Mortality of employees of the United Kingdom Atomic Energy Authority, 1946-97

Our plain-English summary of Mortality of employees of the United Kingdom Atomic Energy Authority, 1946-97, by W.D. Atkinson, D.V. Law, K.J. Bromley, et al (Occupational and Environmental Medicine, 2004).

The study

• Authors: W.D. Atkinson, D.V. Law, K.J. Bromley, H.M. Inskip
• Journal: Occupational and Environmental Medicine
• Published: 2004;61(7):577-85
• Cited by: 51 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Background: The workforce of the UK Atomic Energy Authority has been the subject of several previous epidemiological investigations.

Aims: To detect and investigate associations between mortality rates and employment in a substantially increased cohort size and follow up extended to 1997.

Methods And Results: The new cohort included 51 367 employees, of whom 10 249 were dead. Mortality rates for all workers were low compared to national rates, as were rates in radiation workers and for workers monitored for internal contamination. For radiation workers all cause mortality and all cancer mortality were significantly lower than for non-radiation workers. There was no overall trend of increasing mortality with radiation dose. There was little evidence of raised mortality from leukaemia. The association of prostatic cancer with radiation dose was much less significant than in previous reports. However, the relatively high mortality from uterine cancers among radiation workers remained, though the numbers were very small. The association was with endometrial rather than cervical cancer. Mortality from cancer of the pleura was high among radiation workers, but was not correlated with dose.

Conclusion: Overall, radiation workers at UKAEA showed no excess mortality. The previously detected association of prostate cancer with high radiation dose may have been a statistical artefact or a risk associated with discontinued activities. Endometrial cancer occurred at higher rates in female radiation workers, but, because there was no correlation with dose, may well be due to something other than their radiation exposure. Cancer of the pleura in radiation workers was almost certainly related to past asbestos exposure.

In plain English

This was a further analysis of a cohort of 51 367 people who worked for the United Kingdom Atomic Energy Authority (UKAEA). Deaths were followed from 1946 to the end of 1997, by which time 10 249 had died. About half were radiation workers, and the study's exposure data were radiation dose records. Compared with England and Wales, the whole workforce had lower death rates: the standardised mortality ratio was 78 for all causes and 80 for all cancers, and no cause of death was significantly raised. Radiation workers had a significantly higher rate of death from cancer of the pleura than non-radiation workers (rate ratio 5.35, lower 95% confidence limit 1.36), based on 10 deaths. This rate did not rise with radiation dose. Workers monitored for plutonium also had a higher pleural cancer rate than other radiation workers (rate ratio 6.7, 95% CI 1.5 to 28.5). The authors concluded that cancer of the pleura in radiation workers was almost certainly related to past asbestos exposure. They suggested that radiation workers did more industrial work and were exposed to asbestos in production facilities and industrial buildings.

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 mortality study (further analysis of an existing workforce cohort), comparing death rates with England and Wales and comparing radiation workers with non-radiation workers
• Who was studied: 51 367 UKAEA employees (29% women, 51% radiation workers) employed before 31 March 1996 at Culham, Dounreay, Harwell, London and Winfrith, plus Risley and Culcheth recruits after 1 January 1965. Follow-up ran to 31 December 1997, with 10 249 deaths.
• Exposure: Ionising radiation: external whole body radiation dose, with records of monitoring for internal contamination (for example plutonium and tritium). Asbestos exposure was not measured; the authors raised it as an explanation for pleural cancer.
• Main results:
  • Whole workforce compared with England and Wales: SMR 78 (95% CI 76.1 to 79.1) for all causes of death and 80 (95% CI 77.3 to 83.1) for all malignant neoplasms. No cause of death was significantly raised.
  • Radiation workers compared with non-radiation workers: significantly raised risk of death from cancer of the pleura, based on 10 deaths (RR 5.35, lower 95% confidence limit 1.36; the upper limit is not legible in the text). There was no trend with radiation dose.
  • Plutonium-monitored workers: SMR for cancer of the pleura 282 (95% CI 91 to 659), described as nearly significant. With exposure lagged by 10 years it was 329 (95% CI 106 to 768), which was significant.
  • Plutonium-monitored workers compared with other radiation workers: pleural cancer death rate significantly higher (RR 6.7, 95% CI 1.5 to 28.5), with no significant trend with dose.
  • All radiation workers compared with England and Wales: SMR 75 (95% CI 73.5 to 77.5) for all causes and 76 (95% CI 72.2 to 79.8) for all malignant neoplasms. Both were significantly lower than for non-radiation workers.
  • Female radiation workers: endometrial cancer SMR 386 (95% CI 185 to 711), based on 10 deaths. The rate ratio against non-radiation workers was 6.3 (95% CI 2.2 to 20.0), with no relation to radiation dose.
  • The previously reported trend of prostate cancer death with radiation dose was much weaker in this analysis and did not reach statistical significance (p = 0.13).
• The authors' conclusion: The authors concluded that cancer of the pleura in radiation workers was almost certainly related to past asbestos exposure. They thought it likely that radiation workers, being more involved with industrial work, were exposed to asbestos in production facilities and other industrial buildings.
• Limitations the authors state:
  • Mesotheliomas have long latent periods, so the authors expected the pleural excess to become more apparent in the future.
  • Radiation dose received after the last period of UKAEA employment was generally not available.
  • Numbers of endometrial cancer deaths were small, and there were no data on risk factors that might explain the excess.
  • Low SMRs are likely at least partly explained by the recruitment of healthy workers.

Topics

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

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