Heat insulation workers of the Province of Quebec causes of mortality (French)

Our plain-English summary of Heat insulation workers of the Province of Quebec causes of mortality (French), by M. Myre, P.V. Pelnar (1981).

The study

• Authors: M. Myre, P.V. Pelnar
• Published: L'Union Medicale du Canada, Volume 110 No4. April 1981
• Type of article: Journal article
• Our copy: from Johns-Manville's own medical library. The article is still under copyright, so we describe it here rather than post it.

In plain English

This French-language article described the causes of death of 40 heat insulation workers in the Province of Quebec who died between 1967 and 1977. Quebec had about 600 registered insulators. The author took 36 deaths from files kept by Dr. Selikoff in New York and found 4 more in Quebec Workmen's Compensation Board files. The article says Quebec insulators worked mainly with chrysotile, sometimes mixed with amosite and rarely with crocidolite. Of the 40 deaths, 18 (45%) were from cancer, including 9 lung cancers and 4 gastrointestinal cancers. Eight (20%) were from cardiovascular disease and 5 from asbestosis. Three expert pathologists confirmed one case of mesothelioma. The author counted 22 deaths as possibly or probably related to the work. The number of insulators who worked during those ten years could not be obtained, so results were given only as percentages of deaths, without any comparison of mortality with the general population. Age at death and work histories were also unavailable. The author concluded that this and earlier reports tended to show a higher cancer risk among insulators, and called for prospective surveillance.

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: Descriptive review of the causes of death in a series of deceased workers (results given as percentages of deaths, with no comparison group)
• Who was studied: 40 heat insulation workers of the Province of Quebec who died from 1967 to 1977. 36 came from Dr. Selikoff's files and 4 from the files of the Quebec Workmen's Compensation Board. About 600 insulators were registered in Quebec.
• Exposure: Work as heat insulators. The author states that Quebec insulators worked mainly with chrysotile, sometimes mixed with amosite and rarely with crocidolite. Individual exposure histories were not available.
• Main results:
  • 18 of the 40 deaths (45%) were from cancer.
  • 9 deaths were from lung cancer. This was 22% of all deaths and 50% of cancer deaths.
  • 4 deaths were from gastrointestinal cancer (2 stomach, 2 colon), which was 10% of deaths.
  • 8 deaths (20%) were from cardiovascular diseases.
  • One case of mesothelioma was confirmed by a group of three expert pathologists. The article does not say whether it was pleural or peritoneal. The author also learned of a second mesothelioma case who died while the report was being prepared.
  • Two deaths from generalized cancer were not autopsied, so it could not be known whether the lung cancer was primary or secondary.
  • 5 deaths were from asbestosis. For one death described as cor pulmonale, there were not enough details to link it to asbestosis.
  • Adding the lung cancers, gastrointestinal cancers, generalized cancers, asbestosis and cor pulmonale deaths, the author reached 22 of the 40 deaths as possibly or probably related to the work done.
  • The Quebec death certificate diagnosis agreed with Dr. Selikoff's final diagnosis in 36 of 37 cases.
• The authors' conclusion: The author concluded that this report and several earlier ones tend to show that insulators' risk of developing cancer is higher. In the English summary, the author contrasted only 20% cardiovascular deaths among these workers with more than 50% in the primary asbestos industry. The author hoped close prospective surveillance of these high-risk workers would begin in Quebec.
• Limitations the authors state:
  • The author acknowledged the risk of drawing statistics from such a small group.
  • Ten years is a short period.
  • The material was selected, since many subjects had a biopsy or autopsy.
  • Because the insulator population is migratory and unstable, the total number of insulators who worked during the 10 years could not be obtained. Results are therefore percentages only, and excess mortality relative to the general population could not be stated.
  • Age at death, chest X-rays and occupational histories (years worked and years exposed) could not be obtained.

Topics

Medical terms in this study, explained in our Lexicon: Insulator, Chrysotile, Amosite, Crocidolite, Lung Cancer, Mesothelioma.

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