Asbestos fiber burden in lung tissues of occupationally exposed workers

Our plain-English summary of Asbestos fiber burden in lung tissues of occupationally exposed workers, by D.K. Verma, N.E. Clark (Journal of Occupational and Environmental Hygiene, 2012).

The study

• Authors: D.K. Verma, N.E. Clark
• Journal: Journal of Occupational and Environmental Hygiene
• Published: 2012;9(10):D177-82
• Cited by: 1 article, as counted by NIH iCite
• Read it: PubMed · Publisher

In plain English

This short report described asbestos fibers measured in lung tissue from 16 men with occupational histories. Pathologists supplied 45 samples and asked whether asbestos was present. Most samples came from autopsied lungs, and two came from living, recently diagnosed men. Chrysotile and amosite were found in 13 of the 16 cases (81%), and crocidolite and tremolite in 50%. Average total fiber levels ranged from 0.3 to 784.6 million fibers per gram of dry lung tissue. Levels overlapped between groups: 0.3 to 784 million in cases without mesothelioma and 2.3 to 33.2 million in mesothelioma cases. Twelve of the 16 cases had total levels above 1 million fibers per gram. Other researchers have suggested that more than 1 to 2 million fibers per gram indicates occupational exposure. Compared with published studies, the authors' non-mesothelioma cases had broadly similar levels and their mesothelioma cases generally lower ones. The authors could draw no conclusion about smoking and fiber retention. The data set was too small, smoking status was incomplete, and the men's exposures differed. The authors concluded that lung fiber analysis can help estimate a person's past exposure.

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 (short report) measuring asbestos fiber type and concentration in lung tissue samples
• Who was studied: 16 male cases, 45 lung tissue samples, mostly from autopsied lungs, with two from recently diagnosed living cases; specimens supplied by pathologists
• Exposure: occupational asbestos exposure of varying kinds. Table I lists jobs including asbestos, gold and nickel mining; steel making; shipyard and Navy work; asbestos transite pipe manufacturing; brake making; and tractor clutch and brake repair. One case was listed with no definite exposure to asbestos.
• Main results:
  • Chrysotile and amosite were detected in 13 of 16 cases (81%); crocidolite and tremolite were detected in 50% of cases
  • Mean total fiber concentrations overlapped between groups: 0.3 to 784 million fibers per gram of dry tissue in non-mesothelioma cases and 2.3 to 33.2 million fibers per gram in mesothelioma cases (0.3 to 784.6 million across all cases)
  • 12 of the 16 cases had total fiber levels above 1 million fibers per gram of dry tissue. Separately, others have suggested that more than 1 to 2 million fibers per gram indicates occupational exposure.
  • Compared with previously published studies, the non-mesothelioma cases had broadly similar levels and the mesothelioma cases generally lower levels
• The authors' conclusion: The authors concluded that analyzing fiber concentrations in lung tissue can help estimate a person's past asbestos exposure and help confirm diagnosis of asbestos-related disease. They noted that chrysotile, amosite, crocidolite and tremolite were detected in their cases.
• Limitations the authors state:
  • The data set was too small and incomplete regarding smoking status
  • The cases did not come from a homogeneous group with broadly similar exposure, and their degree of occupational exposure likely varied
  • The authors could make no conclusion about the effect of smoking on fiber retention

Topics

Medical terms in this study, explained in our Lexicon: Fiber Burden.

Related studies

• Asbestos fiber burdens in lung tissues of Hong Kong Chinese with and without lung cancer — Y. Liu, P. Zhang, et al. (2001)
• Lung fiber burden in the Nottingham gas mask cohort — G. Berry, F. Pooley, et al. (2009)
• The analysis of asbestos count data with "nondetects": the example of asbestos fiber concentrations in the lungs of brake workers — M.M. Finkelstein (2013)
• Residual fibre lung burden among patients with pleural mesothelioma who have been occupationally exposed to asbestos — E. Merler, A. Somigliana, et al. (2017)
• Biopersistence of refractory ceramic fiber in human lung tissue and a 20-year follow-up of radiographic pleural changes in workers — J.E. Lockey, V.L. Roggli, et al. (2012)
• Fiber size and number in workers exposed to processed chrysotile asbestos, chrysotile miners, and the general population — A. Churg, B. Wiggs (1986)

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