Mortality among U.S. military participants at eight aboveground nuclear weapons test series

Our plain-English summary of Mortality among U.S. military participants at eight aboveground nuclear weapons test series, by J.D. Boice, S.S. Cohen, M.T. Mumma, et al (International Journal of Radiation Biology, 2022).

The study

• Authors: J.D. Boice, S.S. Cohen, M.T. Mumma, H. Chen, A.P. Golden, H.L. Beck, J.E. Till
• Journal: International Journal of Radiation Biology
• Published: 2022;98(4):679-700
• Cited by: 38 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Background: Approximately 235,000 military personnel participated at one of 230 U.S. atmospheric nuclear weapons tests from 1945 through 1962. At the Nevada Test Site (NTS), the atomic veterans participated in military maneuvers, observed nuclear weapons tests, or provided technical support. At the Pacific Proving Ground (PPG), they served aboard ships or were stationed on islands during or after nuclear weapons tests.

Material And Methods: Participants at seven test series, previously studied with high-quality dosimetry and personnel records, and the first test at TRINITY formed the cohort of 114,270 male military participants traced for vital status from 1945 through 2010. Dose reconstructions were based on Nuclear Test Personnel Review records, Department of Defense. Standardized mortality ratios (SMR) and Cox and Poisson regression models were used in the analysis.

Results: Most atomic veterans were enlisted men, served in the Navy at the PPG, and were born before 1930. Vital status was determined for 96.8% of the veterans; 60% had died. Enlisted men had significantly high all-causes mortality SMR (1.06); officers had significantly low all-causes mortality SMR (0.71). The pattern of risk over time showed a diminution of the 'healthy soldier effect': the all-causes mortality SMR after 50 years of follow-up was 1.00. The healthy soldier effect for all cancers also diminished over time. The all-cancer SMR was significantly high after 50 years (SMR 1.10) primarily from smoking-related cancers, attributed in part to the availability of cigarettes in military rations. The highest SMR was for mesothelioma (SMR 1.56) which was correlated with asbestos exposure in naval ships. Prostate cancer was significantly high (SMR 1.13). Ischemic heart disease was significantly low (SMR 0.84). Estimated mean doses varied by organ were low; e.g., the mean red bone marrow dose was 6 mGy (maximum 108 mGy). Internal cohort dose-response analyses provided no evidence for increasing trends with radiation dose for leukemia (excluding chronic lymphocytic leukemia (CLL)) [ERR (95% CI) per 100 mGy -0.37 (-1.08, 0.33); n = 710], CLL, myelodysplastic syndrome, multiple myeloma, ischemic heart disease, or cancers of the lung, prostate, breast, and brain.

Conclusion: No statistically significant radiation associations were observed among 114,270 nuclear weapons test participants followed for up to 65 years. The 95% confidence limits were narrow and excluded mortality risks per unit dose that are two to four times higher than those reported in other investigations. Significantly elevated SMRs were seen for mesothelioma and asbestosis, attributed to asbestos exposure aboard ships.

In plain English

This study followed 114,270 male U.S. military personnel who took part in eight aboveground nuclear weapons test series, tracing deaths from 1945 through 2010. The authors compared their death rates with those of U.S. men in general and tested whether estimated radiation doses were linked to causes of death. Overall deaths were slightly below expected (standardized mortality ratio, SMR, 0.97). Enlisted men were above expected (1.06) and officers below (0.71). Deaths from mesothelioma were elevated (SMR 1.56, 153 deaths). The elevated risk was seen only among Navy personnel who served on ships in the Pacific (SMR 2.15, 130 deaths), and the excess was statistically significant only 40 to 65 years after follow-up began. Asbestosis deaths were also elevated (SMR 2.13, 65 deaths; Navy in the Pacific SMR 3.22, 60 deaths). Across the whole cohort, mesothelioma showed a statistically significant positive association with radiation dose. No such trend appeared among non-Navy veterans, and the authors attributed the link to confounding by asbestos. No radiation dose trend was found for leukemia other than CLL, lung cancer or asbestosis. The authors concluded that the mesothelioma excess could be explained by asbestos exposure aboard ships in the Pacific.

