Pneumoconiosis in coalminers and exposure to dust of variable quartz content

y in Midlothian considered that a small number showed unusually rapid progression of pneumoconiotic abnormalities. A case-control study based on these radiographs suggested an association with workplace exposure to dusts containing higher proportions of quartz than had previously been seen in the research, and further investigations were initiated.This report describes the design and execution of a study in which existing radiographs for men at this colliery were subjected to intensive re-examination, with the objective of relating any evidence of radiographic abnormalities to data already held on the individual men’s exposures to respirable airborne dust in the coalmine, and on lung function and smoking habits.All available radiographs from over 1400 men employed at that colliery who had attended any of the medical research surveys in 1970, 1974 and 1978 were collected; these were classified for pneumoconiotic abnormalities according to the ILO (1980) scheme, by an experienced panel of non-medical readers reading each radiograph independently and in randomised order, on two separate occasions. On the second occasion, the reading included radiographs which had been collected from the same men during a survey by the NCB’s Medical Service in 1980. In an additional reading, two medically qualified readers experienced in the radiology of pneumoconiosis viewed series of radiographs from a sample of the men, and classified the films within those series for progression of disease over time.Analyses of the data from these classifications, using the statistical techniques of logistic regression, confirmed that appearances of small pneumoconiotic shadows of profusion at least 1/0 on the ILO (1980) scale were associated most strongly with the …