Hip Strength Across the Menopausal Transition

描述(申请人提供)：建议的R-01建立在全国妇女健康研究(天鹅)骨质疏松症项目的基础上。SWAN是一项多中心的纵向研究，旨在描述以社区为基础的非裔美国人、高加索人、中国人、日本人和西班牙裔妇女在更年期过渡期间发生的生物学和心理社会变化。SWAN的首要目标是“阐明哪些因素能将最易受卵巢激素缺乏的长期病理生理影响的女性与受保护的女性区分开来。”在Swan中，卵巢老化的主要生理后果之一是骨骼质量的变化。因此，七个天鹅诊所中的五个正在使用双X射线骨密度仪(DXA)进行年度骨密度(BMD)测量。除西班牙裔妇女外，所有天鹅民族都参加了天鹅骨骼项目。然而，骨密度只是影响骨强度的几个因素之一；骨结构特性，包括大小、厚度、形状和骨量在横截面上的空间分布也起到了作用。此外，骨折是由于骨骼强度和骨骼承受的负荷之间的不平衡造成的。因此，骨折风险取决于相对于其所承受的负荷的骨骼强度；后者取决于身体的大小。我们建议使用Thomas Beck博士开发的髋关节结构分析程序和Arun Karlamangla博士开发的复合强度指数来测量髋关节几何形状和强度。我们还建议将区域DXA扫描获得的髋关节结构参数和强度指数与使用定量计算机断层扫描(QCT)对一组女性进行三维成像获得的髋关节结构参数和强度指数进行比较。我们研究的具体目的是：1)确定基于区域DXA的髋关节几何和力量估计与QCT测量之间的相关性；2)确定基准时股骨颈大小、结构和综合强度指数的种族差异的方向和大小；3)确定基线股骨颈大小、结构和强度的预测因子；4)确定不同民族的股骨颈大小、结构和综合强度指数随年龄和绝经过渡而纵向变化率；5)确定与股骨颈大小和强度指数纵向变化相关的因素，并比较它们对大小和强度的影响以及对骨密度的影响；6)检验基线股骨颈大小以及结构和综合强度指数预测中年女性发生骨折风险的假设。我们的长期目标是大幅提高我们对老龄化和绝经对多民族中年女性髋关节大小、结构和力量测量指标的影响的理解。

DESCRIPTION (provided by applicant): The proposed R-01 builds upon the Study of Woman's Health Across the Nation (SWAN) osteoporosis project. SWAN is a multi-center, longitudinal study, designed to characterize the biological and psychosocial changes that occur during the menopausal transition in a community-based sample of African-American, Caucasian, Chinese, Japanese, and Hispanic women. An overarching goal of SWAN is "to elucidate factors that differentiate women most susceptible to long-term pathophysiological consequences of ovarian hormone deficiency from women who are protected." One of the key physiological consequences of ovarian aging that was specifically targeted in SWAN was change in skeletal mass. Thus, five of the seven SWAN clinical sites are making annual measures of bone mineral density (BMD) by Dual X-ray Absorptiometry (DXA). All SWAN ethnic groups except the Hispanic women are represented in the SWAN bone project. However, BMD is only one of several factors that contribute to bone strength; bone structural properties including size, thickness, shape and spatial distribution of bone mass in a cross-section also contribute. Additionally, fractures result from an imbalance between bone strength and the load the bone bears. Thus, fracture risk depends on bone strength relative to the load it has to bear; the latter depends on body size. We propose to measure hip geometry and strength using the Hip Structural Analysis Program developed by Dr. Thomas Beck, and the Composite Strength Indices developed by Dr. Arun Karlamangla. We also propose to compare hip structural parameters and strength indices obtained from areal DXA scans with those obtained from 3-dimensional imaging using Quantitative Computed Tomography (QCT) on a subset of women. The specific aims of our study are to: 1) Determine the correlations between areal DXA based estimates of hip geometry and strength with QCT measures; 2) Determine the direction and magnitude of ethnic differences in femoral neck size, structure, and composite strength indices at baseline; 3) Identify predictors of baseline femoral neck size, structure, and strength; 4) Determine the rate of longitudinal change in femoral neck size and structural and composite strength indices with aging and with transition through menopause in different ethnic groups; 5) Identify factors associated with longitudinal changes in femoral neck size and strength indices and to compare their effects on size and strength with their effects on bone density; 6) Test the hypothesis that baseline femoral neck size and structural and composite strength indices predict incident fracture risk in midlife women. Our long-term objective is to substantially improve our understanding of the impact of aging and menopause on measures of hip size, structure, and strength in a well-characterized multiethnic cohort of mid-life women.