Asbestosis and environmental causes of usual interstitial pneumonia

Our plain-English summary of Asbestosis and environmental causes of usual interstitial pneumonia, by M. Gulati, C.A. Redlich (Current Opinion in Pulmonary Medicine, 2015).

The study

• Authors: M. Gulati, C.A. Redlich
• Journal: Current Opinion in Pulmonary Medicine
• Published: 2015;21(2):193-200
• Type of article: Review
• Cited by: 41 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Purpose Of Review: Recent epidemiologic investigations suggest that occupational and environmental exposures contribute to the overall burden of idiopathic pulmonary fibrosis (IPF). This article explores the epidemiologic and clinical challenges to establishing exposure associations, the current literature regarding exposure disease relationships and the diagnostic work-up of IPF and asbestosis patients.

Recent Findings: IPF patients demonstrate a histopathologic pattern of usual interstitial pneumonia. In the absence of a known cause or association, a usual interstitial pneumonia pattern leads to an IPF diagnosis, which is a progressive and often terminal fibrotic lung disease. It has long been recognized that asbestos exposure can cause pathologic and radiographic changes indistinguishable from IPF. Several epidemiologic studies, primarily case control in design, have found that a number of other exposures that can increase risk of developing IPF include cigarette smoke, wood dust, metal dust, sand/silica and agricultural exposures. Lung mineralogic analyses have provided additional support to causal associations. Genetic variation may explain differences in disease susceptibility among the population.

Summary: An accumulating body of literature suggests that occupational and environmental exposure can contribute to the development of IPF. The impact of exposure on the pathogenesis and clinical course of disease requires further study.

In plain English

This article was a narrative review, not a new study. The authors summarized published research on usual interstitial pneumonia, the lung-scarring pattern seen in idiopathic pulmonary fibrosis (IPF), and on asbestosis. They also described how patients are diagnosed. They wrote that asbestos exposure can cause lung changes indistinguishable from IPF. They described earlier studies, mostly case-control in design, that linked IPF with cigarette smoke, metal dust, wood dust, sand or silica, and farming. For example, a cited UK study of 218 patients and 569 controls reported an odds ratio of 1.69 (95% confidence interval 1.07 to 2.65) for metal dust. For asbestosis, the authors wrote that a strong exposure history plus scarring on high-resolution CT is enough for diagnosis. They cited pathology criteria of at least 2 asbestos bodies per square centimetre of lung. They noted it is unknown whether the newer IPF drugs nintedanib and pirfenidone work in asbestosis. The authors concluded that a growing body of literature suggests exposures besides asbestos may contribute to IPF, and that this needs further study.

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: Narrative review of published literature
• Who was studied: No new study population. The authors reviewed published literature on exposures linked to IPF and usual interstitial pneumonia, and on the diagnostic work-up of IPF and asbestosis patients.
• Exposure: Asbestos: chrysotile (serpentine) and the amphiboles crocidolite, amosite, anthophylite, actinolite and tremolite. Also cigarette smoke, wood dust, metal dust, sand/silica and agricultural exposures as possible contributors to IPF.
• Main results:
  • The authors stated that it has long been recognized that asbestos exposure can cause pathologic and radiographic changes indistinguishable from IPF.
  • The authors described a cited UK study of 218 IPF patients and 569 controls. It reported higher IPF risk with metal dust (OR 1.69, 95% CI 1.07–2.65) and wood dust (OR 1.71, 95% CI 1.01–2.92).
  • The authors wrote that, for a patient with possible asbestosis, a strong exposure history together with fibrotic lung disease on high-resolution CT is sufficient for diagnosis.
  • Citing published pathology criteria, the authors wrote that an average of at least 2 asbestos bodies per square centimetre of lung is generally recommended to diagnose asbestosis.
  • The authors described a cited North American insulator cohort study. In it, asbestosis together with smoking was reported to increase lung cancer mortality, with a rate ratio of 7.40 (95% CI 4.0–13.7) among nonsmokers and 36.8 (95% CI 30.1–45.0) among smokers. The comparison group is not stated in this article.
  • The authors stated that the efficacy of the IPF drugs nintedanib and pirfenidone in asbestosis patients is unknown.
• The authors' conclusion: The authors concluded that an accumulating body of literature suggests that exposures other than asbestos, such as cigarette smoking, metal and wood dust and agricultural exposures, may also contribute to IPF. They added that the impact of these exposures requires further study.
• Limitations the authors state:
  • The authors stated that epidemiologic studies of IPF have been hindered by changes in disease classification and diagnosis, and by the difficulty of assessing chronic, mixed exposures over many years.
  • The authors noted that exposure intervention studies are limited.
  • The authors noted that the belief that asbestosis progresses more slowly than usual interstitial pneumonia rests on limited evidence.

Topics

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

Medical terms in this study, explained in our Lexicon: Interstitial, Environmental Exposure, Idiopathic, Pulmonary Fibrosis, Asbestos Exposure.

Related studies

• Dyskeratosis congenita showing usual interstitial pneumonia — S. Imokawa, A. Sato, et al. (1994)
• Usual interstitial pneumonia in asbestos-exposed cohorts - concurrent idiopathic pulmonary fibrosis or atypical asbestosis? — R.L. Attanoos, F.S. Alchami, et al. (2016)
• Asbestos exposure increases the incidence of histologically confirmed usual interstitial pneumonia — Y. Kawabata, Y. Shimizu, et al. (2016)
• Desquamative interstitial pneumonia induced by metal exposure. A case report and literature review — T. Blin, A. De Muret, et al. (2020)
• Biphasic malignant mesothelioma with epithelioid and sarcomatoid components (dedifferentiated mesothelioma) and intrapulmonary growth: a rare entity mimicking desquamative interstitial pneumonia — J. Laforga, A. Gonzalez Garcia (2020)
• Peribronchiolar metaplasia: a common histologic lesion in diffuse lung disease and a rare cause of interstitial lung disease: clinicopathologic features of 15 cases — J. Fukuoka, T.J. Franks, et al. (2005)

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