Radiological changes in vermiculite workers exposed to tremolite.
Armstrong-BG; Mcdonald-JC; Sebastien-P; Althouse-R; Amandus-HE; Wheeler-R
Ann Occup Hyg, Inhaled Particles VI 1988 Dec; 32(Suppl 1):469-474
Complementary radiographic studies were conducted independently by groups from McGill University and NIOSH among employees of a Montana mine where the vermiculite ore is contaminated by amphibole fibres. In the McGill study, 173 current and 80 past employees were X-rayed in 1983. The x-rays were read by three experienced readers using the ILO (1980) classification. In the NIOSH study, the most recent routinely taken chest x-rays from 184 men who were employed 5 years or more and at some time since 1975 were similarly classified by three qualified readers. In the McGill studies, prevalence of small parenchymal opacities (>/= 1/0), pleural thickening on the chest wall and pleural calcification were 18.4%, 27.9% and 11.9%. The corresponding figures from NIOSH were lower at 9.8%, 13.0% and 3.8%. Both studies found small opacities to be independently related to age, smoking and fibre-year. The increase in prevalence of small opacities at age 65 following exposure to 100 f.y. predicted from the McGill and NIOSH studies were similar, at 7.3% and 5.2%. The relationship between pleural changes and fibre-years was weaker and reached statistical significance in the McGill study only.
Radiographic-analysis; Radiodiagnosis; Statistical-analysis; Epidemiology; Respiratory-system-disorders; Pulmonary-system-disorders; Lung-disorders
Dodgson-J; McCallum-RI; Bailey-MR; Fisher-DR
Annals of Occupational Hygiene, Inhaled Particles VI