A case-cohort study of lung cancer in poultry and control workers: occupational findings

We conducted a mortality study of members of the United Food and Commercial Workers International Union who worked in poultry slaughtering/processing plants, and controls. Excess deaths from cancer at 11 different cancer sites including lung cancer were observed in the poultry workers. The study described here is a pilot case-cohort study of lung cancer nested within the cohort to examine if it is possible, in a larger study to be conducted later, to identify specific potentially carcinogenic occupational exposures in poultry workers.

Subjects or the next of kin of deceased subjects were interviewed by phone. Logistic regression ORs and Cox proportional HRs were estimated.

Elevated risks for poultry exposure were recorded for subjects who (1) killed chickens at work (OR 4.2, 95% CI 1.2 to 14.7; HR 1.8, 95% CI 1.0 to 3.3) and (2) ever had direct contact with chicken blood at work (OR 1.9, 95% CI 1.0 to 3.8; HR 1.3, 95% CI 0.9 to 2.0). These activities are associated with high exposure to oncogenic viruses.

These results may have important public health implications, since the general population is also exposed to these viruses. Elevated risks were observed for non-poultry-related occupational exposures such as working in a stockyard, working in a chemical plant, use of chemicals to kill moulds, and working in plants where plastic products were manufactured. These preliminary findings indicate that full scale epidemiological studies of adequate statistical power are needed to examine the role of occupational exposures in cancer occurrence in poultry workers.