Current therapies for breast cancer prevention only prevent estrogen receptor positive (ER+) disease and toxicity limits use of these agents. Vitamin D is a potential prevention therapy for both ER+ and ER− disease and is safe with few side effects. This study evaluates the effect of 1-year of vitamin D supplementation on mammographic density (MD), a biomarker of breast cancer risk in a multicenter randomized controlled trial. Premenopausal women with ≥25% MD and no history of cancer were randomly assigned to 2,000 international units (IU) of vitamin D or placebo orally daily for 1 year. Change in percent MD was evaluated using Cumulus software after all participants completed treatment. Three hundred women enrolled between January 2011 and December 2013 with a mean age of 43 and diverse ethnicity [14% Hispanic, 12% African American (AA)]. Supplementation significantly increased vitamin D levels compared with placebo (14.5 ng/mL vs. −1.6 ng/mL; P < 0.0001) with all participants on the vitamin D arm achieving vitamin D sufficiency at 12 months. Vitamin D was safe and well tolerated. After adjustment for baseline MD, the mean between-arm difference (vitamin D vs. placebo) at 1 year was −0.75 (−0.26, 1.76; P = 0.56). A greater effect was seen for women with ≥50% MD and AA women, although neither reached significance. This randomized controlled trial demonstrated significant improvement in vitamin D levels with 2,000 IU for 1 year, with 100% of supplemented women achieving sufficiency. However, a null effect was seen regarding change in MD for premenopausal women (the primary outcome of the study). Prevention Relevance: Current therapies for breast cancer prevention only prevent estrogen receptor positive (ER+) disease and are underutilized due to toxicity and side effects. Vitamin D is a potential prevention therapy for both ER+ and ER− disease and is safe with few side effects.

中文翻译：

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维生素 D 对乳腺 X 光密度的影响：来自 CALGB 70806（联盟）一项随机临床试验的结果

目前用于预防乳腺癌的疗法只能预防雌激素受体阳性 (ER+) 疾病，并且毒性限制了这些药物的使用。维生素 D 是 ER+ 和 ER- 疾病的潜在预防疗法，并且安全且副作用少。本研究评估了 1 年维生素 D 补充剂对乳腺 X 光密度 (MD) 的影响，这是一项多中心随机对照试验中乳腺癌风险的生物标志物。MD ≥ 25% 且无癌症病史的绝经前妇女被随机分配到每天口服 2,000 国际单位 (IU) 维生素 D 或安慰剂组，持续 1 年。在所有参与者完成治疗后，使用 Cumulus 软件评估 MD 百分比的变化。2011 年 1 月至 2013 年 12 月期间招募了 300 名平均年龄为 43 岁且来自不同种族的女性 [14% 西班牙裔，12% 非裔美国人 (AA)]。与安慰剂相比，补充剂显着提高了维生素 D 水平（14.5 ng/mL 与 -1.6 ng/mL；P < 0.0001），维生素 D 组的所有参与者在 12 个月时都达到了维生素 D 充足。维生素 D 是安全且耐受性良好的。调整基线 MD 后，1 年时的平均臂间差异（维生素 D 与安慰剂）为 −0.75（−0.26、1.76；P = 0.56）。对于 MD ≥ 50% 的女性和 AA 女性，效果更好，但两者均未达到显着性。这项随机对照试验表明，服用 2,000 IU 1 年可显着改善维生素 D 水平，100% 的补充女性达到了充足水平。然而，对于绝经前妇女的 MD 变化（该研究的主要结果），观察到无效效应。预防相关性：目前用于预防乳腺癌的疗法只能预防雌激素受体阳性 (ER+) 疾病，并且由于毒性和副作用而未得到充分利用。维生素 D 是 ER+ 和 ER- 疾病的潜在预防疗法，并且安全且副作用少。