Department of Ultrasound, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, Shandong, China.
Department of Ultrasound, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, Shandong, China.
Breast Cancer Res Treat. 2020 Jul;182(1):1-8. doi: 10.1007/s10549-020-05669-4. Epub 2020 May 13.
Observational studies suggest an inverse association between circulating vitamin D levels and risk of breast cancer. However, the potential benefits of vitamin D supplementation to reduce the risk of breast cancer remain controversial, based on the results of current randomized controlled trials (RCTs). The aim of this study was to evaluate the value of vitamin D supplementation on breast cancer prevention.
PubMed, Embase, and Cochrane library were searched from inception to February 2020. We performed a trial sequential meta-analysis of RCTs reporting the effect of vitamin D supplementation, with or without calcium, on the risk of breast cancer. The effect was estimated using a relative risk reduction threshold of 30%.
Eight trials comprising 72,275 participants were included in this study, with a median follow-up period ranging from 1 to 11.9 years. The median dosage of vitamin D supplementation was 967 IU per day (range 400-3704 IU per day) across the trials. This study yielded a relative risk of 1.04 (95% CI 0.85-1.29, P = 0.68) for the effect of vitamin D supplementation (6 trials, 33,472 participants), and 0.99 (95% CI 0.91-1.07, P = 0.73) for co-administration of vitamin D and calcium (4 trials, 41,957 participants). The effect estimate for vitamin D with or without calcium on breast cancer risk lay within the futility boundary, indicating that vitamin D supplementation does not alter the relative risk by 30% or more.
Our analyses suggest that vitamin D supplementation, with or without calcium, does not reduce breast cancer risk by 30% or more. Future trials with similar designs are unlikely to alter this finding.
观察性研究表明，循环维生素 D 水平与乳腺癌风险呈负相关。然而，基于目前随机对照试验（RCT）的结果，维生素 D 补充剂是否可降低乳腺癌风险仍存在争议。本研究旨在评估维生素 D 补充剂预防乳腺癌的价值。
从建库至 2020 年 2 月，我们检索了 PubMed、Embase 和 Cochrane 图书馆。我们对报告了维生素 D 补充剂（无论是否添加钙）对乳腺癌风险影响的 RCT 进行了试验序贯荟萃分析。采用相对风险降低 30%的阈值来评估效果。
纳入了 8 项包含 72275 名参与者的试验，中位随访时间范围为 1 至 11.9 年。各试验中维生素 D 补充剂的中位剂量为每天 967 IU（范围为每天 400-3704 IU）。该研究得出维生素 D 补充剂的效果的相对风险为 1.04（95%CI 0.85-1.29，P=0.68）（6 项试验，33472 名参与者），维生素 D 与钙联合使用的效果为 0.99（95%CI 0.91-1.07，P=0.73）（4 项试验，41957 名参与者）。维生素 D 与或不与钙联合使用对乳腺癌风险的效果估计位于无效边界内，表明维生素 D 补充剂不能使相对风险降低 30%或更多。
我们的分析表明，维生素 D 补充剂（无论是否添加钙）都不能使乳腺癌风险降低 30%或更多。具有类似设计的未来试验不太可能改变这一发现。
