Cohort profile: four early uranium processing facilities in the US and Canada

Area of Science:

• Occupational health and safety
• Environmental toxicology
• Epidemiology

Background:

• Workers in uranium refining and processing facilities face potential exposures to radioactive materials and ionizing radiation.
• Understanding long-term health risks associated with these exposures is crucial for worker protection and public health.
• Previous studies may have limitations in cohort size or exposure assessment for uranium processing workers.

Purpose of the Study:

• To investigate the long-term health risks, including cancer and non-malignant diseases, in a large cohort of uranium processing workers.
• To assess the association between occupational exposures to uranium, its decay products, and external ionizing radiation with specific health outcomes.
• To provide updated insights into the mortality risks for workers involved in uranium refining and processing.

Main Methods:

• Pooled individual-level data from over 12,400 workers across four uranium processing facilities in the U.S. and Canada.
• Harmonized exposure data for uranium, radium, radon decay products, and gamma radiation, along with dose reconstruction.
• Calculated Standardized Mortality Ratios (SMR) for various causes of death, including lung cancer, respiratory diseases, ischemic heart disease, and dementia/Alzheimer's disease.

Main Results:

• A total of 560 lung cancer deaths, 503 non-malignant respiratory diseases, 67 renal diseases, 1,596 ischemic heart diseases, and 101 dementia and Alzheimer's disease (AD) cases were identified.
• Mean cumulative doses included 45 mSv for external ionizing radiation and 172 mGy for lung dose from radon decay products.
• A statistically significant increase in SMR for dementia and AD was observed among males (SMR=1.29).

Conclusions:

• This study represents the largest investigation to date on the long-term health risks experienced by uranium processing workers.
• The findings suggest a potential link between occupational exposures in uranium processing and increased risk of dementia and Alzheimer's disease in males.
• Further research may be warranted to elucidate the specific mechanisms and dose-response relationships for observed health outcomes.