The incidence of malignant mesothelioma in Australia, 1947-1980

Our plain-English summary of The incidence of malignant mesothelioma in Australia, 1947-1980, by A.W. Musk, P.J. Dolin, B.K. Armstrong, et al (The Medical Journal of Australia, 1989).

The study

• Authors: A.W. Musk, P.J. Dolin, B.K. Armstrong, J.M. Ford, N.H. de Klerk, M.S. Hobbs
• Journal: The Medical Journal of Australia
• Published: 1989;150(5):242-3, 246
• Cited by: 36 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. 000136).

Abstract

Details of patients with malignant mesothelioma that was diagnosed in Australia before 1981 were obtained by searching all possible sources throughout Australia as far into the past as possible and up to and including 1980. The earliest patient with mesothelioma who was identified was diagnosed in Victoria in 1947. By 1980, 535 (81%) men and 123 (19%) women had been diagnosed with the disease; only 14 persons were aged less than 35 years at the time of diagnosis (the youngest person was 15 years of age). The incidence rate in subjects who were 35 years or older at diagnosis was less than 1.0 cases per million person-years until 1964-1968, and then it rose progressively to 15.5 cases per million person-years in 1979-1980. The highest rate (69.7 cases per million person-years) was observed in 65- to 74-year-old men in 1979-1980. The incidence rate in Western Australia was greater than were the rates in other states of Australia after the mid 1960s. Pleural mesotheliomas accounted for 88% of cases in which the site of the tumour was known; peritoneal mesotheliomas accounted for 10% of such cases and "other" sites for 2% of such cases. In 6% of cases the site was not specified. The exposure to asbestos was stated as "definite" in 59% of the cases with a recorded history of exposure: 8% of all the cases in the study had been exposed to crocidolite (blue asbestos) from Wittenoom Gorge in Western Australia. The age at diagnosis of patients with known exposure to asbestos was similar to that in those without known exposure. The increases in the incidence of malignant mesothelioma in Australia follow the published trends in the production and use of the amphibole varieties of asbestos in this country after a lag period of between 20 and 30 years.

In plain English

This study counted all identifiable malignant mesothelioma cases diagnosed in Australia through 1980. Sources included cancer registries, pathologists and The Australian Mesothelioma Surveillance Program. They identified 674 cases (535 men, 123 women, 16 of unknown sex), the earliest in Victoria in 1947. Tumour sites were pleural in 560, peritoneal in 66, other in eight and unrecorded in 40. By 1979-1980, age-standardized rates among people aged 35 or older were 28 cases per million person-years in men, three in women. Nationally, men aged 65-74 had the highest age-specific rate, 69.7 cases per million person-years in 1979-1980. After 1964-1968, Western Australia consistently had the highest age-standardized rates among men aged 35 or older. Of 163 cases with known asbestos exposure, 52 involved crocidolite (blue asbestos) from Wittenoom. Exposure information existed for only 41% of cases; mean age at diagnosis was similar with known exposure (58.9 years) and without known exposure (60.2 years). The authors concluded the rise followed trends in amphibole asbestos production and use after a 20- to 30-year lag. They noted that early cases may have been undercounted.

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: Population-wide incidence study that compiled all identifiable cases of malignant mesothelioma from cancer registries, pathologists and The Australian Mesothelioma Surveillance Program, and calculated age-standardized incidence rates
• Who was studied: 674 separate cases of malignant mesothelioma diagnosed in Australia from 1947 to 1980 (535 men, 123 women, 16 of unknown sex). Rates were examined for people aged 35 years or older.
• Exposure: Recorded history of exposure to asbestos as reported for each case, including crocidolite (blue asbestos) exposure at Wittenoom in Western Australia. Rates were compared with published trends in the production and use of amphibole asbestos.
• Main results:
  • Age-standardized incidence rate in people aged 35 or older, 1979-1980: rose to 28 cases per million person-years in men and three cases per million person-years in women
  • For all people aged 35 or older, the rate was less than 1.0 case per million person-years until 1964-1968, then rose to 15.5 per million person-years in 1979-1980
  • Nationally, men aged 65-74 had the highest age-specific rate: 69.7 cases per million person-years in 1979-1980. Some individual state rates in Table 1 were higher.
  • After 1964-1968, incidence rates were consistently highest in Western Australia. These are the state age-standardized rates for men aged 35 or older shown in Figure 3.
  • Site of the tumour among the 674 cases: pleural in 560, peritoneal in 66, other in 8, not specified in 40
  • Information on exposure to asbestos was available for only 41% of subjects (278 of 674 in Table 2)
  • Of the 163 cases with known exposure to asbestos, 52 had been exposed to crocidolite (blue asbestos) at Wittenoom
  • Mean age at diagnosis was 58.9 years in those known to have been exposed to asbestos and 60.2 years in those without known exposure (P=0.37, described as similar)
  • Only 14 people were younger than 35 at diagnosis; the youngest was 15
• The authors' conclusion: The authors concluded that the increases in incidence follow the published trends in the production and use of amphibole asbestos in Australia after a lag of 20 to 30 years
• Limitations the authors state:
  • Incidence in the earlier years may have been underestimated. The authors gave four possible reasons: lost records, low awareness of the disease or reluctance to diagnose it, lack of autopsy or biopsy material, and no recognized link with asbestos before 1960.
  • Cases from Victoria may have been under-counted, since no upward trend was seen there after 1964
  • The state where a case was diagnosed was not necessarily the state, or even the country, where the asbestos exposure occurred

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: Mesothelioma, Peritoneal mesothelioma.

Medical terms in this study, explained in our Lexicon: Mesothelioma, Incidence, Pleural Mesothelioma, Peritoneal Mesothelioma, Crocidolite, Wittenoom, Amphibole Group.

Related studies

• Incidence and survival trends for malignant pleural and peritoneal mesothelioma, Australia, 1982-2009 — M.J. Soeberg, J. Leigh, et al. (2016)
• Epidemiology of malignant mesothelioma in Western Australia — B.K. Armstrong, A.W. Musk, et al. (1984)
• The incidence of malignant mesothelioma in Australia 1982-1988 — J. Leigh, C.F. Corvalán, et al. (1991)
• Cancer incidence among women and girls environmentally and occupationally exposed to blue asbestos at Wittenoom, Western Australia — A. Reid, J. Heyworth, et al. (2008)
• Prevalence of radiographic asbestosis in crocidolite miners and millers at Wittenoom, Western Australia — W.O. Cookson, N.H. De Klerk, et al. (1986)
• Morphology of bronchogenic carcinoma in workers formerly exposed to crocidolite at Wittenoom Gorge in Western Australia — J.E. Baker, D.C. Reutens, et al. (1986)

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