title: Consumption of beer and colorectal cancer incidence: a meta-analysis of observational studies.
abstract: BACKGROUND
  Several meta-analyses and reports from the World Cancer Research Fund supported a risk association between alcohol consumption and colorectal cancer (CRC). However, the association for beer consumption, the common type of alcoholic beverage, remains unclear.
  
  
  METHODS
  We identified studies by a literature search of PUBMED and EMBASE through 30 June 2014. Summary relative risks (SRRs) with their 95% CIs were calculated with a fixed or random effects model.
  
  
  RESULTS
  Twelve case-control and nine cohort studies were included. Compared with non-alcohol drinkers or non-beer drinkers, any beer drinkers were associated with an increased risk of CRC (SRR = 1.20, 95% CI, 1.06-1.37; p(heterogeneity) <0.001, I(2) = 73.3%), which was stronger in the rectum than in the colon. The categorical meta-analysis indicated that heavy (≥ 2 drinks/day) beer drinking was related to increased risk of CRC (SRR = 1.37, 95% CI 1.26-1.49), while light or moderate beer drinking was not. The dose-response analysis demonstrated that an increase of one drink per day in beer consumption was related to an increased risk of CRC (SRR = 1.13, 95% CI, 1.06-1.21). There was evidence of a potential nonlinear association between beer intake and CRC incidence (p = 0.002 for nonlinearity).
  
  
  CONCLUSIONS
  The results from this meta-analysis suggest that heavy (≥ 2 drinks/day) beer drinking may be associated with increased CRC risk. More researches with improved control of confounding and actual measurement of beer consumption are needed to confirm these findings.
authors: Department of Colorectal Surgery, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, 1630 Dongfang Road, Pudong New District, 200127, Shanghai, China.
authors: Cheng
authors: C
authors: Zhang
authors: Min
authors: M
authors: Zhong
mesh_terms: D000428:Alcohol Drinking / Q000009:adverse effects / Q000453:epidemiology*; D001515:Beer; D015179:Colorectal Neoplasms / Q000453:epidemiology* / Q000209:etiology; D006801:Humans; D015994:Incidence; D012306:Risk