The association among ferruginous body, uncoated fibers, asbestos and non-asbestos fibers in lung tissue in terms of length

Our plain-English summary of The association among ferruginous body, uncoated fibers, asbestos and non-asbestos fibers in lung tissue in terms of length, by T. Suzuki, Y. Sakakibara, N. Hisanaga, et al (Industrial Health, 2016).

The study

• Authors: T. Suzuki, Y. Sakakibara, N. Hisanaga, K. Sakai, I.J. Yu, H.S. Lim, H. Mikamo, H. Seno, F. Kobayashi, E. Shibata
• Journal: Industrial Health
• Published: 2016;54(4):370-6
• Cited by: 1 article, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

To demonstrate the correlations between the concentrations of ferruginous body as well as uncoated fiber both of which can be observed with phase-contrast microscope and the concentration of various inorganic fibers including asbestos which requires the observation with TEM or SEM, we measured those indices among Japanese and Korean cases. Though the concentration of ferruginous body in lung tissue is an important index of asbestos exposure, uncoated fibers observed with phase-contrast microscope might be another index especially in such cases with relatively low exposure due to their history of living in a general environment. However, to establish the reliability of uncoated fibers as an index of asbestos exposure, analysis with more cases and from various backgrounds must be carried out.

In plain English

This study examined autopsy lung tissue from 18 Japanese people who died of diseases not associated with asbestos (autopsied 1978–1987 around Nagoya) and 39 Korean people, most of whom died in accidents. Using a phase-contrast light microscope, the authors counted ferruginous bodies (iron-protein-coated fibers) and uncoated fibers. They compared these counts with chrysotile, amphibole and non-asbestos fiber counts from a transmission electron microscope. Every measure was significantly higher in the Japanese cases than in the Korean cases. Three of the 18 Japanese cases had more than 1,000 ferruginous bodies per gram of dry lung; all Korean cases were below that level. Both light-microscope counts were significantly correlated with asbestos, chrysotile and non-asbestos fibers. Within length groups, ferruginous bodies did not correlate significantly with amphibole fibers, but uncoated fibers did for amphiboles 1 micrometer or longer. Uncoated fibers were more closely associated with asbestos fibers than ferruginous bodies were. The authors concluded that uncoated fibers might be another index of exposure, especially at relatively low, general-environment exposure. They noted that most cases were not occupationally exposed and that more cases are needed.

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: Autopsy lung tissue study comparing light-microscope (phase-contrast) counts of ferruginous bodies and uncoated fibers with electron-microscope (TEM) counts of asbestos and non-asbestos fibers, using correlation tests
• Who was studied: 57 autopsy cases. 18 Japanese (12 males, 6 females, mean age 62.3) who died of diseases not associated with asbestos and were autopsied 1978–1987 in Nagoya, Japan, and surrounding area. 39 Korean (33 males, 6 females, mean age 38.4), most of whom died from accidents, autopsied in Seoul and some local cities. Their lung fiber concentrations had already been reported in earlier papers.
• Exposure: Lung burden of ferruginous bodies, uncoated fibers, chrysotile, amphibole asbestos and non-asbestos inorganic fibers, mostly from general-environment exposure. Among the Japanese male cases, 8 (7 blue-collar workers and a scientist) were suspected to have been occupationally exposed to asbestos. Detailed occupational histories of the Korean cases could not be obtained.
• Main results:
  • All measured indices (ferruginous body, uncoated fiber, chrysotile, amphibole and non-asbestos fibers) were significantly higher (p less than 0.01) in the Japanese cases than in the Korean cases. Geometric means, Japanese versus Korean: ferruginous bodies 0.59 versus 0.11 thousand per g dry lung; uncoated fibers 34.26 versus 0.72 thousand per g; asbestos fibers 2.38 versus 0.36 million fibers per g.
  • All Korean cases had fewer than 1,000 ferruginous bodies per g dry lung; 3 of 18 Japanese cases had more than that level.
  • Asbestos fibers of any kind, and chrysotile fibers, were found in all Japanese cases. Detection rates in the Korean cases were 82.1% for any asbestos and 59.0% for chrysotile.
  • For fibers shorter than 1 micrometer and for fibers 1 micrometer or longer, both ferruginous body and uncoated fiber counts were significantly correlated with total inorganic fibers, asbestos, chrysotile and non-asbestos fibers.
  • The authors' text states that amphiboles were not correlated with either phase-contrast index, but Table 3 gives a more mixed result. Within length groups, ferruginous bodies were not significantly correlated with amphibole fibers (coefficients 0.29, 0.35 and 0.24); across all lengths the coefficient was 0.46, p less than 0.05. Uncoated fibers were not significantly correlated with amphiboles shorter than 1 micrometer (0.01) or 5 micrometers or longer (0.24). They were significantly correlated with amphiboles 1 micrometer or longer (0.46, n=32, p less than 0.01).
  • For fibers 5 micrometers or longer, significant correlations were found between ferruginous bodies and asbestos fibers (p less than 0.05). Uncoated fibers were significantly correlated with inorganic fibers (p less than 0.01), asbestos fibers (p less than 0.05) and non-asbestos fibers (p less than 0.05).
  • Uncoated fibers were more strongly associated with asbestos fibers than ferruginous bodies were. Across all lengths, the correlation coefficient with asbestos fibers was 0.71 for uncoated fibers (n=50) versus 0.55 for ferruginous bodies (n=35).
• The authors' conclusion: The authors concluded that ferruginous body concentration is an important index of asbestos exposure, and that uncoated fibers seen with phase-contrast microscopy might be another index, especially in cases with relatively low exposure from living in the general environment. They said analysis of more cases from various backgrounds is needed to establish this.
• Limitations the authors state:
  • The range of concentrations in the samples was too small to establish the association between ferruginous bodies and asbestos fibers.
  • Most cases were not occupationally exposed, so the associations found apply only to relatively low exposure levels.
  • Amphibole fibers were found at low levels in a rather small number of cases, which the authors linked to the apparently inconsistent amphibole results.
  • The Japanese cases were on average 20 years older than the Korean cases.
  • Detailed occupational histories of the Korean cases could not be obtained.

Topics

Medical terms in this study, explained in our Lexicon: Ferruginous body, Asbestos Exposure.

Related studies

• A comparison of the ferruginous body and uncoated fiber content in the lungs of former asbestos workers — R.F. Dodson, M.G. Williams, et al. (1985)
• Relationships between ferruginous bodies and uncoated asbestos fibers in lung tissue — R.F. Dodson, M. O'Sullivan, et al. (1996)
• Standardized methods for preparation and bi-variate length & diameter counting/sizing of aerosol and tissue digestion fiber samples — D.M. Bernstein, P. Kunzendorf (2018)
• Pulmonary asbestos and non-asbestos fiber concentrations in autopsied inhabitants in Pohang, Korea — H.S. Lim, J.Y. Kim, et al. (2004)
• Asbestos fiber length and its relation to disease risk — C.A. Barlow, M. Grespin, et al. (2017)
• Discrepancies of asbestos body and fiber content between formalin-fixed and corresponding paraffin embedded lung tissue — B.K. Kuhn, F. Barresi, et al. (2021)

Browse more research in Industrial Health, or return to medical research.