Asbestos-related cancer and the amphibole hypothesis. The amphibole hypothesis: neither gone nor forgotten

Our plain-English summary of Asbestos-related cancer and the amphibole hypothesis. The amphibole hypothesis: neither gone nor forgotten, by A.M. Langer, R.P. Nolan (American Journal of Public Health, 1997).

The study

• Authors: A.M. Langer, R.P. Nolan
• Journal: American Journal of Public Health
• Published: 1997;87(4):688-9; author reply 690-1
• Type of article: Comment, Letter
• Cited by: 2 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

In plain English

This is a letter to the editor, not a new study. The authors responded to a 1996 review by Stayner and colleagues and to an annotation by Cullen that called the amphibole hypothesis "gone but not forgotten," arguing that neither presented how the hypothesis developed. They summarized earlier published reports. In Wagner's 1964 series of 120 mesotheliomas in South Africa, 100 occurred in people exposed to Cape Province crocidolite, 1 followed chrysotile exposure in Swaziland, and none followed amosite exposure in the Transvaal. In Webster's report, 93 of 100 environmental mesothelioma cases were in people living in and along the Cape crocidolite field. The authors also cited 14 mesothelioma deaths among 528 deaths in 820 former US amosite factory employees, and 4 among 165 deaths in Montana vermiculite miners and millers. They stated that tremolite asbestos causes cancer while cleavage fragments do not, and that chrysotile is consistently much less potent than crocidolite in causing mesothelioma. The authors concluded that the hypothesis, now evolved into a "tremolite hypothesis," is not gone.

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 (commentary) responding to a published review by Stayner et al. and an annotation by Cullen; it reports no new data and draws on earlier published studies
• Who was studied: No study population of its own. The letter cites published reports on mesothelioma cases in South Africa, former employees of a US amosite factory, and miners and millers of Montana vermiculite
• Exposure: Amphibole asbestos (crocidolite, amosite, tremolite-actinolite asbestos) compared with chrysotile, including tremolite present in chrysotile deposits and non-asbestos tremolite cleavage fragments
• Main results:
  • Cited from Wagner (1964): of 120 mesotheliomas in South Africa, 100 were in people exposed to crocidolite mined and milled in the Cape Province. 10 were in industrial workers (9 exposed to crocidolite). 1 followed chrysotile exposure in Swaziland. None followed amosite exposure in the Transvaal. There were no exposure data for the remaining cases.
  • Cited from Webster (reported in 1978): of 712 confirmed South African mesothelioma cases, 127 were associated with asbestos mining and milling. Of 100 cases after environmental exposure, 93 were in people living in and along the Cape crocidolite field, 2 were in the area of the Pieterburg crocidolite mine and mill, 1 was in the Transvaal amosite field, none were known in the Swaziland chrysotile field, and 4 had uncertain or unknown exposure.
  • Cited from Seidman et al.: among 820 former employees of a US amosite asbestos factory, 14 of 528 deaths were due to mesothelioma, which was 2.7% of total mortality.
  • Cited: Montana vermiculite miners and millers were exposed to tremolite-actinolite asbestos among other fibrous minerals. Of 165 deaths in the cohort, 4 were mesotheliomas, which was 2.4% of total mortality.
  • Cited from Pooley: lung content analyses of 20 asbestosis cases from Canada showed a high concentration of tremolite fibers.
  • The authors stated that tremolite asbestos is a human and animal carcinogen but tremolite cleavage fragments are not.
  • The authors stated that chrysotile's relative potency as a lung carcinogen varies, but its potency to cause mesothelioma is consistently much less than that of crocidolite.
• The authors' conclusion: The authors concluded that the amphibole hypothesis has evolved into a tremolite hypothesis and is neither gone nor forgotten, contrary to Cullen's annotation.

Topics

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

Medical terms in this study, explained in our Lexicon: amphibole hypothesis.

Related studies

• The amphibole hypothesis of asbestos-related cancer--gone but not forgotten — M.R. Cullen (1996)
• Asbestos-related cancer and the amphibole hypothesis. The first documentation of the association — J.C. Wagner (1997)
• Asbestos-related cancer and the amphibole hypothesis. The hypothesis is still supported by scientists and scientific data — B.T. Mossman, J.B. Gee (1997)
• Occupational exposure to chrysotile asbestos and cancer risk: a review of the amphibole hypothesis — L.T. Stayner, D.A. Dankovic, et al. (1996)
• Mechanisms of asbestos carcinogenesis and toxicity: the amphibole hypothesis revisited — B.T. Mossman (1993)
• Pleural mesothelioma cases in Biancavilla are related to a new fluoro-edenite fibrous amphibole — P. Comba, A. Gianfagna, et al. (2003)

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