A comparison of the ferruginous body and uncoated fiber content in the lungs of former asbestos workers

Our plain-English summary of A comparison of the ferruginous body and uncoated fiber content in the lungs of former asbestos workers, by R.F. Dodson, M.G. Williams, M.F. O'Sullivan, et al (The American Review of Respiratory Disease, 1985).

The study

• Authors: R.F. Dodson, M.G. Williams, M.F. O'Sullivan, C.J. Corn, S.D. Greenberg, G.A. Hurst
• Journal: The American Review of Respiratory Disease
• Published: 1985;132(1):143-7
• Cited by: 53 articles, as counted by NIH iCite
• Read it: PubMed · Publisher
• In J-M's library: Johns-Manville's company medical library held a copy (J-M no. 000469).

Abstract

Tissue samples from 12 former asbestos workers were digested and analyzed for ferruginous body and uncoated fiber populations. It was noted that there were large numbers of nonasbestos fibers in each of the samples. In some samples, these fibers constituted over 80% of the total uncoated fibers, and they could greatly influence the data as to asbestos content of the tissue unless differentiated by light and electron microscopic techniques, such as X-ray energy-dispersive analysis. There were great variations in the numbers of uncoated fibers per ferruginous body between the individual workers. The digested samples from lungs of 2 workers yielded no ferruginous bodies by light microscopy, even though these samples by electron microscopy contained respective loads of 780,000 and 1.2 million uncoated amphibole fibers per gram. Light microscopy examination of adjacent tissues confirmed mild fibrosis in both workers. Ferruginous bodies serve as a general marker for asbestos exposure. However, our data suggest that their absence in tissue with interstitial fibrosis from a worker with previous occupational exposure may not be sufficiently conclusive to rule out asbestos-induced disease. Rather, as shown by our data, individual exceptions may require correlated analysis by analytical electron microscopy in order to define particulate load and support the diagnosis of the disease.

In plain English

This study examined autopsy lung tissue from 12 men who worked 2 weeks to 15 years at an amosite asbestos plant in East Texas. Plant production records showed amosite was the only form of asbestos they were exposed to, though diatomaceous earth and some mineral wool were also used. The authors counted ferruginous (asbestos) bodies by light microscopy and identified uncoated fibers by electron microscopy with X-ray analysis. Ferruginous bodies ranged from 0 to 1.2 million per gram of dry lung. Uncoated amosite fibers were found in all 12 men. The ratio of uncoated amosite fibers to ferruginous bodies ranged from 11:1 to 30,000:1. Chrysotile was found in 8 men. Non-asbestos fibers were found in all 12 and averaged 20% of the total fiber population. In two men they made up 41% and 86% of all uncoated fibers and were mostly calcium-rich. Two men had no ferruginous bodies on their filters, yet carried 780,000 and 1.2 million amphibole fibers per gram of dry tissue. The authors concluded that light microscopy combined with quantitative electron microscopy and X-ray analysis best measures total lung particulate load. They noted that their sample was small.

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: Laboratory analysis of autopsy lung tissue from a small group of former asbestos workers, comparing ferruginous body counts with uncoated fiber counts using light microscopy, electron microscopy and X-ray energy-dispersive analysis
• Who was studied: 12 men, former workers at a local amosite asbestos plant, who were followed through the Tyler Asbestos Worker's Program of The University of Texas Health Center at Tyler. Employment ranged from 2 weeks to 15 years, with an average of 3.7 years. All had smoked cigarettes, from 2 to 122 pack-years (mean 53.8).
• Exposure: Occupational exposure to amosite as the only form of asbestos, according to plant production data. Diatomaceous earth and some mineral wool were also used in the fabrication process.
• Main results:
  • In the 12 workers, ferruginous bodies ranged from 0 to 1.2 x 10^6 per gram dry weight, with an average of 210 x 10^3 per gram dry weight
  • Light microscopy of the digested-sample filters found ferruginous bodies in 10 of the 12 workers
  • Electron microscopy found uncoated amosite fibers in all 12 workers
  • Across the workers, the ratio of amosite fibers to ferruginous bodies ranged from 11:1 to 30,000:1
  • Chrysotile fibers were found in 8 of the 12 workers
  • Non-asbestos inorganic fibers made up 41% of total uncoated fibers in Patient 6 and 86% in Patient 4. The text prints this as '86070', which is OCR damage; the results section prints '86%'. In these two patients the fibers predominantly gave a calcium peak by X-ray analysis.
  • Non-asbestos fibers were found in all 12 workers and averaged 20% of the total fiber population. The text prints this as '20070', which is OCR damage for 20%.
  • Two workers (Patients 1 and 6) had no ferruginous bodies detected by light microscopy of the filters. Their samples carried 780,000 and 1.2 million amphibole fibers per gram of dry tissue, respectively.
  • Every one of the 12 workers showed at least mild pulmonary fibrosis in at least one tissue specimen next to the digested sample
  • Thirteen percent of all measured fibers were less than 0.2 micrometers in diameter, at or below the resolution limit of light microscopy
• The authors' conclusion: The authors concluded that light microscopy combined with quantitative electron microscopy and correlated X-ray energy-dispersive analysis gives the most accurate assessment of total lung particulate load. They added that in certain cases this combined information may be critical in diagnosing asbestos-related lung disease.
• Limitations the authors state:
  • The authors stated that their data came from a small sampling of one asbestos cohort. They nonetheless suggested that, in exceptional cases, requiring ferruginous bodies for an asbestosis diagnosis might be too restrictive.
  • The authors acknowledged that more data are needed before uncoated asbestos fiber counts can readily be used to help diagnose asbestos-related disease
  • The authors noted that all the workers smoked, and that cigarette smoking by itself has been implicated in producing interstitial fibrosis

Topics

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

Medical terms in this study, explained in our Lexicon: Ferruginous body, Amphibole Group, Fibers Per Gram, Fibrosis, Asbestos Exposure, Interstitial Fibrosis, Occupational Exposure.

Related studies

• Analysis of cores of ferruginous bodies from former asbestos workers — R.F. Dodson, M.F. O'Sullivan, et al. (1982)
• The association among ferruginous body, uncoated fibers, asbestos and non-asbestos fibers in lung tissue in terms of length — T. Suzuki, Y. Sakakibara, et al. (2016)
• Asbestos content of lung tissue, lymph nodes, and pleural plaques from former shipyard workers — R.F. Dodson, M.G. Williams, et al. (1990)
• Pulmonary fibrosis, carcinoma, and ferruginous body counts in amosite asbestos workers. A study of six cases — V.L. Roggli, S.D. Greenberg, et al. (1980)
• Relationships between ferruginous bodies and uncoated asbestos fibers in lung tissue — R.F. Dodson, M. O'Sullivan, et al. (1996)
• Analysis of ferruginous bodies in bronchoalveolar lavage from foundry workers — R.F. Dodson, M. O'Sullivan, et al. (1993)

Browse more research in The American Review of Respiratory Disease, or return to medical research.