着提高CT测量的辨别能力。在这里，我们建议开发计算机算法来评估QCT髋关节图像的肌肉大小和衰减，前瞻性地验证这些措施在与髋关节QCT骨骼变量结合使用时可以改善骨折预测，并确定它们预测骨折的机制。研究队列将从5000名老年人中选择，这些老年人在前瞻性年龄基因/环境-雷克雅未克（AGES-R）研究中进行了基线QCT检查，目前正在接受髋部和其他骨骼部位意外骨折的随访。本研究项目的最终目标是开发一种重要的非骨骼风险因素的定量评估方法，该方法可以与QCT骨骼测量相结合，从而在不增加额外手术成本的情况下显著提高诊断效率。公共卫生相关性：基于临床可用的髋关节QCT骨骼成像的肌肉量化程序的发展是改善髋部骨折风险评估的重要途径。通过提供反映跌倒风险的额外非骨骼测量，它可能会改变髋部骨折风险患者的管理。这种定量测量是可修改的，可以成为特定运动或药物治疗的治疗终点。

DESCRIPTION (provided by applicant): Osteoporotic fracture has a complex etiology involving skeletal fragility, risk of falling, and impaired reaction to a fall once it is initiated. Currently, quantitative bone assessments such as dual x-ray absorptiometry (DXA) and quantitative computed tomography (QCT) act as surrogates for skeletal strength but are of limited value as surrogates of fracture risk because they do not provide information on non-skeletal risk factors such as falls. Studies have shown that fall risk is associated with reduced muscle strength, particularly of the proximal femoral musculature. The QCT image of the hip provides information on the size and composition of the proximal femoral muscles, and studies at various skeletal sites have shown correlations between muscle strength and muscle size and attenuation measured by x-ray CT. In our laboratory, we have recently shown that combination of muscle size and attenuation data with the CT skeletal measures markedly improves the discriminatory power of the CT measurement. Here, we propose to develop computer algorithms to assess muscle size and attenuation from QCT hip images, prospectively validate that these measures improve fracture prediction when used in combination with hip QCT bone variables, and determine the mechanism by which they predict fracture. The study cohort will be selected from 5000 elderly individuals who have had baseline QCT examinations in the prospective Age Gene/Environment -Reykjavik (AGES-R) study and who are now being followed for incident fractures of the hip and other skeletal sites. The ultimate goal of this research program is to develop a quantitative assessment of an important non-skeletal risk factor that can be combined with QCT bone measurements, thus significantly improving diagnostic efficacy without the cost of an additional procedure. PUBLIC HEALTH RELEVENCE: Development of a muscle quantification procedure based on clinically available hip QCT skeletal imaging is an important pathway to improving estimation of hip fracture risk. It would potentially modify management of patients at risk for hip fractures by providing an additional non-skeletal measure reflective of fall risk. This quantitative measurement is modifiable and could become a treatment endpoint for specific exercise or drug therapies.