Mortality of older construction and craft workers employed at Department of Energy (DOE) nuclear sites

Our plain-English summary of Mortality of older construction and craft workers employed at Department of Energy (DOE) nuclear sites, by J.M. Dement, K. Ringen, L.S. Welch, et al (American Journal of Industrial Medicine, 2009).

The study

• Authors: J.M. Dement, K. Ringen, L.S. Welch, E. Bingham, P. Quinn
• Journal: American Journal of Industrial Medicine
• Published: 2009;52(9):671-82
• Cited by: 28 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Background: The U.S. Department of Energy (DOE) established medical screening programs at the Hanford Nuclear Reservation, Oak Ridge Reservation, the Savannah River Site, and the Amchitka site starting in 1996. Workers participating in these programs have been followed to determine their vital status and mortality experience through December 31, 2004.

Methods: A cohort of 8,976 former construction workers from Hanford, Savannah River, Oak Ridge, and Amchitka was followed using the National Death Index through December 31, 2004, to ascertain vital status and causes of death. Cause-specific standardized mortality ratios (SMRs) were calculated based on US death rates.

Results: Six hundred and seventy-four deaths occurred in this cohort and overall mortality was slightly less than expected (SMR = 0.93, 95% CI = 0.86-1.01), indicating a "healthy worker effect." However, significantly excess mortality was observed for all cancers (SMR = 1.28, 95% CI = 1.13-1.45), lung cancer (SMR = 1.54, 95% CI = 1.24-1.87), mesothelioma (SMR = 5.93, 95% CI = 2.56-11.68), and asbestosis (SMR = 33.89, 95% CI = 18.03-57.95). Non-Hodgkin's lymphoma was in excess at Oak Ridge and multiple myeloma was in excess at Hanford. Chronic obstructive pulmonary disease (COPD) was significantly elevated among workers at the Savannah River Site (SMR = 1.92, 95% CI = 1.02-3.29).

Conclusions: DOE construction workers at these four sites were found to have significantly excess risk for combined cancer sites included in the Department of Labor' Energy Employees Occupational Illness Compensation Program (EEOCIPA). Asbestos-related cancers were significantly elevated.

(c) 2009 Wiley-Liss, Inc.

In plain English

This study followed 8,976 former construction and trade workers from four U.S. Department of Energy nuclear sites (Hanford, Oak Ridge, Savannah River and Amchitka). All were interviewed in voluntary medical screening programs from 1998 through 2004. Deaths through 2004 were found via the National Death Index and compared with U.S. death rates. There were 674 deaths, and overall mortality was slightly below expected (SMR 0.93, 95% CI 0.86 to 1.01). Deaths were significantly higher than expected from all cancers (SMR 1.28, 95% CI 1.13 to 1.45), lung cancer (97 deaths, SMR 1.54, CI 1.24 to 1.87), mesothelioma (8 deaths, SMR 5.93, CI 2.56 to 11.68) and asbestosis (13 deaths, SMR 33.89, CI 18.03 to 57.95). Elevated mesothelioma and asbestosis risk was confined to workers first employed before 1980. However, the authors said the small number of deaths (137) among later hires hampered interpretation. Non-Hodgkin's lymphoma was elevated at Oak Ridge, multiple myeloma at Hanford and COPD at Savannah River. The authors concluded that the excess mesothelioma, lung cancer and asbestosis reflect significant past asbestos exposure. They noted short follow-up, few deaths, possible self-selection and work at non-DOE sites.

