Cancer in the respiratory organs of Swedish farmers.

In a cohort of 254,417 male Swedish farmers (4,330,717 person-years) the incidence of cancer of the respiratory organs was compared to a reference cohort of 1,725,845 men (30,131,664 person-years) employed in other economic activities than agriculture or forestry. In the study cohort 1450 cases of cancer in the respiratory organs were found in 1961 to 1979 resulting in an estimated relative risk (RR) of 0.38 (95% confidence interval [CI]: 0.36-0.40). For cancer of trachea, bronchus and lung, the decreased risk was equal for adenocarcinoma and squamous cell carcinoma. No time related trend in RR for any of the histologic subtypes could be seen. However, for squamous cell carcinoma in nose and nasal sinuses RR has increased from 0.42 (95% CI: 0.20-0.80) in 1961 to 1966 to 2.06 (95% CI: 1.22-3.50) in 1974 to 1979.