Association between Vitamin D Supplementation and Cancer Mortality: A Systematic Review and Meta-Analysis

• Published in: Cancers Vol. 14; no. 15; p. 3717
• Main Authors: Zhang, Renjie, Zhang, Yu, Liu, Zheran, Pei, Yiyan, Xu, Ping, Chong, Weelic, Hai, Yang, He, Ling, He, Yan, Yu, Jiayi, Wang, Jingjing, Fang, Fang, Peng, Xingchen
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 30.07.2022; MDPI
• Subjects: Bias; Breast cancer; cancer incidence; cancer mortality; Clinical trials; Dietary supplements; Intervention; Lung cancer; Meta-analysis; Mortality; Nutrient deficiency; Prostate; Risk assessment; Software; Supplements; Systematic Review; Tumors; Vitamin D; Vitamin D supplementation
• ISSN: 2072-6694; 2072-6694
• DOI: 10.3390/cancers14153717

Background: Vitamin D deficiency is related to increased cancer risk and deaths. However, whether vitamin D supplementation reduces cancer mortality remains unclear, and several randomized controlled trials yield inconsistent results. Methods: Medline, Embase, and the Cochrane Central Register of Controlled Trials were searched from their inception until 28 June 2022, for randomized controlled trials investigating vitamin D supplementation. Pooled relative risks (RRs) and their 95% confidence intervals (CIs) were estimated. Trials with vitamin D supplementation combined with calcium supplementation versus placebo alone and recruiting participants with cancer at baseline were excluded in the present study. Results: This study included 12 trials with a total of 72,669 participants. Vitamin D supplementation did not reduce overall cancer mortality (RR 0.96, 95% CI 0.80–1.16). However, vitamin D supplementation was associated with a reduction in lung cancer mortality (RR 0.63, 95% CI 0.45–0.90). Conclusions: Vitamin D supplementation could not reduce cancer mortality in this highly purified meta-analysis. Further RCTs that evaluate the association between vitamin D supplementation and total cancer mortality are still needed.