title: A meta-analysis of coffee and tea consumption and the risk of glioma in adults.
abstract: BACKGROUND
  Coffee contains many compounds, including antioxidants, which could prevent cancerogenesis, and coffee has been related with lower incidence of cancer at several sites. Tea is also rich in antioxidants, mainly polyphenols. To provide a quantitative overall estimate on the relation between coffee and tea consumption and glioma, we combined all published data, using a meta-analytic approach.
  
  
  METHODS
  In September 2012, a bibliography search was carried out in both PubMed and Embase to identify observational studies providing quantitative estimates on the issue. Pooled estimates of the relative risks (RR) and the corresponding 95 % confidence intervals (CI) were calculated using random-effects models.
  
  
  RESULTS
  Six studies (four cohort and two case-control studies) were available for meta-analysis, for a total of about 2100 cases. The summary RRs and 95 % CIs of glioma for drinkers versus non/occasional drinkers were 0.96 (95 % CI: 0.81-1.13) for coffee and 0.86 (95 % CI: 0.78-0.94) for tea, with no heterogeneity between studies. When we compared the highest versus the lowest categories of consumption, the RRs were 1.01 (95 % CI: 0.83-1.22) for coffee, 0.88 (95 % CI: 0.69-1.12) for tea, and 0.75 (95 % CI: 0.54-1.05) for coffee plus tea.
  
  
  CONCLUSIONS
  This meta-analysis, although based on few studies, suggests a lack of association between coffee intake and glioma risk, and a tendency, if any, to a lower risk for tea and coffee plus tea drinkers.
authors.affiliation: Department of Epidemiology, Istituto di Ricerche Farmacologiche Mario Negri, Via Giuseppe La Masa 19, 0157, Milan, Italy.
authors.forename: Stefano
authors.initials: S
authors.lastname: Malerba
authors.forename: Carlotta
authors.initials: C
authors.lastname: Galeone
authors.forename: Claudio
authors.initials: C
authors.lastname: Pelucchi
authors.forename: Federica
authors.initials: F
authors.lastname: Turati
authors.forename: Mia
authors.initials: M
authors.lastname: Hashibe
authors.forename: Carlo
authors.initials: C
authors.lastname: La Vecchia
authors.forename: Alessandra
authors.initials: A
authors.lastname: Tavani
mesh_terms: D000328:Adult; D001932:Brain Neoplasms / Q000453:epidemiology* / Q000209:etiology / Q000517:prevention & control; D003069:Coffee; D005910:Glioma / Q000453:epidemiology* / Q000209:etiology / Q000517:prevention & control; D006801:Humans; D012307:Risk Factors; D013662:Tea
chemical_list: D003069:Coffee; D013662:Tea