Lower vitamin D levels were associated with poorer overall survival, melanoma-specific survival, and disease-free survival independent of a strong association between lower vitamin D and higher C-reactive protein, a study published in the Journal of Clinical Oncology has shown.1
For the study, researchers sought to evaluate the association between vitamin D levels and outcome measures in patients with melanoma after controlling for systemic inflammatory response by simultaneously measuring C-reactive protein.
Researchers assayed plasma samples from 1042 prospectively observed patients with melanoma for vitamin D and C-reactive protein. Vitamin D levels of 30 to 100 ng/mL were considered to be sufficient.
Results showed that at a median follow-up of 7.1 years, a lower vitamin D level was associated with the blood draw during the fall or winter months (P<.001), older age (P=.001), increased C-reactive protein (P<.001), increased tumor thickness (P<.001), ulcerated tumor (P=.0105), and advanced melanoma stage (P=.0024).
In terms of outcome measures, researchers found that lower vitamin D was associated with poorer overall survival (P<.001), melanoma-specific survival (P=.0025), and disease-free survival (P=.0466). This association persisted after researchers adjusted for C-reactive protein and other variables.
The study also demonstrated that each unit reduction in vitamin D improved the risk for overall survival (HR, 1.02; 95% CI: 1.01-1.04; P=.0051), melanoma-specific survival (HR, 1.02; 95% CI: 1.00-1.04; P=.048), and disease-free survival (HR, 1.02; 95% CI: 1.00-1.04; P=.0427) by 2%.
The findings suggest that investigation into the mechanism involved in these associations may be beneficial to patients with melanoma.
- Fang S, Sui D, Wang Y, et al. Association of vitamin d levels with outcome in patients with melanoma after adjustment for C-reactive protein [published online ahead of print March 21, 2016]. J Clin Oncol. doi: 10.1200/JCO.2015.64.1357.