Asbestos and mesothelioma in man

Our plain-English summary of Asbestos and mesothelioma in man, by J.S. Harrington (Nature, 1971).

The study

• Author: J.S. Harrington
• Journal: Nature
• Published: 1971;232(5305):54-5
• Cited by: 35 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. 001360).

In plain English

This was a short letter in Nature by J. S. Harington, J. C. Gilson and J. C. Wagner. It addressed a puzzle: diffuse mesothelioma was clearly linked to crocidolite dust in South Africa's north-western Cape, yet was very rare in the Transvaal, where crocidolite and amosite were both mined. The authors disputed explanations others had offered. Official production records showed that more amosite than crocidolite was produced in the north-eastern Transvaal. This excess of amosite over crocidolite lasted until about the mid-1950s even when north-western Cape crocidolite output was added in. Amosite had been actively produced for about 51 years, which the authors judged long enough for mesotheliomas to develop. Two of the authors had visited four Transvaal mission hospitals in 1959. A return visit in 1969 confirmed that only two pleural mesotheliomas had been diagnosed in the intervening 10 years, one in a person exposed elsewhere, although many asbestosis patients had been seen. The authors concluded it was highly likely that, over the past 10 to 20 years, mesothelioma risk had differed greatly between people working in the two areas where these closely related amphiboles were mined and milled.

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: Short letter (correspondence) drawing on official asbestos production records, published evidence, and informal visits to Transvaal hospitals in 1959 and 1969; not a formal epidemiological study
• Who was studied: Four mission hospitals in the Transvaal, which received most chest-disease cases in the African population of the region, plus the pathologist at Pietersburg, visited in 1959 and again in 1969; compared with the crocidolite mining area of the north-western Cape, South Africa
• Exposure: Mining and milling of crocidolite in the north-western Cape, and of crocidolite and amosite in the (north-eastern) Transvaal
• Main results:
  • At the 1969 return visit, the Transvaal hospitals reported that in the intervening 10 years only two pleural mesotheliomas had been diagnosed, one in a person exposed elsewhere, although numerous asbestosis patients had been seen
  • Production in thousands of tons (Table 2, from official records): north-eastern Transvaal amosite exceeded Transvaal crocidolite in every period from 1928-1935 to 1960-1968 (for example, 639 versus 83 in 1960-1968). The authors stated that this excess of amosite over crocidolite was still present until about the mid-1950s even when north-western Cape crocidolite output was included
  • Active amosite production began in 1914-1917, about 51 years before the time of writing. The authors judged this long enough for mesotheliomas to develop, citing an induction period of about 16 to 55 years from other publications
  • The authors did not consider poor medical follow-up in the Transvaal a likely explanation. Medical services in the two areas did not differ greatly, and deaths of miners and ex-miners in both areas had to be reported to the Miners' Medical Bureau
• The authors' conclusion: The authors concluded it was highly likely that, over the past 10 to 20 years, there had been a large difference in mesothelioma risk among those working in the two areas where these closely related amphiboles are mined and milled

Topics

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

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

Related studies

• Excess mortality from stomach cancer, lung cancer, and asbestosis and/or mesothelioma in crocidolite mining districts in South Africa — J.L. Botha, L.M. Irwig, et al. (1986)
• Radiological features of diffuse mesothelioma — A. Solomon (1970)
• Asbestosis in South African asbestos miners — G.K. Sluis-Cremer (1970)
• Asbestos and mesothelioma in South Africa — R.P. Abratt, D.A. Vorobiof, et al. (2004)
• Asbestos-related disease in South Africa: the social production of an invisible epidemic — L. Braun, S. Kisting (2006)
• Radiology of asbestosis — A. Solomon (1970)

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