Abstract
Background: Epidemiologic studies of radiation-exposed populations form the basis for human safety standards. They also help shape public health policy and evidence-based health practices by identifying and quantifying health risks of exposure in defined populations. For more than a century, epidemiologists have studied the consequences of radiation exposures, yet the health effects of low levels delivered at a low-dose rate remain equivocal. Materials and Methods: The Million Person Study (MPS) of U.S. Radiation Workers and Veterans was designed to examine health effects following chronic exposures in contrast with brief exposures as experienced by the Japanese atomic bomb survivors. Radiation associations for rare cancers, intakes of radionuclides, and differences between men and women are being evaluated, as well as noncancers such as cardiovascular disease and conditions such as dementia and cognitive function. The first international symposium, held November 6, 2020, provided a broad overview of the MPS. Representatives from four U.S. government agencies addressed the importance of this research for their respective missions: U.S. Department of Energy (DOE), the Centers for Disease Control and Prevention (CDC), the U.S. Department of Defense (DOD), and the National Aeronautics and Space Administration (NASA). The major components of the MPS were discussed and recent findings summarized. The importance of radiation dosimetry, an essential feature of each MPS investigation, was emphasized. Results: The seven components of the MPS are DOE workers, nuclear weapons test participants, nuclear power plant workers, industrial radiographers, medical radiation workers, nuclear submariners, other U.S. Navy personnel, and radium dial painters. The MPS cohorts include tens of thousands of workers with elevated intakes of alpha particle emitters for which organ-specific doses are determined. Findings to date for chronic radiation exposure suggest that leukemia risk is lower than after acute exposure; lung cancer risk is much lower and there is little difference in risks between men and women; an increase in ischemic heart disease is yet to be seen; esophageal cancer is frequently elevated but not myelodysplastic syndrome; and Parkinson’s disease may be associated with radiation exposure. Conclusions: The MPS has provided provocative insights into the possible range of health effects following low-level chronic radiation exposure. When the 34 MPS cohorts are completed and combined, a powerful evaluation of radiation-effects will be possible. This final article in the MPS special issue summarizes the findings to date and the possibilities for the future. A National Center for Radiation Epidemiology and Biology is envisioned.
| Original language | English |
|---|---|
| Pages (from-to) | 795-821 |
| Number of pages | 27 |
| Journal | International Journal of Radiation Biology |
| Volume | 98 |
| Issue number | 4 |
| DOIs | |
| State | Published - 2022 |
Funding
The U.S. Department of Energy (US DOE) has supported all aspects of the MPS since the feasibility study in 2009–2010, funded by the Office of Science and now by the Office of Environment, Health, Safety & Security. Twenty-six percent (260,000) of the MPS study population comes from former U.S. DOE radiation workers (Boice, Cohen et al.et al. 2019). The U.S. DOE and its predecessors have a long history in conducting and supporting radiation epidemiological studies. Surveillance of radiation exposure and its health effects were implemented shortly after the Manhattan Project began in 1942. The Radiation Exposure Information and Reporting System (REIRS) was established in 1968 to serve as the central repository of occupational radiation exposure records (Hagemeyer et al. ; NRC ). The feasibility studies of using personnel, employment, medical, radiation exposure, and facility records to conduct epidemiologic mortality studies were completed in the 1960s while the health and mortality studies of radiation workers across U.S. DOE facilities were carried out from the early 1970s (Ellis et al. ). The Epidemiological Records Moratorium, "an agency-wide freeze" on the destruction of all epidemiological records, was issued in 1990. The Comprehensive Epidemiologic Data Resource (CEDR) also was created in 1990 to allow researchers to access data from the U.S. DOE epidemiological studies program (US DOE ). The CEDR became a major source of data used to extend the follow up U.S. DOE worker cohorts for the MPS. The U.S. DOE has data for over 650,000 former radiation workers and about 75,000 current radiation workers. The MPS can provide valuable research findings to improve U.S. DOE former worker medical screening and compensation programs, and to enhance the protection of current radiation workers. NCRP acknowledges the financial support of the MPS-related work presented in this symposium from U.S. DOE [grants # DE-AU0000042 and DE-AU0000046], NASA [grants # 80NSSC17M0016 and 80NSSC19M0161], Naval Sea Systems Command [contract # N00024-17-C-4322], U.S. NRC (grant # NRC-HQ-60-14-G-0011), and the CDC [grant # 5NUE1EH001315]. The authors appreciate all who attended this first MPS virtual symposium, especially those who participated by asking questions and joining in the discussions. The authors appreciate the radioanalytical brain autopsy results provided by Dr. John Brockman and Dana Wegge from the University of Missouri. The authors appreciate the technical support graciously provided by Burk and Associates, whose team (lead by Brett Burk) donated their time and expertise to ensure a flawless virtual symposium. The conclusions and opinions in this report are those solely of the authors. Its publication does not imply endorsement by the National Council on Radiation Protection and Measurements, Vanderbilt University, Memorial Sloan Kettering Cancer Center, the Health Physics Society or any of the acknowledged agencies. Specifically, the views expressed are those of the authors and do not reflect the official policy or position of the DOE, CDC, DOD, NASA, or the US Government.
Keywords
- Million person study
- cancer
- cognition impairment
- radiation dosimetry
- radiation epidemiology
