One of objective methods of early and differential diagnosis of occupational pulmonary diseases in miners (pneumoconiosis, silicotuberculosis, dust bronchitis) is bronchoscopy with a cytologic examination of bronchoalveolar lavage fluid (BAF). BAF-examination was carried out in a total of 88 patients with incipient and advanced forms of dust bronchitis, pneumoconiosis and silicotuberculosis. A direct relationship has been revealed between a decline in local cell-bound immunity caused by a dust-inducted affection mononuclear phagocytes and advancing of stages of dust-related diseases.
Employing incidence data from the Quebec Tumor Registry, we examined the relative risks of cancer of all sites for the years 1969-73 in the asbestos-mining, rural, and metropolitan counties of Quebec Province, Canada. Generally, rates for males exceeded those for females, and the relative risks in the asbestos-mining counties for 7-10 different sites of cancer, all of low incidence, were from 1.50 to 8.08 times those of other rural counties of the Province for both sexes. Metropolitan counties exhibited equally high risk for many of these sites. We discovered higher risks among males in asbestos-mining counties for cancer of the pleura, peritoneum, lip, tongue, salivary gland, mouth, and small intestine and higher risks among females for cancer of the pleura, lip, kidney, salivary gland, and for melanoma. Because of the likelihood of a long latent period for asbestos-related cancers, the risks we observed were possibly the product of since-altered occupational and environmental conditions existing 20-30 years ago in the asbestos-mining areas. The similarities in risks for most cancers in asbestos-mining and urban areas were noteworthy.
The aim of this study was to investigate the incidence of cancer among 318 male employees of a niobium mining company which was only operated between 1951 and 1965. Many of the workers, especially underground miners, were exposed to the daughters of radon and thoron and also to thorium. The accumulated doses to the workers from short-lived radon and thoron daughters in the mine atmosphere were assessed to be relatively low; up to 300 working-level months. During the follow-up period 1953-1981, 24 new cases of cancer were observed compared to an expected number of 22.8. Twelve cases of lung cancer had occurred versus 3.0 expected. Among the 77 miners, 9 cases of lung cancer were observed against 0.8 expected. Associations between the occurrence of lung cancer and exposure to alpha radiation and smoking were found. For the radon and thoron daughter exposure, about 50 excess cases per million person-years at risk per working-level month were observed.
In miners anthracosilicosis is caused by chronic exposure to coal dust and is characterized by progressive development of the inflammatory process, the expressed disorders of lipid metabolism, and immunodeficiency. In the experiment we revealed the stages of anthracosilicosis development according to which adequate measures of prevention and correction of the disorders caused by long exposure of an organism to coal dust are recommended.
Studies covered incidence of coronary heart disease, its risk factors and features of constitutional types among Kouzbass coal miners suffering from anthracosilicosis and chronic dust bronchitis. Findings are reliably higher incidence of coronary heart disease among coal miners having lung diseases caused by dust. Coronary heart disease among the miners with anthracosilicosis is favored by arterial hypertension, overweight and hypersthenic constitutional type, that among those with dust bronchitis is favored only by overweight.
The association between cumulative radon exposure and coronary heart disease mortality was studied in a retrospective cohort investigation of Newfoundland fluorspar miners.
Multivariate Poisson regression techniques were used to estimate relative risks of coronary heart disease mortality by level of radon exposure. Relative risks (RR) were adjusted by attained age, calendar period, duration of exposure, and smoking status. Death from coronary heart disease was the outcome measure of interest and was identified by record linkage to the Canadian Mortality Database.
An elevated risk of mortality from coronary heart disease was observed among miners with a cumulative radon exposure exceeding 1000 working-level months [RR 1.5, 95% confidence interval (95% CI) 0.77-2.75]. The association between radon exposure and coronary heart disease was not statistically significant according to a test for trend across exposure categories (P = 0.09). The smokers were 1.8 times more likely than the nonsmokers to die from coronary heart disease (95% CI 1.1-2.8).
These results suggest a positive association between coronary heart disease and radon exposure. However, these findings should be interpreted cautiously due to the inability to control for the confounding influence of other known risk factors of coronary heart disease.