Ferruginous bodies and pulmonary fibrosis in dead low to moderately exposed asbestos cement workers: histological examination

Our plain-English summary of Ferruginous bodies and pulmonary fibrosis in dead low to moderately exposed asbestos cement workers: histological examination, by L.G. Johansson, M.P. Albin, K.M. Jakobsson, et al (British Journal of Industrial Medicine, 1987).

The study

• Authors: L.G. Johansson, M.P. Albin, K.M. Jakobsson, H.E. Welinder, P.J. Ranstam, R.G. Attewell
• Journal: British Journal of Industrial Medicine
• Published: 1987;44(8):550-8
• Cited by: 12 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text
• In J-M's library: Johns-Manville's company medical library held a copy (J-M no. 000978).

Abstract

Histological slides from the lungs of 89 dead asbestos cement workers have been examined with respect to ferruginous bodies and fibrosis. The results have been compared with individually matched controls with no known exposure to asbestos, and related to asbestos exposure, expressed as duration of exposure and cumulative asbestos dose, and smoking habits. The asbestos cement workers studied had been employed for on average 15 years, with a mean cumulative dose of 26 fibre-years per ml (f-y/ml). Clear dose-response relations between exposure (duration of exposure and cumulative asbestos dose) and level of ferruginous bodies were found. An association was evident already at a low cumulative dose (1-10 f-y/ml). Fibrosis was more common and more pronounced among the exposed workers than among controls. An association between ferruginous bodies and fibrosis was also found. Among the controls, but not among exposed workers, there was an association between smoking history and fibrosis.

In plain English

This study examined lung tissue slides taken at autopsy from 89 deceased workers of an asbestos cement plant in southern Sweden. The asbestos used at the plant was mainly chrysotile. Each worker was paired with a control of the same sex and similar age at death, taken from hospital autopsy files. The workers' average estimated cumulative asbestos dose was 26 fibre-years per ml. Ferruginous bodies (coated fibres seen under the microscope) were found in 57 of the 89 workers, compared with 13% of controls. The proportion of workers with many such bodies rose with dose, and a difference from controls appeared at 1 to 10 fibre-years per ml. Lung fibrosis was found in 68 workers (16 severe) and 56 controls (six severe). It was more pronounced in the workers. A link between dose and fibrosis was suggested but was not statistically significant. Smoking was associated with fibrosis among controls but not among workers. The authors noted that effects were seen at low cumulative doses. They also said the clinical significance of microscopic fibrosis was unclear.

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: Histological examination of autopsy lung slides, comparing deceased asbestos cement workers with individually matched controls (same sex, age at death within five years) from hospital autopsy files
• Who was studied: 89 deceased asbestos cement workers (84 men, five women; mean age at death 66, range 35-91) autopsied in Lund, drawn from a cohort of 3144 blue collar workers employed between 1907 and 1977 at a plant in southern Sweden; plus 89 matched controls
• Exposure: Asbestos cement manufacturing; asbestos was mainly chrysotile (over 90%), with small amounts of crocidolite before 1966 and possibly amosite in the 1950s
• Main results:
  • Exposed workers' average estimated cumulative asbestos dose was 26 (range 0.2-230) fibre-years per ml
  • 57 of the 89 exposed workers had ferruginous bodies, 21 of them with score 2-3
  • 13% of controls had ferruginous bodies
  • Among exposed workers, ferruginous bodies of grade 2-3 were found in 2% of those with under 10 fibre-years per ml, 29% with 11-40, and 69% with over 40
  • In the paired comparison, the effect on ferruginous bodies became apparent at doses of 1-10 fibre-years per ml (exposed worker scored higher than control in 15 of 31 pairs, 48%)
  • Fibrosis was found in 56 of 89 controls (six severe, grades 3-4) and 68 of 89 exposed workers (16 severe)
  • In the paired analysis, fibrosis was more pronounced among exposed workers than controls (p = 0.005)
  • An association between cumulative dose and degree of fibrosis was suggested but not statistically significant
  • Ferruginous bodies were associated with fibrosis in both exposed workers and controls
  • Smoking history was associated with fibrosis among controls but not among exposed workers
  • According to final autopsy reports, five exposed workers and no controls died from pulmonary fibrosis
• The authors' conclusion: The authors concluded that effects (more ferruginous bodies, and more pronounced fibrosis) were seen at low cumulative asbestos doses
• Limitations the authors state:
  • The technical quality of the tissue was sometimes low
  • It was usually not known which lung lobe the samples came from
  • Job information used for individual dose estimates was incomplete for some workers
  • Grading of microscopic fibrosis is somewhat uncertain
  • Light microscopy of ferruginous bodies is only a rough measure of lung fibre content
  • Because exposure was mainly chrysotile with some amphibole, effects of different fibre types could not be compared
  • The clinical significance of microscopic fibrosis is unclear

Topics

Medical terms in this study, explained in our Lexicon: Ferruginous Bodies, Pulmonary Fibrosis, Asbestos-Cement, Fibrosis, Asbestos Exposure, Habit, Cumulative Dose, Dose-response relationship.

Related studies

• Analysis of cores of ferruginous bodies from former asbestos workers — R.F. Dodson, M.F. O'Sullivan, et al. (1982)
• Pulmonary fibrosis and ferruginous bodies associated with exposure to synthetic fibers — A.J. Ghio, W. Funkhouser, et al. (2006)
• 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)
• Mineral fibres, fibrosis, and asbestos bodies in lung tissue from deceased asbestos cement workers — M. Albin, L. Johansson, et al. (1990)
• Ferruginous bodies as markers of environmental exposure to inorganic particles: experience with 270 autopsy cases in Mexico — F.J. Arenas-Huertero, M. Salazar-Flores, et al. (1994)
• Asbestos and other ferruginous bodies: their formation and clinical significance — A.M. Churg, M.L. Warnock (1981)

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