Asbestos exposure assessment by mineralogical analysis of bronchoalveolar lavage fluid

Our plain-English summary of Asbestos exposure assessment by mineralogical analysis of bronchoalveolar lavage fluid, by P. Sartorelli, G. Scancarello, R. Romeo, et al (Journal of Occupational and Environmental Medicine, 2001).

The study

• Authors: P. Sartorelli, G. Scancarello, R. Romeo, G. Marcianò, P. Rottoli, G. Arcangeli, S. Palmi
• Journal: Journal of Occupational and Environmental Medicine
• Published: 2001;43(10):872-81
• Cited by: 14 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Mineralogical analysis of bronchoalveolar lavage fluid (BALF) by electron microscopy can represent the most suitable method for assessing asbestos exposure. However, it has been claimed that no standardized or systematic approach to the subject of mineralogical analysis exists. This study aimed to evaluate BALF mineralogical analysis by transmission electron microscopy as biomarker of asbestos fiber load. BALF was examined in 108 exposed workers and 57 patients who underwent diagnostic fiberoptic bronchoscopy for various clinical purposes. Asbestos bodies in BALF were counted with a phase-contrast microscope. Fibers were counted and analyzed by transmission electron microscopy, which showed a significant difference between the two populations and positive results for all exposed subjects. Only 82.2% of the exposed population tested positive for asbestos bodies. Subjects with long-term exposure had higher concentrations of fibers than did those with more recent exposure, probably because of the higher workplace exposure levels in the past. The results of the study confirm that fiber concentration in BALF can be considered as a reliable biomarker of past asbestos exposure, even many years after the end of exposure.

In plain English

This Italian study measured asbestos in fluid washed from the lungs (bronchoalveolar lavage fluid). It compared 108 occupationally exposed male workers, hospitalized in Siena from 1992 to 1998 for suspected asbestos-related disease, with 57 patients without occupational exposure who had bronchoscopy for other reasons, mostly sarcoidosis. Asbestos fibers (chrysotile and amphiboles) were counted by transmission electron microscopy, and asbestos bodies by light microscopy. Fibers were found in all exposed workers, but asbestos bodies in only 82.2%. Fiber concentrations were significantly higher in workers than in controls. The 99% confidence intervals for fiber concentration were 1054 to 1812 fibers per milliliter for workers and 102 to 186 for controls. A statistical test did not demonstrate a correlation between fiber and asbestos body counts. Fiber concentrations did not differ significantly by time since last or first exposure; asbestos body concentrations differed significantly by time since first exposure. The authors concluded that fiber concentration in this fluid can be considered a reliable biomarker of past asbestos exposure even many years after exposure ended, but said comparisons between laboratories are very difficult.

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: Comparison of lung-lavage fluid analysis (transmission electron microscopy fiber counts and light-microscopy asbestos body counts) between occupationally exposed workers and unexposed patients
• Who was studied: 108 male workers with occupational asbestos exposure, from Tuscany and other Italian regions, hospitalized 1992 to 1998 at the Institute of Occupational Medicine, University of Siena, for suspected asbestos-related diseases. The comparison group was 57 patients (41 men, 16 women) with no occupational asbestos exposure who had diagnostic bronchoscopy, 37 of them for sarcoidosis.
• Exposure: Occupational asbestos exposure in railway rolling stock production (32.4%), electric energy production (26.9%), shipbuilding yards (12%), steel industry (7.4%) and other sectors (21.3%). Mean exposure duration was 21.1 years (range 1 to 46). Fibers in the lavage fluid were classified as chrysotile and amphiboles.
• Main results:
  • Asbestos fibers were found in all 108 exposed workers by electron microscopy. Asbestos bodies were found in only 82.2% of them.
  • Total asbestos fiber concentration was significantly higher in exposed workers than in controls. The 99% confidence intervals of fiber concentration, calculated after logarithmic transformation, were 1054 to 1812 fibers per milliliter in the exposed workers and 102 to 186 fibers per milliliter in the controls. These are confidence intervals, not ranges of individual measurements.
  • Among exposed workers, the Spearman test did not demonstrate a correlation between fiber concentrations and asbestos body concentrations.
  • The highest asbestos body concentration in controls was 4 per milliliter. 70.1% of exposed workers were above that value, and 17.8% of exposed workers had asbestos bodies below the detection limit.
  • Using 600 fibers per milliliter as a reference point (the maximum seen in controls), 17% of exposed workers had a lower fiber concentration.
  • Among exposed workers grouped by time since last exposure (0 to 10, 11 to 20, and over 20 years), there were no statistically significant differences in fiber or asbestos body concentrations.
  • Workers were grouped by time since first exposure (split at 30 years). Asbestos body concentrations differed significantly between the two groups, but mean fiber concentrations did not.
  • Among exposed workers, fiber concentrations (chrysotile, amphiboles and all asbestos fibers) did not differ significantly between those with non-asbestos-related disease and those with asbestos-related disease.
  • Fiber concentrations differed significantly between workers from railway rolling stock production and workers from shipbuilding yards and other sectors. Asbestos body concentrations did not.
• The authors' conclusion: The authors concluded that asbestos fiber concentration in lung-lavage fluid can be considered a reliable biomarker of past asbestos exposure, even many years after exposure ended. They also said laboratories should establish their own baseline studies in exposed workers and controls.
• Limitations the authors state:
  • Results are very difficult to compare between laboratories.
  • No workplace air monitoring data were available, so exposure was characterized only by duration, continuity and whether it was definite or probable.
  • In controls, there was enough fluid to measure asbestos bodies in only 40% of samples. Because of this, asbestos body concentrations could not be statistically compared between groups.

Topics

Medical terms in this study, explained in our Lexicon: Asbestos Exposure, Bronchoalveolar Lavage (BAL), Transmission Electron Microscopy (TEM), Biomarker, Bronchoscopy, Asbestos Bodies.

Related studies

• Measurement of asbestos fibre concentrations in fluid of repeated bro-choalveolar lavages of exposed workers — P. Sartorelli, R. Romeo, et al. (2007)
• Inorganic particles in bronchoalveolar lavage fluids from nonoccupationally exposed subjects — M. Falchi, L. Biondo, et al. (1996)
• 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 fluids of brake lining and asbestos cement workers — P. Dumortier, P. De Vuyst, et al. (1990)
• Fibres and asbestos bodies in bronchoalveolar lavage fluids of asbestos sprayers — T. Tuomi, P. Oksa, et al. (1992)
• Diagnostic value of asbestos bodies in bronchoalveolar lavage fluid — P. De Vuyst, P. Dumortier, et al. (1987)

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