Interstitial Lung Abnormalities Detected by CT in Asbestos-Exposed Subjects Are More Likely Associated to Age.

François Laurent,Christophe Paris,Antoine Gislard,Bénédicte Clin,Gael Dournes,Isabelle Thaon,Ilyes Benlala,Gilbert Ferretti,Soizick Chammings,Justine Gallet,Celine Gramond,Pascal Andujar,Fleur Delva,Jean-Claude Pairon,Aude Lacourt,Patrick Brochard

doi:10.3390/jcm10143130

Abstract

Objective: the aim of this study was to evaluate the association between interstitial lung abnormalities, asbestos exposure and age in a population of retired workers previously occupationally exposed to asbestos. Methods: previously occupationally exposed former workers to asbestos eligible for a survey conducted between 2003 and 2005 in four regions of France, underwent chest CT examinations and pulmonary function testing. Industrial hygienists evaluated asbestos exposure and calculated for each subject a cumulative exposure index (CEI) to asbestos. Smoking status information was also collected in this second round of screening. Expert radiologists performed blinded independent double reading of chest CT-scans and classified interstitial lung abnormalities into: no abnormality, minor interstitial findings, interstitial findings inconsistent with UIP, possible or definite UIP. In addition, emphysema was assessed visually (none, minor: emphysema <25%, moderate: between 25 and 50% and severe: >50% of the lung). Logistic regression models adjusted for age and smoking were used to assess the relationship between interstitial lung abnormalities and occupational asbestos exposure. Results: the study population consisted of 2157 male subjects. Interstitial lung abnormalities were present in 365 (16.7%) and emphysema in 444 (20.4%). Significant positive association was found between definite or possible UIP pattern and age (OR adjusted =1.08 (95% CI: 1.02–1.13)). No association was found between interstitial abnormalities and CEI or the level of asbestos exposure. Conclusion: presence of interstitial abnormalities at HRCT was associated to aging but not to cumulative exposure index in this cohort of former workers previously occupationally exposed to asbestos.

Highlights

The development and severity of asbestosis is related to intensity of exposure to asbestos and time since first exposure [1]
This study has shown the association between interstitial abnormalities and age after adjustment on smoking status and asbestos exposure in a population of retired workers previously occupationally exposed to asbestos
This result is consistent with the CT lung cancer screening study by Vehmas et al [22] among asbestos-exposed workers, where a positive correlation was found between interstitial lung abnormalities at CT and aging after adjustment to smoking status, asbestos exposure and body mass index

Summary

Introduction

The development and severity of asbestosis is related to intensity of exposure to asbestos and time since first exposure [1]. The surveillance of the former exposed workers is justified by financial compensations and because of the elevated risk of bronchial cancer. High resolution computed tomography (HRCT) is able to detect asbestos-induced pulmonary changes much earlier than chest x-ray and is useful for early diagnosis of asbestosis [2,3,4]. Interstitial lung abnormalities (ILA) are defined as early interstitial changes in nondependent areas of the lung, and has been validated as evidence of subclinical interstitial lung disease (ILD) [8].

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Methods

Results

Conclusion