Early detection of interstitial lung disease in asbestos exposed non-smoking workers by mid-expiratory flow rate and high resolution computed tomography

Our plain-English summary of Early detection of interstitial lung disease in asbestos exposed non-smoking workers by mid-expiratory flow rate and high resolution computed tomography, by Z. Dujić, J. Tocilj, M. Saric (British Journal of Industrial Medicine, 1991).

The study

• Authors: Z. Dujić, J. Tocilj, M. Saric
• Journal: British Journal of Industrial Medicine
• Published: 1991;48(10):663-4
• Cited by: 9 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. 004152).

Abstract

Ten years of lung function and radiological findings in six non-smoking asbestos exposed subjects who had increased mid-expiratory flow rate (FEF 25-75%) as the only functional abnormality were prospectively analysed. A biphasic change in FEF25-75% was noted. It initially increased up to the fifth year, and then a decrease was seen. In the final three years of the study, FEF25-75% reduction correlated well with a decrease in pulmonary capacity for CO (DLCO). During that time high resolution computed tomography (HRCT) probability scores correlated inversely with FEF25-75% and with DLCO, whereas chest radiography was unchanged (International Labour Organisation (ILO) profusion below 1/1). For five of the six subjects HRCT probability of asbestosis was intermediate. An increase in FEF25-75% in some asbestos exposed non-smoking workers may be one of the earliest functional signs indicative of future development of parenchymal asbestosis. Early asbestos related parenchymal abnormalities are seen more frequently on HRCT than on chest radiography.

In plain English

This short report followed six non-smoking men from a cohort of 285 workers in an asbestos cement factory. They were exposed mainly to chrysotile asbestos, and their earliest lung-function abnormality was an increase in mid-expiratory flow rate (FEF25-75%, a measure of airflow in the small airways). Lung function and chest X-rays were checked every year for 10 years, with high resolution CT (HRCT) scans in the final three years. The group's average FEF25-75% rose from 98% to 121% of predicted by year four, peaked at 136% in year five, and then fell. Gas transfer (DLCO) was unchanged for seven years, then fell from 101% to 83% of predicted. Over the last three examinations, FEF25-75% and DLCO moved together, and both were inversely related to HRCT scores. Chest X-rays showed no evidence of pleural or parenchymal fibrosis. Five of the six men had HRCT findings suggestive of asbestosis, all rated intermediate probability. The authors concluded that early diagnosis of asbestosis could be made in some exposed non-smokers with normal chest X-rays by HRCT and FEF25-75% monitoring.

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: Longitudinal (prospective) study of a small selected group, followed with yearly examinations for 10 years
• Who was studied: Six non-smoking men (median age 44, range 37-51 years; median asbestos exposure at the start of the study 13 years, range nine to 17 years). They were chosen from a cohort of 285 workers in an asbestos cement factory. The authors were based in Split and Zagreb, Yugoslavia; the article does not name the factory's location.
• Exposure: Work in an asbestos cement factory, with exposure predominantly to chrysotile asbestos
• Main results:
  • In the six men, mean FEF25-75% was significantly increased four years after the start of the study: 121 plus or minus 13 versus 98 plus or minus 11% of predicted values, p less than 0.01
  • The highest mean FEF25-75% was found at the fifth annual examination (136 plus or minus 11%), followed by a decrease
  • Other spirometric measures (FVC, FEV1, FEV1/FVC) were unchanged during the study
  • DLCO was unchanged for the first seven years and significantly decreased in the final three years, from 101 plus or minus 4 to 83 plus or minus 6% at the last measurement, p less than 0.005
  • FEF25-75% and DLCO were significantly correlated over the last three examinations (r = 0.88; p less than 0.01)
  • Chest radiographs gave no evidence of pleural or parenchymal fibrosis; at the last examination, ILO profusion of small opacities was graded 1/0 in three subjects
  • In the last two examinations, five subjects had abnormal HRCT suggestive of asbestosis and one had a near normal HRCT; all five had intermediate probability of asbestosis
  • HRCT scores were significantly inversely correlated with FEF25-75% (r = -0.71; p less than 0.05) and with DLCO (r = -0.64; p less than 0.05) over the last three examinations
  • None of the usual clinical findings of asbestosis (finger clubbing, basal rales) were noted in these subjects
• The authors' conclusion: The authors concluded that asbestos exposure may cause a two-phase change in FEF25-75% (an initial increase, then a decrease) in non-smokers. They concluded that early diagnosis of asbestosis appears possible in some exposed non-smokers with normal chest radiographs by HRCT and FEF25-75% monitoring.

Topics

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

Medical terms in this study, explained in our Lexicon: Interstitial Lung Disease, Biphasic Mesothelioma, Diffusing Capacity (DLCO), High-Resolution CT (HRCT).

Related studies

• Pulmonary function, smoking habits, and high resolution computed tomography (HRCT) early abnormalities of lung and pleural fibrosis in shipyard workers exposed to asbestos — S. Neri, P. Boraschi, et al. (1996)
• Agreement between chest radiography and high-resolution computed tomography in diagnosing dust-related interstitial lung fibrosis — R.R. Tiwari (2015)
• Findings from high resolution computed tomography of the lung and pleura of symptom free workers exposed to amosite who had normal chest radiographs and pulmonary function tests — S. Neri, A. Antonelli, et al. (1994)
• Computed tomography-guided interstitial high-dose-rate brachytherapy in the local treatment of primary and secondary intrathoracic malignancies — N. Tselis, K. Ferentinos, et al. (2011)
• Relationships (I) of International Classification of High-resolution Computed Tomography for Occupational and Environmental Respiratory Diseases with the ILO International Classification of Radiographs of Pneumoconioses for parenchymal abnormalities — T. Tamura, N. Suganuma, et al. (2015)
• High-resolution computed tomography of asbestos-related diseases — D.R. Aberle (1991)

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