Analysis of mortality in a pooled cohort of Canadian and German uranium processing workers with no mining experience

Abstract of the journal article published in International Archives of Occupational and Environmental Health, September 2017

Author(s):
Lydia B. Zablotska¹, Nora Fenske², Maria Schnelzer², Sergey Zhivin³, Dominique Laurier⁴ and Michaela Kreuzer²

¹ Department of Epidemiology and Biostatistics, University of California, San Francisco, San Francisco, CA, USA
² Department of Radiation Protection and Health, Federal Office for Radiation Protection, Neuherberg, Germany
³ French National Institute of Health and Medical Research, INSERM, Paris, France
⁴ Institute for Radiological Protection and Nuclear Safety, IRSN, Fontenay-Aux-Roses, France

Abstract

Long-term health risks of occupational exposures to uranium processing were examined to better understand potential differences with uranium underground miners and nuclear reactor workers.

A cohort study of mortality of workers from Port Hope, Canada (1950–1999) and Wismut, Germany (1946–2008) employed in uranium milling, refining and processing was conducted. The Poisson regression method was used to evaluate the association between cumulative exposures to radon decay products and gamma rays, and causes of death potentially related to uranium processing.

The pooled cohort included 7,431 workers (270,201 person-years of follow-up). Mean radon decay products exposures were lower than in miners, while gamma ray doses were higher than in reactor workers. Both exposures were highly correlated (weighted rho = 0.81). Radiation risks of lung cancer and cardiovascular disease in males were increased, but not statistically significant, and were compatible with risks estimated for miners and reactor workers, respectively. Higher cardiovascular disease risks associated with radon decay products were observed for exposures 5–14 years prior to diagnosis compared to later exposures and among those employed <5 years. Radiation risks of solid cancers (excluding lung cancer) were increased, but not statistically significant, both for males and females, while all other causes of death were not associated with exposures.

In the largest study of uranium processing workers to systematically examine radiation risk of multiple outcomes from radon decay products exposures and gamma rays, estimated radiation risks were compatible with risks reported for uranium miners and nuclear reactor workers. Continued follow-up and pooling with other cohorts of uranium processing workers are necessary for future comparisons with other workers of the nuclear fuel cycle.

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