Asbestos and public health

Our plain-English summary of Asbestos and public health, by F.D. Liddell (Canadian Medical Association Journal, 1981).

The study

• Author: F.D. Liddell
• Journal: Canadian Medical Association Journal
• Published: 1981;125(3):237-9
• Type of article: Editorial
• Cited by: 1 article, as counted by NIH iCite
• Read it: PubMed · Free full text
• In J-M's library: Johns-Manville's company medical library held a copy (J-M no. 001979).

In plain English

This was a 1981 editorial, not an original study. The author commented on published epidemiologic evidence about asbestos and health, drawing especially on a Quebec chrysotile mining cohort that the author helped study. The author wrote that the evidence fits a "fibre gradient," with crocidolite the most hazardous and chrysotile the least, and that the gradient is almost certainly steeper for mesothelioma than for other diseases. Citing the Quebec work, the author described the lung cancer exposure-response relationship as effectively linear, which the author saw as evidence against a "safe" threshold. The author also stated that the link with gastrointestinal cancer was uncertain, and that smoking raised lung and laryngeal cancer risk among asbestos workers but not mesothelioma risk. The author noted that few studies had measured exposure beyond its duration. The author called for much more stringent regulation of crocidolite, and probably amosite. The author concluded that decisions on control limits, on damaged asbestos and on substitutes should rest on the best available scientific evidence rather than on emotion.

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: Editorial (commentary on published evidence, not an original study)
• Who was studied: No population was studied directly. The editorial discussed published studies, including a Quebec birth cohort of 11 379 chrysotile production workers born between 1891 and 1920, and a paper in the same journal issue by Finkelstein and coworkers on 172 former workers certified as having asbestosis.
• Exposure: Occupational asbestos exposure, comparing chrysotile (mined mainly in Quebec) with the amphiboles crocidolite and amosite. Nonoccupational exposure was also discussed.
• Main results:
  • The author described the epidemiologic findings as fitting a "fibre gradient," with crocidolite the most hazardous and chrysotile the least.
  • According to the author, the Quebec chrysotile studies (which the author co-authored) found an effectively linear exposure-response relationship for lung cancer. The author viewed this, together with other studies, as strong evidence against a threshold or "safe" exposure.
  • The author stated that the fibre gradient is almost certainly steeper for mesothelioma than for other responses. For lung cancer, the author wrote that risk was only mildly increased in chrysotile production and always much higher with pure crocidolite exposure.
  • The author described the association of asbestos exposure with gastrointestinal cancer as uncertain, and the evidence on laryngeal cancer as even more equivocal.
  • The author stated that among asbestos workers, cigarette smoking increases the risks of lung and laryngeal cancer, but not mesothelioma or gastrointestinal cancer, and perhaps not asbestosis. The author also wrote that chrysotile exposure in mining and milling at the then-current control limits was equivalent in carcinogenic potency to smoking about three or four cigarettes a week.
  • The author wrote that today's cases of asbestos-related disease reflect working conditions 30 to 40 years earlier.
  • The author stated that no ill effects had yet been demonstrated from asbestos in drinking water, food or beverages, or the general atmosphere.
• The authors' conclusion: The author concluded that no control limit can guarantee absolute safety. The author recommended much more stringent regulation of crocidolite, and probably of amosite as well. The author held that decisions on control limits, on repairing or replacing damaged asbestos, and on substitutes should be based on the best available scientific evidence, not on emotions stirred by past excessive exposures.
• Limitations the authors state:
  • The author stated that so few studies had assessed exposure in terms more refined than duration that exposure-response relationships could not be estimated for each fibre type and each disease.
  • The author noted that in most studies even workplace asbestos levels had not been measured.

Related studies

• Asbestos and disease - a public health success story? — B. Järvholm, A. Burdorf (2024)
• Asbestos in the air of public buildings: a public health risk? — J. Whysner, V.T. Covello, et al. (1994)
• Comments on the Health Effects Institute-Asbestos Research (HEI-AR) report: "Asbestos in public and commercial buildings," with emphasis on risk assessment methods used — T.D. Sterling, C.W. Collett, et al. (1993)
• Public health significance of smoking-asbestos interactions — A.L. Frank (1979)
• Public perceptions of cancer risk factors: a Western Australian study — A. MacTiernan, L. Fritschi, et al. (2014)
• Malignant mesothelioma due to non-occupational asbestos exposure from the Italian national surveillance system (ReNaM): epidemiology and public health issues — A. Marinaccio, A. Binazzi, et al. (2015)

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