Tobacco smoking and the risk of pancreatitis: A systematic review and meta-analysis of prospective studies

Background: Tobacco smoking has been associated with increased risk of pancreatitis in several studies, however, not all studies have found an association and it is unclear whether there is a dose-response relationship between increasing amount of tobacco smoked and pancreatitis risk. We conducted a systematic review and meta-analysis of prospective studies on tobacco smoking and pancreatitis to clarify the association. Methods: PubMed and Embase databases were searched for relevant studies up to April 13th, 2019. Prospective studies that reported adjusted relative risk (RR) estimates and 95% confidence intervals (CIs) for the association between tobacco smoking and pancreatitis were included and summary RRs were calculated using a random effects model. Results: Ten prospective studies were included. The summary RR for acute pancreatitis was 1.49 (95% CI: 1.29-1.72, I-2 = 68%, n = 7) for current smokers, 1.24 (95% CI: 1.15-1.34, I-2 = 0%, n = 7) for former smokers, and 1.39 (95% CI: 1.25-1.54, I-2 = 69%, n = 7) for ever smokers compared to never smokers. Similar results were observed for chronic pancreatitis and acute/chronic pancreatitis combined. The summary RR per 10 cigarettes per day was 1.30 (95% CI: 1.18-1.42, I-2 = 42%, n = 3) and per 10 pack-years in current smokers was 1.13 (95% CI: 1.08-1.17, I-2 = 14%, n = 4) for acute pancreatitis and results were similar for chronic pancreatitis and acute/chronic pancreatitis combined. Conclusions: These results suggest that tobacco smoking increases the risk of acute and chronic pancreatitis and acute and chronic pancreatitis combined and that there is a dose-response relationship between increasing number of cigarettes and pack-years and pancreatitis risk. (C) 2019 IAP and EPC. Published by Elsevier B.V. All rights reserved.