Exposure to uranium may increase CVD mortality
MedWire News: Results from a preliminary study suggest that workers who are exposed to uranium over long periods of time may be at increased risk for dying from cardiovascular disease (CVD) compared with the general population.
The researchers found that the greatest risk for CVD mortality was associated with exposure to slowly soluble reprocessed uranium (RPU), although exposure to natural uranium (NU) also significantly increased risk.
On the basis of previous research in Russian and British nuclear workers showing a greater risk for CVD in those handling plutonium and uranium than in the general population, Irina Guseva Canu (Institute of Radiological Protection and Nuclear Safety, Fontenay-aux-Roses, France) and colleagues assessed risks for CVD-associated death (all cardiovascular [CV]-related death, death from ischemic heart disease [IHD], or death from cerebrovascular disease [CD]) in 2897 French workers in a uranium processing plant.
The workers were followed up between 1960 and 2006 (27.6 years on average) and data on 79,892 person-years of exposure to uranium were available.
Of the 2897 workers, 2331 were exposed to at least one type of NU, with 945 workers exposed to NU compounds of three different solubilities. RPU exposure was less common and 390 workers handled RPU compounds of three different solubilities. Approximately 377 workers were exposed to all types of uranium processed at the plant during the follow-up period.
Of 455 deaths that occurred over the follow-up period, 111 were from CVD-related causes (48 IHD, 31 CD, 32 other CV causes).
Canu and co-authors found that mean CVD mortality was significantly higher in workers exposed to RPU (hazard ratio [HR]=2.13) or NU (HR=1.73) compared with unexposed workers. They note that the risk increased in those who had a greater cumulative and longer duration of exposure.
When the researchers restricted their analysis to 260 smokers, CVD death risks associated with NU and RPU exposure were higher than in non-smokers, but statistical power was not high enough to accurately estimate risk.
"We observed that exposure to slowly soluble uranium increases the risk of CSD [circulatory system disease] and that this increase might be higher after exposure to RPU," writes the team in Occupational and Environmental Medicine.
"However, these results should be considered as preliminary since many other factors are known to cause circulatory diseases."
They conclude that "more detailed investigations are necessary to confirm our findings and analyse in depth the pathogenesis of internal radiation exposure for the circulatory system."
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By Helen Albert