The clinical utility and reliability of asbestos bodies in bronchoalveolar fluid

Our plain-English summary of The clinical utility and reliability of asbestos bodies in bronchoalveolar fluid, by D.A. Schwartz, J.R. Galvin, L.F. Burmeister, et al (The American Review of Respiratory Disease, 1991).

The study

• Authors: D.A. Schwartz, J.R. Galvin, L.F. Burmeister, R.K. Merchant, C.S. Dayton, J.A. Merchant, G.W. Hunninghake
• Journal: The American Review of Respiratory Disease
• Published: 1991;144(3 Pt 1):684-8
• Cited by: 22 articles, as counted by NIH iCite
• Read it: PubMed · Publisher
• In J-M's library: Johns-Manville's company medical library held a copy (J-M no. 004173).

Abstract

Although asbestos bodies are easily identified in bronchoalveolar lavage (BAL) fluid and are thought to be strongly associated with the asbestos body burden in the lung parenchyma, the clinical utility and reliability of this biologic measure of exposure has not been sufficiently studied. To assess the clinical relevance of BAL asbestos bodies we compared this bioassay of exposure to other measures of exposure and also indices of lung disease in asbestos-exposed workers (n = 71). The median concentration of asbestos bodies was 0.8 bodies per ml of BAL fluid (range 0 to 34.3). Seven workers or 9.9% had zero asbestos bodies identified in the BAL fluid. The concentration of BAL asbestos bodies was not associated with the duration of exposure (r = -0.02), the time from first exposure to asbestos (r = 0.12), or the time since last exposure to asbestos (r = 0.05). Moreover, radiographic and physiologic measures of asbestos-induced lung disease were not found to be associated with the concentration of BAL asbestos bodies. In fact, of the seven study subjects with zero BAL asbestos bodies, the mean duration of exposure was 32 yr, and six of these subjects had radiographic evidence of asbestos-induced lung disease. To assess the reliability of measuring BAL asbestos bodies, we performed a second bronchoscopy on 54 subjects and directly compared the concentration of BAL asbestos bodies from both the first and second BAL samples. Within these 54 subjects, the concentration of BAL asbestos bodies was found to be a very reliable measure (r = 0.76; p = 0.0001).(ABSTRACT TRUNCATED AT 250 WORDS)

In plain English

This study tested whether asbestos bodies counted in fluid washed from the lungs (bronchoalveolar lavage, BAL) were clinically useful and reliable. It included 71 white men, mostly sheet metal workers (56%) and plumbers and pipefitters (25%). All had at least 1 year of direct occupational asbestos exposure and at least 20 years since first exposure. The median count was 0.8 bodies per ml of fluid (range 0 to 34.3), and seven men (9.9%) had none. Counts were not associated with duration of exposure, time since first or last exposure, asbestosis or pleural fibrosis on chest X-ray, interstitial changes or pleural fibrosis on CT scan, or lung function. Six of the seven men with no asbestos bodies had radiographic evidence of asbestos-induced lung disease. In 54 men given a second lavage about 6 months later, counts correlated closely (r = 0.76). The authors concluded that BAL asbestos bodies are a reproducible measure of exposure but appear to have little utility in most clinical settings. They noted that the results may not apply to workers mainly exposed to amphibole asbestos.

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 of asbestos-exposed workers comparing asbestos body counts in bronchoalveolar lavage (BAL) fluid with exposure history, chest radiograph and high resolution CT findings, and lung function. A second lavage in a subset tested reproducibility.
• Who was studied: 71 asbestos-exposed workers (all white men, mean age 60.0 years) enrolled mainly through the Sheet Metal Worker's 1986 screening program and the University of Iowa Occupational Medicine Clinic. Job titles were sheet metal workers (56%), plumbers and pipefitters (25%), general construction workers (6%), insulators (3%), electricians (3%), railroad workers (3%) and armed services (4%). People with asbestosis or pleural disease were preferentially invited.
• Exposure: Occupational asbestos exposure of at least 1 year in a high exposure setting (direct contact with asbestos), with at least 20 years between first exposure and study entry. Mean duration of exposure was 32.8 years (SD 10.3) and mean time from first exposure was 37.5 years (SD 9.2). Fiber type was not measured. The authors hypothesized that these US construction workers had primarily been exposed to chrysotile.
• Main results:
  • Among the 71 subjects, the median BAL asbestos body concentration was 0.8 bodies per ml (range 0 to 34.3). The mean was 3.3 per ml (SD 6.5).
  • Seven of the 71 subjects (9.9%) had no asbestos bodies found in the BAL fluid sample.
  • BAL asbestos body concentration was not associated with duration of exposure (r = -0.02, 95% CI -0.25 to 0.21), time from first exposure (r = 0.12, 95% CI -0.12 to 0.34), or time since last exposure (r = 0.05, 95% CI -0.19 to 0.28).
  • Radiographic and lung function measures of asbestos-induced lung disease were not associated with BAL asbestos body concentration. Subjects with asbestosis on chest radiograph (ILO profusion 1/0 or greater, n = 24) had a mean of 2.4 (SD 3.3) and median of 1.0 bodies per ml. Subjects below 1/0 (n = 47) had a mean of 3.8 (SD 7.6) and median of 0.7.
  • On high resolution CT, done in 61 subjects, asbestos body concentration was not associated with asbestos-induced lung disease. Subjects with interstitial changes on CT (n = 33) had a mean of 2.6 (SD 4.7) and median of 1.0 bodies per ml. Subjects with normal parenchyma (n = 28) had a mean of 3.6 (SD 6.8) and median of 0.8.
  • Pleural fibrosis, as assessed by both chest radiograph and high resolution CT, did not appear to be associated with BAL asbestos body concentration.
  • Using the ILO 12-point scale of interstitial fibrosis on the chest radiograph, the correlation with BAL asbestos body concentration was r = -0.05 (p = 0.65).
  • No statistically or clinically meaningful relationship was found between BAL asbestos body concentration and measures of airflow, lung volumes or gas exchange.
  • Of the seven subjects with no BAL asbestos bodies, mean duration of exposure was 32 years, and six had radiographic evidence of asbestos-induced lung disease.
  • In 54 of the 71 subjects (76%), a repeat lavage about 6 months later gave counts that correlated closely with the first (r = 0.76; p = 0.0001).
• The authors' conclusion: The authors concluded that BAL asbestos bodies are a reproducible bioassay of exposure but appear to have little utility in most clinical settings.
• Limitations the authors state:
  • No reliable measure of the intensity of exposure was available.
  • Reproducibility was shown only over a 6-month interval and may not hold over longer periods.
  • The results may not apply to workers primarily exposed to amphibole asbestos.
  • The exposure measures used (duration, years since first exposure, years since last exposure) may not be entirely reliable in all situations.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Asbestosis.

Medical terms in this study, explained in our Lexicon: Asbestos Bodies, Bronchoalveolar Lavage (BAL), Asbestos Body Formation, Parenchyma, BAL Fluid, Bronchoscopy.

Related studies

• Influence of cigarette smoking on bronchoalveolar lavage cellularity in asbestos-induced lung disease — D.A. Schwartz, J.R. Galvin, et al. (1992)
• 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)
• Asbestos bodies in bronchoalveolar lavage fluid in relation to occupational history — A. Karjalainen, S. Anttila, et al. (1994)
• Fibres and asbestos bodies in bronchoalveolar lavage fluids of asbestos sprayers — T. Tuomi, P. Oksa, et al. (1992)

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