Cigarette smoking and pancreas cancer: a case-control study based on direct interviews

Background: Cigarette smoking is the most consistently reported risk factor for pancreas cancer, yet the dose-response relationship in many pancreas cancer studies is weak. Because of the poor prognosis for pancreas cancer, many case-control studies have been based largely on interviews with proxy respondents, who are known to report less reliable information on detailed smoking habits than original subjects. Purpose: Our purpose was to evaluate cigarette smoking as a risk factor for pancreas cancer based on data obtained only from direct interviews and to estimate the effects of quitting smoking and of switching from nonfiltered to filtered cigarettes on risk. Our objective also was to estimate the contribution of cigarette smoking toward explaining the higher pancreas cancer incidence experienced by black Americans compared with white Americans. Methods: A population-based, case-control study of pancreas cancer was conducted during 1986-1989 in Atlanta, Ga., Detroit, Mich., and 10 counties in New Jersey. Direct interviews were successfully completed with 526 case patients and 2153 control subjects aged 30-79 years, making this the largest population-based, case-control study of pancreas cancer to date based only on direct interviews. Results: Cigarette smokers had a significant, 70% increased risk of pancreas cancer compared with the risk in nonsmokers. A significant, positive trend in risk with increasing duration smoked was apparent (P