Research Paper Volume 12, Issue 18 pp 18415—18435

Association of vitamin C intake with breast cancer risk and mortality: a meta-analysis of observational studies

Dai Zhang1,2, *, , Peng Xu1,2, *, , Yiche Li3, *, , Bajin Wei1, , Si Yang1,2, , Yi Zheng1,2, , Lijuan Lyu1,2, , Yujiao Deng1,2, , Zhen Zhai2, , Na Li1,2, , Nan Wang1,2, , Jun Lyu4, , Zhijun Dai1, ,

  • 1 Department of Breast Surgery, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China
  • 2 Department of Oncology, The Second Affiliated Hospital of Xi’an Jiaotong University, Xi’an, China
  • 3 Breast Center Department, The Fourth Hospital of Hebei Medical University, Hebei Medical University, Shijiazhuang, China
  • 4 Department of Clinical Research, The First Affiliated Hospital of Jinan University, Guangzhou 510632, China
* Equal contribution

Received: May 4, 2020       Accepted: July 9, 2020       Published: September 29, 2020
How to Cite

Copyright: © 2020 Zhang et al. This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.


The association between vitamin C intake and breast cancer is unclear. This meta-analysis aimed to precisely assess the association of vitamin C intake with breast cancer risk and mortality. We searched the PubMed, Embase, and Web of Science databases up to June 2020 and found 69 studies relevant to breast cancer risk (54 studies) and survival (15 studies). Relative risks and 95% confidence intervals were calculated using the random-effects models. Pooled results suggested that the highest versus lowest vitamin C intake was significantly associated with a lower risk of breast cancer incidence (Relative Risk = 0.86; 95% confidence interval, 0.81–0.92). Dietary vitamin C but not supplements was found to reduce breast cancer risk (Relative Risk = 0.89; 95% confidence interval, 0.82–0.96). For the highest versus lowest vitamin C intake, the pooled hazard risk for breast cancer-specific mortality was 0.78 (95% confidence interval, 0.69–0.88), totality mortality was 0.82 (95% confidence interval, 0.74–0.91), and recurrence was 0.81 (95% confidence interval, 0.67–0.99). Our analysis suggests that higher vitamin C intake is significantly associated with reduced breast cancer incidence and mortality. However, the intake of vitamin C supplements has no significant effect on breast cancer prevention.


RR: Relative risks; OR: Odds ratio; HR: Hazard risk; CI: Confidence intervals; BC: Breast cancer; VitC: Vitamin C; HIF: Hypoxia inducible factor.