A Case-Cohort Study to Investigate the Excess of Liver Cancer Observed in Workers in Poultry Slaughtering & Processing Plants

This is a case-cohort study to examine whether the excess of liver cancer deaths observed in workers in poultry plants could be explained by oncogenic viruses and chemical carcinogenic exposures within the plants. A detailed telephone questionnaire was administered, and responses were analyzed by logistic regression. Odds ratios for several indicators of high exposure to oncogenic viruses or chemical carcinogens in poultry plants and related industries were elevated, but not statistically significant, except the odds ratio for direct contact with the blood of meat in kitchens, eating places, etc. Established risk factors were replicated, and new ones identified. The study was unable to unequivocally assess risks due to oncogenic viruses or chemical carcinogenic exposures in poultry plants, mainly because observed elevated risks did not achieve statistical significance. The same also applies to some non-occupational factors. Noteworthy risk factors identified include the increased risks for eating cabbage, mussels, blood sausage, meringue, playing football, and decreased risks for history of frequent intake of soft drinks, gelatin-based meals, vitamins, frequent use of microwave oven to cook, and history of childhood diseases, and nonspecific symptoms. The significance of these findings is unknown, and they will need to be replicated in studies with adequate statistical power.