Airway obstruction in asbestos-exposed shipyard workers: with and without irregular opacities

Our plain-English summary of Airway obstruction in asbestos-exposed shipyard workers: with and without irregular opacities, by K.H. Kilburn, R.H. Warshaw (Respiratory Medicine, 1990).

The study

• Authors: K.H. Kilburn, R.H. Warshaw
• Journal: Respiratory Medicine
• Published: 1990;84(6):449-55
• Cited by: 4 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. 003792).

Abstract

Airway obstruction was measured by spirometry in 296 boilermakers with 15 or more years shipyard exposure to asbestos. Percent of predicted was used to adjust each worker's pulmonary function values for height (mean 174 cm), age (mean 52.5 years) and cigarette smoking (mean 23.3 years). Mean values were significantly (P less than 0.05) below predicted for FVC 4.23 l 94.2% FEV1 3.06 l 89.3%, FEF25-75 2.51 l sec-1 82.3% and FEF75-85 0.574 l sec-1 77.8%. Corresponding values for the 106 men with pulmonary asbestosis (ILO profusion of opacities 1/0 or greater), were below these levels. Those without radiographic signs of asbestosis had intermediate values significantly below predicted. Correlation coefficients for pulmonary functions with ILO categories of asbestosis (profusion of irregular opacities) were: FVC -0.2381, FEV1 -0.2494, FEF25-75 -0.2403 and FEF75-85 -0.1629. All were significant P less than 0.05. The subgroup with radiographic asbestosis (ILO 1/0 or greater), had more functional loss. Data on this large cohort of asbestos-exposed workers establish that airway obstruction occurs after 15 years of exposure and before the slightest profusion of asbestosis scarring in the lungs of shipyard workers, and worsens progressively with greater profusions of irregular opacities.

In plain English

This cross-sectional study measured breathing function by spirometry in 296 male Caucasian boilermakers from a Jacksonville, Florida union local. All had been exposed to asbestos in shipyards, mostly in ship repair, at least 15 years earlier, for at least 5 years. Each man's results were compared with predicted values from a Michigan population sample, adjusted for height, age and years of cigarette smoking. As a group, the workers' FVC was 94.2% of predicted, and the reductions in all four spirometric measures were statistically significant. The 106 men (35%) whose chest X-rays showed asbestosis (ILO profusion 1/0 or greater) had 8% lower vital capacity, 11% lower FEV1, 19% lower midflow and 14% lower terminal flow than men without it. They were also older and had longer asbestos exposure. The 190 men without X-ray asbestosis still showed smaller but significant reductions. Greater profusion of irregular opacities was associated with lower function, but it accounted for only 2.65% to 6.22% of the variation. The authors concluded that airway obstruction occurs before the slightest X-ray signs of asbestosis.

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: Cross-sectional study of volunteer workers examined by spirometry and chest radiographs, with results compared to predicted values from a Michigan population sample adjusted for height, age and duration of cigarette smoking
• Who was studied: 296 male Caucasian boilermakers, members of a Jacksonville, Florida local of the boilermakers' union, who volunteered for examinations. A further group of 275 similar workers was examined but not reported here. Study dates are not given.
• Exposure: Shipyard asbestos exposure, mostly in ship repair with some new ship construction, beginning at least 15 years earlier and lasting at least 5 years. Fiber types are not specified.
• Main results:
  • All 296 workers: the four spirometric measures (FVC, FEV1, FEF25-75 and FEF75-85) were reduced below predicted (FVC 94.2% of predicted), and all four reductions were statistically significant. Lung volume measured from chest X-rays (TGV) was 98.0% of predicted and was not marked as significantly different.
  • The 106 men (35%) with radiographic asbestosis (ILO profusion 1/0 or greater) had 8% lower vital capacity, 11% lower FEV1, 19% lower midflow and 14% lower terminal flow than those without asbestosis (P less than 0.05)
  • The men with asbestosis were older and had 6.3 more years of asbestos exposure than those without
  • The 190 men without radiographic asbestosis showed smaller but significant reductions in flows and FVC compared with referent values
  • In all 296 workers, lung function correlated negatively with ILO profusion category (for example, r = -0.2381 for FVC), with all correlations significant
  • Radiographic asbestosis accounted for 2.65% to 6.22% of the variance in vital capacity and flows
  • Lung function of asbestos-exposed welders and non-welders did not differ significantly
• The authors' conclusion: The authors concluded that airway obstruction occurs after 15 years of exposure and before the slightest profusion of asbestosis scarring, and that it worsens with greater profusion of irregular opacities
• Limitations the authors state:
  • Age, years of smoking and years of asbestos exposure are interdependent, which may interfere with the analysis
  • Comparisons based on percentage of predicted may have adjusted for only part of the differences between groups

Topics

The National Library of Medicine indexes this study under subjects our site covers: Shipyards and maritime work.

Medical terms in this study, explained in our Lexicon: Spirometry, Shipyard Exposure, FEV1, Asbestosis.

Related studies

• High prevalence of reversible airway obstruction in asbestos-exposed workers — S. Delpierre, M.J. Delvolgo-Gori, et al. (2002)
• Does asbestos exposure cause airway obstruction, in the absence of confirmed asbestosis? — J. Ameille, M. Letourneux, et al. (2010)
• Association between increased small airway obstruction and asbestos exposure in patients with asbestosis — X. Yang, Y. Yan, et al. (2018)
• Irregular opacities in the lung, occupational asthma, and airways dysfunction in aluminum workers — K.H. Kilburn, R.H. Warshaw (1992)
• Airway disease in non-smoking asbestos workers — K.H. Kilburn, R.H. Warshaw, et al. (1985)
• Does asbestos exposure (asbestosis) cause (clinical) airway obstruction (small airway disease)? — A. Miller, W.N. Rom (2010)

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