Asbestos bodies in bronchoalveolar lavage fluid in relation to occupational history

Our plain-English summary of Asbestos bodies in bronchoalveolar lavage fluid in relation to occupational history, by A. Karjalainen, S. Anttila, T. Mäntylä, et al (American Journal of Industrial Medicine, 1994).

The study

• Authors: A. Karjalainen, S. Anttila, T. Mäntylä, E. Taskinen, P. Kyyrönen, P. Tukiainen
• Journal: American Journal of Industrial Medicine
• Published: 1994;26(5):645-54
• Cited by: 16 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Concentrations of asbestos bodies (AB) were assessed by optical microscopy of 10 ml iron-stained samples and compared with the exposure history acquired by personal interview for 156 patients. Concentrations equalling or exceeding 1 AB/ml were found in 85% of patients who had been heavily exposed to asbestos and only 7% of those who were unlikely to have been exposed. Elevated AB concentrations were observed among primary asbestos, shipyard and construction workers. Smoking was not found to affect the AB concentrations. The use of Papanicolaou-stained cytological Millipore preparations during routine screening was a less sensitive method for the assessment of AB concentrations than that involving iron-stained preparations. The expression of AB concentration as AB/ml or AB/million cells were found to be equally useful indicators of exposure. The correlation between AB concentration and exposure history was greater than in earlier studies on workers exposed to chrysotile. Concentrations exceeding 1 AB/ml were indicative of a nontrivial exposure to asbestos. Despite the observed correlation between AB concentration and exposure history, the individual variability of AB counts, methodological differences and laboratory-bound reference values are important in the interpretation of AB concentrations in bronchoalveolar lavage (BAL) fluid at individual level.

In plain English

This Finnish study compared counts of asbestos bodies in lung-wash fluid (bronchoalveolar lavage) with work histories taken by physician interview. It covered 156 patients who had diagnostic bronchoscopy in Helsinki between November 1991 and January 1993. Patients were grouped as heavily, moderately, possibly or unlikely exposed. One or more asbestos bodies per ml was found in 85% of the heavily exposed group and 7% of the unlikely-exposed group. All six patients with the highest counts were in the heavy group. Counts were significantly above average among primary asbestos, shipyard and construction workers, but not among garage workers doing brake repair. Smoking did not correlate with counts. A routine cytology slide method found at least 1 per ml in only 13 of 33 samples that reached that level by the iron-stain method. The fibers inside the bodies were not analyzed. The authors concluded that 1 or more asbestos bodies per ml indicated a nontrivial exposure. They added that individual variability, differences in methods, and each laboratory's own reference values matter when interpreting one person's result.

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: Clinical study comparing asbestos body counts in bronchoalveolar lavage (BAL) fluid, by optical microscopy of iron-stained samples, with occupational histories taken by personal interview
• Who was studied: 156 patients (133 males, 23 females; mean age 59) who underwent diagnostic bronchoscopy at Helsinki University Central Hospital, Laakso Pulmonary Hospital or the Institute of Occupational Health, Helsinki, Finland, between November 1991 and January 1993. They had suspected asbestos-related disease, suspected lung malignancy, or other lung diseases.
• Exposure: Occupational asbestos exposure, graded from interview into heavy (A), moderate (B), possible (C) and unlikely (D) by job type and duration. Job types were primary asbestos work (insulation or asbestos product manufacture), shipyard work, construction work, garage work involving brake repair, and industrial maintenance work. Fiber types were not measured.
• Main results:
  • Heavy exposure group (40 patients): asbestos bodies were detected in 98%. In 85% the concentration exceeded 1 AB/ml.
  • Moderate exposure group (39 patients): asbestos bodies were detected in 85%. In 62% the concentration exceeded 1 AB/ml.
  • Concentrations exceeding 1 AB/ml were found in only 26% of the possible exposure group (47 patients) and 7% of the unlikely exposure group (30 patients).
  • All six patients with 100 or more AB/ml were in the heavy exposure group.
  • Readings overlapped substantially between groups. Even so, the distribution of concentrations differed significantly between groups A and B (p less than 0.001), B and C (p = 0.002), and C and D (p = 0.01).
  • Asbestos body counts were significantly above average among primary asbestos, shipyard and construction workers. Counts among maintenance workers were elevated but not statistically significant. Counts among garage workers doing brake repair were not above average.
  • Counts correlated with years of employment in primary asbestos work (partial correlation 0.43), shipyard work (0.32) and construction work (0.39), each with p less than 0.001. The authors described the correlation with duration as weak but statistically significant.
  • After adjustment for exposure category, smoking (pack-years) did not correlate with asbestos body concentrations.
  • In 69 samples tested by both methods, 33 had 1 or more AB/ml on the 10 ml iron-stained preparation. Only 13 of these (39%) reached 1 or more AB/ml on the routine 1-2 ml Papanicolaou-stained cytology (MiPo) preparation.
  • In 87 samples, counts per ml of fluid and per million cells correlated highly (r = 0.958).
  • Patients with asbestosis (9) had higher average concentrations (median 13 AB/ml, range 0.2-800) than patients with pleural disease only or with lung cancer. Concentrations overlapped substantially between disease groups.
• The authors' conclusion: The authors concluded that 1 or more asbestos bodies per ml of BAL fluid indicates a nontrivial exposure to asbestos. They also found the correlation with exposure history greater than in earlier studies of chrysotile-exposed workers. They cautioned that individual variability, methodological differences and laboratory-bound reference values are important when interpreting an individual's result.
• Limitations the authors state:
  • The lung cancer patients studied were not necessarily an epidemiologically representative sample of Finnish lung cancer patients.
  • No standardized questionnaire was used in the interviews.
  • The core fibers of the asbestos bodies were not analyzed, so fiber types were not identified.
  • Duration of employment is not an exact measure of actual exposure.
  • Concentrations by job category reflect the exposure of diseased workers, not the average exposure in those jobs.
  • Differences between individuals reduce the value of the test as a quantitative measure of exposure for a single person.
  • BAL fluid counts were not compared with asbestos body concentrations in lung tissue.

Topics

Medical terms in this study, explained in our Lexicon: Asbestos Bodies, Bronchoalveolar Lavage (BAL), Occupational History, Exposure History, Chrysotile.

Related studies

• Fibres and asbestos bodies in bronchoalveolar lavage fluids of asbestos sprayers — T. Tuomi, P. Oksa, et al. (1992)
• Asbestos bodies in bronchoalveolar lavage in relation to asbestos bodies and asbestos fibres in lung parenchyma — A. Karjalainen, R. Piipari, et al. (1996)
• Diagnostic value of asbestos bodies in bronchoalveolar lavage fluid — P. De Vuyst, P. Dumortier, et al. (1987)
• Asbestos bodies in bronchoalveolar lavage fluids of brake lining and asbestos cement workers — P. Dumortier, P. De Vuyst, et al. (1990)
• Erionite bodies and fibres in bronchoalveolar lavage fluid (BALF) of residents from Tuzköy, Cappadocia, Turkey — P. Dumortier, L. Coplü, et al. (2001)
• Pleural plaques, asbestos exposure, and asbestos bodies in bronchoalveolar lavage fluid — E. Orlowski, J.C. Pairon, et al. (1994)

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