Plasma Carotenoids and Breast Cancer Risk-Pooled Analysis of Prospective Studies

描述(由申请人提供)： 乳腺癌的流行病学研究表明，生活方式因素在病因中起着一定的作用。饮食作为乳腺癌发病率人群差异的一个可能因素受到了很多关注，但结果并不完全一致。类胡萝卜素是水果和蔬菜中重要的微量营养素，由于其抗氧化特性而引起了人们的特别兴趣。与饮食中类胡萝卜素摄入量的相关性较弱或为零，而在绝经前妇女和吸烟者等亚组中观察到较强的相关性。然而，由于饮食回忆中的错误以及类胡萝卜素的吸收和代谢的个体差异，膳食摄入量评估可能被错误分类。到目前为止，只有六项关于血浆类胡萝卜素与乳腺癌风险的前瞻性研究发表，超过60例。大多数这些研究都报告了与一种或多种类胡萝卜素的显著负相关，但具体的类胡萝卜素在不同研究中并不一致。在这项申请中，我们建议对这六项进行得很好的前瞻性研究的现有数据进行协作分析，以便更全面地了解类胡萝卜素与乳腺癌之间的联系。在这项研究中，我们将利用六项前瞻性病例对照研究中的现有数据，研究血浆类胡萝卜素与乳腺癌风险的关系。本申请包括以下研究：密苏里州哥伦比亚；瑞典乌梅埃；纽约大学妇女健康研究；马里兰州华盛顿县；护士健康研究；和妇女健康研究。这些研究代表了世界上发表的关于血浆类胡萝卜素和乳腺癌风险的文献的90%。合并分析将包括2348例病例和2535名对照。为了解决不同研究之间实验室差异的可能性，我们将在中心位置重新分析每个研究的20个样本，并使用这些样本将原始类胡萝卜素值重新校准到共同的标度。虽然每项单独研究的分组分析的人数有限，但我们将有能力通过绝经状态、吸烟状况和饮酒以及肿瘤特征(例如ER+/PR+与ER-/PR-)来检查类胡萝卜素与乳腺癌风险的关联。这种协作分析将使我们能够更清楚地回答类胡萝卜素是否会影响乳腺癌风险的问题。我们将能够探索特定的类胡萝卜素之间的联系，以及检查在以前的文献中已经提出但力量不足的亚群之间的联系。鉴于几乎没有可改变的乳腺癌危险因素，追求潜在的可改变因素，如饮食，在乳腺癌发病率中的作用具有公共卫生重要性。

DESCRIPTION (provided by applicant): The epidemiology of breast cancer suggests that lifestyle factors play a role in the etiology. Diet has received much attention as a possible factor in population differences in breast cancer incidence, but results are not entirely consistent. Carotenoids, prominent micronutrients in fruits and vegetables, have been of specific interest because of their antioxidant properties. Weak inverse or null associations have been observed with dietary intake of carotenoids, with stronger associations observed in subgroups, such as premenopausal women and smokers. However, dietary intake assessment is potentially misclassified due to errors in dietary recall as well as individual differences in absorption and metabolism of carotenoids. To date, only six prospective studies with more than 60 cases have been published on plasma carotenoids and breast cancer risk. Most of these studies have reported significant inverse associations with one or more carotenoids, but the specific carotenoid is not consistent across studies. In this application, we propose a collaborative analysis of existing data from these six well- conducted prospective studies to allow a more comprehensive understanding of the association between carotenoids and breast cancer. In this study, we will utilize existing data from six prospective case-control studies of plasma carotenoids and the risk of breast cancer. The following studies are included in this application: Columbia, Missouri; Ume¿, Sweden; New York University Women's Health Study; Washington County, Maryland; Nurses' Health Study; and Women's Health Study. These studies represent >90% of the world's published literature on plasma carotenoids and breast cancer risk. The combined analysis will include 2,348 cases and 2,535 controls. To address the potential of laboratory differences between studies, we will re-assay 20 samples from each study at a central location and use these to recalibrate original carotenoid values to a common scale. Although each individual study was limited by small numbers for subgroup analyses, we will have the power to examine the association of carotenoids with breast cancer risk by menopausal status, smoking status and alcohol consumption, as well as by tumor characteristics (e.g., ER+/PR+ vs. ER-/PR-). This collaborative analysis will allow us to get a clearer answer to the question of whether carotenoids impact breast cancer risk. We will be able to explore the associations of specific carotenoids, as well as examine the associations among subgroups that have been suggested, but underpowered, in previous literature. Given there are few breast cancer risk factors that are modifiable, it is of public health importance to pursue the role of potentially modifiable factors, such as diet, in breast cancer incidence.