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、纵向研究，旨在描述非裔美国人、高加索人、中国人、日本人和西班牙裔妇女的社区样本在绝经过渡期间发生的生物学和心理社会变化。SWAN的首要目标是“阐明区分最易受卵巢激素缺乏长期病理生理后果影响的妇女与受保护妇女的因素。“卵巢衰老的一个关键生理后果是骨骼质量的变化，这是专门针对SWAN的。因此，七个SWAN临床站点中的五个正在通过双X射线吸收测定法（DXA）进行骨矿物质密度（BMD）的年度测量。除西班牙裔妇女外，所有天鹅族裔群体都参加了天鹅骨项目。然而，BMD只是影响骨强度的几个因素之一;骨结构特性，包括横截面中骨量的大小、厚度、形状和空间分布也有影响。此外，骨折是由骨强度和骨承受的负荷之间的不平衡引起的。因此，骨折风险取决于骨强度相对于它必须承受的负荷;后者取决于身体大小。我们建议使用托马斯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测量髋关节几何形状和强度。我们还建议比较髋关节的结构参数和强度指数获得的区域DXA扫描与获得的三维成像，使用定量计算机断层扫描（QCT）的一个子集的妇女。我们研究的具体目的是：1）确定基于DXA的髋关节几何形状和强度的面积估计值与QCT测量值之间的相关性; 2）确定基线时股骨颈尺寸、结构和复合强度指数的种族差异的方向和幅度; 3）确定基线股骨颈尺寸、结构和强度的预测因子; 4）确定不同种族人群中股骨颈尺寸和结构及复合强度指数随年龄和绝经过渡的纵向变化率;第五章）确定与股骨颈尺寸和强度指数纵向变化相关的因素，并将其对尺寸和强度的影响与6）验证股骨颈基线尺寸、结构和复合强度指数预测中年女性发生骨折风险的假设。我们的长期目标是在一个特征鲜明的多种族中年妇女队列中，大大提高我们对衰老和绝经对髋关节尺寸、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.