The application of ICOERD and lung function data in asbestos workers

Introduction: Many studies investigating the relationship between lung function and asbestos-related findings on chest X rays (CXR) reported only weak associations, with might be due to the low sensitivity of CXR. The aim of our study was to describe the association of CT findings in asbestos workers, classified with a standardised tool, with lung function.

Methods: In an ongoing surveillance project 745 former male asbestos workers (mean age 64 years, range 36 - 84 years) were examined so far using low-dose 58.8 fibre years. 37.2% were current smokers, 43.5% former smokers (mean cumulative tobacco consumption 32.8 pack years) and 19.3% never smokers. Every Ct-series was diagnosed by three experienced readers (one radiologist, two occupational health physicians) resulting in a standardised classification as a consensus reading using the International Classification of occupational and environmental diseases (ICOERD)- sheet. Spirometry, bodyplethysmography and diffusion capacity was measured at the same day of the CT-scan. Results: 37.6% of the cases had parenchymal, 62.4% had pleural abnormalities consistent with an asbestos-related finding. There was no association between cumulative asbestos exposure and lung function in the subgroup without CT-findings. There was a strong significant association between vital capacity (VC) and profusion grade of irregular opacities and between profusion of emphysema and FEV1, MEF/%-25, PEF, sRtot, RV, TLC, ITGV, TLCO, KCO. Inconsistent results were found for the association between pleural findings and lung function parameters.

Discussion: The application of the ICOERD sheet proved to be feasible in the routine of the surveillance of asbestos workers. Compared to studies using CXR, stable and plausible associations were found between presence and profusion of parenchymal findings and lung function parameters, while the influence of pleural findings on lung function remains inconsistent in this cohort.