title: Vitamin D and lung cancer risk: a comprehensive review and meta-analysis.
abstract: OBJECTIVE
  Vitamin D has been suggested to have important roles against cancer development. There were several published studies on the association between vitamin D and lung cancer risk, but not conclusive results were available.
  
  
  METHODS
  To clarify the role of vitamin D in lung carcinogenesis, we performed a comprehensive review of the literature and a meta-analysis to evaluate the association of serum vitamin D levels and dietary vitamin D intake with lung cancer risk. Twelve studies (9 prospective cohort and 3 nested case-control studies) with a total of 288,778 individuals were included. The summary relative risk (RR) with 95% confidence interval (CI) was used to assess lung cancer risk.
  
  
  RESULTS
  Meta-analysis of total 12 studies showed that RR for the association of high vitamin D status with lung cancer was 0.84 (95%CI 0.78-0.90, P < 0.001). The RR of lung cancer for the highest versus lowest quintile of serum vitamin D levels was 0.83 (95%CI 0.77-0.90, P < 0.001). The RR of lung cancer for the highest versus lowest quintile of vitamin D intake was 0.89 (95%CI 0.74-1.06, P = 0.184).
  
  
  CONCLUSIONS
  Current data suggest an inverse association between serum vitamin D and lung cancer risk. Further studies are needed to investigate the effect of vitamin D intake on lung cancer risk and to evaluate whether vitamin D supplementation can prevent lung cancer.
authors.affiliation: Department of Respiratory Diseases, Beijing Military Region General Hospital of PLA, Beijing, China.
authors.forename: Liqun
authors.initials: L
authors.lastname: Zhang
authors.forename: Sihai
authors.initials: S
authors.lastname: Wang
authors.forename: Xiaoyu
authors.initials: X
authors.lastname: Che
authors.forename: Xuehui
authors.initials: X
authors.lastname: Li
mesh_terms: D019587:Dietary Supplements; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000097:blood / Q000453:epidemiology* / Q000517:prevention & control; D008297:Male; D012306:Risk; D014807:Vitamin D / Q000008:administration & dosage / Q000097:blood* / Q000627:therapeutic use
chemical_list: D014807:Vitamin D