Employment as butcher and cancer risk in a record-linkage study from Sweden

Objective: To investigate the risk of cancer among butchers and other meat workers in a large record-linkage study from Sweden. Methods: The Swedish Cancer Environment Register III contains nationwide data on cancer incidence during 1971-1989 for all residents, by occupation and industry of employment as reported at the 1960 and 1970 censuses. We identified 25,049 men classified as butchers or meat workers at either census. We used as a comparison group the remaining part of the active male population, after exclusion of workers with direct contact with animals. Results: Butchers in the meat industry had a slight increase in the risk of cancer (relative risk [RR] 1.1, 95% confidence interval [CI] 1.0-1.3), which was due to an increased risk of cancers of the oral cavity and pharynx (RR 1.6, 95% CI 1.0-2.7), stomach (RR 1.6, 95% CI 1.1-2.7), larynx (RR 1.4, 95% CI 0.6-3.4), and lung (RR 1.4, 95% CI 1.1-1.9). The risk of stomach cancer was highest during the first 5 years of the study, and among butchers from urban areas. No temporal or geographic variations were seen for lung cancer risk, with elevations restricted to squamous cell carcinoma. An increased risk of stomach, laryngeal and lung cancers was present in butchers and meat workers outside the meat industry. There was no clear indication of an increased risk of other neoplasms. Conclusions: The increased risk of oral, laryngeal, lung and stomach cancers among Swedish butchers may be at least partly due to confounding by tobacco smoking, alcohol drinking, and other lifestyle factors. However, exposures in the meat industry (e.g., viruses, nitrosamines, polycyclic aromatic hydrocarbons) may contribute the elevated cancer risks.