Asbestos‐related pleural plaques and lung function

Abstract

The present study examines the association between asbestos-related pleural plaques and lung function in a group of workers with occupational exposure to asbestos. Exposure, smoking, and respiratory histories, chest radiographs, flow-volume loops, and single breath DLCOs were obtained on 383 railroad workers. A score based on the ILO-1980 classification system was used to quantify the extent of plaquelike thickening. In order to eliminate potential confounders, we excluded from final analysis subjects with diffuse pleural thickening (n = 10) or small irregular opacities classified as profusion 0/1 or greater (n = 6) on chest radiograph. Definite pleural plaques were observed in 22.6%. The single breath DLCO was similar in the groups with and without plaques (p = 0.0550). Decrement in FVC and the occurrence of pulmonary restriction were associated with the presence of definite plaques (p = 0.0306 and 0.0431, respectively) and with quantitative pleural score (p = 0.0135 and 0.0126), controlling for duration of asbestos exposure and smoking. A test for trend revealed an association between level of diagnostic certainty (none, suspect, definite) for pleural plaques and these measures of lung function (p less than 0.02). Our findings reveal an association between asbestos-related pleural plaques and decrement in lung function as measured by FVC and criteria for pulmonary restriction.

Association between asbestos-related pleural plaques and resting hyperventilation.

“…Measuring the D LCO components membran e diffu sing capacity and capillary blood volume might pro ve useful in gaining some insight into the mechanisms involved. Oliver et al (2,3) reported restricti ve functional impairments in railroad workers, a finding which is in accord with our results, exc ept for D , which was less affected in their sample. In LCO • addition our study included arterial gas determinations and revealed a strikingly high prevalence of hypocapnia in the asbe sto s-exposed work ers with plaques.…”

Quantification of pleural plaques by computed tomography and correlations with pulmonary function: preliminary study

“…Some chest radiograph based studies (9-13) have reported the presence of pleural plaque is associated with decreased pulmonary function, but several studies based on CT (3,6-8) have reported no significant correlation. Differences in the results may be due to low sensitivity and specificity of chest radiograph for assessing pleural plaque and studies based on chest radiograph had a problem with inclusion of diffuse pleural thickening and other pulmonary abnormalities (9,10,12,13). CT provides a better means of detecting and quantifying pleural plaque than chest radiography (6,(16)(17)(18), but few have investigated the possible association between the presence of pleural plaque and pulmonary function (6-8, 19,20), and fewer have attempted to quantify pleural plaques.…”

“…Several studies have reported pleural plaque has no significant effect on pulmonary function (3,(6)(7)(8), although others have shown diminished pulmonary function in subjects with pleural plaques (9)(10)(11)(12)(13). However, chest radiography has low sensitivity and specificity for detecting pleural plaques, and might include diffuse pleural thickening and/or pulmonary abnormalities.…”

Are pleural plaques an appropriate endpoint for risk analyses?

“…In summary, in the six cross-sectional studies of non-Libby populations that evaluated the association between pleural plaques and pulmonary function with adjustment for asbestos exposure (Broderick et al, 1992;Clin et al, 2011;Lilis et al, 1991;Miller et al, 1994;Oliver et al, 1988;Wang et al, 2001), results varied depending on the measure of lung function, with no consistent patterns of association with spirometric or symptom-based outcomes. Moreover, two studies did not distinguish LPT from DPT (Miller et al, 1994;Wang et al, 2001), only one used highresolution computed tomography to detect LPT (Clin et al, 2011) and all six were susceptible to residual confounding by asbestos exposure and occult parenchymal fibrosis.…”