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: deaths compared with expected numbers from the U.S. male general population (standardized mortality ratios), plus within-cohort Cox regression analyses of organ-specific radiation dose
• Who was studied: 114,270 male U.S. military participants at eight test series (CASTLE, CROSSROADS, GREENHOUSE, HARDTACK I, PLUMBBOB, REDWING, Project TRINITY, UPSHOT-KNOTHOLE) at the Nevada Test Site and Pacific Proving Ground. They were followed for vital status through December 31, 2010. 61.5% were Navy and 84.1% were enlisted men.
• Exposure: Ionizing radiation, mainly external gamma radiation from fallout, estimated as organ-specific doses (mean red bone marrow dose 6 mGy, maximum 108 mGy). Asbestos exposure aboard Navy ships was not measured in this paper; the authors attributed it to the ships, citing earlier work (Till et al. 2018b). No fiber type is named.
• Main results:
  • All-causes mortality in the whole cohort was slightly below that of U.S. men in general: SMR 0.97 (95% CI 0.96, 0.98).
  • Enlisted men had higher all-causes mortality than the general population (SMR 1.06; 95% CI 1.05, 1.07). Officers had lower mortality (SMR 0.71; 95% CI 0.70, 0.72).
  • Mesothelioma deaths were significantly elevated in the whole cohort (SMR 1.56, n=153; table: 95% CI 1.32-1.82). The elevation was seen only among Navy personnel who served on ships in the Pacific Proving Ground (SMR 2.15, n=130). In the tables this category is cancers of the pleura and peritoneum together with mesothelioma.
  • The mesothelioma excess was statistically significant only 40 to 65 years after follow-up began (table: SMR 1.48 at 40-49 years and 1.84 at 50 or more years). Deaths also occurred earlier: the table shows 3, 4 and 8 deaths at 10-19, 20-29 and 30-39 years, which were not significantly elevated.
  • Asbestosis deaths were significantly elevated in the whole cohort (SMR 2.13, n=65; table: 95% CI 1.64-2.71). The elevation was seen only among Navy personnel serving in the Pacific Proving Ground (SMR 3.22, n=60).
  • In the whole cohort, the internal analysis showed a positive association between radiation dose and mesothelioma: excess relative risk (ERR) per 100 mGy 0.45 (95% CI 0.04, 0.86). The hazard ratios by dose category were significant only at the lowest dose categories.
  • Among 43,574 non-Navy personnel, described as having minimal to no asbestos exposure, there was no radiation trend for mesothelioma: ERR per 100 mGy -0.34 (95% CI -3.51, 2.81), n=23.
  • There was no radiation dose trend for asbestosis: ERR per 100 mGy -0.18 (95% CI -2.15, 1.80), n=65.
  • There was no radiation dose response for leukemia other than CLL: ERR per 100 mGy -0.37 (95% CI -1.08, 0.33), n=710.
  • Lung cancer was not associated with radiation dose to the lung: ERR per 100 mGy 0.04 (95% CI -0.11, 0.19), n=7,980.
  • Prostate cancer deaths were significantly elevated overall (SMR 1.13).
• The authors' conclusion: The authors concluded that there was no evidence the low radiation doses increased the risk of cancer or ischemic heart disease. They concluded that the mesothelioma excess could be explained by asbestos exposure aboard ships at the Pacific Proving Ground, and that the dose-mesothelioma association reflected confounding by asbestos.
• Limitations the authors state:
  • Mean organ doses were small, so statistical power to detect radiation effects was limited.
  • Pay grade was used as a stand-in for socioeconomic status and lifestyle such as smoking, and may be inadequate to adjust for known and unknown causes of disease.
  • Organ doses from intakes of radionuclides are uncertain.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Mesothelioma.

Medical terms in this study, explained in our Lexicon: standardized mortality ratio (SMR), Mesothelioma, Asbestos Exposure, Dose-response relationship, Myeloma.

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• Comparison of x-ray films and low-dose computed tomographic scans: demonstration of asbestos-related changes in 2760 nuclear weapons workers screened for lung cancer — A. Miller, S.A. Widman, et al. (2013)
• Risk and significance of chest radiograph and pulmonary function abnormalities in an elderly cohort of former nuclear weapons workers — M.A. Mikulski, P.G. Hartley, et al. (2011)
• Asbestos-related cancer in naval personnel: findings from participants in the British nuclear tests 1952-1967 — R.T. Gun, G.M. Kendall (2023)
• Occupational exposure to particulate air pollution and mortality due to ischaemic heart disease and cerebrovascular disease — K. Torén, I.A. Bergdahl, et al. (2007)

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