BONE DENSITY, ENDOGENOUS HORMONES, & BREAST CANCER RISK

描述：（申请人的描述）最近的研究表明， 女性的骨矿物质密度（BMD）与她的风险直接相关， 乳腺癌 其他研究表明内源性激素 BMD和患乳腺癌的风险。 到目前为止，还没有研究 这些因素在一起，以澄清这些独立性 影响和可能的因果途径的性质。 在这项提案中， 研究人员试图通过评估这些因素来扩展以前的研究， 在一个独立的研究人群中， BMD、激素水平和乳腺癌之间的相互关系。 研究人群包括8076名接受筛查的绝经后妇女 在骨折干预试验的11个部位中的4个， 随机临床试验，检查阿仑膦酸钠在 骨折的二级预防。 在这8076名女性中，他们预计有131名 在4年的随访中，乳腺癌的发病率。 他们提议 进行：（1）一项回顾性队列研究，以评估增加BMD作为 乳腺癌风险的预测因子;（2）巢式病例对照研究， 检查是否增加游离雌二醇水平，雌二醇结合， 白蛋白和总雌二醇，以及与性别结合的雌二醇水平较低 激素结合球蛋白（SHBG）和SHBG，与增加 乳腺癌风险;（3）巢式病例对照分析，以检查是否有 BMD与乳腺癌之间的正相关是由激素介导的 水平;（4）回顾性队列分析，以评估 乳腺癌风险与已知影响BMD的因素（饮食 维生素D、氟化物和钙的摄入;钙的补充; 运动;和重量）。 有证据表明骨密度和乳腺癌之间的关联是 有限但具有启发性;然而，迄今为止还没有研究将 测量内源性雌二醇，以检查这种关联是否 与荷尔蒙状态无关。 调查人员将检查 BMD与乳腺癌风险之间的关系独立于内源性 雌二醇，并一起检查它们的贡献。 如果BMD预测 除了女性的激素水平外， 将检查影响BMD的其他因素，因此也可能 影响乳腺癌风险。 通过这种方式，他们可能能够识别 乳腺癌的病因学中涉及的其他途径。 鉴定 一个连接妇女两种最常见健康状况的共同途径， 骨质疏松症和乳腺癌，将有非常重要的意义， 了解两者的病因和随后的预防。

DESCRIPTION: (Applicant's Description) Recent studies suggest that a woman's bone mineral density (BMD) is directly correlated with her risk of breast cancer. Other studies suggest a link between endogenous hormones with both BMD and risk of breast cancer. To date, no studies have examined these factors together in an effort to clarify the independence of these effects and the nature of a possible causal pathway. In this proposal the investigators seek to extend previous research by evaluating these associations in an independent study population and by determining the interelationships between BMD, hormone levels, and breast cancer. The study population consists of 8076 postmenopausal women who were screened at four of the eleven sites from the Fracture Intervention Trial, a randomized clinical trial examining the efficacy of alendronate in the secondary prevention of fractures. In these 8076 women they expect 131 incident breast cancer cases during 4 years of followup. They propose to conduct: (1) a retrospective cohort study to assess increasing BMD as a predictor of risk of breast cancer; (2) a nested case-control study to examine whether increasing levels of free estradiol, estradiol bound to albumin, and total estradiol, and lower levels of estradiol bound to sex hormone binding globulin (SHBG), and SHBG, are associated with an increase in breast cancer risk; (3) a nested case-control analysis to examine if any positive association between BMD and breast cancer is mediated by hormone levels; and (4) a retrospective cohort analysis to assess the relationship between breast cancer risk and factors known to influence BMD (dietary intake of vitamin D, fluoride, and calcium; calcium supplementation; exercise; and weight). Evidence demonstrating the association between BMD and breast cancer is limited but suggestive; however, no studies to date have incorporated the measurement of endogenous estradiol to examine if this association is independent of hormonal status. The investigators will examine the relationship between BMD and breast cancer risk independent of endogenous estradiol as well as examine their contribution together. If BMD predicts breast cancer risk in this cohort, beyond a woman's hormone levels, they will examine other factors that affect BMD, and could therefore also influence risk of breast cancer. In this way, they may be able to identify other pathways involved in the etiology of breast cancer. Identification of a common pathway linking two of the most common health conditions of women, osteoporosis and breast cancer, will have very important implications for understanding the etiology and subsequent prevention of both.