Adult-onset acute leukemia and employment in the meat industry: a New Zealand case-control study

Objectives: To assess the risks for adult-onset acute leukemia associated with employment in the New Zealand meat industry. Methods: A total of 110 incident leukemia cases identified from referrals to one of six treatment centers between 1989 and 1991 were compared with 199 general population controls. Detailed occupational exposure histories were obtained by interview. Results: There was an elevated risk associated with ever having worked in an abattoir (OR = 2.3, 95% CI 1.0-5.2), which appeared confined to those with over 2 years exposure (OR = 4.9, 95% CI 1.5-15.6). The excess risk was confined to abattoir workers having direct contact with animals or animal products (OR = 5.2, 95% CI 1.2-22.2). Ever having worked as a butcher was associated with elevated risk (OR = 2.9, 95% CI 1.1-7.2), confined to those individuals who worked as a butcher in an abattoir (OR = 4.8) or who butchered livestock on farms (OR = 8.2). No increased risk was found for work as a retail/wholesale butcher or meatpacker (OR = 1.2). Conclusions: This study found increased leukemia risks associated with employment in the meat industry. These were confined to abattoir workers with over 2 years employment in the industry, and to persons whose jobs involved contact with animals or animal tissue, implying that biological exposures may be responsible.