Rheumatoid pneumoconiosis: a study in colliery populations in the East Midlands coalfield.

Abstract

The routine chest radiographs of more than 21,000 miners from 23 unselected collieries in the East Midlands have been used for a study of rheumatoid pneumoconiosis and progressive massive fibrosis (P.M.F.). A broadened radiological concept of rheumatoid pneumoconiosis was used in diagnosis. The prevalence of simple pneumoconiosis categories 1, 2, and 3 was 5·5%, and of P.M.F. 0·59%. There were 55 cases accepted as rheumatoid pneumoconiosis, a prevalence of 0·26%. Thirty-two of these had positive latex fixation or Rose-Waaler tests for rheumatoid factor. The prevalence of P.M.F. was found to increase with increasing simple pneumoconiosis prevalence. A slight correlation between rheumatoid pneumoconiosis and simple pneumoconiosis prevalence was also found, but the bulk of the increase in P.M.F. was due to non-rheumatoid cases. The latter was closely paralleled in incidence by that of category 3 simple pneumoconiosis. Grouped results showed that rheumatoid pneumoconiosis occurred in between 2·3% and 6·2% of all men affected by pneumoconiosis. When examined on a geographical basis all areas exhibited a similar prevalence of rheumatoid cases, with the exception of Mansfield, where there was a significant excess. This excess was not significant when serologically positive cases only were considered. The findings are discussed in the light of the auto-immune theory for the development of massive lesions in the lungs of coal miners.