Rectal cancer and occupational risk factors: A hypothesis-generating, exposure-based case-control study

In 1979, a hypothesis-generating, population-based case-control study was u ndertaken in Montreal, Canada, to explore the association between occupatio nal exposure to 294 substances, 130 occupations and industries, and various cancers. Interviews were carried out with 3,630 histologically confirmed c ancer cases, of whom 257 had rectal cancer, and with 533 population control s, to obtain detailed job history and data on potential confounders. The jo b history of each subject was evaluated by a team of chemists and hygienist s and translated into occupational exposures. Logistic regression analyses adjusted for age, education, cigarette smoking, beer consumption, body mass index, and respondent status were performed using population controls and cancer controls, e.g., 1,295 subjects with cancers at sites other than the rectum, lung, colon, rectosigmoid junction, small intestine, and peritoneum . We present here the results based on cancer controls. The following subst ances showed some association with rectal cancer: rubber dust, rubber pyrol ysis products, cotton dust, wool fibers, rayon fibers, a group of solvents (carbon tetrachloride, methylene chloride, trichloroethylene, acetone, alip hatic ketones, aliphatic esters, toluene, styrene), polychloroprene, glass fibers, formaldehyde, extenders, and ionizing radiation. The independent ef fect of many of these substances could not be disentangled as many were hig hly correlated with each other. Int. J. Cancer 87: 874-879, 2000. (C) 2000 Wiley-Liss, Inc.