Does asbestos exposure (asbestosis) cause (clinical) airway obstruction (small airway disease)?

Our plain-English summary of Does asbestos exposure (asbestosis) cause (clinical) airway obstruction (small airway disease)?, by A. Miller, W.N. Rom (American Journal of Respiratory and Critical Care Medicine, 2010).

The study

• Authors: A. Miller, W.N. Rom
• Journal: American Journal of Respiratory and Critical Care Medicine
• Published: 2010;182(4):444-5
• Type of article: Comment, Editorial
• Cited by: 3 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

In plain English

This item is an editorial commenting on a paper by Ameille and coworkers in the same journal issue. That paper asked whether asbestos exposure causes airway obstruction in the absence of confirmed asbestosis, and answered no, because lung function was unrelated to estimated cumulative exposure in 3,660 former workers. The authors questioned its methods, noting that breathing tests were done at many sites without concurrent quality control, that lung-volume methods varied, and that exposure estimates were not based on fiber counts. Only 6.7% of that study's CT scans showed interstitial abnormality and mean forced vital capacity was 99.6% of predicted, which the authors said suggests many claimed exposures were slight. They also described an earlier study by one of them of 2,611 long-term insulators. In that study, 6% of nonsmokers and 35% of continuing smokers had a reduced FEV1/FVC. The authors concluded that a 2004 American Thoracic Society statement remains valid: asbestos has a relatively small effect on airway function. They added that smoking combined with asbestosis seems to increase the risk of clinically significant airways obstruction.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Editorial commentary on another study (Ameille and coworkers, same journal issue); no new data collected
• Who was studied: No population of its own. The editorial discusses the Ameille study of 3,660 former workers with spirometry (lung volumes in 3,104 and HRCT in 3,333). It also discusses earlier studies, including 2,611 long-term insulators studied by one of the editorialists.
• Exposure: Estimated cumulative asbestos exposure in the Ameille study (fiber types not specified in the editorial). The authors noted these estimates were not based on fiber counts and used imprecise categories.
• Main results:
  • The Ameille study asked about asbestos exposure in the absence of confirmed asbestosis.
  • Ameille and coworkers answered that asbestos exposure does not cause airway obstruction, because FEV1, FEV1/FVC and FEF25–75% were not related to exposure.
  • The authors criticized the Ameille study's methods. Flow–volume curves and lung volumes were done at many sites without concurrent quality control, lung-volume methods varied, HRCT categories were generic and nonquantitative, and no chest radiograph readings were reported.
  • In the Ameille study, only 6.7% of HRCTs showed interstitial abnormality, and mean FVC was 99.6% of predicted after 27.7 years of exposure. The authors said this points to a population resistant to asbestos effects or to a healthy volunteer effect.
  • The authors suggested that many claimed exposures in the Ameille study must have been slight.
  • In an earlier study of 2,611 long-term insulators by one of the editorialists, 6% of nonsmokers had a reduced FEV1/FVC. The editorial gives 12% for nonsmokers in the general population.
  • In the same earlier insulator study, 35% of continuing smokers had a reduced FEV1/FVC. The editorial gives 21.5% for smokers in the general population.
• The authors' conclusion: The authors concluded that the 2004 ATS statement remains valid: asbestos has a relatively small effect on airway function and by itself is unlikely to cause functional impairment or COPD. They wrote that Ameille and coworkers confirm this in a workforce with lesser exposures. However, smoking combined with asbestosis seems to increase the risk of clinically significant airways obstruction.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Asbestosis.

Medical terms in this study, explained in our Lexicon: Asbestos Exposure.

Related studies

• Does asbestos exposure cause airway obstruction, in the absence of confirmed asbestosis? — J. Ameille, M. Letourneux, et al. (2010)
• Association between increased small airway obstruction and asbestos exposure in patients with asbestosis — X. Yang, Y. Yan, et al. (2018)
• High prevalence of reversible airway obstruction in asbestos-exposed workers — S. Delpierre, M.J. Delvolgo-Gori, et al. (2002)
• Airway obstruction in asbestos-exposed shipyard workers: with and without irregular opacities — K.H. Kilburn, R.H. Warshaw (1990)
• Airway disease in non-smoking asbestos workers — K.H. Kilburn, R.H. Warshaw, et al. (1985)
• Auscultated forced expiratory time as a clinical and epidemiologic test of airway obstruction — D.G. Kern, S.R. Patel (1991)

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