title: Meta-analysis: Tobacco smoking may enhance the risk of acute pancreatitis.
abstract: OBJECTIVE
  Questions remain unclear about the association of smoking status and the development of acute pancreatitis (AP). We performed a meta-analysis of observational studies explore this association.
  
  
  METHODS
  A computerized literature search was performed in MEDLINE and EMBASE through November 30, 2014. We also searched the reference lists of pertinent articles. We used a random-effects model to calculate the summary relative risks (SRRs) and their corresponding 95% confidence intervals (CIs).
  
  
  RESULTS
  A total of 3690 incident cases of AP included 12 observational studies (6 case-control and 6 prospective cohort/nested case-control studies) were identified. Compared with never smokers, the summary RR estimates were 1.54 (95% CI, 1.31-1.80) for ever smokers, 1.71 (95% CI, 1.37-2.14) for current smokers, and 1.21 (95% CI, 1.02-1.43) for former smokers. Smoking is found to be a potential risk factor for alcohol use, idiopathic factors and drugs related AP, but not for gallstone related AP, in the ever and current smokers. A dose-response effect of tobacco use on the risk was ascertained: current smokers had a 40% (95% CI, 30%-51%) increased risk of AP for every additional 10 cigarettes per day.
  
  
  CONCLUSIONS
  The present analysis suggests that smokers have an elevated risk of AP development. Further studies, however, are warranted before definitive conclusions can be drawn.
authors: Department of Internal Medicine, The Second People's Hospital of Nantong, Nantong, Jiangsu 226002, China. Electronic address: sunxiaob123@126.com.
authors: Xiaobing
authors: X
authors: Sun
authors: Department of Internal Medicine, The Second People's Hospital of Nantong, Nantong, Jiangsu 226002, China.
authors: Xiaoquan
authors: X
authors: Huang
authors: Department of Internal Medicine, The Second People's Hospital of Nantong, Nantong, Jiangsu 226002, China.
authors: Ruifeng
authors: R
authors: Zhao
authors: Department of Internal Medicine, The Second People's Hospital of Nantong, Nantong, Jiangsu 226002, China.
authors: Beibei
authors: B
authors: Chen
authors: Department of Internal Medicine, The Second People's Hospital of Nantong, Nantong, Jiangsu 226002, China.
authors: Qin
authors: Q
authors: Xie
mesh_terms: D000208:Acute Disease; D006801:Humans; D015233:Models, Statistical; D064887:Observational Studies as Topic; D010195:Pancreatitis / Q000209:etiology*; D012307:Risk Factors; D012907:Smoking / Q000009:adverse effects*
keywords: Acute pancreatitis; Confidence interval; Meta-analysis; Observational studies; Smoking status; Summary relative risk