Relationship of pulmonary impairment in simple coal workers' pneumoconiosis to type of radiographic opacity.

Seaton, A., Lapp, N. L., and Morgan, W. K. C. (1972). Brit. J. industr. Med., 29, 50-55. Relationship of pulmonary impairment in simple coal workers' pneumoconiosis to type of radiographic opacity. From a group of 1 461 working coal miners who participated in an epidemiological study, 223 men with simple pneumoconiosis were selected on the basis of the type of small rounded opacity noted to be present in their chest films. No differences in spirometry or lung volumes were found between those with the micronodular (q) and those with pinhead (p) opacities. Twenty-five non-smoking miners with category 2 or 3 simple coal workers'pneumoconiosiswere subsequently selected for further pulmonary function testing. Studies of lung volumes and pulmonary mechanics showed no difference between those with the pinhead and micronodular types of opacity; however, transfer factor was somewhat lower in those with the former.