Causation, impairment, disability: an analysis of coal workers' pneumoconiosis evaluations

The relation of exposure, impairment, and awarded disability in coal dust disease cases is often unclear. Surveillance data from large mining populations has demonstrated a decline in pulmonary function associated with coal dust exposure, even in miners with normal roentgenographs, though the frequency with which this results in impairment is not well defined. This study examines a more specific group, 374 disability claimants, for whom evaluation data is less extensive. In this group, several pulmonary function variables declined in association with years mining, even after controlling for roentgenograph status and smoking. This was particularly seen among underground miners, although the declines were small and of marginal statistical significance. Awards were evaluated for 203 resolved cases. Among 59 with completely normal roentgenographs and pulmonary function tests (PFTs), 38 (64%) received some disability award. These findings support development of a more rational impairment/disability system for those with potential coal dust disease.