Alcohol drinking and pancreatic cancer risk: a meta-analysis of the dose-risk relation.

In order to provide a more precise quantification of the association between alcohol consumption and pancreatic cancer risk, we performed a meta-analysis of relevant dose-risk results. We conducted a PubMed search of all case-control (N=21) and cohort (N=11) studies published up to March 2009. We computed summary relative risk (RR) estimates using either fixed- or, in the presence of heterogeneity, random-effects models. The pooled RR was 0.92 (95% confidence interval, 95% CI, 0.86-0.97) for <3 drinks/day and 1.22 (95% CI, 1.12-1.34) for > or = 3 drinks/day. The increased risk for heavy drinking was similar in women and men, but apparently stronger in cohort studies (RR=1.29), in studies with high quality index (RR=1.30), and did not appear to be explained by residual confounding by either history of pancreatitis or tobacco smoking. This meta-analysis provides strong evidence for the absence of a role of moderate drinking in pancreatic carcinogenesis, coupled to an increased risk for heavy alcohol drinking. Given the moderate increase in risk and the low prevalence of heavy drinkers in most populations, alcohol appears to be responsible only for a small fraction of all pancreatic cancers.