Human Exposure to Poultry and Poultry Products and the Risk of Death from Hematopoietic & Lymphatic Cancers

Purpose: The purpose of this study was to obtain preliminary information on occupational exposures responsible for the excess of hematopoietic & lymphatic (H&L) cancers previously observed in cohort mortality studies of workers in poultry slaughtering and processing plants.

Methods: A pilot case-cohort study was conducted nested within a combined cohort of 30,411 poultry workers and 16,408 controls, identified from several United Food & Commercial Workers (UFCW) unions across the United States. Interviewed cases were 48 deaths out of a total of 130 deaths (37%) from H & L tumors that occurred in the cohort between 1990-2003. Controls were N=152 subjects that were successfully interviewed out of 1516 subjects (10%) randomly selected from all cohort members alive as of January 1, 1990. Telephone interviews were obtained directly from live control subjects or next-of-kin for deceased cases and controls. Mortality risk was assessed using logistic regression odds ratios and hazard ratios.

Results: Poultry farming [OR=10.8 (95% CI: 3.0-39.1)] and spreading chicken wastes as manure [OR=5.6 (95% CI: 1.5-20.4)] were significantly associated with lymphoma; handling raw eggs in supermarkets [OR=4.3 (95% CI: 1.0-18.0)] was significantly associated with leukemia. Non-poultry exposures significantly associated with these tumors included coal by-products, selling seafood, and killing of pigs.

Conclusion: This preliminary study identifies possible occupational exposures that may be associated with excess deaths from H & L tumors in poultry workers. Case-control studies of sufficient statistical power are now needed to confirm these findings and discover new ones.