Malignant mesothelioma in Australia, 1945-2002

Our plain-English summary of Malignant mesothelioma in Australia, 1945-2002, by J. Leigh, T. Driscoll (International Journal of Occupational and Environmental Health, 2003).

The study

• Authors: J. Leigh, T. Driscoll
• Journal: International Journal of Occupational and Environmental Health
• Published: 2003;9(3):206-17
• Type of article: Historical article
• Cited by: 107 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Using register data, time trends in mesothelioma incidence in Australia from 1945 to 2002 were calculated. Incidences are reported by age, sex, anatomic site, and state of notification. Associations with occupational and environmental asbestos exposure histories and lifetime risks in different exposure categories were investigated. Lung-fiber content was measured in a subset of cases. Australia had 7,027 cases from 1945 to 2001, with 488 more in January 2002 through June 2003. Incidence rates for Australia per million population > or = 20 years old (1999) were: male 53.3; female 10.2; total 31.8. Rates have continually increased and are the highest reported national rates in the world. Western Australia had the highest rate (1999 total 47.7), but most cases arose from the two most populous eastern states, New South Wales and Victoria. In 88% of cases (male 90%, female 61%), histories of asbestos exposures were obtained. In 80% of cases with no history of exposure, TEM lung asbestos fiber counts > 200,000 fibers > 2 microm length/g dry lung were obtained, suggesting unrecognized exposure. Australia's high incidence of mesothelioma is related to high past asbestos use, of all fiber types, in a wide variety of settings. The number of cases is expected to be about 18,000 by 2020, with about 11,000 yet to appear.

In plain English

This article described mesothelioma in Australia from 1945 to 2002. It used data from the Australian Mesothelioma Surveillance Program, which began in 1980, and from the Register that continued it. The authors counted 7,027 cases from 1945 to 2001. In 1999 the rate among people 20 and older was 53.3 per million in males, 10.2 in females and 31.8 overall, up from 11.8 overall in 1982. Western Australia had the highest rate, but most cases arose in New South Wales and Victoria, and Wittenoom contributed only 5% of cases. Of Program cases, 93.2% were pleural and 6.5% peritoneal. Of 530 assessed cases, 55% had mixed amphibole and chrysotile first exposures. Among earlier cases with no known exposure history, 81% had lung fiber counts above 200,000 fibers per gram of dry lung. Estimated approximate lifetime risk was highest for Wittenoom mine or mill workers (16.6%). The authors projected about 18,000 cases from 1945 to 2020. They concluded that the high incidence is due to high past asbestos use, and they noted that the exposure assessments were subjective.

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: Descriptive study of national mesothelioma register and surveillance data: incidence trends, exposure histories, lung-fiber counts in a subset, approximate lifetime risks by occupation, and projection of future cases
• Who was studied: Mesothelioma cases in Australia. There were 6,349 notifications to the Program and Register from 1 January 1980 to 31 December 2001, plus 658 earlier cases (535 male, 123 female) from 1945 to 1979, for a total of 7,027. A further 488 notifications came from January 2002 to June 2003.
• Exposure: Occupational, para-occupational, domestic and environmental asbestos exposure of all fiber types, taken from histories and coded by two occupational hygienists. Lung asbestos fiber content was measured by light and transmission electron microscopy in a subset of cases. For first exposures in 530 cases: 55% mixed amphibole and chrysotile, 13% amphibole only, 7% amphibole plus possible chrysotile, 6% chrysotile with possible amphibole, 4% chrysotile only, and 15% unknown fiber type.
• Main results:
  • Incidence per million population aged 20 or older in 1999: male 53.3, female 10.2, total 31.8.
  • The combined incidence rate for males and females rose from 11.8 per million per year in 1982 to 31.8 in 1999.
  • Western Australia had the highest rate (1999 total 47.7; male 84.7; female 10.6), but most cases arose in New South Wales and Victoria.
  • Wittenoom contributed only 5% of Australian cases.
  • Of all Program cases, 93.2% were pleural, 6.5% peritoneal and 0.3% in other sites. Among women, 86.3% were pleural and 13.7% peritoneal.
  • Of cases that underwent pathology panel review, 96% were confirmed as mesothelioma.
  • In 1999, age-specific incidence increased with age up to 80 years and then fell.
  • Of 203 earlier cases classed as having no history of exposure, 57 actually had some exposure recorded, so only 19% had no known history. Of this no-known-history group, 81% had lung fiber counts above 200,000 fibers per gram of dry lung.
  • Approximate lifetime risks for occupational groups exposed 30 to 50 years earlier, based on cases notified 1986 to 2000: Wittenoom mine or mill 16.6%, power station worker 11.8%, railway labourer 6.4%, navy/merchant navy 5.1%, Wittenoom town 3.1%, carpenter/joiner 2.4%. For comparison: all Australian men 0.39% and all Australian women 0.05%.
  • Latency (time from exposure to diagnosis) ranged from 4 to 75 years.
  • The expected total number of mesothelioma cases in Australia from 1945 to 2020 was estimated at about 18,000, with about 11,000 yet to appear.
• The authors' conclusion: The authors concluded that the high and increasing incidence of mesothelioma in Australia is due to high past asbestos use, combined with poor hygiene practice, relatively high amphibole use in asbestos cement products, slow recognition that chrysotile causes mesothelioma, and excessive focus on Wittenoom to the exclusion of more common exposures.
• Limitations the authors state:
  • The two hygienists who coded exposure histories could not be blinded to case status, discussed cases together, and so were not independent.
  • Grading of exposure intensity was very subjective in many cases, and exposure duration depended on recollection.
  • Since 1986 the Register has used a less detailed questionnaire, with no pathology panel diagnosis, and lung-fiber counts have been done only sporadically.
  • The 488 notifications from 2002 to mid-2003 were thought to be a large underestimate because of new privacy legislation and changes at the commission that runs the Register.
  • Notifications before 1982 were considered artificially low because of slow initial acceptance of the Program.
  • Incidence rates were calculated only to the end of 1999 because of delays in notification.

Topics

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

Medical terms in this study, explained in our Lexicon: Malignant Mesothelioma, Mesothelioma, Asbestos Exposure, Incidence.

Related studies

• Incidence and survival trends for malignant pleural and peritoneal mesothelioma, Australia, 1982-2009 — M.J. Soeberg, J. Leigh, et al. (2016)
• Italian National Register of Occupational Cancers: data system and findings — A. Scarselli, S. Massari, et al. (2010)
• 24 years of pneumoconiosis mortality surveillance in Australia — D.R. Smith, P.A. Leggat (2006)
• Malignant mesothelioma in Italy, 1997 — M. Nesti, A. Marinaccio, et al. (2004)
• Malignant mesothelioma in Australia 2015: Current incidence and asbestos exposure trends — M.J. Soeberg, J. Leigh, et al. (2016)
• Turkey National Mesothelioma Surveillance and Environmental Asbestos Exposure Control Program — S. Metintaş, H.F. Batırel, et al. (2017)

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