Malignant mesothelioma after environmental exposure to blue asbestos

Our plain-English summary of Malignant mesothelioma after environmental exposure to blue asbestos, by J. Hansen, N.H. de Klerk, J.L. Eccles, et al (International Journal of Cancer, 1993).

The study

• Authors: J. Hansen, N.H. de Klerk, J.L. Eccles, A.W. Musk, M.S. Hobbs
• Journal: International Journal of Cancer
• Published: 1993;54(4):578-81
• Cited by: 52 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

To determine the magnitude of the population at risk from non-occupational exposure to crocidolite at Wittenoom, Western Australia (WA), a cohort of 4,890 residents who never worked for the mining company Australian Blue Asbestos (ABA) has been assembled from all 18,553 available records: the local school register, hospital attendances, the WA electoral roll, birth certificates, workers who answered a mailed questionnaire in 1979, participants in a cancer-prevention programme using vitamin-A dietary supplements, and other sources. The majority of subjects were relatives and friends of ABA employees, and nearly half the cohort were either born at Wittenoom or first went there as children under 10 years of age. As most residents were at Wittenoom when the mine and mill were in operation during the period 1943 to 1966, 82% were first exposed to crocidolite 20 or more years ago. The proportion of other workers (i.e., not employed by ABA) and their families increased once the mining operations ceased. To date, 24 cases of mesothelioma have been reported in this cohort: 9 males and 15 females. Time from first exposure to diagnosis ranged from 23 to 44 years and residence in Wittenoom ranged from 6 weeks to 11 years.

In plain English

This study built a register of people who had lived or worked at Wittenoom, Western Australia, but never worked for Australian Blue Asbestos (ABA). ABA mined crocidolite (blue asbestos) there from 1943 to 1966. The authors merged 18,553 records, including school, hospital and electoral records, and identified 5017 people. After excluding one hundred and twenty-seven people listed as miners or as employees of CSR or ABA, the cohort was 4890 (2187 men, 2703 women). Residents were exposed through general contamination from milling, mill tailings used on roads, yards and playgrounds, and household contact with workers. Most (55.5%) were relatives or friends of ABA employees, and 43.1% first arrived as children under 10. So far, 24 cases of malignant mesothelioma were known in the cohort. These were 9 wives and 9 children of ABA workers, 5 other workers, and 1 son of a non-ABA worker. Eleven of the 24 were diagnosed in the last 4 years. The authors said that many cases may be yet to develop. Disease rates had not yet been calculated.

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: Assembly of a register (cohort) of non-ABA residents, intended as the basis for a planned retrospective cohort study; reports a case series of mesothelioma
• Who was studied: 4890 people (2187 men, 2703 women) who lived or worked at Wittenoom, Western Australia, since 1943 but were not known to have worked for ABA, identified from 18,553 records (5017 individuals before one hundred and twenty-seven exclusions)
• Exposure: Non-occupational exposure to crocidolite from general environmental contamination from the milling operations, mill tailings used for paving and dust control, and household contact with workers and their clothes
• Main results:
  • 18,553 records yielded 5017 individuals
  • One hundred and twenty-seven persons were excluded because their stated occupation was miner or their employer was CSR or ABA
  • 55.5% of the cohort were relatives and friends of ABA employees
  • 43.1% of the cohort first went to Wittenoom as children under 10 years of age, and 50.8% stayed less than 2 years
  • 81.9% of the cohort were first exposed to crocidolite 20 or more years ago
  • 24 cases of malignant mesothelioma were known in the cohort (9 males, 15 females)
  • Of the 24 cases, 9 occurred in wives and 9 in children of ABA workers, 5 in other workers, and 1 in a son of a non-ABA worker
  • 11 of the 24 cases were diagnosed in the last 4 years
  • Among the cases, survival from diagnosis ranged from a few days to 26 months
• The authors' conclusion: The authors stated that most of the cohort (72.6%) were first exposed 20 to 40 years ago and that potentially many cases of mesothelioma are yet to develop; they intended the cohort to allow estimation of risks from low-level crocidolite exposure
• Limitations the authors state:
  • No indoor levels of crocidolite fibres had been measured
  • Other mesothelioma cases reported to the Registry, in people who claimed to have lived at Wittenoom, were not included because the authors could not independently confirm their residence
  • Vital status and cause of death of the cohort had not yet been established; this was planned

Mines named here

Asbestos mines this study is about. Each mine's page says who ran it, when it worked, and what it produced.

• Wittenoom, Western Australia

All asbestos mines

Topics

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

Medical terms in this study, explained in our Lexicon: Malignant Mesothelioma, Environmental Exposure, Crocidolite, Non-Occupational Exposure, Wittenoom, Australian Blue Asbestos, Mesothelioma.

Related studies

• Are children more vulnerable to mesothelioma than adults? A comparison of mesothelioma risk among children and adults exposed non-occupationally to blue asbestos at Wittenoom — A. Reid, P. Franklin, et al. (2018)
• Cancer incidence among women and girls environmentally and occupationally exposed to blue asbestos at Wittenoom, Western Australia — A. Reid, J. Heyworth, et al. (2008)
• Gynecologic and breast cancers in women after exposure to blue asbestos at Wittenoom — A. Reid, A. Segal, et al. (2009)
• Environmental exposure to crocidolite and mesothelioma: exposure-response relationships — J. Hansen, N.H. de Klerk, et al. (1998)
• Age and sex differences in malignant mesothelioma after residential exposure to blue asbestos (crocidolite) — A. Reid, G. Berry, et al. (2007)
• Mortality of former crocidolite (blue asbestos) miners and millers at Wittenoom — A.W. Musk, N.H. de Klerk, et al. (2008)

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