Mortality rates among nuclear industry workers at Lucas Heights Science and Technology Centre

Our plain-English summary of Mortality rates among nuclear industry workers at Lucas Heights Science and Technology Centre, by R.R. Habib, S.M. Abdallah, M. Law, et al (Australian and New Zealand Journal of Public Health, 2005).

The study

• Authors: R.R. Habib, S.M. Abdallah, M. Law, J. Kaldor
• Journal: Australian and New Zealand Journal of Public Health
• Published: 2005;29(3):229-37
• Cited by: 17 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Objectives: To assess whether workers at Lucas Heights Science and Technology Centre (LHSTC) have different levels of mortality from the New South Wales (NSW) and Australian populations.

Methods: A retrospective cohort study was undertaken at LHSTC. Data on 7,076 workers employed between 1957-98 were abstracted from personnel, dosimetry, and medical files. Deaths registrations in the cohort were identified to 1998 through electronic linkage of records with NSW and national registers of cancer incidence and mortality. Two inception cohorts were defined as including 4,717 and 3,543 workers in employment between 1972-98 and 1980-98, to examine cancer mortality and all-cause mortality respectively.

Results: All-cause mortality was 31% lower than the national rates; all-cancer mortality was 19% below the NSW rate. Of 37 specific cancers and groups of cancers examined, statistically significant excesses relative to NSW rates were observed only for pleural cancer mortality (SMR = 21.11; 95% Cl 8.79-50.72).

Conclusions: The observed increase in the risk of cancer of the pleura was probably due to unmeasured exposures, given the lack of an established association with radiation exposure and the strong link to asbestos exposure.

In plain English

This retrospective cohort study examined deaths among workers employed between 1957 and 1998 at the Lucas Heights Science and Technology Centre, site of Australia's only nuclear reactor. Of 7,076 workers, 53 with incomplete records were excluded, as were 2,306 who left before 1972. Cancer deaths among 4,717 workers employed in or after 1972 were compared with New South Wales rates, and all deaths among 3,543 employed in or after 1980 with national rates. Overall mortality was 31% lower than the national rate, and cancer mortality was 19% below the NSW rate. The only cancer with a statistically significant excess was of the pleura and other thoracic organs: 5 deaths where 0.24 were expected (standardised mortality ratio 21.11; 95% confidence interval 8.79 to 50.72). Four were radiation-monitored men with pleural cancer, all first employed before 1964; one was a non-monitored woman with thymus cancer. Site hygienists reported asbestos use in the late 1950s and 1960s, but no exposure data were available. The authors concluded the pleural excess was probably due to unmeasured exposures, given no established link with radiation and a strong link to asbestos.

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: Retrospective cohort study comparing workers' death rates with general-population rates (standardised mortality ratios), using record linkage to cancer and death registers
• Who was studied: 7,076 workers employed at Lucas Heights Science and Technology Centre (near Sydney, NSW, Australia) from 1957 to 1998. 53 were excluded for incomplete data, leaving 7,023. The 2,306 who left employment between 1957 and 1971 were excluded from the analysis cohorts. Cancer mortality was analysed in 4,717 workers employed in or after 1972. All-cause mortality was analysed in 3,543 workers employed in or after 1980. Follow-up ran to the end of 1998.
• Exposure: External ionising radiation. Workers were classed as monitored (film badge dosimetry) or not monitored. Asbestos exposure was not measured. Senior occupational hygienists at the site reported that asbestos was used during reactor construction in the late 1950s and in the 1960s, and that asbestos lagging was removed from 1986 to 1992. No fiber type is named.
• Main results:
  • All workers, cohort employed 1980-98, compared with Australia: all-cause mortality was 31% lower than national rates (SMR 0.69; 95% CI 0.60-0.80; 193 deaths).
  • All workers, cohort employed 1972-98, compared with NSW: all-cancer mortality was 19% below the NSW rate (SMR 0.81; 95% CI 0.69-0.96; 135 cancer deaths).
  • All workers: cancer of the pleura and other thoracic organs was the only significant excess compared with NSW rates. There were 5 observed deaths versus 0.24 expected (SMR 21.11; 95% CI 8.79-50.72).
  • Monitored workers: SMR 23.53 (95% CI 8.83-62.69), based on four men who died of cancer of the pleura (ICD-9 164.9). All four were first employed at the site before 1964.
  • Non-monitored workers: SMR 14.97 (95% CI 2.11-106.24), based on one woman who died of cancer of the thymus (ICD-9 164.0).
  • All workers, cohort employed 1972-98: there were 26 lung cancer deaths, a deficit compared with NSW rates (SMR 0.63; 95% CI 0.43-0.92).
• The authors' conclusion: The authors concluded that the increased risk of pleural cancer was probably due to unmeasured exposures. They gave two reasons: there is no established association between pleural cancer and radiation, and there is a strong link to asbestos. They added that the excess was unlikely to be related to radiation because it appeared in both monitored and non-monitored workers.
• Limitations the authors state:
  • No information on asbestos exposure was available, so the pleural cancer excess could not be investigated further.
  • Smoking could not be evaluated because there was no information on smoking status.
  • Vital status was unknown for about 20% of the 1972-98 cohort. These workers were assumed alive, which may slightly lower the SMRs.
  • Deaths were found through linkage to routine registers. Linkage may be incomplete, and causes of death may have been misclassified.
  • Small numbers of deaths gave very wide confidence intervals for the pleural cancer finding and low precision for most specific cancers.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Power plants and utilities.

Medical terms in this study, explained in our Lexicon: Cohort Study, Pleura, Asbestos Exposure.

Related studies

• Cancer incidence among Australian nuclear industry workers — R.R. Habib, S.M. Abdallah, et al. (2006)
• Mortality among workers in the geothermal power plants at Larderello, Italy — E. Pira, M. Turbiglio, et al. (1999)
• Mortality patterns among electrical workers employed in the U.S. construction industry, 1982-1987 — C.F. Robinson, M. Petersen, et al. (1999)
• Mortality and cancer morbidity in a cohort of Canadian petroleum workers — R.J. Lewis, A.R. Schnatter, et al. (2003)
• French cohort of the uranium processing workers: mortality pattern after 30-year follow-up — I. Guseva Canu, E. Cardis, et al. (2010)
• Risk of cancer among Danish utility workers--a nationwide cohort study — C. Johansen, J.H. Olsen (1998)

Browse more research in Australian and New Zealand Journal of Public Health, or return to medical research.