Development of pleural hyalinosis in long term studies of persons exposed to asbestos dust

Our plain-English summary of Development of pleural hyalinosis in long term studies of persons exposed to asbestos dust, by M. Navrátil, J. Dobiás (Environmental Research, 1973).

The study

• Authors: M. Navrátil, J. Dobiás
• Journal: Environmental Research
• Published: 1973;6(4):455-72
• Cited by: 23 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. 002401).

Summary of the article

The authors studied how pleural hyalinosis (pleural plaques and thickening) developed over time in workers exposed to asbestos (chrysotile), and how it related to asbestosis and to pleural mesothelioma. The subjects were employees and pensioners of a Czechoslovak factory making asbestos textiles, friction materials, asbestos metal products and boards. The authors had followed them since 1953, with X-ray screening of all employees and pensioners from 1966. Fifty persons had pleural hyalinosis. Twenty-five also had asbestosis (15 men, 10 women) and 25 had no radiologic signs of asbestosis (18 men, 7 women). By August 1, 1972, 10 persons (40%) had died in the asbestosis group and 3 (12%) in the other group, a statistically significant difference (p < 0.05). The groups had similar age at death (64 and 66 years) and length of exposure (22.4 and 21.0 years). Bronchogenic cancer caused four deaths in the asbestosis group. One pleural mesothelioma was proved at autopsy and a second was diagnosed clinically. Among 35 persons followed for more than five years, the authors described two forms. 'Hyalinosis simplex' progressed gradually. 'Hyalinosis complicata' was marked by sterile pleural effusion followed by diffuse pleural thickening and restrictive functional impairment. The complicated form occurred in 6 of 23 persons with asbestosis and 1 of 12 without, and was associated with higher mortality. The authors concluded that pleural hyalinosis in asbestos-exposed workers is not rare, develops gradually and has a long latency. They drew no firm conclusions about the complicated form because the numbers were small.

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 study followed employees and pensioners of an asbestos plant in Czechoslovakia, called "factory A," which made asbestos textiles, friction materials, metal products and boards. The authors had observed the plant for 19 years, and they describe the exposure as chrysotile asbestos. Fifty people had pleural hyalinosis: 25 who also had asbestosis and 25 without X-ray signs of asbestosis. By August 1, 1972, ten of the 25 with asbestosis (40%) had died, against three in the group without asbestosis. That difference was statistically significant. The authors found it was not explained by age, length of exposure or time since first exposure. Bronchogenic (lung) cancer caused four of the ten deaths in the asbestosis group. One pleural mesothelioma was confirmed at autopsy, and a second was diagnosed clinically only. Among people followed for more than five years, the authors described a gradual form ("hyalinosis simplex") and a form with pleural effusion and later extensive thickening ("hyalinosis complicata"). The authors reported considerably lower mortality among people with the simple form. The authors concluded that pleural hyalinosis in asbestos-exposed employees is not rare, develops gradually and has a long latency, but they noted their numbers were small.

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: Long-term clinical and radiologic follow-up of workers and pensioners at one asbestos plant (a descriptive case series comparing two groups)
• Who was studied: Employees and former employees (pensioners) of factory A, studied since 1953, with suspicious findings examined at the Clinic of Occupational Diseases in Prague. Fifty had pleural hyalinosis. The first group was 25 with asbestosis (15 men, 10 women). The second group was 25 without radiologic signs of asbestosis (18 men, 7 women). Data run to August 1, 1972.
• Exposure: Direct occupational exposure to asbestos (chrysotile) in manufacturing of asbestos textile and friction materials, asbestos metal products and boards. Mean exposure was 22.4 years in the group with asbestosis and 21.0 years in the group without asbestosis.
• Main results:
  • In the group with pleural hyalinosis and asbestosis, ten of 25 persons (40%) died by August 1, 1972. Three persons died in the group without asbestosis. The difference was reported as statistically significant (test value 5.09, p less than 0.05).
  • The authors reported that the higher number of deaths in the asbestosis group was not caused by differences in age, length of exposure, or time since onset of exposure.
  • Bronchogenic cancer was the cause of death in two men and two women among the ten deaths in the asbestosis group. Both men who died had smoked fewer than 15 cigarettes per day, and none of the women smoked.
  • In the group without asbestosis, the three deaths were in men aged 63-67 years. The causes were bronchogenic cancer, cardiosclerosis and a carcinoma (the site is illegible in the scan).
  • In the asbestosis group, pleural mesothelioma was proven by autopsy in one man aged 78. A second pleural mesothelioma was clinically diagnosed in a woman aged 69 but not verified by autopsy.
  • Some people were followed for more than five years: 23 in the group with asbestosis and 12 in the group without. Of the 23, 17 had hyalinosis simplex and 6 had hyalinosis complicata. In the group without asbestosis the ratio was 11 to 1.
  • The authors reported considerably lower mortality among persons with hyalinosis simplex than among those with hyalinosis complicata. In the simple form, the cause of death was never tied to the pleural process.
• The authors' conclusion: The authors concluded that pleural hyalinosis in employees exposed to asbestos dust is not rare, develops gradually, and has a long latency period.
• Limitations the authors state:
  • The authors declined to draw conclusions about the link between hyalinosis complicata and high mortality because the number of persons observed was small.
  • The authors stated that causes of death other than bronchogenic cancer could not be quantitatively evaluated because of small numbers.
  • The authors stated that X-ray examination cannot detect all pleural hyalinosis, only lesions that are calcified enough or thick enough.
  • The authors questioned whether all mesotheliomas had been recorded, because they are difficult to diagnose clinically.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Pleural plaques and thickening.

Medical terms in this study, explained in our Lexicon: Pleural Plaques, Chrysotile, Pleural Mesothelioma, Asbestos Textiles, Bronchogenic Carcinoma, Autopsy, Pleural Effusion, Diffuse Pleural Thickening.

Related studies

• Follow-up study of pleural hyalinosis in individuals not exposed to asbestos dust — M. Navrátil, K. Morávková, et al. (1978)
• Prevalence of pleural calcification in persons exposed to asbestos dust, and in the general population in the same district — M. Navrátil, F. Trippé (1972)
• The long term fibrogenic effects of chrysotile and crocidolite asbestos dust injected into the pleural cavity of experimental animals — J.M. Davis (1970)
• Pleuropulmonary fibrosis after long-term treatment with the dopamine agonist pergolide for Parkinson Disease — R. Tintner, P. Manian, et al. (2005)
• Chest imaging and lung function impairment after long-term occupational exposure to low concentrations of chrysotile — D. Spyratos, D. Chloros, et al. (2012)
• Bilateral pleural thickening: a manifestation of asbestos dust exposure — E.N. Sargent, J. Gordonson, et al. (1978)

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