Fibres and asbestos bodies in bronchoalveolar lavage fluids of asbestos sprayers

Our plain-English summary of Fibres and asbestos bodies in bronchoalveolar lavage fluids of asbestos sprayers, by T. Tuomi, P. Oksa, S. Anttila, et al (British Journal of Industrial Medicine, 1992).

The study

• Authors: T. Tuomi, P. Oksa, S. Anttila, O. Taikina-aho, E. Taskinen, A. Karjalainen, P. Tukiainen
• Journal: British Journal of Industrial Medicine
• Published: 1992;49(7):480-5
• Cited by: 14 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. 004409).

Abstract

The alveolar content of fibres and asbestos bodies was assessed by bronchoalveolar lavage (BAL) in 21 asbestos sprayers. Transmission and scanning electron microscopy (TEM and SEM) and two light microscopical (LM) methods, cytocentrifugation, and Millipore filtration were used. The subjects had been exposed mainly to crocidolite asbestos for an average of 2.8 (range 0.2-13) years in 1950-75. The mean (median) total fibre count (of asbestos bodies and uncoated fibres) per ml of BAL fluid was 5500 (2800) by TEM and 2900 (1000) by SEM. The mean (median) count of asbestos bodies per ml with LM was 810 (500) with cytocentrifugation and 750 (480) with Millipore filtration, 840 (320) by TEM, and 1750 (420) by SEM. The mean proportion of coated fibres was 35% by TEM and 45% by SEM. The mean length of the coated fibres was 22 (range 4-65) microns by TEM and 34 (range 4.5-170) microns by SEM. The total fibre count exceeded 1000 fibres per ml in 70% of the cases by TEM. Asbestos body counts exceeded 1 per ml in 95% of the cases by LM. The fibre counts by SEM were in good accordance with counts by TEM except in a few cases in which the TEM result was considerably higher. In these cases the proportion of coated fibres was also low. All four counting methods appeared to give consistent results in heavily exposed cases when fibre load in the lungs was high. The counting of asbestos bodies may, however, underestimate the total alveolar fibre load in some cases.

In plain English

This Finnish study measured asbestos fibres and asbestos bodies (coated fibres) in lung-washing (bronchoalveolar lavage) fluid from 21 male former asbestos sprayers. It compared four counting methods: transmission and scanning electron microscopy (TEM and SEM) and two light microscopy methods. The men had sprayed asbestos in construction and shipbuilding between 1956 and 1975, for an average of 2.8 years (range 0.2 to 13). They were selected for x ray or lung function abnormalities. Crocidolite made up 95% of the fibres found. The mean (median) total fibre count per ml of fluid was 5500 (2800) by TEM and 2900 (1000) by SEM. Total fibres exceeded 1000 per ml in 70% of cases by TEM, and asbestos bodies exceeded 1 per ml in 95% of cases by light microscopy. Fibre counts showed a weak correlation with time spent spraying, but no statistically significant correlation with time since first spraying. The authors concluded that all four methods gave consistent results in heavily exposed cases, that counting asbestos bodies may underestimate total fibre load in some cases, and that electron microscopy is needed to identify fibre types.

