Asbestos and other fiber-related diseases of the lungs and pleura. Distribution and determinants in exposed populations

Our plain-English summary of Asbestos and other fiber-related diseases of the lungs and pleura. Distribution and determinants in exposed populations, by M.R. Becklake (Chest, 1991).

The study

• Author: M.R. Becklake
• Journal: Chest
• Published: 1991;100(1):248-54
• Cited by: 19 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. 004146).

Summary of the article

This review, published in the proceedings of the Fourth Annual Chicago Lung Conference, examined the epidemiologic literature on the distribution and determinants of lung (parenchymal) and pleural fibrosis in populations exposed to asbestos and other fibers. Workforce studies from the 1970s in mining and milling, textile manufacture and asbestos cement manufacture had calculated cumulative exposure for each worker. Most 1980s studies concerned occupations with intermittent, often high, exposure, such as insulators, railroad workers, marine engineers and sheet metal workers. In these, pleural changes were proportionally more common than parenchymal changes, by up to almost 13-fold. The author reviewed prospective studies of radiologic progression and its determinants. In an earlier review of about 375 published asbestosis cases, 39% had a restrictive lung function profile, about 18% an obstructive profile and 18% a mixed profile. Restrictive profiles were not related to exposure in the only 2 studies that examined this. Obstructive profiles were related to smoking. All pleural lesions could cause impairment: isolated plaques the least, diffuse pleural thickening the most. Commercial silicates appeared less toxic, with disease mostly attributed to contamination by tremolite, chrysotile or quartz; kaolin was the exception. The author concluded that pleural disease was becoming more frequent and was often the only sign of exposure. Lung dust burden might explain differences between workforces better than exposure measurements, although exposure-response relationships remained the basis of regulation.

PubMed has no abstract for this study, and the article doesn't print one. We wrote this summary from the full article with the help of AI. It is not the authors' wording.

In plain English

This article was a review of research on lung and pleural (lung lining) disease in people exposed to asbestos and other fibers, presented at the Fourth Annual Chicago Lung Conference. It drew on studies of miners, millers, textile and asbestos-product workers, and workers with intermittent exposure such as insulators and railroad workers. In the 1980s studies of workers with intermittent exposure, pleural changes on X-ray were proportionally more common than changes in the lung tissue, up to almost 13-fold in some work forces. Obstructive breathing patterns were no less common than restrictive ones, and neither showed a relationship to exposure in the few studies that examined this. All pleural lesions could impair breathing, least with isolated pleural plaques and most with diffuse pleural thickening. Disease from most other commercial fibrous silicates had been attributed to contamination by tremolite, other asbestos or quartz, with kaolin the exception. The author concluded that asbestos-related pleural disease was becoming more frequent and was now often the only sign of exposure, particularly in occupations with intermittent but often high exposure.

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: Review of published epidemiologic studies, with some animal and earlier review data (conference proceedings paper)
• Who was studied: Published studies of asbestos-exposed work forces: miners and millers, asbestos textile workers, asbestos cement and product workers, and occupations with intermittent exposure (insulators, railroad workers, marine engineers, sheet metal workers). The studies were mostly from the 1970s and 1980s, in Canada, South Africa, the United Kingdom, the United States, Italy and Corsica. The review also covered workers exposed to other silicates and to man-made mineral fibers.
• Exposure: Asbestos, including chrysotile and crocidolite as named in the reviewed studies. Also clay and nonclay silicates (kaolin, bentonite, talc, vermiculite, mica), which may be contaminated by quartz or tremolite, and man-made mineral fibers (glass, slag and rock wools, ceramic fiber).
• Main results:
  • Most of the 1980s studies were of men in occupations with intermittent, often very high, exposure. In this material, rates of pleural change were proportionally higher than rates of parenchymal (lung tissue) change, up to almost 13-fold in some work forces. This did not hold for every work force in Table 1.
  • The 1980s studies in this material concerned occupations with intermittent exposure, often to very high levels.
  • In an earlier review of about 375 published cases of asbestosis, only 39% had a restrictive lung function profile.
  • Obstructive function profiles were no less common than restrictive ones in asbestos-exposed groups. Neither profile was related to exposure in the few studies that examined this.
  • All pleural lesions may cause impairment. Effects were least severe with isolated pleural plaques and most severe with diffuse pleural thickening.
  • In a sheep model, fiber retention was almost fivefold greater with the alveolitis-type response than with the peribronchiolar fibrosis response.
  • There was indirect evidence that stopping exposure lowers the rate of new radiologic changes (attack rates).
  • Disease from most commercial fibrous silicates other than kaolin had been attributed to contaminants. For kaolin miners, reported prevalence of radiologic opacities ranged from 3% to 9%.
  • Among man-made mineral fibers, only vitreous fibers of fine diameter had been implicated in pneumoconiosis.
• The authors' conclusion: The author concluded that asbestos-related pleural disease was becoming more frequent and was now often the only manifestation of exposure, especially in occupations with intermittent, often high, exposure.
• Limitations the authors state:
  • Most 1980s studies of intermittent-exposure occupations lacked systematic industrial hygiene measurements. Usually the only exposure measure was duration of exposure.
  • The author noted that the reviewed lung function studies may have failed to show exposure-response relationships for several reasons. Exposure was usually measured only as duration. Function profiles were inconsistently defined. Results could be confounded by radiologic abnormality and smoking. Workers had concurrent exposures to other dusts and fumes.

Topics

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

Medical terms in this study, explained in our Lexicon: Pleura, Fibrosis, Asbestos-Cement, Cumulative Exposure, Insulator, Restrictive Lung Disease, Diffuse Pleural Thickening, Silicate.

Related studies

• Fiber burden and asbestos-related lung disease: determinants of dose-response relationships — M.R. Becklake, B.W. Case (1994)
• Determinants of respiratory symptoms in insulation workers exposed to asbestos and synthetic mineral fibres — P. Ernst, S. Shapiro, et al. (1987)
• Surveillance of respiratory diseases among construction and trade workers at Department of Energy nuclear sites — J.M. Dement, L. Welch, et al. (2003)
• Fibre distribution in the lungs and pleura of subjects with asbestos related diffuse pleural fibrosis — A.R. Gibbs, M. Stephens, et al. (1991)
• Pleural determinants of restrictive lung function and respiratory symptoms in an asbestos-exposed population — P.H. Wright (1993)
• Man-made mineral fibers and interstitial lung diseases — E. Fireman (2014)

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