A systematic review of the association between pleural plaques and changes in lung function

OBJECTIVES: To conduct a systematic review of changes in lung function in relation to presence of pleural plaques in asbestos-exposed populations. METHODS: Database searches of PubMed and Web of Science were supplemented by review of papers’ reference lists and journals’ tables of contents. Methodological features (eg, consideration of potential confounding by smoking) of identified articles were reviewed by ≥two reviewers. Meta-analyses of 20 studies estimated a summary effect of the decrements in per cent predicted (%pred) forced vital capacity (FVC) and forced expiratory volume in 1 s (FEV(1)) associated with presence of pleural plaques. RESULTS: Among asbestos-exposed workers, the presence of pleural plaques was associated with statistically significant decrements in FVC (4.09%pred, 95% CI 2.31 to 5.86) and FEV(1) (1.99%pred, 95% CI 0.22 to 3.77). Effects of similar magnitude were seen when stratifying by imaging type (X-ray or high-resolution CT) and when excluding studies with potential methodological limitations. Undetected asbestosis was considered as an unlikely explanation of the observed decrements. Several studies provided evidence of an association between size of pleural plaques and degree of pulmonary decrease, and presence of pleural plaques and increased rate or degree of pulmonary impairment. CONCLUSIONS: The presence of pleural plaques is associated with a small, but statistically significant mean difference in FVC and FEV(1) in comparison to asbestos-exposed individuals without plaques or other abnormalities. From a public health perspective, small group mean decrements in lung function coupled with an increased rate of decline in lung function of the exposed population may be consequential.