PLoS ONE ：维生素D或有助预防乳腺癌

    中科院上海生科院营养所王慧研究组在最新研究中发现高血浆25(OH)D水平能显著降低乳腺癌的患病风险。相关成果日前在线发表于美国《科学公共图书馆·综合》。

　　据介绍，维生素D是人体必需的脂溶性维生素，其缺乏与包括肿瘤、自身免疫疾病、糖尿病、心血管疾病等在内的多种慢性代谢性疾病密切相关。25-羟维生素D（25(OH)D）则代表体内维生素D的营养状态。它可被肾脏中的1-α羟化酶转化成生物活性较强的1α,25-(OH)2D，从而和维生素D受体（VDR）结合执行生物学功能，参与细胞周期、外源物质代谢和肠内钙吸收等多条信号通路。

　　王慧研究组和复旦大学附属肿瘤医院、徐汇区中心医院合作，对上海人群中593例乳腺癌病例和580例正常对照样本进行了血清25(OH)D水平及其与乳腺癌患病风险的关联性分析。研究发现，我国正常女性和乳腺癌人群中，处于极度缺乏状态（血浆25(OH)D浓度小于20纳克/毫升）者分别占80%和99.3%。同时，在该研究人群中，25(OH)D血浆水平每增加1纳克/毫升，乳腺癌风险降低16%。

　　研究人员还对已报道的相关观察性流行病学研究进行了荟萃分析。结果显示，在11项前瞻性巢式病例对照研究中，高血清25(OH)D水平人群比低血清25(OH)D水平人群患乳腺癌的风险降低14%。在另外10项病例对照研究中，血清25(OH)D水平也与乳腺癌发病率呈显著负相关，提示维生素D对乳腺癌具有预防作用。

　　相关专家认为，该研究分析了我国乳腺癌人群维生素D的缺乏现状，并揭示了维生素D缺乏与我国乳腺癌发生风险的关系，为乳腺癌的预防和临床干预提供了理论指导。

来源：中国科学报

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Higher Blood 25(OH)D Level May Reduce the Breast Cancer Risk: Evidence from a Chinese Population Based Case-Control Study and Meta-Analysis of the Observational Studies

Experimental data suggest a protective effect of vitamin D on breast cancer; however, epidemiologic results remain inclusive. With a Chinese population-based case-control study and meta-analysis of the observational studies, we here systematically evaluated the association of blood 25(OH)D level and breast cancer risk. With 593 breast cancer cases and 580 cancer-free controls from Shanghai, China, we found that 80% of the normal women had severe vitamin D deficiency (less than 20 ng/mL) and 15.2% had mild deficiency (20 to 30 ng/mL) and only 4.8% of women had sufficient vitamin D level (>30 ng/mL) while the proportion was 96.1%, 3.2% and 0.7% respectively for the breast cancer patients. Compared to those with the lowest quartile of plasma 25(OH)D level, women with highest quartile 25(OH)D level showed a significant decreased breast cancer risk (Q4 vs.Q1: OR = 0.10, 95% CI = 0.06–0.15) and every 1 ng/ml increment of plasma 25(OH)D level led to a 16% lower odds of breast cancer (OR = 0.84, 95% CI = 0.81–0.87; P<0.001). From the meta-analysis of the observational studies, we found that women with highest quantile of blood 25(OH)D level was associated with a significantly reduced breast cancer risk compared to those with lowest quantile of blood 25(OH)D level for the 11 nested case-control and retrospective studies (pooled OR = 0.86, 95% CI = 0.75–1.00) and 10 case-control studies (7 population based, OR = 0.35, 95% CI = 0.24–0.52; 3 hospital based, OR = 0.08, 95% CI = 0.02–0.33). These results suggest that vitamin D may have a chemo-preventive effect against breast cancer.