Mixed dust fibrosis and tuberculosis in comparison with silicosis and macular pneumoconiosis.

Background To assess the relationship between mixed dust fibrosis (MDF) and tuberculosis. Methods We performed a comparative analysis with MDF, silicosis, and macular pneumoconiosis (Mac), using autopsy records from 1975 to 1994. Results Prevalences of having tuberculosis among MDF, silicosis, and Mac were not significantly different, albeit a tendency of higher prevalence in silicosis. Cure rates of tuberculosis were, in order, silicosis  MDF=Mac (P=0.911). With respect to the two types of association with tuberculosis, i.e., combined type (tuberculopneumoconiosis) and complicated one (pneumoconiosis with tuberculosis); the former was significantly dominant in silicosis, the latter was significantly dominant in Mac, and intermediate in MDF. As a whole, the complicated type had a tendency of a higher cure rate than the combined type (P=0.071). Although the differences of profiles between the combined and complicated types were not statistically significant, the combined type had a tendency to have longer duration of exposure to dusts, earlier registration for treatment, higher profusion score, and earlier death compared with the complicated type. Conclusions From our findings, MDF takes an intermediate position between silicosis and Mac regarding the relationship with tuberculosis. The type of association with tuberculosis rather than the kind of background pneumoconiosis seemed to be more important in light of responsiveness to the treatment. Am. J. Ind. Med. 37:260–264, 2000. © 2000 Wiley-Liss, Inc.