Investigation of asbestos concentration in ambient and lavage fluids of patients referred for bronchoscopy, Ahvaz

Our plain-English summary of Investigation of asbestos concentration in ambient and lavage fluids of patients referred for bronchoscopy, Ahvaz, by N. SabzeAli, N. Jaafarzadeh, M.H. Shoushtari, et al (Journal of Environmental Health Science & Engineering, 2022).

The study

• Authors: N. SabzeAli, N. Jaafarzadeh, M.H. Shoushtari, M. Khadem, S.H. Borsi, A. Zahedi, H. Raji
• Journal: Journal of Environmental Health Science & Engineering
• Published: 2022;20(2):641-646
• Read it: PubMed · Publisher · Free full text

Abstract

Introduction: The amount of fibers in the lungs is considered to reflect the cumulative intensity of past asbestos exposure, and bronchoalveolar lavage (BAL) has been proposed to be a good indicator of the presence and quantity of asbestos particles in the lungs. This study evaluated the asbestos concentration in BAL fluids of asbestos-exposed and unexposed pulmonary patients and the environment of Ahvaz city.

Methods: This prospective study was conducted on 80 patients underwent diagnostic fiberoptic bronchoscopy referred to Imam Khomeini Hospital in Ahvaz, Iran, in 2019. Patients with Lung diseases were divided into three groups based on CT scan results: normal (n = 32), lung cancer (n = 40) and Interstitial lung disease (n = 8). The analysis of asbestos fiber concentration in BAL fluid was carried out by Scanning Electron Microscope (SEM).

Results: The positive asbestos test was detected in 69% of all subjects, including 64% of whom had asbestos-related jobs and 74.5% of those with non-related jobs (p = 0.240). The concentrations of asbestos fiber in the BAL in normal patients, lung cancer and interstitial fibrosis (ILD) were 8.13 ± 5.38, 9.66 ± 7.30 and 6.31 ± 1.98 f/ml, respectively (P = 0.492). There was no significant difference between the asbestos levels and exposure history (P = 0.877). The mean concentration of asbestos in the ambient air during the current year was 2.69 ± 0.57 f/ml (2.26-3.70), and the correlation between asbestos levels in BAL and the air was not significant (r = 0.147; P = 0.243).

Conclusions: The exposure of different occupational and non-occupational groups to this carcinogenic substance indicates the need for environmental and individual control measures to reduce and prevent asbestos exposure.

© Springer Nature Switzerland AG 2022.

In plain English

This prospective study at Imam Khomeini Hospital in Ahvaz, Iran, in 2019 measured asbestos in bronchoalveolar lavage (BAL) fluid, lung washings taken at bronchoscopy. It included 80 lung patients and measured outdoor air asbestos. CT scans placed patients in three groups: normal (32), lung cancer (40) or pulmonary fibrosis (8). Twenty-five patients had occupational asbestos exposure; fiber types were not reported. The article reported asbestos in the BAL fluid of 58 patients (69%), although 58 of 80 would be 72.5% and Table 2 lists 57; positive patients averaged 8.65 fibers per ml. Positive tests occurred in 64% of occupationally exposed patients and 74.5% of others; the article gives conflicting P values for this comparison. BAL concentrations did not differ significantly between CT groups or with occupational exposure. Outdoor air averaged 2.69 f/ml, not significantly related to BAL levels. The authors concluded that BAL fiber measurement was not efficient for linking asbestos with lung disease or exposure history, and called for exposure controls. They noted a small sample, especially for fibrosis, and that findings cannot be generalized to Ahvaz's population.

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: Prospective hospital-based study comparing asbestos in BAL fluid across CT-defined patient groups, with year-long outdoor air sampling
• Who was studied: 80 pulmonary patients (100 enrolled) referred for diagnostic bronchoscopy at Imam Khomeini Hospital, Ahvaz, Iran, in 2019. Average age was 58.30 years (range 18 to 89). By CT they were grouped as normal (n = 32), lung cancer (n = 40) and pulmonary fibrosis/interstitial lung disease (n = 8).
• Exposure: Two exposures were studied: asbestos-related versus unrelated jobs, with 25 patients (31.3%) occupationally exposed for an average of 18.75 years, and ambient air asbestos in five areas of Ahvaz measured by SEM. Specific jobs and fiber types were not reported.
• Main results:
  • The Results text says asbestos was detected in the BAL fluid of 58 patients (69%) and not detected in 26 (31%). These figures are internally inconsistent: 58 plus 26 totals 84, not 80, and 58 of 80 would be 72.5%. Table 2 counts total 57 positive and 23 negative.
  • Among patients with a positive test, mean BAL asbestos concentration was 8.65 plus or minus 6.21 f/ml.
  • 64% of patients with occupational exposure tested positive, compared with 74.5% of those with unrelated jobs. The text gives P = 0.024; the abstract gives p = 0.240.
  • Whether asbestos was present in BAL fluid did not differ significantly by type of lung disease (P = 0.913).
  • BAL asbestos concentration was 8.13 in the normal-CT group, 9.66 in the lung cancer group and 6.31 f/ml in the pulmonary fibrosis group. The difference was not statistically significant (P = 0.492).
  • BAL asbestos amount was not significantly related to occupational exposure (P = 0.877).
  • Mean ambient air asbestos concentration in Ahvaz was 2.69 plus or minus 0.57 f/ml (range 2.26 to 3.70).
  • Ambient air asbestos concentration was not significantly related to BAL fluid asbestos concentration.
• The authors' conclusion: The authors concluded that measuring asbestos fibers in BAL fluid was not efficient for establishing a relationship between asbestos and lung diseases, or even patients' exposure history. They also said exposure across occupational and non-occupational groups shows the need for environmental and individual control measures. In the discussion they proposed that environmental asbestos is the primary source of BAL asbestos in Ahvaz residents.
• Limitations the authors state:
  • Small sample size, especially for pulmonary fibrosis.
  • Patients with proven asbestos-related disease, such as malignant mesothelioma, could not be specifically selected.
  • No environmental asbestos data from other cities of Khuzestan province for comparison.
  • Air asbestos was averaged over the year; seasonal and monthly results were not examined.
  • Findings cannot be generalized to the Ahvaz population.
  • The planned sample size was reduced because of limited funding.

Topics

Medical terms in this study, explained in our Lexicon: Bronchoscopy, Asbestos Exposure, Bronchoalveolar Lavage (BAL), CT Scan, Lung Cancer, Interstitial Lung Disease, Interstitial Fibrosis, Exposure History.

Related studies

• Association between neutrophil concentration in bronchoalveolar lavage fluid and recent losses in diffusing capacity in men formerly exposed to asbestos — M.R. Cullen, W.W. Merrill (1992)
• Measurement of asbestos fibre concentrations in fluid of repeated bro-choalveolar lavages of exposed workers — P. Sartorelli, R. Romeo, et al. (2007)
• Historical ambient airborne asbestos concentrations in the United States - an analysis of published and unpublished literature (1960s-2000s) — A. Abelmann, M.E. Glynn, et al. (2015)
• Evaluation of ambient asbestos concentrations in buildings following the Loma Prieta earthquake — D.R. van Orden, R.J. Lee, et al. (1995)
• Ambient air concentrations of asbestos fibers near the town of Asbestos, Québec — B. Singh, J.P. Thouez (1985)
• Response to Letter to the Editor Regarding "Ambient Asbestos Fiber Concentrations and Long-Term Trends in Pleural Mesothelioma Incidence Between Urban and Rural Areas in the United States (1973-2012)" by Finkelstein — K.A. Keeton, M.E. Glynn, et al. (2018)

Browse return to medical research.