International Pooled Analysis of Uranium Processing Workers (iPAUW)

Background: Workers employed in the nuclear fuel cycle are exposed to radiation and a variety of hazardous materials. The main steps of the cycle include 1) uranium exploration and mining; 2) uranium milling, processing and refining in preparation for uranium conversion, enrichment and fuel manufacturing; 3) use of fuel in nuclear reactor; and 4)  nuclear fuel reprocessing and waste management. Uranium processing workers could be exposed to uranium radioisotopes and other minerals from the uranium ore, other radiation types (e.g., gamma-ray, long-lived radionuclides) and non-radioactive exposures. To date, epidemiological studies of workers involved in step 1 have reported increased risks of lung cancer due to radon decay products (RDP) exposure. Large pooled studies of nuclear reactor workers involved in step 3 estimated increased risks of solid cancers, leukemia, and cardiovascular diseases (CVD) associated with external gamma-ray radiation.

Aim: Only a few studies have examined risks of exposures in the uranium processing industry (step 2) and reported inconsistent results, necessitating further research in this area.

Methods: Investigators representing 16 cohorts of uranium processing workers are in the process of checking and assembling informative data to conduct a first pooled analysis of long-term health risks of employment in uranium processing industry.

Results/Conclusions: Exposure information on ~100,000 uranium processing workers will be harmonized and a new set of organ doses from uranium bioassay, RDP and external ionizing radiation exposures will be calculated by applying a harmonized protocol. Outcomes of interest will be cancers and non-cancer diseases of uranium-target organs, including lung and bronchi, liver, kidney, bone, brain, and lympho-hematopoietic tissues. Larger statistical power of the analysis of pooled data will allow the proposed collaborative study to have substantially greater ability to describe radon-, gamma- and long-lived radionuclide-associated risks for this unique group of workers many years after exposure.