Circulating Vitamin D and Overall Survival in Breast Cancer Patients: A Dose-Response Meta-Analysis of Cohort Studies

Integr Cancer Ther. 2018 Jun;17(2):217-225. doi: 10.1177/1534735417712007. Epub 2017 Jun 7.


Studies have shown that vitamin D could have a role in breast cancer survival; however, the evidence of the relationship between patients' vitamin D levels and their survival has been inconsistent. This meta-analysis explores possible dose-response relationships between vitamin D levels and overall survival by allowing for differences in vitamin D levels among populations of the various studies. Studies relating vitamin D (25-OH-D [25-hydroxyvitamin D]) levels in breast cancer patients with their survival were identified by searching PubMed and Embase. A pooled HR (hazard ratio) comparing the highest with the lowest category of circulating 25-OH-D levels were synthesized using the Mantel-Haenszel method under a fixed-effects model. A two-stage fixed-effects dose-response model including both linear (a log-linear dose-response regression) and nonlinear (a restricted cubic spline regression) models were used to further explore possible dose-response relationships. Six studies with a total number of 5984 patients were identified. A pooled HR comparing the highest with the lowest category of circulating 25-OH-D levels under a fixed-effects model was 0.67 (95% confidence interval = 0.56-0.79, P < .001). Utilizing a dose-response meta-analysis, the pooled HR for overall survival in breast cancer patients was 0.994 (per 1 nmol/L), Pfor linear trend < .001. At or above a 23.3 nmol/L threshold, for a 10 nmol/L, 20 nmol/L, or 25 nmol/L increment in circulating 25-OH-D levels, the risk of breast cancer overall mortality decreased by 6%, 12%, and 14%, respectively. There was no significant nonlinearity in the relationship between overall survival and circulating 25-OH-D levels. Our findings suggest that there is a highly significant linear dose-response relationship between circulating 25-OH-D levels and overall survival in patients with breast cancer. However, better designed prospective cohort studies and clinical trials are needed to further confirm these findings.

Keywords: breast cancer; dose-response meta-analysis; dose-response relationship; meta-analysis; overall survival; vitamin D.

Publication types

  • Meta-Analysis

MeSH terms

  • Breast Neoplasms / blood*
  • Breast Neoplasms / mortality*
  • Cohort Studies
  • Dose-Response Relationship, Drug
  • Female
  • Humans
  • Risk Factors
  • Vitamin D / analogs & derivatives*
  • Vitamin D / blood


  • Vitamin D
  • 25-hydroxyvitamin D