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, I2 = 68%, n = 7) for current smokers, 1.24 (95% CI: 1.15–1.34, I2 = 0%, n = 7) for former smokers, and 1.39 (95% CI: 1.25–1.54, I2 = 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, I2 = 42%, n = 3) and per 10 pack-years in current smokers was 1.13 (95% CI: 1.08–1.17, I2 = 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.