French cohort of the uranium processing workers: mortality pattern after 30-year follow-up

Our plain-English summary of French cohort of the uranium processing workers: mortality pattern after 30-year follow-up, by I. Guseva Canu, E. Cardis, C. Metz-Flamant, et al (International Archives of Occupational and Environmental Health, 2010).

The study

• Authors: I. Guseva Canu, E. Cardis, C. Metz-Flamant, S. Caër-Lorho, B. Auriol, P. Wild, D. Laurier, M. Tirmarche
• Journal: International Archives of Occupational and Environmental Health
• Published: 2010;83(3):301-8
• Cited by: 27 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Objective: To investigate mortality among nuclear workers with potential internal exposure to uranium.

Methods: The cohort included 2,709 workers employed at the AREVA NC Pierrelatte plant for at least 6 months (72,787 person-years). This plant processed uranium enrichment during the period 1960-1996 and chemical conversion since 1980. Mortality was compared to the national and regional mortality rates available for the period 1968-2005. For causes of death of interest with respect to occupational exposure, mortality trends according to occupational characteristics were assessed.

Results: As expected, an important healthy worker effect (all causes SMR = 0.55 (95% CI: 0.50-0.61), n = 411; all cancers SMR = 0.70 (95% CI: 0.60-0.81), n = 193) was observed. Among cancer sites a priori related to uranium exposure, only mortality for lymphatic cancer was increased among potentially exposed workers (SMR = 1.49 (95% CI: 0.68-2.82); n = 9). An important increase in mortality from pleural cancer was observed (SMR = 2.85 (95% CI: 0.93-6.66), n = 5); none of the deceased workers were exposed to radiation whereas all handled asbestos.

Conclusion: In spite of limited statistical power, results show consistency with previous studies of nuclear workers potentially exposed to uranium. Further investigation based on more precise uranium exposure data should allow the estimation of uranium hazard effects among this cohort.

In plain English

This study followed 2,709 male workers who had worked at least 6 months at the AREVA NC Pierrelatte uranium plant in South-East France. It tracked their deaths from 1968 to 2005, adding up to 72,786.82 person-years. The authors compared the workers' death rates with those of French men nationally and in four nearby regions. Uranium exposure was not measured directly. Whether a worker was monitored for external radiation was used as a stand-in. Overall, the workers died less often than expected (all causes SMR 0.55, 95% CI 0.50 to 0.61, 411 deaths). Five workers died of pleural cancer, more than expected, but the uncertainty ranges were wide and included 1 (SMR 2.45, 95% CI 0.79 to 5.73 against national rates; 2.85, 0.93 to 6.66 against regional rates). All five were first employed in 1960 to 1966, and none had been monitored for radiation. Their medical records showed past occupational exposure to asbestos. The article does not name a fiber type. The authors concluded the excess pleural cancer was probably caused by asbestos exposures. They noted the cohort was small and young.

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 mortality study comparing observed deaths with expected deaths (standardized mortality ratios) based on national and regional French male death rates; the authors describe it as descriptive, not etiological
• Who was studied: 2,709 male workers employed for at least 6 months at the AREVA NC Pierrelatte plant (South-East France) between 1960 and 2005, followed 1968 to 2005; 72,786.82 person-years; female workers and former uranium miners excluded
• Exposure: Potential internal uranium exposure at a uranium enrichment and conversion plant, approximated by external radiation monitoring status and cumulative external dose; asbestos exposure (fiber type not stated) was found in the medical records of the workers who died of pleural cancer
• Main results:
  • Whole cohort, all causes of death compared with national rates: SMR 0.55 (95% CI 0.50 to 0.61), 411 deaths; all cancers SMR 0.70 (95% CI 0.60 to 0.81), 193 deaths
  • Whole cohort, pleural cancer: 5 deaths; SMR 2.45 (95% CI 0.79 to 5.73) using national rates and 2.85 (95% CI 0.93 to 6.66) using regional rates
  • Pleural cancer among workers not monitored for radiation: SMR 3.19 (95% CI 1.03 to 7.44), 5 deaths; no pleural cancer deaths among monitored workers
  • None of the 5 workers who died of pleural cancer had been monitored for radiation. All were first employed in the plant's earliest period (1960 to 1966). Their medical records showed past occupational exposure to asbestos.
  • Whole cohort: mortality from respiratory cancers and respiratory diseases was not increased compared with national or regional rates
  • Whole cohort: mortality from non-Hodgkin lymphoma and rectal cancer was increased by about 30% and 50% respectively, though not statistically significant (NHL SMR 1.32, 95% CI 0.57 to 2.60, 8 deaths; rectum SMR 1.48, 95% CI 0.71 to 2.72, 10 deaths, national rates)
  • Skilled, manual and unskilled workers: lymphatic and hematopoietic cancer SMR 1.49 (95% CI 0.68 to 2.82), 9 deaths
  • Analyses by radiation monitoring status and cumulative external dose showed no consistent pattern
• The authors' conclusion: The authors concluded that the elevated pleural cancer mortality was probably caused by asbestos exposures. They found no statistically significant increase in cancers of potential uranium-target organs. They called for further study using internal uranium exposure data and taking associated chemical exposures into account.
• Limitations the authors state:
  • The cohort was relatively small and the mean attained age was young, so statistical power was limited
  • Some positive findings could be due to chance because many statistical tests were performed
  • External radiation monitoring status is a crude proxy for uranium exposure
  • No data on tobacco consumption were available

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: Occupational Exposure, Healthy Worker Effect.

Related studies

• Impact of chemical exposure on cancer mortality in a French cohort of uranium processing workers — S. Zhivin, D. Laurier, et al. (2013)
• Exposure assessment for a cohort of workers at a former uranium processing facility — J.L. Anderson, R.D. Daniels, et al. (2012)
• Comparative assessing for radiological, chemical, and physical exposures at the French uranium conversion plant: Is uranium the only stressor? — I. Guseva Canu, F. Paquet, et al. (2009)
• Mortality of older construction and craft workers employed at department of energy (DOE) nuclear sites: follow-up through 2011 — K. Ringen, J. Dement, et al. (2015)
• USTUR Special Session Roundtable-US Transuranium and Uranium Registries (USTUR): A Five-decade Follow-up of Plutonium and Uranium Workers — S.Y. Tolmachev, M.J. Swint, et al. (2019)
• Mortality and cancer morbidity in a cohort of Canadian petroleum workers — R.J. Lewis, A.R. Schnatter, et al. (2003)

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