Causes of death in a cohort of 260 plutonium workers

Our plain-English summary of Causes of death in a cohort of 260 plutonium workers, by B. Gold, R.L. Kathren (Health Physics, 1998).

The study

• Authors: B. Gold, R.L. Kathren
• Journal: Health Physics
• Published: 1998;75(3):236-40
• Cited by: 10 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

The United States Transuranium and Uranium Registries (USTUR) is a unique postmortem research study of the biokinetics, dosimetry, and possible biological effects of actinide elements in persons with occupational exposure to these radioelements. Evaluation of the causes of death in the admittedly biased self-selected cohort of the first 260 deceased participants in the USTUR revealed, in general, no apparently elevated causes of death except for six cases of mesothelioma and six cases of astrocytoma glioblastoma multiforme. The mesothelioma cases had a documented occupational exposure to asbestos, and the six brain tumor deaths all occurred at a single work site and were not radiation related but rather are likely attributable to a factor specific to the work site or surrounding area. Incidental findings in this cohort did not suggest any radiation related illness or cause of death.

In plain English

This article reviewed the causes of death among the first 260 deceased volunteers in the United States Transuranium and Uranium Registries, which collects autopsy tissues from workers exposed to elements such as plutonium (about 90% of this group). A physician used autopsy reports, death certificates and other available records to establish the cause of death in 244 of the 260 cases. Because the group was self-selected and biased, no standard mortality ratios were calculated. Of 87 cancer deaths, six were pleural mesothelioma, about 7%. The authors called this several fold greater than might be expected, citing a general-population figure of up to about 1%. Five of the six mesothelioma cases were known to have had at least the potential for occupational asbestos exposure. One, a uranium worker, had no indication of it. No relationship was seen between radiation dose and mesothelioma. All six astrocytoma and glioblastoma multiforme deaths occurred among Rocky Flats workers. The authors concluded that, apart from mesothelioma and these brain tumors, no cause of death appeared elevated. They added that asbestos exposure in the sixth mesothelioma case could not be unequivocally ruled out.

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: Descriptive review of causes of death in a self-selected registry cohort of deceased tissue donors; no standard mortality ratios or similar quantitative analysis
• Who was studied: 260 deceased volunteer registrants of the United States Transuranium and Uranium Registries (program begun in 1968). All but five were male, and the group was overwhelmingly and perhaps exclusively Caucasian.
• Exposure: Occupational radiation exposure and potential low-level intake of actinides, mainly plutonium (about 90% of cases). For asbestos, five of the six mesothelioma cases had at least the potential for occupational exposure. No fiber type is named.
• Main results:
  • Cause of death was established in 244 of the 260 cases (94%).
  • Six of the 87 cancer deaths in the cohort (about 7%) were from mesothelioma.
  • The authors described the mesothelioma proportion as several fold greater than expected in a general-population cohort of this size, where mesothelioma may account for as many as about 1% of cancer deaths (a figure from another study, Peto et al. 1995).
  • One mesothelioma case, a uranium worker, had no indication of occupational asbestos exposure.
  • No apparent relationship was found between radiation dose and mesothelioma.
  • Lung cancer accounted for 28 of the 87 cancer deaths (32%), which the authors judged not appreciably different from the general American male population.
  • All six astrocytoma and glioblastoma multiforme deaths were among active or former Rocky Flats workers, who made up 98 of the 260 deceased registrants.
• The authors' conclusion: The authors concluded that there was no apparent excess cause of death except mesothelioma and malignant brain tumors. Five of the six mesothelioma cases had documented occupational asbestos exposure, and asbestos exposure in the remaining case could not be unequivocally ruled out. They judged the brain tumors not likely radiation related but more likely due to a factor specific to the work site or surrounding area.
• Limitations the authors state:
  • The cohort was small and biased because it was self-selected, and it included some people who enrolled after a terminal cancer diagnosis.
  • Cases that enrolled because of a diagnosis could not be identified, so the bias could not be corrected or measured.
  • As nuclear workers, the cohort would be expected to show a healthy worker effect.
  • It was not known how many cohort members worked with or were exposed to asbestos.

Topics

Medical terms in this study, explained in our Lexicon: Occupational Exposure, Mesothelioma.

Related studies

• 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)
• Lung cancer and internal lung doses among plutonium workers at the Rocky Flats Plant: a case-control study — S.C. Brown, M.F. Schonbeck, et al. (2004)
• Lung fibrosis in plutonium workers — L.S. Newman, M.M. Mroz, et al. (2005)
• The legacy of weapons grade plutonium production: Health status of Hanford complex workers who manage the waste — D. Cherry, E. Friedman, et al. (2021)
• Comparison of Two Information Sources for Cause-of-Death Follow-up in the Russian Federation: The Asbest Chrysotile Cohort Study — J. Schüz, E. Kovalevskiy, et al. (2020)
• Mortality by cause of death and risk behaviors in farmers versus non-farmers: the importance of avoiding the healthy worker effect — G. Zhao, E. Ronda, et al. (2019)

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