Serum vitamin D, vitamin D binding protein, and lung cancer survival

• We examined the association between serum 25(OH)D and lung cancer survival.
• Pre-diagnostic serum 25(OH)D concentration was measured in 500 lung cancer cases.
• Higher serum 25(OH)D concentration was not associated with overall survival.
• Higher serum 25(OH)D concentration may prolong survival for some histology types.
• Vitamin D binding protein concentration did not modify associations with 25(OH)D.

ObjectivesVitamin D may prolong cancer survival by inhibiting tumor progression and metastasis, however, there are limited epidemiologic studies regarding the association between circulating 25-hydroxyvitamin D (25(OH)D) and lung cancer survival. The aim of this study was to examine the relationship between serum 25(OH)D and lung cancer specific survival and to evaluate whether vitamin D binding protein (DBP) concentration modified this association.Materials and methods25(OH)D and DBP were measured in fasting serum samples from 500 male lung cancer cases in the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study. Cox proportional hazards regression was used to estimate hazard ratios (HRs) and 95% confidence intervals (CI) for lung cancer related death according to quartiles of season-specific 25(OH)D, DBP, and the molar ratio of 25(OH)D:DBP, a proxy for free circulating 25(OH)D.ResultsComparing highest to lowest quartiles, serum 25(OH)D (HR = 1.18; 95% CI: 0.89–1.56) and DBP (HR = 0.95; 95% CI: 0.71–1.26) were not associated with lung cancer survival and DBP concentration did not modify the association with 25(OH)D (p for interaction = 0.56). There was suggestion of an association between higher serum 25(OH)D and better survival from adenocarcinoma (HR = 0.64; 95% CI: 0.17–2.45) and small cell carcinoma (HR = 0.55; 95% CI: 0.21–1.45), but these estimates were based on a relatively small number of cases.ConclusionSerum 25(OH)D was not associated with overall lung cancer survival regardless of DBP concentration, however, these findings should be examined in other studies that include women and subjects with higher 25(OH)D levels.