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学，涉及骨骼脆弱性、跌倒风险以及一旦发生跌倒反应受损。目前，定量骨评估，如双能X线吸收测定法（DXA）和定量计算机断层扫描（QCT）作为骨骼强度的替代品，但作为骨折风险的替代品的价值有限，因为它们不提供非骨骼风险因素，如福尔斯的信息。研究表明，跌倒风险与肌肉力量下降有关，特别是股骨近端肌肉组织。髋关节的QCT图像提供了有关股骨近端肌肉的大小和组成的信息，在各种骨骼部位的研究表明，肌肉强度与肌肉大小之间存在相关性，并且通过X射线CT测量衰减。在我们的实验室中，我们最近表明，肌肉大小和衰减数据与CT骨骼测量相结合，显着提高了CT测量的区分能力。在这里，我们建议开发计算机算法，以评估肌肉的大小和衰减从QCT髋关节图像，前瞻性地验证，这些措施提高骨折预测结合使用时，髋关节QCT骨变量，并确定其预测骨折的机制。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，目前正在随访髋关节和其他骨骼部位的偶发骨折。这项研究计划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，该评估可以与QCT骨测量相结合，从而显着提高诊断效率，而无需额外的程序成本。公共卫生救济：基于临床可用的髋部QCT骨骼成像开发肌肉量化程序是改善髋部骨折风险估计的重要途径。通过提供反映跌倒风险的额外非骨骼措施，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.