Association of serum 25-hydroxy-vitamin D concentration and risk of mortality in cancer survivors in the United States

Abstract

Abstract Purpose Cancer survivors have a high risk of mortality, and vitamin D (VD) is associated with the risk of mortality. This study is aim to examine the impact of VD on mortality in cancer survivors. Methods A prospective study was conducted using data from the National Health and Nutrition Examination Survey. Participants were obtained information on their baseline characteristics, dietary habits, comorbidities, lifestyle, and serum 25-hydroxy VD [25(OH)D] concentrations. The weighted Cox proportional hazard and competing risk regression models were used to estimate the hazard ratio and 95% confidence intervals (HR, 95% CI) of mortality for different serum 25(OH)D concentrations. Restricted cubic spline (RCS) curves were utilized to illustrate the dose–response relationship between serum 25(OH)D concentrations and mortality. Results The study encompassed 2,495 participants with cancer diagnoses. Multivariate models indicated that, compared to serum 25(OH)D concentrations below 58.5 nmol/L, concentrations exceeding 81.6 nmol/L were associated with reduced HRs for all-cause mortality (HR = 0.70; 95% CI: 0.56–0.87), cardiovascular mortality (HR = 0.53; 95% CI: 0.32–0.86), and cancer-specific mortality (HR = 0.66; 95% CI: 0.45–0.99). RCS curves revealed “L-shaped” associations between serum 25(OH)D concentration and both all-cause and cancer-specific mortality, with threshold effects at 87.9 nmol/L and 84.6 nmol/L, respectively. Conversely, the relationship between serum 25(OH)D concentration and cardiovascular mortality exhibited a more linear pattern, with a threshold at 88.7 nmol/L. Subgroup analyses highlighted a gender-specific interaction that elevated serum 25(OH)D concentrations were significantly more protective against mortality in males than in females, especially regarding cancer-specific mortality (P-interaction = 0.009). Conclusion Elevated serum 25(OH)D concentrations were correlated with decreased risks of all-cause, cardiovascular, and cancer-specific mortality in cancer survivors, with benefit thresholds at 87.9, 88.7, and 84.6 nmol/L, respectively. These findings suggested that cancer survivors might benefit from higher vitamin D recommendations than the general population.