Associations of the risk of lung cancer with serum 25-hydroxyvitamin D level and dietary vitamin D intake A dose-response PRISMA meta-analysis

The associations of the risk of lung cancer with the vitamin D intake and serum level are controversial. We performed a comprehensive dose-response meta-analysis to evaluate the precise relationships between the above mentioned parameters. We performed a web search of the PubMed, Medline, and Embase databases to identify potential studies that evaluated the relationships between vitamin D intake or serum 25-hydroxyvitamin D (25([OH] D) levels and the risk of lung cancer on December 5, 2017. According to the inclusion and exclusive criteria, 16 studies were included in this meta-analysis. The pooled relative risks (RRs) with 95% confidence intervals (CIs) were used to assess the strength of the associations. A dose-response analysis was conducted to quantitate the relationship between the serum 25(OH) D or vitamin D intake and the risk of lung cancer. The pooled RR (highest level vs lowest level) showed that the serum 25(OH) D level was not associated with the risk of lung cancer (RR = 1.046, 95% CI = 0.945-1.159). A high vitamin D intake was inversely correlated with the lung cancer risk (RR = 0.854, 95% CI = 0.741-0.984). No significant dose-response relationship was observed between the serum 25(OH) D level and the lung cancer risk. The linearity model of the dose-response analysis indicated that with every 100IU/day increase in vitamin D intake, the risk of lung cancer decreased by 2.4% (RR = 0.976, 95% CI = 0.957-0.995, P = .018). A high vitamin D intake provides limited protection against lung cancer carcinogenesis.