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: Cross-sectional laboratory study of bronchoalveolar lavage (BAL) fluid from exposed workers, describing fibre burden and comparing electron and light microscopy counting methods
• Who was studied: 21 voluntary male former asbestos sprayers, chosen from 61 former sprayers examined in 1987 at the Institute of Occupational Health, Helsinki, Finland. They were selected because of x ray or pulmonary function abnormalities suggesting lung or pleural fibrosis. Mean age in the study year (1989) was 47 (range 39 to 58). Pulmonary fibrosis (ILO class 1/0 or more) was found in 19% and pleural plaques in 25%.
• Exposure: Asbestos spraying in the construction industry and shipbuilding between 1956 and 1975, for a mean of 2.8 years (range 0.2 to 13), mainly with crocidolite. Most subjects also worked in other occupations with probable asbestos exposure. Crocidolite made up 95% of fibres found in BAL fluid; only a few anthophyllite, amosite, chrysotile and tremolite fibres were found.
• Main results:
  • Among the 21 sprayers, the mean (median) total fibre count (asbestos bodies plus uncoated fibres) per ml of BAL fluid was 5500 (2800) by TEM and 2900 (1000) by SEM.
  • The mean (median) asbestos body count per ml was 810 (500) by light microscopy with cytocentrifugation, 750 (480) by light microscopy with Millipore filtration, 840 (320) by TEM and 1750 (420) by SEM.
  • On average, 35% of fibres were coated (asbestos bodies) by TEM and 45% by SEM. The proportion ranged from less than 4% to 83% of the total fibre count.
  • The total fibre count exceeded 1000 fibres per ml in 70% of cases by TEM. Asbestos body counts exceeded 1 per ml in 95% of cases by light microscopy.
  • No statistically significant correlation was found between time since first spraying and fibre concentrations with any method. There was a weak correlation between spraying time and fibre and asbestos body concentrations. It was statistically significant at the 5% level for all counts except asbestos body counts by SEM and by light microscopy (Millipore filter method).
  • Grouped by spraying duration (less than one year, one to five years, over five years), mean total fibre concentrations by TEM were 1500 (n = 8), 6400 (n = 9) and 12 000 (n = 4) fibres per ml. This tendency was not statistically significant.
  • TEM and SEM counts generally agreed (Spearman correlation coefficients 0.73 to 0.87, p less than 0.001). Light microscopy was the most sensitive method for asbestos bodies: it found several asbestos bodies per ml in three patients in whom electron microscopy found none.
  • Coated fibres were on average four times longer than uncoated ones. No coated fibres shorter than 4 micrometres were found.
  • One subject, who had sprayed asbestos for one year, died of lung cancer in 1991. That subject's BAL fluid had 3000 fibres per ml, and the lung tissue had 190 million fibres per g dry tissue by SEM.
• The authors' conclusion: The authors concluded that all four counting methods appeared to give consistent results in heavily exposed cases with high lung fibre load, but that counting asbestos bodies may underestimate total alveolar fibre load in some cases. They considered light microscopical asbestos body counting reliable for indicating exposure in this group, and electron microscopy necessary when fibre types must be identified to attribute them to a specific exposure.
• Limitations the authors state:
  • Both electron microscopy methods had a high detection limit within a reasonable counting time.
  • The sample preparation method did not allow sample volumes larger than 20 ml.
  • Repeated lavages were not done.
  • Fibre concentrations varied between subjects with comparable spraying time. The authors suggested this may be due to differences in exposure and variations in the lavage technique.

Topics

Medical terms in this study, explained in our Lexicon: Asbestos Bodies, Bronchoalveolar Lavage (BAL), Scanning Electron Microscopy (SEM), Crocidolite, BAL Fluid, Asbestos Body Formation.

Related studies

• Asbestos bodies in bronchoalveolar lavage fluid in relation to occupational history — A. Karjalainen, S. Anttila, et al. (1994)
• Erionite bodies and fibres in bronchoalveolar lavage fluid (BALF) of residents from Tuzköy, Cappadocia, Turkey — P. Dumortier, L. Coplü, et al. (2001)
• Asbestos bodies in bronchoalveolar lavage in relation to asbestos bodies and asbestos fibres in lung parenchyma — A. Karjalainen, R. Piipari, et al. (1996)
• Asbestos bodies in bronchoalveolar lavage fluids of brake lining and asbestos cement workers — P. Dumortier, P. De Vuyst, et al. (1990)
• Diagnostic value of asbestos bodies in bronchoalveolar lavage fluid — P. De Vuyst, P. Dumortier, et al. (1987)
• Pleural plaques, asbestos exposure, and asbestos bodies in bronchoalveolar lavage fluid — E. Orlowski, J.C. Pairon, et al. (1994)

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