Association of Vitamin D levels with outcome in patients with melanoma after adjustment for C-reactive protein

Purpose: To evaluate for an association between 25-hydroxyVitamin D levels (Vitamin D) and outcome measures in patients with melanoma after evaluation is controlled for systemic inflammatory response (SIR) on the basis of simultaneous C-reactive protein (CRP) measurement. Materials and Methods: Plasma samples from1,042 prospectively observed patientswithmelanomawere assayed for Vitamin D and CRP. The associations of demographics and CRP with Vitamin D were determined, followed by a determination of the association between vitaminD and stage and outcomemeasures fromthe date of blood draw. The Vitamin D level was considered sufficient if it was 30 to 100 ng/mL. Kaplan-Meier and Cox regression analyses were performed. Results: The median Vitamin D level was 25.0 ng/mL. The median follow-up time was 7.1 years. A lower Vitamin D was associated with the blood drawduring fall/wintermonths (P,.001), older age (P=.001), increasedCRP (P ,.001), increased tumor thickness (P < .001), ulcerated tumor (P = .0105), and advanced melanoma stage (P = .0024).On univariate analysis, lower Vitamin Dwas associated with poorer overall (OS; P, .001), melanoma-specific survival (MSS; P = .0025), and disease-free survival (DFS; P = .0466). The effect of Vitamin D on these outcome measures persisted after adjustment for CRP and other covariates. Multivariable hazards ratios per unit decrease of vitaminDwere 1.02 forOS (95%CI, 1.01 to 1.04;P=.0051), 1.02 for MSS (95% CI, 1.00 to 1.04; P = .048), and 1.02 for DFS (95% CI, 1.00 to 1.04; P = .0427). Conclusion: Lower Vitamin D levels in patients with melanoma were associated with poorer outcomes. Although lower Vitamin D was strongly associated with higher CRP, the associations of lower Vitamin D with poorer OS, MSS, and DFS were independent of this association. Investigation of mechanisms responsible for these associations may be of value to patients with melanoma.