Smoking and risk for acute pancreatitis: a systematic review and meta-analysis

We aimed to better understand the relationship between smoking and a risk for acute pancreatitis (AP) in existing observational studies. We identified studies by searching the PubMed, Scopus, and Web of Science databases (from inception through August 31, 2013) and by searching bibliographies of relevant articles. Summary relative risks (RRs) with 95% confidence intervals (CIs) were calculated with fixed-effects and random-effects models. A total of 5 studies met inclusion criteria for analysis. Both current smoking (summary RR, 1.74; 95% CI, 1.39-2.17; n = 5 studies) and former smoking (summary RR, 1.32; 95% CI, 1.03-1.71; n = 4 studies) were associated with an increased risk for AP. The positive association of current smoking and risk for AP remained when we limited the meta-analysis to studies that controlled for alcohol intake and body mass index (summary RR, 1.76; 95% CI, 1.31-2.36; n = 4 studies). Both current and former smoking are associated with increased risk for AP. Further investigations, both epidemiological and mechanistic, are needed to establish the extent to which the association can be explained by a causal link and whether smoking cessation can prevent the occurrence and development of AP.