Cancer incidence among women and girls environmentally and occupationally exposed to blue asbestos at Wittenoom, Western Australia

Our plain-English summary of Cancer incidence among women and girls environmentally and occupationally exposed to blue asbestos at Wittenoom, Western Australia, by A. Reid, J. Heyworth, N.H. de Klerk, et al (International Journal of Cancer, 2008).

The study

• Authors: A. Reid, J. Heyworth, N.H. de Klerk, B. Musk
• Journal: International Journal of Cancer
• Published: 2008;122(10):2337-44
• Cited by: 44 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

The impact of crocidolite exposure on the health of former Wittenoom miners and millers (largely male) has been well documented. Less is known about the health outcomes of the 2,968 women and girls who lived (N = 2,552) and worked (N = 416) in the blue asbestos milling and mining town of Wittenoom between 1943 and 1992. Quantitative exposure measurements were derived from dust studies undertaken over the lifetime of the mine and mill and the township. Incident cancers were obtained from the Western Australian (WA) Cancer Registry and the National Cancer Clearing House. Standardized incidence ratios (SIRS) compared Wittenoom females with the WA female population. Exposure-response relationships were examined using a matched case-control study design. There were (47) mesothelioma and (55) lung cancer cases among the 437 cancers in the Wittenoom females over the period 1960-2005. When compared to the WA female population, Wittenoom women and girls had higher rates of mesothelioma and possibly lung cancer. Mesothelioma incidence rates are increasing with the incidence rate of 193 per 100,000 in the period 2000-2005 being more than double that for the period 1995-1999 at 84 per 100,000. A significant exposure-response relationship was present for mesothelioma, but not for lung cancer. Forty years after the asbestos mine and mill at Wittenoom were closed, there is a high toll from cancer among the former female residents of the town and company workers.

(c) 2008 Wiley-Liss, Inc.

In plain English

This cohort study followed 2,968 women and girls who had lived (2,552) or worked for the Australian Blue Asbestos Company (416) at Wittenoom, Western Australia, where crocidolite (blue asbestos) was mined and milled. Cancers from 1960 to 2005 were found through registries and record searches. Comparisons with Western Australian women counted mesothelioma from 1960 but other cancers only from 1982, as earlier registration completeness was unknown. There were 437 cancers in 387 women, including 47 mesotheliomas (46 pleural) and 55 lung cancers. Two ways of counting women lost to follow-up gave mesothelioma incidence 55.9 (95% CI 41.1–74.4) and 77.0 (95% CI 56.6–102.5) times expected; the 2000–05 rate was 193 per 100,000 person-years (95% CI 112–332). Lung cancer was 1.84 (95% CI 1.30–2.38) and 2.54 (95% CI 1.80–3.29) times expected; an indirect allowance for smoking, based on limited data, gave 1.27 and 1.75. Breast cancer was not significantly raised. Mesothelioma risk rose with estimated cumulative exposure among workers and residents, but lung cancer risk did not rise significantly. The authors concluded that former residents and workers had a high toll from cancer.

