Fissural thickening and exposure to asbestos: occurrence, determinants, and functional impact

The occurrence and determinants of thickened interlobar fissures were assessed in 147 insulators, in order to test the hypothesis that radiographic abnormalities in minor (FMN) and/or major (FMJ) interlobar fissures are associated with restrictive respiratory impairment, which may reflect early parenchymal lung fibrosis. According to the diagnostic criteria developed, definite interlobar thickening was found in 33 (FMN) and in 73 (FMJ) men, and was frequently associated with the presence of classical asbestos pleural disease, though not parenchymal abnormality. Multivariate analyses did not demonstrate any association between either FMN or FMJ and lung function. Such an association, however, was found in the case of the usual asbestos-related pleural change. These findings suggest that fissural thickening seen on chest radiography represents a component of asbestos pleural disease and not asbestosis.