Lung cancer in miners

Lung cancer among Dutch coal miners: a case-control study

A case-control study was conducted in the southern part of The Netherlands to investigate the risk of lung cancer in coal miners; 381 age-matched pairs of primary lung cancer cases and controls, diagnosed between 1972 and 1988, were selected from the pathology department of the University Hospital in the region. Information about past employment in coal mines was obtained through the registers of the collaborative pension fund for Dutch miners. 20% of the cases were (at some time) employed in coal mining, compared with 21% of the controls (odds ratio 0.95; 95% confidence interval: 0.65-1.38). 9% of both cases and controls had an underground work history (odds ratio 0.96; 95% confidence interval: 0.56-1.65). The duration of underground coal mining did not differ substantially between cases and referents (average duration: respectively 117 and 108 months). No relation between specific histologic tumor cell types and coal mining could be demonstrated. The study gives no indication that workers in Dutch coal mines have an increased risk of developing lung malignancies.

Silica, pneumoconiosis, and carcinoma of the lung

The current argument about the carcinogenicity of inhaled silica is not clarified by reliance on morbidity and mortality experience divorced from or incompletely related to data on environmental exposure. Human evidence provides the ultimate basis for assessing such risks, and numerous studies of the effects of inhaling dusts rich or poor in silica content on the prevalence of pulmonary carcinoma have been performed on large series of cases from major mining areas of the world. When due allowance is made for substances inhaled concomitantly with exposure to silica and for personal pollution by cigarette smoking, the weight of evidence is against a carcinogenic role for uncombined silicon dioxide. Moreover, pneumoconiosis due to compact mineral particles does not appear to determine the onset of lung cancer. Cellular behaviour suggests reasons for the different responses to compact and fibrous particles acting alone.