title: Association between coffee consumption and the risk of oral cancer: a meta-analysis of observational studies.
abstract: OBJECTIVE
  Quantification of the association between the coffee consumption and risk of oral cancer is still conflicting. Thus, we conducted a meta-analysis to summarize the evidence from epidemiological studies of coffee consumption with the risk of oral cancer.
  
  
  METHODS
  Pertinent studies were identified by a search of PubMed and Web of Knowledge to March 2015. The random effect model was used. Sensitivity analysis and publication bias were conducted.
  
  
  RESULTS
  Data from 12 studies including 4,037 oral cancer cases and 1,872,231 participants were used in this meta-analysis. Pooled results suggested that highest coffee consumption amount versus lowest amount was significantly associated with the risk of oral cancer [summary relative risk (RR) = 0.694, 95% CI = 0.543-0.886, I(2) = 65.0%]. The association was also significant in Europe [summary RR = 0.571, 95% CI = 0.378-0.863], but not in America. No publication bias was found.
  
  
  CONCLUSIONS
  Our analysis suggested that the higher coffee consumption might reduce the risk of oral cancer, especially in Europe.
authors.affiliation: Department of Emergency, School of Stomatology, China Medical University No. 117 North Nanjing Road, Shenyang 110001, China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Department of Emergency, School of Stomatology, China Medical University No. 117 North Nanjing Road, Shenyang 110001, China.
authors.forename: Xi
authors.initials: X
authors.lastname: Wang
authors.affiliation: Department of Emergency, School of Stomatology, China Medical University No. 117 North Nanjing Road, Shenyang 110001, China.
authors.forename: Dan
authors.initials: D
authors.lastname: Cui
keywords: Coffee consumption; meta-analysis; oral cancer