title: Effect of coffee consumption on the risk of gastric cancer: a systematic review and meta-analysis of prospective cohort studies.
abstract: OBJECTIVE
  Results from observational epidemiologic studies on the relationship between coffee consumption and gastric cancer are inconsistent and inconclusive. To assess the association between coffee consumption and the risk of gastric cancer, we summarized evidence from prospective cohort studies.
  
  
  METHODS
  Relevant studies were retrieved through computer searches (PubMed, EmBase and the Cochrane Library) and a review of references up to December 2014. The quality of the included studies was evaluated by Newcastle-Ottawa quality assessment scale. We used a meta-analytic approach to estimate overall hazard ratios (HRs) and 95% confidence intervals (CIs) for regular coffee drinkers versus individuals who seldom drank coffee. Sensitivity analysis and subgroup analysis were performed to assess the reliability of our results. A dose-response analysis was performed to assess the risk of gastric cancer based on the level of coffee consumption.
  
  
  RESULTS
  Nine prospective cohort studies involving 1,250,825 participants and 3027 gastric cancer cases were included in this meta-analysis. The pooled HR of gastric cancer for the study-specific regularly versus seldom coffee drinking categories was 1.05 (95% CI, 0.88 to 1.25) with significant heterogeneity across studies (I(2) = 74.0%, P = 0.000). After the sensitivity analysis, three studies were deleted; however the association remained insignificant (HR, 0.99; 95% CI, 0.91 to 1.08). Subgroup analysis by anatomic location showed a risk for coffee consumption associated with cardia cancer (HR, 1.23; 95% CI, 1.04 to 1.45; heterogeneity, I(2) = 36.4, P = 0.207). In the dose-response analysis, there was no significant association between coffee intake (in cups) and the risk of gastric cancer (P for linearity trend and non-linearity > 0.05).
  
  
  CONCLUSIONS
  Our meta-analysis demonstrated that coffee consumption was not associated with overall gastric cancer risk; however, coffee consumption may be a risk factor for gastric cardia cancer.
authors.affiliation: Department of General Surgery, The Second Affiliated Hospital of Wenzhou Medical University, Wenzhou 325027, China.
authors.forename: Haibin
authors.initials: H
authors.lastname: Liu
authors.affiliation: Department of Obstetrics and Gynecology, The Second Affiliated Hospital of Wenzhou Medical University, Wenzhou 325027, China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Hua
authors.affiliation: Department of General Surgery, The Second Affiliated Hospital of Wenzhou Medical University, Wenzhou 325027, China.
authors.forename: Xiangyun
authors.initials: X
authors.lastname: Zheng
authors.affiliation: Department of Obstetrics and Gynecology, The Second Affiliated Hospital of Wenzhou Medical University, Wenzhou 325027, China.
authors.forename: Zhaojun
authors.initials: Z
authors.lastname: Shen
authors.affiliation: Department of Obstetrics and Gynecology, The Second Affiliated Hospital of Wenzhou Medical University, Wenzhou 325027, China.
authors.forename: Hui
authors.initials: H
authors.lastname: Luo
authors.affiliation: Department of Obstetrics and Gynecology, The Second Affiliated Hospital of Wenzhou Medical University, Wenzhou 325027, China.
authors.forename: Xuejiao
authors.initials: X
authors.lastname: Tao
authors.affiliation: Department of Emergency Medicine, The Second Affiliated Hospital of Wenzhou Medical University, Wenzhou 325027, China.
authors.forename: Zhiyi
authors.initials: Z
authors.lastname: Wang
mesh_terms: D003069:Coffee; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008297:Male; D011446:Prospective Studies; D039781:PubMed; D012307:Risk Factors; D013274:Stomach Neoplasms / Q000453:epidemiology* / Q000209:etiology*
chemical_list: D003069:Coffee