Tobacco and the risk of pancreatic cancer : a review and meta-analysis

Background/Aim: Smoking is a recognized risk factor for pancreatic cancer. The aim of this study was to perform a meta-analysis to provide a robust estimate of the strength of the association between smoking and pancreatic cancer, to determine the risk of pipe and cigar smoking, and to estimate the duration of an elevated risk after smoking cessation. Methods: We performed a meta-analysis of 82 published studies containing epidemiologic information about smoking and pancreatic cancer. Information on studies published between 1950 and 2007 was abstracted and prepared for analysis using standard meta-analytic procedures. Results: The overall risk of pancreatic cancer estimated from the combined results for current and former smokers was, respectively, 1.74 (95% CI 1.61-1.87) and 1.2 (95% CI 1.11-1.29). The risk of pancreatic cancer for current and former pipe and/or cigar smokers was respectively 1.47 (95% CI 1.17-1.83) and 1.29 (95% CI 0.68-2.45). For former cigarette smokers, the risk remains elevated for a minimum of 10 years after cessation. Conclusions: Based on estimates from four continents, smoking cigarettes causes a 75% increase in the risk of pancreatic cancer compared to non-smokers, and the risk persists for a minimum of 10 years after smoking cessation. This implies that in a population where the prevalence of smoking is 30%, the population's attributable risk (the proportion of pancreatic cancer explained by smoking) is estimated to be 20%.