Age and latency in mesothelioma

Our plain-English summary of Age and latency in mesothelioma, by G. McDonald, A. McDonald (Lancet, 1979).

The study

• Authors: G. McDonald, A. McDonald
• Journal: Lancet
• Published: 1979;2(8151):1074
• Type of article: Letter
• Cited by: 3 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. 002090).

In plain English

This was a letter to The Lancet replying to Dr Chovil and Dr Stewart, who had cited the authors' paper on Canadian gas mask assembly workers. The authors noted that the paper did not mention age. Among their nine mesothelioma cases in these workers, age at death ranged from 43 to 72 years, only two were over 54, and the latent period was 24 to 36 years. Citing earlier studies, they noted that mesothelioma accounted for 16% of deaths so far in the Canadian and 10% in the Nottingham gas mask workers, both exposed to pure crocidolite. The figure was 0.2% in Quebec chrysotile miners and millers despite much greater exposure. Using North American data from a U.S. cancer survey and their own pathologist-based case finding, they wrote that most deaths occurred at age 45 or over but perhaps 10% occurred earlier, despite obvious problems of diagnosis and ascertainment. Five cases whose fathers had been asbestos workers died at 31, 32, 42, 42 and 51. The authors suggested that indirect occupational exposure in the home may explain some younger cases.

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: Letter to the editor (correspondence) replying to an earlier letter, summarising data from the authors' own and others' studies
• Who was studied: Nine mesothelioma cases among Canadian gas mask assembly workers. For comparison: Nottingham gas mask workers, Quebec chrysotile miners and millers, and North American mesothelioma deaths from the 3rd U.S. National Cancer Survey and the authors' ascertainment through pathologists in Canada since 1966 and the U.S.A. for 1972
• Exposure: Pure crocidolite in gas mask manufacture (Canadian and Nottingham workers), compared with chrysotile in Quebec mining and milling. Also indirect occupational exposure in the home among children of asbestos workers
• Main results:
  • In the nine Canadian gas mask worker cases, age at death ranged from 43 to 72 years and only two were over 54
  • Latent period in the Canadian series was 24 to 36 years. Jones et al. reported 20 to 35 years in Nottingham. Both fell within the 6 to 44 years range found by Chovil and Stewart
  • Mesothelioma accounted for 10% of deaths so far in Nottingham and 16% in Canadian gas mask workers (crocidolite), versus 0.2% in Quebec chrysotile miners and millers even after much greater exposure (figures from cited earlier studies)
  • In North American data, most mesothelioma deaths were in persons aged 45 and over, but perhaps 10% occurred earlier
  • Five cases in persons whose fathers had been asbestos workers died at ages 31, 32, 42, 42 and 51 years
• The authors' conclusion: The authors disputed the view that mesothelioma due to asbestos develops only in old age. They suggested that indirect occupational exposure in the home may account for some younger cases
• Limitations the authors state:
  • The authors acknowledged obvious problems of diagnosis and ascertainment in the North American data

Topics

The National Library of Medicine indexes this study under subjects our site covers: Lung cancer, Mesothelioma.

Medical terms in this study, explained in our Lexicon: Latency, Mesothelioma.

Related studies

• Latency periods in neoplastic diseases — A.P. Polednak (1974)
• Latency attention deficit: Asbestos abatement workers need us to investigate — C. Roelofs (2015)
• Analysis of latency time and its determinants in asbestos related malignant mesothelioma cases of the Italian register — A. Marinaccio, A. Binazzi, et al. (2007)
• The latency period of mesothelioma among a cohort of British asbestos workers (1978-2005) — G. Frost (2013)
• Lymphoid and plasma cell malignancies: asbestos-related disorders of long latency — E. Kagan, R.J. Jacobson (1983)
• Disease Latency according to Asbestos Exposure Characteristics among Malignant Mesothelioma and Asbestos-Related Lung Cancer Cases in South Korea — D.A. Huh, W.R. Chae, et al. (2022)

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