Roentgenographic manifestations and pulmonary function effects of asbestos-induced pleural thickening.

Pleural thickening is the most common roentgenographic manifestation of past asbestos exposure. In addition to pleural thickening serving as a specific market of exposure, discrete (plaques) and diffuse pleural fibrosis are important abnormalities because they have been found to be associated with increased risk for other asbestos-related sequelae and to themselves have an adverse effect on pulmonary function. We review here the results of an evaluation of a cohort of asbestos-exposed workers, plumbers and pipefitters, who were consecutively enrolled in a large cross-sectional prevalence study. Among the 681 male participants, pleural abnormalities were associated with decreased values of forced vital capacity, an effect independent of ILO profusion grade. The risk for pleural disease was unexplained by smoking status. Diffuse pleural thickening was more common and was associated with greater decrements in function than was discrete thickening.