Longitudinal study of the radiology of coal workers′ pneumoconiosis

Summary One thousand five hundred sixty-one chest radiographs of 318 coal workers with pneumoconiosis, who could be traced over at least 10 years and who were free from tuberculosis were evaluated for the prevalence, incidence, type, and density of small and large opacities.The predominant small opacity seen was the q-type (53.7%); the p-type was seen in 24.3% of the cases. The predominant type changed only in 7% of the subjects. Its density increased together with the size.Large opacities developed in 48% of the cases, a very high percentage. They were less frequent in the presence of p-type small opacities in the younger age group. Their prevalence was correlated linearly with age, so that it seems that the fibrotic process does not diminish with age.With support of the European Communities, Luxembourg