Health Services Research Unit, University of Aberdeen, Aberdeen, United Kingdom.
Department of Public Health and Primary Care, University of East Anglia, Norwich, United Kingdom.
Am J Clin Nutr. 2018 Apr 1;107(4):652-663. doi: 10.1093/ajcn/nqx047.
Low 25-hydroxyvitamin D status has been associated with a higher risk of cancer in epidemiologic studies.
The aim of this study was to undertake a systematic review and meta-analysis of randomized clinical trials (RCTs) investigating the effect of vitamin D supplementation alone on cancer incidence and mortality.
A systematic review was undertaken. MEDLINE, Embase, CENTRAL, conference abstracts, and clinical trial registries were searched (last search March 2017) for RCTs investigating vitamin D supplementation alone. RCTs with ≥12 mo of follow-up and in participants with a mean or median age ≥60 y were eligible. During-study events were used as the main analysis, but after-study events were included in a secondary analysis. Subgroup analyses concerning different forms of vitamin D supplementation, 25-hydroxyvitamin D status at baseline, vitamin D dose, and exclusion of open-label trials were undertaken.
Thirty studies in 18,808 participants were included in the systematic review, with a median follow-up ranging from 1 to 6.2 y. The results of the meta-analysis for during-study events showed no evidence of an effect of vitamin D supplementation for cancer incidence (RR: 1.03; 95% CI: 0.91, 1.15) and cancer-related deaths (RR: 0.88; 95% CI: 0.70, 1.09). Including after-study events, the RRs were 1.02 (95% CI: 0.92, 1.13) and 0.86 (95% CI: 0.72, 1.03), respectively. These results did not appear to be affected by baseline 25-hydroxyvitamin D status, vitamin D dose, or the exclusion of open-label trials.
We did not find evidence to suggest that vitamin D supplementation alone reduces the incidence of cancer or cancer mortality, even after including long-term follow-up results.
在流行病学研究中，低 25-羟维生素 D 状态与癌症风险增加有关。
本研究旨在对单独补充维生素 D 对癌症发病率和死亡率影响的随机临床试验（RCT）进行系统评价和荟萃分析。
进行了系统评价。检索了 MEDLINE、Embase、CENTRAL、会议摘要和临床试验注册处（最后一次搜索日期为 2017 年 3 月），以寻找单独补充维生素 D 的 RCT。具有≥12 个月随访期且参与者的平均或中位年龄≥60 岁的 RCT 符合纳入标准。研究期间的事件被用作主要分析，但研究后的事件被纳入次要分析。进行了亚组分析，涉及不同形式的维生素 D 补充、基线时 25-羟维生素 D 状态、维生素 D 剂量以及排除开放标签试验。
纳入了 18808 名参与者的 30 项研究，中位随访时间为 1 至 6.2 年。研究期间事件的荟萃分析结果显示，维生素 D 补充对癌症发病率（RR：1.03；95%CI：0.91，1.15）和癌症相关死亡率（RR：0.88；95%CI：0.70，1.09）没有影响。包括研究后事件后，RR 分别为 1.02（95%CI：0.92，1.13）和 0.86（95%CI：0.72，1.03）。这些结果似乎不受基线 25-羟维生素 D 状态、维生素 D 剂量或排除开放标签试验的影响。
我们没有发现证据表明单独补充维生素 D 可降低癌症发病率或癌症死亡率，即使包括长期随访结果。
