Hip Strength Across the Menopausal Transition

描述（由申请人提供）：拟议的R-01建立在全国妇女健康研究（SWAN）骨质疏松症项目的基础上。SWAN是一项多中心的纵向研究，旨在描述非裔美国人、白种人、中国、日本和西班牙裔妇女在绝经过渡期间发生的生物学和社会心理变化。SWAN的首要目标是“阐明区分最易受卵巢激素缺乏长期病理生理后果影响的女性与受到保护的女性的因素”。卵巢衰老的关键生理后果之一是骨骼质量的变化，这是SWAN专门针对的。因此，7个SWAN临床站点中有5个使用双x线吸收仪（DXA）进行骨矿物质密度（BMD）的年度测量。除西班牙裔妇女外，所有SWAN种族都代表了SWAN骨骼项目。然而，骨密度只是影响骨骼强度的几个因素之一；骨结构特性包括骨量在横截面上的大小、厚度、形状和空间分布也起作用。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它所承受的载荷的骨强度；后者取决于体型。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。我们还建议对一部分女性的髋关节结构参数和强度指数进行比较，这些参数和强度指数是由平面DXA扫描获得的，与使用定量计算机断层扫描（QCT）获得的三维成像获得的。我们研究的具体目的是：1)确定基于髋关节几何形状和强度的面积DXA估计与QCT测量之间的相关性；2)确定基线时股骨颈大小、结构和综合强度指标的民族差异方向和幅度；3)确定基线股骨颈大小、结构和强度的预测因素；4)确定不同民族股骨颈大小、结构及复合强度指标随年龄增长和绝经期过渡的纵向变化率；5)确定股骨颈尺寸和强度指标纵向变化的相关因素，比较其对股骨颈尺寸和强度的影响及其对骨密度的影响；6)验证基线股骨颈尺寸、结构和复合强度指标预测中年女性意外骨折风险的假设。我们的长期目标是在一个多种族的中年妇女队列中，大幅度提高我们对衰老和更年期对髋部尺寸、结构和力量测量的影响的理解。

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.