The clinical relevance of asbestos-induced pleural fibrosis.

Asbestos-induced pleural fibrosis is the most common radiographic abnormality among asbestos-exposed persons. Circumscribed pleural plaques and diffuse pleural thickening account for more than 90% of the asbestos-induced chest wall abnormalities, and their prevalence is expected to increase for the next 15 to 20 years. Several investigators have recently found that pleural plaques and diffuse pleural thickening independently contribute to the development of restrictive lung function. The work presented in this paper indicates that asbestos-induced pleural fibrosis is also associated with evidence of interstitial lung abnormalities, even among those with normal parenchyma on chest X-ray film. These parenchymal abnormalities include an increased percentage of lymphocytes on bronchoalveolar lavage and an increase in the interstitial changes observed on high-resolution chest computerized tomography (HRCT) scan. However, neither a lymphocytic alveolitis nor an interstitial parenchymal fibrosis influenced the relationship between pleural fibrosis and restrictive lung function. We conclude that asbestos-induced pleural disease contributes to the development of restrictive lung function and identify a group of exposed individuals who are at excess risk of asbestosis.