title: Allium vegetables and upper aerodigestive tract cancers: a meta-analysis of observational studies.
abstract: METHODS
  To provide updated quantitative overall estimations of the relation between total allium, garlic, and onion intake on the risk of cancer of the upper aerodigestive tract (UADT).
  
  
  RESULTS
  We combined data of published observational studies (21 case-control and four cohort studies), using a meta-analytic approach and random effects models. The overall relative risks (RR) and 95% confidence intervals (CIs) for the squamous cell carcinoma of the UADT were 0.79 (95% CI 0.56-1.11) for total allium, 0.74 (95% CI 0.57-0.95) for garlic, and 0.72 (95% CI 0.57-0.91) for onion for the highest versus the lowest consumption. The inverse relation was apparently stronger in case-control studies (RR 0.56, 95% CI 0.38-0.83 for total allium), in Chinese studies (RR 0.67, 95% CI 0.45-0.98 for garlic intake), and for esophageal than for head and neck cancers. Apparently, there was no relation between allium vegetable intake and adenocarcinoma of the esophagus.
  
  
  CONCLUSIONS
  We found a moderate inverse association between allium vegetable intake and the risk of squamous cell carcinoma of the UADT in case-control studies. The relation was unclear in cohort studies and for adenocarcinoma of the esophagus.
authors.affiliation: Department of Clinical Sciences and Community Health, Università degli Studi di Milano, Milan, Italy.
authors.forename: Valentina
authors.initials: V
authors.lastname: Guercio
authors.affiliation: Department of Epidemiology, IRCCS - Istituto di Ricerche Farmacologiche Mario Negri, Milan, Italy.
authors.forename: Federica
authors.initials: F
authors.lastname: Turati
authors.affiliation: Department of Clinical Sciences and Community Health, Università degli Studi di Milano, Milan, Italy.
authors.forename: Carlo
authors.initials: C
authors.lastname: La Vecchia
authors.affiliation: Department of Epidemiology, IRCCS - Istituto di Ricerche Farmacologiche Mario Negri, Milan, Italy.
authors.forename: Carlotta
authors.initials: C
authors.lastname: Galeone
authors.affiliation: Department of Epidemiology, IRCCS - Istituto di Ricerche Farmacologiche Mario Negri, Milan, Italy.
authors.forename: Alessandra
authors.initials: A
authors.lastname: Tavani
mesh_terms: D000490:Allium / Q000737:chemistry*; D016208:Databases, Factual; D004032:Diet; D004938:Esophageal Neoplasms / Q000453:epidemiology*; D005770:Gastrointestinal Neoplasms / Q000453:epidemiology*; D006258:Head and Neck Neoplasms / Q000453:epidemiology*; D006801:Humans; D064887:Observational Studies as Topic; D012307:Risk Factors
keywords: Allium vegetables; Diet; Epidemiology; Squamous cell carcinoma; Upper aerodigestive tract cancer