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 using standardized mortality ratios (SMRs), comparing the cohort's deaths with U.S. national death rates adjusted for age, race, sex and calendar year
• Who was studied: 8,976 former building trades workers from Hanford, Savannah River, Oak Ridge and Amchitka. All completed an intake interview in a DOE medical screening program between 1998 and December 31, 2004. The cohort was 94.6% male, with a mean age of 58.2 years at the start of follow-up. Deaths were followed through December 31, 2004 (30,707 person-years).
• Exposure: Construction and trade work at DOE nuclear sites (mean 10.1 years at a DOE site). Potential exposures included external and internal radiation, asbestos, silica, solvents, metals, and welding/cutting gases and fumes. The article does not name asbestos fiber types. Individual exposure measurements were not used in the mortality analysis.
• Main results:
  • All causes, whole cohort: 674 observed deaths versus 722.51 expected, SMR 0.93 (95% CI 0.86 to 1.01). The authors described this as a healthy worker effect.
  • All cancers, whole cohort: 248 observed versus 193.68 expected, SMR 1.28 (95% CI 1.13 to 1.45), statistically significant
  • Cancer of the trachea, bronchus and lung, whole cohort: 97 observed versus 63.19 expected, SMR 1.54 (95% CI 1.24 to 1.87), statistically significant
  • Mesothelioma, whole cohort: 8 observed versus 1.35 expected, SMR 5.93 (95% CI 2.56 to 11.68), statistically significant
  • The 8 mesothelioma deaths occurred among Hanford workers (6 deaths, SMR 11.08, 95% CI 4.07 to 24.11, statistically significant) and Oak Ridge workers (2 deaths, SMR 5.18, 95% CI 0.63 to 18.70, not statistically significant). There were none at Amchitka or Savannah River.
  • Asbestosis, whole cohort: 13 observed versus 0.38 expected, SMR 33.89 (95% CI 18.03 to 57.95). By site: Hanford 5 deaths (SMR 29.82), Oak Ridge 5 deaths (SMR 45.62), Savannah River 3 deaths (SMR 50.47), Amchitka none.
  • Elevated risk for mesothelioma and asbestosis was confined to workers first employed before 1980. The authors cautioned that interpretation for workers first employed in 1980 or later was hampered by the small number of deaths in that group (137).
  • All-cause mortality by trade was significantly elevated for asbestos workers/insulators (221 workers, 18 deaths, SMR 1.93; 95% CI 1.15 to 3.05 in the text and 1.15 to 3.06 in Table III). It was also significantly elevated for teamsters (SMR 1.60, 95% CI 1.13 to 2.19).
  • Asbestosis among electricians: six cases, SMR 89.2 (95% CI 32.75 to 194.23). Asbestosis among pipe trades/boilermakers: three cases, SMR 34.3 (95% CI 7.06 to 100.11).
  • Non-Hodgkin's lymphoma at Oak Ridge: 6 deaths, SMR 2.78 (95% CI 1.02 to 6.04). Multiple myeloma at Hanford: 5 deaths, SMR 3.20 (95% CI 1.04 to 7.47).
  • COPD among Savannah River Site workers: 13 deaths, SMR 1.92 (95% CI 1.02 to 3.29). COPD for all sites combined was not significantly elevated (SMR 1.17, 95% CI 0.86 to 1.54).
  • Among 6,904 cohort members with chest X-rays read by ILO criteria, 327 (4.7%) had parenchymal changes with a profusion score of 1/0 or greater, and 1,208 (17.5%) had pleural changes
  • Smoking information was available for 6,993 workers (77.9%). At interview, 21.4% were current smokers, 45.3% past smokers and 33.2% never smokers. The authors judged that smoking alone was not a likely explanation for the excess lung cancer.
• The authors' conclusion: The authors concluded that the excess risk for mesothelioma, lung cancer and asbestosis reflects significant past exposure to asbestos. They also concluded that significant excess risk was seen for the cancer sites covered by the Department of Labor compensation program for DOE workers.
• Limitations the authors state:
  • Follow-up was short, giving few deaths for many disease categories and reduced statistical power
  • Small numbers of deaths prevented detailed trade-specific analyses
  • Because participation was voluntary, self-selection by health status remains possible
  • Many cohort members also did construction work at non-DOE sites, so excess mortality cannot be attributed to DOE work alone
  • Lymphatic and hematopoietic cancer results are hard to interpret because of small numbers of cases
  • Few deaths among workers first employed in 1980 or later hampered interpretation of mesothelioma and asbestosis risks in that group

Topics

Medical terms in this study, explained in our Lexicon: standardized mortality ratio (SMR), Healthy Worker Effect, Lung Cancer, Mesothelioma, Myeloma, COPD.

Related studies

• 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)
• Mortality of older construction and craft workers employed at department of energy nuclear sites: Follow-up through 2016 — K. Ringen, J. Dement, et al. (2019)
• Airways obstruction among older construction and trade workers at Department of Energy nuclear sites — J.M. Dement, L. Welch, et al. (2010)
• Surveillance of respiratory diseases among construction and trade workers at Department of Energy nuclear sites — J.M. Dement, L. Welch, et al. (2003)
• Solid cancer mortality associated with chronic external radiation exposure at the French atomic energy commission and nuclear fuel company — C. Metz-Flamant, E. Samson, et al. (2011)
• Mortality of employees of the United Kingdom Atomic Energy Authority, 1946-97 — W.D. Atkinson, D.V. Law, et al. (2004)

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