Background/aim: To determine whether higher serum 25-hydroxyvitamin D [25(OH)D] at diagnosis is associated with longer survival of patients with breast cancer.
Materials and methods: A meta-analysis was performed of five studies of the relationship between 25(OH)D and mortality from breast cancer. A pooled hazard ratio was calculated using a random-effects model. The Der Simonian-Laird test was used to assess homogeneity.
Results: Higher serum concentrations of 25(OH)D were associated with lower case-fatality rates after diagnosis of breast cancer. Specifically, patients in the highest quintile of 25(OH)D had approximately half the death rate from breast cancer as those in the lowest.
Conclusion: High serum 25(OH)D was associated with lower mortality from breast cancer. Serum 25(OH)D in all patients with breast cancer should be restored to the normal range (30-80 ng/ml), with appropriate monitoring. Clinical or field studies should be initiated to confirm that this association was not due to reverse causation.
Keywords: Breast cancer; epidemiology; meta-analysis; mortality; survival; vitamin D.