A case-control study of reasons for unusual radiological changes of pneumoconiosis among individual mineworkers

The main objective of this study was to investigate the environmental factors associated with rapid progression of coalworkers’ simple pneumoconiosis (CWSP) and progressive massive fibrosis (PMF). A second, subsidiary aim was to describe the occurrence of rapid progression and PMF throughout Britain.The research was carried out in two separate but related phases. In the first, the distributions of new occurrences of rapid progression of CWSP and PMF throughout Britain in the 1970s were investigated. Results refer to almost 100,000 miners, using data collected in the Periodic X-ray Scheme (PXR) of National Coal Board (NCB)* Medical Services. A more intensive case-control study of some of these men was then undertaken to investigate the environmental factors associated with these radiological changes. This required an extensive effort in further data collection.The results from the first phase of the study confirmed that the risks of PMF vary markedly with NCB Area within Britain. Highest risks were found in South Wales and North East England. There is a clear cut increase in risks of PMF with increasing category of CWSP classified according to the full 12-point ILO scale. However, because of relative numbers at risk more than half the cases were found against a background of category 0 and 1 of simple pneumoconiosis. Risks clearly increased with age. * Now known as British Coal