Association between the Serum Vitamin D Concentration and All-Cause and Cancer-Specific Mortality in Individuals with Cancer

Abstract

We aimed to explore the association between the serum 25-hydroxyvitamin D concentration and all-cause and cancer-specific mortality in 2,463 adult patients with cancer from the National Health and Nutrition Examination Survey 2007–2018. We linked mortality data from the survey to the National Death Index records up to December 31, 2019. During a median follow-up period of 70 months, 567 patients died, of whom 194 died due to cancer. Multivariate adjustment was performed for demographic characteristics, lifestyle, dietary factors, 25-hydroxyvitamin D testing period, and cancer site. Higher serum 25-hydroxyvitamin D concentrations up to 75 nmol/L significantly reduced the risk of all-cause and cancer-specific mortality. When 25-hydroxyvitamin D quartiles were compared, the multivariable-adjusted hazard ratios were 0.59 (95% confidence interval: 0.42, 0.84) for all-cause mortality (P for trend <0.001) and 0.48 (95% confidence interval: 0.29, 0.79) for cancer-specific mortality (P for trend = 0.037) in quartile 3 (79.3–99.2 nmol/L). A threshold of 75 nmol/L for serum 25-hydroxyvitamin D may represent an intervention target to reduce mortalities in patients with cancer, and maintaining 25(OH)D concentrations within range (79.3–99.2 nmol/L) is beneficial for reducing all-cause and cancer-specific mortality.