In this paper, we present findings of the analysis of mortality from diseases of the circulatory system in a cohort of Russian nuclear workers who were chronically exposed to ionizing radiation at radiation dose rate of 0.005–0.050 Gy/year. Excess relative risks of mortality from diseases of the circulatory system, cerebrovascular diseases, and ischemic stroke per unit total gamma-ray dose from external exposure accumulated at higher dose rates were found to be higher than the corresponding risks per unit total dose accumulated due to exposure at lower dose rates. Continuous radiation exposure at higher rates over a duration of 5 years was found to increase considerably the risk of mortality from diseases of the circulatory system, cerebrovascular diseases, and ischemic stroke.
Azizova et al. (Tue,) studied this question.