Rapid progression of pleural disease due to exposure to Libby amphibole: "Not your grandfather's asbestos related disease"

Our plain-English summary of Rapid progression of pleural disease due to exposure to Libby amphibole: "Not your grandfather's asbestos related disease", by B. Black, J. Szeinuk, A.C. Whitehouse, et al (American Journal of Industrial Medicine, 2014).

The study

• Authors: B. Black, J. Szeinuk, A.C. Whitehouse, S.M. Levin, C.I. Henschke, D.F. Yankelevitz, R.M. Flores
• Journal: American Journal of Industrial Medicine
• Published: 2014;57(11):1197-206
• Type of article: Case report
• Cited by: 26 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Background: Residents and mine employees from Libby, Montana, have been exposed to asbestiform amphiboles from the vermiculite mine that operated in this location from the mid-1920s until 1990. Clinical observations show a different form of asbestos-related toxicity than other forms of asbestos.

Methods: Five illustrative cases from the Center for Asbestos-Related Diseases in Libby were selected. All had clear exposure histories, multiple follow-up visits, illustrative chest radiographic studies, serial pulmonary function tests, and sufficient length of follow-up to characterize disease progression.

Results: These cases developed increasing symptoms of dyspnea and chest pain, progressive radiological changes that were predominantly pleural, and a restrictive pattern of impaired spirometry that rapidly progressed with significant loss of pulmonary function.

Conclusions: LA exposure can cause a non-malignant pleural disease that is more rapidly progressive and more severe than the usual asbestos-related disease.

© 2014 Wiley Periodicals, Inc.

In plain English

This case series described five men followed at the Center for Asbestos-Related Diseases (CARD) in Libby, Montana. All were exposed to Libby amphibole, asbestiform amphiboles contaminating vermiculite from the local mine. Three had only non-occupational exposure as residents, one worked at the mine, and one delivered equipment to the mine. The authors chose them as illustrative cases, excluding patients with pleural effusion at the start or early in their disease. Four men described worsening breathlessness and four had chest pain, severe in some; one man's pain later became less frequent. CT scans showed thin, layered (lamellar) pleural thickening that spread and grew thicker, and lung function fell. Yearly FEV1 losses (air breathed out in one second) ranged from 63.4 ml/year, averaged over one man's follow-up to 2013, to 646 ml/year in another man between 2004 and 2006. That man died of respiratory failure in 2010; no autopsy was done. The authors concluded that Libby amphibole exposure can cause non-malignant pleural disease that progresses faster and is more severe than usual asbestos-related disease. They noted as a limitation that the pleura and lung tissue were not examined pathologically.

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: Case series of five illustrative patients (clinical case reports)
• Who was studied: Five patients of the Center for Asbestos-Related Diseases (CARD), Libby, Montana: three non-occupationally exposed residents, one mine worker, and one man who brought equipment to the mine site. Patients with pleural effusions as the initial presentation or as an early manifestation of their disease were excluded.
• Exposure: Libby amphibole (LA): asbestiform amphiboles contaminating vermiculite from the Libby mine, through mine work, delivery work at the mine, and community or environmental exposure.
• Main results:
  • Case 1 (a smoker with indirect and community exposure): FVC dropped by 2 L over 5 years. Over 11 years of follow-up, FEV1 declined by 116.3 ml/year.
  • Case 2 (a resident, never a vermiculite worker): vital capacity fell from 4.66 L (96% predicted) in 2001 to 3.16 L (68% predicted) in 2006, an average loss of 300 ml/year.
  • Case 2: by his most recent tests in 2013, his spirometry and lung volumes were within normal limits, but over follow-up he had an average FEV1 loss of 63.4 ml/year, which the authors described as significant by regression.
  • Case 3 (a resident with non-occupational exposure): FEV1 declined by 646 ml/year between 2004 and 2006. He died of respiratory failure in 2010; no autopsy was conducted.
  • Case 4 (a former mine worker with childhood community exposure): by 2005 he had lost 880 ml of FVC (an average of 200 ml/year). In 2010, total lung capacity was 61% predicted.
  • Case 5 (environmental exposure only): FEV1 declined by 164.5 ml/year over follow-up, and a new right pleural effusion was noted by 2006. His severe pleuritic chest pain, present when he first came to the clinic, continued but became less frequent.
  • On CT, the pleural thickening was lamellar (thin and layered) and progressively extended along the chest wall. The authors stated that it did not fit the standard definitions of pleural plaques or diffuse pleural thickening.
  • The authors judged the lung-function decline in these cases to be much greater than that reported in other studies of asbestos workers.
• The authors' conclusion: The authors concluded that Libby amphibole exposure can cause a non-malignant pleural disease that is more rapidly progressive and more severe than the usual asbestos-related disease.
• Limitations the authors state:
  • There was no pathological characterization of the pleura or lung tissue in these patients.

Mines named here

Asbestos mines this study is about. Each mine's page says who ran it, when it worked, and what it produced.

• Libby vermiculite mine, Montana

All asbestos mines

Topics

The National Library of Medicine indexes this study under subjects our site covers: Pleural plaques and thickening.

Medical terms in this study, explained in our Lexicon: Libby amphiboles, Asbestiform, Amphibole Group, vermiculite, Pulmonary Function Test (PFT), Disease Progression, Dyspnea, Spirometry.

Related studies

• "Not your grandfather's pleural disease": rapid progression, ventilatory impairment, and chronic pleuritic pain from Libby vermiculite/amphibole — A. Miller (2014)
• Pulmonary abnormalities as a result of exposure to Libby amphibole during childhood and adolescence-The Pre-Adult Latency Study (PALS) — J. Szeinuk, C.W. Noonan, et al. (2017)
• Libby Amphibole Disease: Pulmonary Function and CT Abnormalities in Vermiculite Miners — A. Miller, J. Szeinuk, et al. (2018)
• Workers with Libby amphibole exposure: retrospective identification and progression of radiographic changes — T.C. Larson, C.A. Meyer, et al. (2010)
• Asbestos-related pleural disease due to tremolite associated with progressive loss of lung function: serial observations in 123 miners, family members, and residents of Libby, Montana — A.C. Whitehouse (2004)
• Lung cancer screening in patients with Libby amphibole disease: High yield despite predominantly environmental and household exposure — G. Loewen, B. Black, et al. (2019)

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