Occupation and bronchial carcinoma.

All patients newly diagnosed as bronchial carcinoma were studied during a 5-year period. There were 212 male and 61 female patients. A careful occupational history was taken and the occupations of the patients in 1950 were compared with the County's official occupational statistics of that year, and their chest X-rays were scrutinized for pleural plaques. A significantly higher proportion of metal workers and workers from the building industry was found among the patients, while agricultural workers were under-represented. Smoking habits did not explain the difference. The number of patients with pleural plaques was four times higher than expected. It is concluded that dust in certain occupations has an additive effect on the carcinogenic effect of smoking.