| Radiation and Mortality of Workers at Oak Ridge National Laboratory: Positive Associations for Doses Received at Older Ages David B. Richardson and Steve Wing Department of Epidemiology, School of Public Health, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA Abstract
We examined associations between low-level exposure to ionizing radiation and mortality among 14,095 workers hired at the Oak Ridge National Laboratory between 1943 and 1972. Workers at the facility were individually monitored for external exposure to ionizing radiation and have been followed through 1990 to ascertain cause of death information. Positive associations were observed between low-level exposure to external ionizing radiation and mortality. These associations were larger for doses received after 45 years of age, larger under longer lag assumptions, and primarily due to cancer causes of death. All cancer mortality was estimated to increase 4.98% [standard error (SE) = 1.5] per 10-mSv cumulative dose received after age 45 under a 10-year lag, and 7.31% (SE = 2.2) per 10-mSv cumulative dose received after age 45 under a 20-year lag. Associations between radiation dose and lung cancer were of similar magnitude to associations between radiation dose and all cancers except lung cancer. Nonmalignant respiratory disease exhibited a positive association with cumulative radiation dose received after age 45, whereas ischemic heart disease exhibited no association with radiation dose. These findings suggest increases in cancer mortality associated with low-level external exposure to ionizing radiation and potentially greater sensitivity to the carcinogenic effects of ionizing radiation with older ages at exposure. Key words: epidemiology, ionizing radiation, Oak Ridge National Laboratory. Environ Health Perspect 107:649-656 (1999) . [Online 29 June 1999] http://ehpnet1.niehs.nih.gov/docs/1999/107p649-656richardson/ abstract.html Address correspondence to D.B. Richardson, Department of Epidemiology, School of Public Health, CB # 8050, Nationsbank Plaza, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-8050 USA. Telephone: (919) 966-6305. Fax: (919) 966-6650. E-mail: drichard@sph.unc.edu The authors are grateful to J. Wood and S. Wolf at the University of North Carolina at Chapel Hill. This research was supported by grant R03 OH03343 from the National Institute for Occupational Safety and Health of the Centers for Disease Control and Prevention. Vital status follow-up, death certificate retrieval, and cause of death coding were conducted at the Center for Epidemiologic Research, Oak Ridge Associated Universities. Received 10 November 1998 ; accepted 29 March 1999.
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