RADIATION RISK OF CARDIOVASCULAR DISEASES IN THE COHORT OF RUSSIAN EMERGENCY WORKERS OF THE CHERNOBYL ACCIDENT

This paper continues a series of publications that analyze the impact of radiation on incidence of circulatory system diseases in the cohort of Russian recovery operation workers (liquidators) and presents the results of the analysis of cardiovascular disease (CVD) incidence. The studied cohort consists of 53,772 liquidators who arrived in the Chernobyl accident zone within the first year after the accident (26 April 1986 to 26 April 1987). The individual doses varied from 0.0001 Gy to 1.42 Gy, and the mean external whole body dose in the cohort was 0.161 Gy. A total of 27,456 cases of CVD were diagnosed during the follow-up period 1986-2012 as a result of annual health examinations. A Poisson regression model was applied to estimate radiation risks and other risk factors associated with CVD. The following factors were identified as risk factors for CVD: the dose, duration of the liquidators' work in the Chernobyl zone, and concomitant diseases (diabetes mellitus, hypertension, overweight, and alcohol dependence). The baseline incidence of CVD is statistically significantly (p < 0.001) associated with all studied concomitant diseases. The incidence of CVD has revealed a statistically significant dose response with the lack of a latent period and with the average ERR Gy(-1) = 0.47, 95% CI = 0.31, 0.63, p < 0.001. Radiation risks of CVD statistically significantly (p = 0.01) varied with the duration of liquidators' stay in the Chernobyl zone; for those who stayed in the Chernobyl zone less than 6 wk, ERR/Gy = 0.80, 95% CI = 0.53; 1.08, p < 0.001.