title: Alcohol drinking and colorectal cancer risk: an overall and dose-response meta-analysis of published studies.
abstract: BACKGROUND
  The International Agency for Research on Cancer (IARC) concluded that alcohol consumption is related to colorectal cancer (CRC). However, several issues remain unresolved, including quantification of the association for light (≤1 drink/day) and moderate (2-3 drinks/day) alcohol drinking, investigation of the dose-response relationship, and potential heterogeneity of effects by sex, colorectal site, and geographical region.
  
  
  METHODS
  Twenty-seven cohort and 34 case-control studies presenting results for at least three categories of alcohol intake were identified from a PubMed search of articles published before May 2010. The summary relative risks (RRs) were estimated by the random effects model. Second-order fractional polynomials and random effects meta-regression models were used for modeling the dose-risk relation.
  
  
  RESULTS
  The RRs were 1.21 [95% confidence interval (CI) 1.13-1.28] for moderate and 1.52 (95% CI 1.27-1.81) for heavy (≥4 drinks/day) alcohol drinking. The RR for moderate drinkers, compared with non-/occasional drinkers, was stronger for men (RR = 1.24, 95% CI 1.13-1.37) than for women (RR = 1.08, 95% CI 1.03-1.13; P(heterogeneity) = 0.02). For heavy drinkers, the association was stronger in Asian studies (RR = 1.81, 95% CI 1.33-2.46; P(heterogeneity) = 0.04). The dose-risk analysis estimated RRs of 1.07 (95% CI 1.04-1.10), 1.38 (95% CI 1.28-1.50), and 1.82 (95% CI 1.41-2.35) for 10, 50, and 100 g/day of alcohol, respectively.
  
  
  CONCLUSIONS
  This meta-analysis provides strong evidence for an association between alcohol drinking of >1 drink/day and colorectal cancer risk.
authors.affiliation: International Agency for Research on Cancer, Lyon, France. Electronic address: fedirkov@fellows.iarc.fr.
authors.forename: V
authors.initials: V
authors.lastname: Fedirko
authors.affiliation: Istituto di Ricerche Farmacologiche 'Mario Negri', Milan, Italy.
authors.forename: I
authors.initials: I
authors.lastname: Tramacere
authors.affiliation: Department of Statistics, University of Milano-Bicocca, Milan, Italy; Division of Epidemiology and Biostatistics, European Institute of Oncology, Milan, Italy.
authors.forename: V
authors.initials: V
authors.lastname: Bagnardi
authors.affiliation: Department of Statistics, University of Milano-Bicocca, Milan, Italy; Department of Clinical Medicine and Prevention, Centre of Biostatistics for Clinical Epidemiology, University of Milano-Bicocca, Monza, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Rota
authors.affiliation: Department of Statistics, University of Milano-Bicocca, Milan, Italy.
authors.forename: L
authors.initials: L
authors.lastname: Scotti
authors.affiliation: International Agency for Research on Cancer, Lyon, France; Digestive Disease Research Center, Shariati Hospital, Tehran University of Medical sciences, Tehran, Iran; King's College London, Thames Cancer Registry, London, UK.
authors.forename: F
authors.initials: F
authors.lastname: Islami
authors.affiliation: Istituto di Ricerche Farmacologiche 'Mario Negri', Milan, Italy.
authors.forename: E
authors.initials: E
authors.lastname: Negri
authors.affiliation: International Agency for Research on Cancer, Lyon, France.
authors.forename: K
authors.initials: K
authors.lastname: Straif
authors.affiliation: International Agency for Research on Cancer, Lyon, France.
authors.forename: I
authors.initials: I
authors.lastname: Romieu
authors.affiliation: Istituto di Ricerche Farmacologiche 'Mario Negri', Milan, Italy; Section of Medical Statistics, Department of Occupational Health, Università degli Studi di Milano, Milan, Italy.
authors.forename: C
authors.initials: C
authors.lastname: La Vecchia
authors.affiliation: The Tisch Cancer Institute, Mount Sinai School of Medicine, New York, NY, USA; International Prevention Research Institute, Lyon, France.
authors.forename: P
authors.initials: P
authors.lastname: Boffetta
authors.affiliation: International Agency for Research on Cancer, Lyon, France.
authors.forename: M
authors.initials: M
authors.lastname: Jenab
mesh_terms: D000428:Alcohol Drinking / Q000009:adverse effects / Q000453:epidemiology*; D016022:Case-Control Studies; D015331:Cohort Studies; D015179:Colorectal Neoplasms / Q000453:epidemiology* / Q000209:etiology; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D008297:Male; D012306:Risk; D012737:Sex Factors