Asbestos burden in cases of mesothelioma from individuals from various regions of the United States

Our plain-English summary of Asbestos burden in cases of mesothelioma from individuals from various regions of the United States, by R.F. Dodson, R. Graef, S. Shepherd, et al (Ultrastructural Pathology, 2005).

The study

• Authors: R.F. Dodson, R. Graef, S. Shepherd, M. O'Sullivan, J. Levin
• Journal: Ultrastructural Pathology
• Published: 2005;29(5):415-33
• Cited by: 19 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Mesothelioma is a rare tumor that is considered an asbestos marker disease. It occurs in individuals following a longer latency period from first exposure than other asbestos-related diseases. The tumor also occurs in individuals with a wide range of exposures, including individuals with lower level or secondary exposures. In the present study lung tissue from 54 individuals with a pathological diagnosis of mesothelioma was evaluated for ferruginous body and uncoated asbestos fiber content. The data were compared with an earlier study of mesothelioma cases from the northwestern United States. Tissue was prepared via a digestion procedure, with the collected digestate reviewed by light microscopy for quantification of asbestos bodies and analytical transmission electron microscopy for determination of uncoated fiber burden. Twenty-seven cases in the present study had over 1000 ferruginous bodies per gram of dry tissue. The data suggest that amosite provides a more likely stimulus for ferruginous coating than the other forms of asbestos. All individuals were found to have asbestos fibers in their lung tissue. Amosite was the most commonly found fiber, with anthophyllite being the second most commonly found type of asbestos. The finding of tremolite in the tissue most often was associated with the finding of anthophyllite. A limited number of asbestos fibers of each type would have been seen in the light microscope, with the least detected being chrysotile. The majority of all fiber types were found as short fibers (< 8 mum), although some longer fibers were represented in each type of asbestos. The majority of the individuals were found to have mixed types of asbestos in their lungs.

In plain English

The authors measured asbestos in lung tissue from 54 people with mesothelioma from 17 US states. They compared these with their earlier study of 55 northwestern US cases, mostly people who had worked in shipyards or related occupations. Only 9 people in the new group had worked in shipyards or on ships. Using light and electron microscopy, the authors found asbestos fibers in every person's lungs, and 44 had mixed types. Amosite was found in 40 cases (74%), anthophyllite in 33 (61%), tremolite in 28 (52%), chrysotile in 27 (50%) and crocidolite in 23 (43%). Coated fibers called ferruginous bodies were not detected in 10 people. Here, 27 people had over 1000 per gram of dry tissue, versus 46 in the earlier study. Most fibers were shorter than 8 micrometers. Only 26% of amosite, 6% of crocidolite and no chrysotile fibers would theoretically have been counted by the light-microscope method used for workplace air. The authors concluded that amosite was less dominant than in their earlier study, but that most people with mesothelioma had mixed asbestos types in their lungs.

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 lung tissue from a series of mesothelioma cases, compared with the authors' earlier study of 55 mesothelioma cases from the northwestern United States. Asbestos bodies were counted by light microscopy and uncoated fibers by analytical transmission electron microscopy.
• Who was studied: 54 people with a pathological diagnosis of mesothelioma (3 women, 51 men), aged 39 to 86, from 17 US states. Only 1 was from the northwest (Oregon). 4 had peritoneal mesothelioma and the rest had pleural or unspecified tumors. Only 9 had worked in shipyards or served on ships. The earlier comparison group consisted mostly of people who had worked in shipyard or related occupational activities.
• Exposure: Asbestos fibers retained in the lung (amosite, crocidolite, chrysotile, anthophyllite, tremolite and actinolite), plus ferruginous (asbestos) bodies. Reported exposures ranged from typical occupational settings (e.g., insulator, machinist, shipyard work) to jobs such as architect, teacher, department store employee and surgeon. They included exposures the authors described as secondary or environmental.
• Main results:
  • All 54 individuals had asbestos fibers in their lung tissue.
  • Uncoated asbestos fibers ranged from 539,215,686 per gram of dry tissue (102,867,830 per gram wet) in case L-35 to 17,361 per gram of dry tissue (3,637 per gram wet) in case L-23.
  • Amosite was found in 40 of 54 cases (74%), crocidolite in 23 (43%) and chrysotile in 27 (50%).
  • Among the noncommercial types, anthophyllite was found in 33 cases (61%) and tremolite in 28 cases (52%).
  • Tremolite and chrysotile were not linked: 13 chrysotile-positive cases also had tremolite, 15 cases had tremolite without chrysotile, and 14 chrysotile cases had no tremolite. Tremolite and anthophyllite were found together in 20 cases.
  • 44 of the 54 cases had mixed types of asbestos in their lungs.
  • Ferruginous bodies were below detectable limits in 10 of 54 individuals (18.5%). Among those with detectable bodies, levels ranged from 1,055,302 to 42 per gram of dry tissue.
  • 27 cases in the present study had over 1000 ferruginous bodies per gram of dry tissue, compared with 46 cases in the earlier northwestern study.
  • Of 374 ferruginous body cores analyzed, 62.03% were amosite, 35.03% crocidolite, 0.53% chrysotile (2 bodies) and 1.07% tremolite-actinolite. The authors suggested amosite is a more potent stimulator of ferruginous body formation.
  • The vast majority of fibers of all types were shorter than 8 micrometers.
  • Under the light-microscope counting definition of a workplace 'regulated fiber', only 26% of amosite and 0% of chrysotile fibers would theoretically have been counted, although 59% of each were longer than 5 micrometers. The figures for the other types were 6% for crocidolite, 40% for anthophyllite, 23% for tremolite and 19% for actinolite.
  • Among those with complete historical information, the average latency from first reported exposure to diagnosis was 42.6 years.
• The authors' conclusion: The authors concluded that amosite was less dominant in this group than in their earlier northwestern study. In both groups, most individuals with mesothelioma had mixed types of asbestos in their lung tissue.
• Limitations the authors state:
  • Lung fiber burden reflects only the fibers remaining after the body has cleared some of them over time.
  • Fibers measured in the lung may only partly represent those that reach the sites where mesotheliomas develop.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Amosite, Anthophyllite, Lung cancer, Mesothelioma, Tremolite.

Medical terms in this study, explained in our Lexicon: Mesothelioma, Latency, Take-home Exposure, Ferruginous body, Asbestos Bodies, Analytical Transmission Electron Microscopy (ATEM), Fiber Burden, Ferruginous Bodies.

Related studies

• Quantitative analysis of asbestos burden in women with mesothelioma — R.F. Dodson, M. O'Sullivan, et al. (2003)
• Tissue burden of asbestos in nonoccupationally exposed individuals from east Texas — R.F. Dodson, M.G. Williams, et al. (1999)
• Mesothelioma incidence in 50 states and the District of Columbia, United States, 2003-2008 — S.J. Henley, T.C. Larson, et al. (2013)
• Environmental risk of mesothelioma in the United States: An emerging concern-epidemiological issues — F. Baumann, M. Carbone (2016)
• Assessing trends and burden of occupational exposure to asbestos in the United States: a comprehensive analysis from 1990 to 2019 — X. Li, X. Su, et al. (2024)
• Quantitative analysis of asbestos burden in a series of individuals with lung cancer and a history of exposure to asbestos — R.F. Dodson, D.R. Brooks, et al. (2004)

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