Review Quality Rating: 9 (strong)
Citation: Goulao B, Stewart F, Ford JA, Maclennan G, & Avenell A. (2018). Cancer and vitamin D supplementation: A systematic review and meta-analysis. American Journal of Clinical Nutrition, 107(4), 652-663.PubMed LinkOut
BACKGROUND: Low 25-hydroxyvitamin D status has been associated with a higher risk of cancer in epidemiologic studies.
OBJECTIVE: 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.
DESIGN: 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 â‰¥12 mo of follow-up and in participants with a mean or median age â‰¥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.
RESULTS: 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: 0.85; 95% CI: 0.70, 1.04). Including after-study events, the RRs were 1.02 (95% CI: 0.92, 1.13) and 0.85 (95% CI: 0.72, 1.00), 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.
CONCLUSION: 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.
Adults (20-59 years), Adult's Health (men's health, women's health), Behaviour Modification (e.g., provision of item/tool, incentives, goal setting), Cancer, Chronic Diseases, Home, Meta-analysis, Nutrition, Primary health care provider office (e.g., Public health nurse, dietitian, social worker), Senior Health, Seniors (60+ years)