title: Association of dietary vitamin E intake with risk of lung cancer: a dose-response meta-analysis.
abstract: OBJECTIVE
  Several epidemiological studies investigating the association between dietary vitamin E intake and the risk of lung cancer have demonstrated inconsistent results. Hence, a meta-analysis was conducted to summarise evidence of the association of dietary vitamin E intake with the risk of lung cancer.
  
  
  METHODS
  In this meta-analysis, a systematic literature search of PubMed and Web of Science was conducted to identify relevant studies published from 1955 to April 2015. If p<0.05 or I2 >50%, a random effect model was used to estimate overall relative risks (RRs) and 95% confidence intervals (CIs). Otherwise, a fixed effect model was applied. Publication bias was estimated using the funnel plot and Egger's test. The doseresponse relationship was assessed using the method of restricted cubic splines with 4 knots at percentiles 5, 35, 65, and 95 of the distribution.
  
  
  RESULTS
  The pooled RR of lung cancer for the highest versus lowest categories of dietary vitamin E intake was 0.84 (95% CI=0.76-0.93). With every 2 mg/d increase in dietary vitamin E intake, the risk of lung cancer statistically decreased by 5% (RR=0.95, 95% CI =0.91-0.99, plinearity=0.0237).
  
  
  CONCLUSIONS
  Our analysis suggests that higher dietary vitamin E intake exerts a protective effect against lung cancer.
authors.affiliation: Department of Cardiology, the First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, China.
authors.forename: Yong-Jian
authors.initials: YJ
authors.lastname: Zhu
authors.affiliation: Department of Nutrition and Food Hygiene, College of Public Health, Zhengzhou University, Zhengzhou, Henan, China.
authors.forename: Ya-Cong
authors.initials: YC
authors.lastname: Bo
authors.affiliation: Department of Nutrition and Food Hygiene, College of Public Health, Zhengzhou University, Zhengzhou, Henan, China.
authors.forename: Xin-Xin
authors.initials: XX
authors.lastname: Liu
authors.affiliation: Department of Cardiology, the First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, China. Email: qiu_contribution@163.com.
authors.forename: Chun-Guang
authors.initials: CG
authors.lastname: Qiu
mesh_terms: D004032:Diet; D004305:Dose-Response Relationship, Drug; D006801:Humans; D008175:Lung Neoplasms / Q000453:epidemiology / Q000517:prevention & control*; D008297:Male; D012306:Risk; D014810:Vitamin E / Q000008:administration & dosage*
chemical_list: D014810:Vitamin E