BONE DENSITY, ENDOGENOUS HORMONES, & BREAST CANCER RISK

描述：(申请人的描述)最近的研究表明 女性的骨密度(BMD)与其患高血压的风险直接相关。 乳腺癌。其他研究表明，内源性荷尔蒙与 既有骨密度，又有患乳腺癌的风险。到目前为止，还没有研究检查过 这些因素结合在一起，努力澄清这些因素的独立性 可能的因果路径的影响和性质。在这份提案中， 研究人员试图通过评估这些研究来扩展之前的研究 独立研究人群中的相关性，并通过确定 骨密度、激素水平与乳腺癌的关系。 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，有4个部位的 随机临床试验检测阿伦磷酸钠治疗慢性阻塞性肺疾病的疗效 骨折的二级预防。在这8076名女性中，他们预计有131名 4年随访期间发生乳腺癌病例。他们提议 开展：(1)一项回顾队列研究，以评估骨密度增加是一种 乳腺癌风险的预测因素；(2)嵌套病例对照研究 检查游离雌二醇水平的增加，雌二醇是否与 白蛋白和总雌二醇，以及与性行为有关的较低水平的雌二醇 激素结合球蛋白(SHBG)和SHBG与 乳腺癌风险；(3)嵌套病例对照分析，以检查是否有 BMD与乳腺癌的正相关是由激素介导的 水平；和(4)回顾队列分析，以评估这种关系 乳腺癌风险和已知影响BMD的因素之间的关系(饮食 摄取维生素D、氟化物和钙；补钙； 锻炼；和体重)。 有证据表明BMD与乳腺癌之间存在联系 有限但具有启发性；然而，到目前为止还没有研究将 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 骨密度与乳腺癌发病风险的非内源性关系 雌二醇，以及检查他们的共同贡献。如果BMD预测 在这个队列中，乳腺癌风险超出了女性的荷尔蒙水平，他们 将研究影响BMD的其他因素，因此也可能 影响患乳腺癌的风险。通过这种方式，他们或许能够识别出 与乳腺癌病因学有关的其他途径。身份识别 一条连接女性最常见的两种健康状况的共同途径， 骨质疏松症和乳腺癌，将对 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.