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: Cohort study comparing cancer incidence with the Western Australian female population (standardized incidence ratios), with a nested case-control analysis of exposure-response
• Who was studied: 2,968 women and girls: 416 former Australian Blue Asbestos Company (ABA) employees and 2,552 former residents of Wittenoom, Western Australia (lived or worked there between 1943 and 1992); cancers counted from 1960 to 2005
• Exposure: Crocidolite (blue asbestos), from three sources: work, the town environment (tailings spread around the town) and the home (washing workers' clothes). Residents were assigned 1.0 fiber/ml from 1943 to 1957 and 0.5 f/ml from 1958 until the 1966 closure, falling to 0.010 f/ml by 1992. Workers' exposure was based on job dust surveys plus residential exposure.
• Main results:
  • 47 cases of malignant mesothelioma were found among the women, 46 of them pleural
  • All women, 1960–2005: the mesothelioma SIR was 55.9 (95% CI 41.1–74.4) under the minimum-estimate censoring method and 77.0 (56.6–102.5) under the maximum-estimate method
  • All women, 1982–2005: the lung, trachea and bronchus cancer SIR (45 cases) was 1.84 (95% CI 1.30–2.38) under the minimum-estimate method and 2.54 (1.80–3.29) under the maximum-estimate method
  • All women: after an indirect (Axelson) adjustment for smoking, the authors estimated the lung cancer SIR at 1.27 (minimum method) and 1.75 (maximum method). No confidence intervals are given for these adjusted estimates.
  • Former workers: the lung cancer SIR was 2.88 (1.42–4.34) and 4.36 (2.15–6.57) under the two methods; after smoking adjustment it was 1.92 and 2.91
  • All women, 1982–2005: the all-cancers SIR was 1.12 (1.00–1.25) and 1.51 (1.35–1.68) under the two methods
  • All women: the breast cancer SIR (82 cases) was 0.89 (0.69–1.08) and 1.19 (0.93–1.44) under the two methods
  • Former workers: cervical cancer was 90% to 250% higher than in Western Australian women, but this was not statistically significant
  • Mesothelioma incidence among all women was 193 per 100,000 person-years (95% CI 112–332) in 2000–05, compared with 84 (42–168) in 1995–99
  • Mesothelioma risk per unit increase in log cumulative exposure (f/ml years): workers OR 1.77 (1.11–2.82), p = 0.017; residents OR 2.73 (1.94–3.82), p less than 0.001
  • Lung cancer risk rose with log cumulative exposure, but not significantly (workers OR 1.25, 0.90–1.72; residents OR 1.09, 0.83–1.41)
  • Residents who lived with an ABA worker had a raised lung cancer risk, OR 2.61 (95% CI 1.09–6.21)
  • Time from first exposure to mesothelioma ranged from 23.5 to 51.8 years (median 38 years), and was shorter for workers than for residents
• The authors' conclusion: The authors concluded that, forty years after the mine and mill closed, there is a high toll from cancer among former female residents and company workers. They found greater rates of mesothelioma and possibly lung cancer than in Western Australian women. The exposure-response relationship was significant for mesothelioma but not for lung cancer.
• Limitations the authors state:
  • 22% of the women were lost to follow-up
  • Difficulty maintaining follow-up may have led to an underestimation of asbestos-related cancers
  • Only limited information on tobacco smoking was available
  • Exposure estimates for women workers are likely underestimates, and worker and resident exposures were derived differently
  • No information was available on domestic exposure among the female workers
  • Completeness of registrations before 1982 is unknown for cancers other than mesothelioma, so those cancers were left out of the SIRs

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, Lung cancer, Mesothelioma.

Medical terms in this study, explained in our Lexicon: Crocidolite, Wittenoom, Cancer Registry, Standardized Incidence Ratio (SIR), Case-Control Study, Mesothelioma, Lung Cancer, Incidence.

Related studies

• Predicted mortality from malignant mesothelioma among women exposed to blue asbestos at Wittenoom, Western Australia — A. Reid, G. Berry, et al. (2009)
• Retinol supplementation and mesothelioma incidence in workers earlier exposed to blue asbestos (Crocidolite) at Wittenoom, Western Australia — H.S. Alfonso, A. Reid, et al. (2010)
• Gynecologic and breast cancers in women after exposure to blue asbestos at Wittenoom — A. Reid, A. Segal, et al. (2009)
• 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)
• Autoimmune antibodies and asbestos exposure: Evidence from Wittenoom, Western Australia — A. Reid, P. Franklin, et al. (2018)
• Plasma vitamin concentrations and incidence of mesothelioma and lung cancer in individuals exposed to crocidolite at Wittenoom, Western Australia — H.S. Alfonso, L. Fritschi, et al. (2006)

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