Cigarette smoking and pancreatic cancer risk: a revisit with an assessment of the nicotine dependence phenotype.

BACKGROUND Cigarette smoking is a well-established risk factor of pancreatic cancer (PC). Although an association between nicotine dependence phenotype, namely time to first cigarette (TTFC) after waking, and the risk of several smoking-related cancers has been reported, an association between TTFC and PC risk has not been reported. We assessed the impact of smoking behavior, particularly TTFC, on PC risk in a Japanese population. MATERIALS AND METHODS We conducted a case-control study using 341 PC and 1,705 non-cancer patients who visited Aichi Cancer Center in Nagoya, Japan. Exposure to risk factors, including smoking behavior, was assessed from the results of a self-administered questionnaire. The impact of smoking on PC risk was assessed with multivariate logistic regression analysis adjusted for potential confounders to estimate odds ratios (ORs) and 95% confidence intervals (CIs). RESULTS Cigarettes per day (CPD) and/or smoking duration were significantly associated with PC risk, consistent with previous studies. For TTFC and PC risk, we found only a suggestive association: compared with a TTFC of more than 60 minutes, ORs were 1.15 (95%CI, 0.65- 2.04) for a TTFC of 30-60 minutes and 1.35 (95%CI, 0.85-2.15) for that of 0-30 minutes (p trend=0.139). After adjustment for CPD or smoking duration, no association was observed between TTFC and PC. CONCLUSIONS In this study, we found no statistically significant association between TTFC and PC risk. Further studies concerning TTFC and PC risk are warranted.