Time-factors in exposure effects among uranium workers.
NIOSH 2006 Feb; :1-36
The Oak Ridge, Tennessee Y-12 plant has operated as a nuclear materials fabrication plant since the 1940s. Given the work environment, and prior findings that lung cancer mortality was elevated among white male Y-12 workers relative to US white males, we investigated whether lung cancer mortality was associated with occupational radiation exposures. We identified a cohort of 3864 workers hired between 1947 and 1974 who had been monitored for internal radiation exposure. Vital status was ascertained through 1990. Over the study period 111 lung cancer deaths were observed. Cumulative external radiation dose under a 5-year lag assumption was positively associated with lung cancer mortality (0.54% increase in lung cancer mortality per 10 mSv, se=0.16, likelihood ratio test [LRT]=5.84, 1 degree of freedom [df]); cumulative internal radiation dose exhibited a highly-imprecise negative association with lung cancer mortality. The positive association between external radiation dose and lung cancer mortality was primarily due to exposure occurring in the period 5-14 years after exposure (0.97% increase in lung cancer mortality rate per 10 mSv, se=0.28, LRT=6.35, 1 df). The association between external radiation dose and lung cancer mortality was negative for exposures occurring at ages <35 years and positive for exposures occurring at ages 35-50 years and 50+ years. Conclusions about the relationship between occupational radiation exposures and lung cancer in this population, however, are constrained by the uncertainties in external and internal radiation dose estimates, the lack of information about exposures to other lung carcinogens, and the limited statistical power of the study.
Ionizing-radiation; Lung-cancer; Respiratory-system-disorders; Pulmonary-cancer; Pulmonary-system-disorders; Nuclear-radiation; Radiation; Radiation-exposure; Epidemiology; Statistical-analysis; Mortality-data; Mortality-rates; Mortality-surveys
David B. Richardson, Department of Epidemiology, School of Public Health, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7435
Final Grant Report
NTIS Accession No.
National Institute for Occupational Safety and Health
University of North Carolina - Chapel Hill