Consumption of beer and colorectal cancer incidence: a meta-analysis of observational studies

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; pheterogeneity <0.001, I2 = 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.