Gynecologic and breast cancers in women after exposure to blue asbestos at Wittenoom

Our plain-English summary of Gynecologic and breast cancers in women after exposure to blue asbestos at Wittenoom, by A. Reid, A. Segal, J.S. Heyworth, et al (Cancer Epidemiology, Biomarkers & Prevention, 2009).

The study

• Authors: A. Reid, A. Segal, J.S. Heyworth, N.H. de Klerk, A.W. Musk
• Journal: Cancer Epidemiology, Biomarkers & Prevention
• Published: 2009;18(1):140-7
• Cited by: 19 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Introduction: Animal studies have suggested an association between asbestos and ovarian cancer, and asbestos fibers have been detected in human ovaries. Sexual intercourse may introduce asbestos fibers into the vagina and to the cervix and ovaries. Occupational cohorts have reported excess mortality from reproductive cancers, but exposure-response relationships are inconsistent. We examine the incidence and exposure-response relationships of these cancers among 2,968 women and girls exposed to blue asbestos at Wittenoom, Western Australia.

Methods: 2,552 women were residents of the town and 416 worked for the asbestos company (Australian Blue Asbestos). Standardized incidence ratios compared the Wittenoom women with the Western Australian population. A nested case-control design and conditional logistic regression examined exposure-response relationships.

Results: Ovarian (standardized incidence ratio, 1.27), cervical (standardized incidence ratio, 1.44), and uterine cancer (standardized incidence ratio, 1.23) increased but not statistically significantly among the Wittenoom women compared with the Western Australian population. Among the Australian Blue Asbestos workers, cervical cancer was twice that of the Western Australian population (standardized incidence ratio, 2.38), but ovarian cancer was less (standardized incidence ratio, 0.65). Women who first arrived at Wittenoom aged >or=40 years had an odds ratio of 13.9 (95% confidence interval, 2.2-90.2) for cervical cancer compared with those aged <15 years at first arrival. Women who lived with or washed the clothes of an Australian Blue Asbestos worker did not have an increased risk for any of the gynecologic or breast cancers.

Discussion: There is no consistent evidence of an increased risk for gynecologic and breast cancers among the women from Wittenoom. Ovarian cancers and peritoneal mesotheliomas were not misclassified in this cohort.

In plain English

The authors studied 2,968 women and girls who lived or worked at Wittenoom, a crocidolite (blue asbestos) mining town in Western Australia. Of these, 416 were former Australian Blue Asbestos workers and 2,552 were former residents. They compared ovarian, cervical, uterine and breast cancer rates from 1982 to 2006 with the Western Australian female population. A nested case-control analysis examined exposure measures. Gynecologic cancers were slightly more common than expected, but no difference was statistically significant. Breast cancer was similar to expected. Among former company workers, the cervical cancer ratio was 1.85 (95% CI 0.38-5.41) to 2.38 (95% CI 0.49-6.96), based on three cases and not statistically significant. Women first exposed at 40 or older had an odds ratio for cervical cancer of 13.9 (95% CI 2.2-90.2) versus those first exposed under 15. Living with or washing the clothes of a company worker was not linked to increased risk. A pathology review found no misclassified ovarian cancers or peritoneal mesotheliomas. The authors concluded there was no consistent evidence of increased risk, and noted they could not account for lifestyle factors.

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 general population (standardized incidence ratios), with a nested case-control analysis of exposure-response and a pathology review of ovarian, colon and peritoneal cancers
• Who was studied: 2,968 women and girls who lived or worked at Wittenoom, Western Australia, between 1943 and 1992: 416 former Australian Blue Asbestos workers (mostly in the company offices, hotel and shop) and 2,552 former residents (wives and daughters of workers, government service workers, teachers and nurses)
• Exposure: Crocidolite (blue asbestos) from mining, milling and mine tailings spread around the town. Residents were assigned 1.0 fibers per mL for 1943 to 1957 and 0.5 fibers per mL for 1958 to 1966, falling to 0.010 fibers per mL by 1992. Cumulative exposure was calculated for each woman. Most women had an estimated cumulative exposure under 10 f/mL-y.
• Main results:
  • There were 145 incident breast or gynecologic cancers among the 2,968 women between 1960 and 2006.
  • All Wittenoom women, 1982 to 2006, standardized incidence ratios using minimum and maximum estimates: ovarian 1.05 (0.43-1.67) to 1.27 (0.52-2.02), 11 cases; cervical 1.21 (0.55-1.86) to 1.44 (0.66-2.22), 13 cases; uterine 1.01 (0.46-1.56) to 1.23 (0.56-1.90), 13 cases; breast 0.90 (0.73-1.10) to 1.10 (0.87-1.33), 88 cases. None differed significantly from the Western Australian female population.
  • Former Australian Blue Asbestos workers, cervical cancer: standardized incidence ratio 1.85 (0.38-5.41) to 2.38 (0.49-6.96), based on 3 cases, not statistically significant. Ovarian cancer in the same group: 0.49 (0.01-2.74) to 0.65 (0.02-3.64), 1 case.
  • Nested case-control analysis: women aged 40 or older at first exposure had an odds ratio for cervical cancer of 13.9 (95% CI 2.2-90.2) compared with those under 15 at first exposure.
  • Risk for all four cancer sites decreased as time since first exposure increased. Women with 40 or more years since first exposure had a statistically significantly lower risk for all sites except uterine cancer, compared with those with under 20 years.
  • Cervical cancer risk was inversely related to exposure intensity: odds ratio 0.29 (0.12-0.72) for 2 or more f/mL compared with under 2 f/mL.
  • Among former residents, no particular excess of any of the cancers was seen in women who washed the clothes of, or lived with, an Australian Blue Asbestos worker.
  • A pathologist reviewed 40 reports and examined histologic sections in 15 cases. None of the specimens had been misclassified.
• The authors' conclusion: The authors concluded that there was no consistent evidence of an increased risk for gynecologic and breast cancers among the Wittenoom women compared with the Western Australian population, and that ovarian cancers and peritoneal mesotheliomas had not been misclassified in this cohort. They suggested that sociodemographic and lifestyle factors may largely explain the cancer patterns observed.
• Limitations the authors state:
  • 22% of the women were lost to follow-up, most from the time they left Wittenoom.
  • Cancer data outside Western Australia ended earlier (1997 for Victoria, 2002 elsewhere). The completeness of records before 1982 is unknown. Wives and families of workers who returned to Italy were not traced. The authors said results may therefore underestimate the number of cancers.
  • The study could not account for individual and lifestyle factors such as childbearing, oral contraceptive use, tubal ligation or human papilloma virus.

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, Ovarian cancer.

Medical terms in this study, explained in our Lexicon: Crocidolite, Wittenoom, Ovarian Cancer, Standardized Incidence Ratio (SIR), Odds Ratio, confidence interval, Peritoneal Mesothelioma.

Related studies

• Cancer incidence among women and girls environmentally and occupationally exposed to blue asbestos at Wittenoom, Western Australia — A. Reid, J. Heyworth, et al. (2008)
• 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)
• 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)
• Mortality of former crocidolite (blue asbestos) miners and millers at Wittenoom — A.W. Musk, N.H. de Klerk, et al. (2008)
• Migration and work in postwar Australia: mortality profile comparisons between Australian and Italian workers exposed to blue asbestos at Wittenoom — A. Reid, E. Merler, et al. (2018)

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