Cui Yan, Rohan Thomas E
Department of Epidemiology and Population Health, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Belfer 1301D, Bronx, NY 10461, USA.
Cancer Epidemiol Biomarkers Prev. 2006 Aug;15(8):1427-37. doi: 10.1158/1055-9965.EPI-06-0075.
Vitamin D and calcium are metabolically interrelated and highly correlated dietary factors. Experimental studies have shown their anticarcinogenic effects due to their participation in regulating cell proliferation, differentiation, and apoptosis in normal and malignant breast cells. Given the emerging interest in their potential roles in the etiology of breast cancer, we review the current epidemiologic literature on dietary and/or supplemental intakes of vitamin D, endogenous circulating levels of vitamin D, and dietary and/or supplemental intakes of calcium in relation to breast cancer risk. To place these studies in context, we also provide a brief review of other supporting epidemiologic evidence. Despite inconsistent results from the epidemiologic studies, several lines of evidence suggest that vitamin D and calcium may be involved in the development of breast cancer. Specifically, (a) there is some epidemiologic evidence for inverse associations between vitamin D and calcium intakes and breast cancer; (b) serum, plasma, and/or blood levels of vitamin D metabolites have been inversely associated with breast cancer risk in some studies; (c) high sunlight exposure, presumably reflecting vitamin D synthesis in the skin, has been associated with a reduced risk of breast cancer; (d) vitamin D and calcium intakes have been inversely related to breast density, an intermediate end point for breast cancer; (e) calcium has been associated with a reduced risk of benign proliferative epithelial disorders of the breast, putative precursors of breast cancer; and (f) certain polymorphisms of the vitamin D receptor might modify breast cancer susceptibility. To further confirm the potential protective effects of calcium and vitamin D on breast cancer, well-designed cohort studies and clinical trials are warranted.
维生素D和钙是代谢上相互关联且高度相关的饮食因素。实验研究表明，它们具有抗癌作用，因为它们参与调节正常和恶性乳腺细胞的增殖、分化和凋亡。鉴于人们对它们在乳腺癌病因学中的潜在作用的兴趣日益浓厚，我们回顾了当前关于维生素D的饮食和/或补充剂摄入量、维生素D的内源性循环水平以及钙的饮食和/或补充剂摄入量与乳腺癌风险关系的流行病学文献。为了将这些研究置于背景中，我们还简要回顾了其他支持性的流行病学证据。尽管流行病学研究结果不一致，但有几条证据表明维生素D和钙可能与乳腺癌的发生有关。具体而言，（a）有一些流行病学证据表明维生素D和钙的摄入量与乳腺癌之间存在负相关；（b）在一些研究中，维生素D代谢物的血清、血浆和/或血液水平与乳腺癌风险呈负相关；（c）高阳光暴露，推测反映了皮肤中维生素D的合成，与降低乳腺癌风险有关；（d）维生素D和钙的摄入量与乳腺密度呈负相关，乳腺密度是乳腺癌的一个中间终点；（e）钙与降低乳腺良性增殖性上皮疾病（乳腺癌的假定前体）的风险有关；（f）维生素D受体的某些多态性可能会改变乳腺癌易感性。为了进一步证实钙和维生素D对乳腺癌的潜在保护作用，有必要进行精心设计的队列研究和临床试验。
