CIGARETTE-SMOKING AND ALCOHOL-CONSUMPTION AND THE RISK OF PANCREATIC-CANCER - A CASE-CONTROL STUDY IN SHANGHAI, CHINA

Cancer of the pancreas has been rising in incidence in Shanghai, China since the early 1970s. In 1987-89, this malignancy ranked eighth in cancer incidence among men and ninth among women in Shanghai. To examine risk factors for this tumor in urban Shanghai, a population-based case-control study was conducted. Cases (n = 451) were permanent residents of Shanghai, 30 to 74 years of age, newly diagnosed with pancreatic cancer between 1 October 1990 and 30 June 1993. Deceased cases (19 percent) were excluded from the study. Controls (n = 1,552) were selected among Shanghai residents, frequency-matched to cases by gender and age. Cases and controls were interviewed about their demographic background and potential risk factors, including tobacco, alcohol and beverage consumption, diet, and medical history. Adjusted odds ratios (OR) and 95 percent confidence intervals (CI) were estimated using logistic regression models. Current cigarette smoking was associated with excess risk of pancreatic cancer in both men (OR = 1.6, CI = 1.1-2.2) and women (OR = 1.4, CI = 0.9-2.4). ORs increased significantly with number of cigarettes smoked per day, and with duration and pack-years of smoking. Risk increased three- to sixfold among those in the highest categories of cigarette consumption, while risk decreased with increasing years since smoking cessation. Former smokers who stopped smoking for 10 or more years had risks comparable to nonsmokers. No association was found between alcohol use and pancreatic cancer. After adjustment for potential confounding factors, it was estimated that during the study period, nearly 25 percent of pancreatic cancer cases among men and six percent of cases among women could be attributed to smoking. Our findings add to the accumulating evidence linking smoking and pancreatic cancer, and suggest that the rising incidence of this malignancy in Shanghai may be related at least partly to the increasing prevalence of smoking.