title: Vitamin intake reduce the risk of gastric cancer: meta-analysis and systematic review of randomized and observational studies.
abstract: OBJECTIVE
  The association between vitamin intake and gastric cancer (GC) has been widely debated due to the relatively weak evidence. In this study, a meta-analysis of prospective and well designed observational studies were performed to explore this association.
  
  
  METHODS
  MEDLINE, Cochrane Library, and Sciencedirect were searched for studies of vitamin consumption and gastric cancer. This produced 47 relevant studies covering 1,221,392 human subjects. Random effects models were used to estimate summary relative risk (RR). Dose-response, subgroup, sensitivity, meta-regression, and publication bias analyses were conducted.
  
  
  RESULTS
  The RR of gastric cancer in the group with the highest vitamin intake was compared to that of the lowest intake group. Total vitamin intake was 0.78 (95% CI, 0.71-0.83). In 9 studies that individuals were given doses at least 4 times above the tolerable upper intake (UL) vitamins, the RR was 1.20 (95% CI, 0.99-1.44). However, in 17 studies that individuals received doses below the UL, the RR was 0.76 (95% CI, 0.68-0.86). Dose-response analysis was conducted on different increments in different types of vitamins (vitamin A: 1.5 mg/day, vitamin C: 100 mg/day, vitamin E: 10 mg/day) intake with a significant reduction in the risk of gastric cancer, respectively, 29% in vitamin A, 26% in vitamin C, and 24% in vitamin E.
  
  
  CONCLUSIONS
  This meta-analysis clearly demonstrated that low doses of vitamins can significantly reduce the risk of GC, especially vitamin A, vitamin C, vitamin E.
authors.affiliation: State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangzhou, China; Department of Gastric and Pancreatic Surgery, Sun Yat-sen University Cancer Center, Guangzhou, China.
authors.forename: Pengfei
authors.initials: P
authors.lastname: Kong
authors.affiliation: State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangzhou, China; Department of Medical Oncology, Sun Yat-sen University Cancer Center, Guangzhou, China.
authors.forename: Qingqing
authors.initials: Q
authors.lastname: Cai
authors.affiliation: State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangzhou, China; Department of Hematology Oncology, Sun Yat-sen University Cancer Center, Guangzhou, China.
authors.forename: Qirong
authors.initials: Q
authors.lastname: Geng
authors.affiliation: State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangzhou, China; Department of Molecular Diagnosis, Sun Yat-sen University Cancer Center, Guangzhou, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Wang
authors.affiliation: Department of Oncological Surgery, the first affiliated hospital of Bengbu medical college, Bengbu, China.
authors.forename: Yadong
authors.initials: Y
authors.lastname: Lan
authors.affiliation: State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangzhou, China; Department of Gastric and Pancreatic Surgery, Sun Yat-sen University Cancer Center, Guangzhou, China.
authors.forename: Youqing
authors.initials: Y
authors.lastname: Zhan
authors.affiliation: State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangzhou, China; Department of Gastric and Pancreatic Surgery, Sun Yat-sen University Cancer Center, Guangzhou, China.
authors.forename: Dazhi
authors.initials: D
authors.lastname: Xu
mesh_terms: D004305:Dose-Response Relationship, Drug; D006801:Humans; D064887:Observational Studies as Topic; D016032:Randomized Controlled Trials as Topic; D012306:Risk; D013274:Stomach Neoplasms / Q000517:prevention & control*; D014815:Vitamins / Q000008:administration & dosage*
chemical_list: D014815:Vitamins