Objectives: Cigarette smoking is an independent risk factor for chronic pancreatitis. We conducted a systematic review of the literature assessing whether cigarette smoking is a risk factor for acute pancreatitis (AP) and recurrent AP (RAP).
Methods: MEDLINE, PubMed, Embase, and Cochrane Database of Systematic Reviews were searched for studies published from database inception through March 2013. Two investigators independently reviewed articles for eligibility; discordant decisions were resolved by a third investigator's review and consensus. When there were sufficient studies, random-effects meta-analyses were performed by estimating pooled hazards ratios (HRs) with 95% confidence intervals (CIs).
Results: Twelve studies met the eligibility criteria: 7 for AP, 5 for RAP. Compared with never smokers, the risk for AP was significantly increased in current smokers (6 studies; HR, 1.75; 95% CI, 1.26-2.44) and former smokers (5 studies; HR, 1.63; 95% CI, 1.18-2.27). Compared with never smokers, ever smokers were at higher risk for developing RAP (5 studies; HR, 1.59; 95% CI, 1.19-2.12).
Conclusions: This meta-analysis provides supportive evidence for the association of smoking status and AP. This effect is most pronounced for current smokers, but the risk exists among the former smokers compared with never smokers. There was an increased risk for RAP among ever smokers compared with that among never smokers.