Systematic review of pleural plaques and lung function

Abstract

ContextUS EPA proposed a Reference Concentration for Libby amphibole asbestos based on the premise that pleural plaques are adverse and cause lung function deficits.ObjectiveWe conducted a systematic review to evaluate whether there is an association between pleural plaques and lung function and ascertain whether results were dependent on the method used to identify plaques.MethodsUsing the PubMed database, we identified studies that evaluated pleural plaques and lung function. We assessed each study for quality, then integrated evidence and assessed associations based on the Bradford Hill guidelines. We also compared the results of HRCT studies to those of X-ray studies.ResultsWe identified 16 HRCT and 36 X-ray studies. We rated six HRCT and 16 X-ray studies as higher quality based on a risk-of-bias analysis. Half of the higher quality studies reported small but statistically significant mean lung function decrements associated with plaques. None of the differences were clinically significant. Many studies had limitations, such as inappropriate controls and/or insufficient adjustment for confounders. There was little consistency in the direction of effect for the most commonly reported measurements. X-ray results were more variable than HRCT results. Pleural plaques were not associated with changes in lung function over time in longitudinal studies.ConclusionThe weight of evidence indicates that pleural plaques do not impact lung function. Observed associations are most likely due to unidentified abnormalities or other factors.

Are pleural plaques an appropriate endpoint for risk analyses?

“…There was little consistency in the direction of effect for the most commonly reported measurements. Kerper et al (2014) found that pleural plaques were not associated with changes in lung function over time in longitudinal studies. These investigators concluded that the weight of evidence indicated that pleural plaques do not have clinically significant impacts on lung function and that the observed association is most likely due to unidentified pleural thickening or other factors.…”

“…The relation between plaques and possible impairment of lung function has been studied extensively (Clark et al, 2014;Jones et al, 1988;Kerper et al, 2014;Kopylev et al, 2014;Lockey et al, 2015;Moolgavkar et al, 2014;Ohlson et al, 1985;Sood & Gee, 1997;Weill et al, 2011;Wilken et al, 2011, Zu et al, 2015 andcontained references). Among the three most recent reviews: Moolgavkar et al (2014) reviewed various studies on the relation between pleural plaques and lung function considered by EPA in their analysis of LAA and concluded:…”

“…Kopylev et al (2014) reviewed the literature and concluded that the presence of pleural plaques is associated with small, but statistically significant differences in forced vital capacity (FVC) and forced expiratory volume in 1 second (FEV 1 ). Kerper et al (2014) reviewed 16 CT and 36 CXR studies and selected six CT and 16 CXR studies as higher quality based on a ''risk-of-bias'' analysis. They found that half of the higher quality studies reported small but statistically significant mean lung function decrements associated with plaques.…”

“…2 As recent review articles have adequately covered respiratory symptoms and possible impairments to lung function (Kerper et al, 2014), this review focuses chiefly on malignant effects.…”

Non-neoplastic asbestos-related respiratory diseases: what relationship with other lung diseases?

“…Another systematic review evaluated whether there is an association between PPs and lung function and if results were dependent on the method used to identify plaques [22]. 6 HRCT and 6 X-ray high quality studies were identified.…”