Long-Term Exposure to Ionizing Radiation from the Semipalatinsk Nuclear Test Site and Risk of Cardiovascular Mortality

Background: Environmental problems can significantly influence population health. Cardiovascular diseases (CVDs) are the most common cause of death in developed countries including in Kazakhstan. The aim of our study was to assess the relationship between exposure to ionizing radiation and mortality risks from major CVDs for the population of Kazakhstan living in areas adjacent to the Semipalatinsk nuclear test site (SNTS). Materials and Methods: The study of the structure and dynamics of cardiovascular mortality was based on the State Scientific Automated Medical Registry (SSAMR) database. Among members of the exposed group, the median equivalent radiation dose was 864.0 mSv, compared to 64.4 mSv in the control group. It should be noted that almost the entire population of the Semipalatinsk region was exposed to some degree of radiation; however, the Kokpekti district received the lowest radiation doses. Results: Mortality rates from CVD were statistically significantly higher in the radiation-exposed population from 1960 to 1994, with RR fluctuating from 1.118 to 8.7. The predominant mortality events were chronic coronary heart disease, chronic cerebrovascular disease, and hemorrhagic stroke throughout the study period, and acute myocardial infarction within 20 years of the start of nuclear testing. In the exposed group, RR = 10.35 for chronic cerebrovascular disease, RR = 3.56 for hemorrhagic stroke, and RR = 5.77 for peripheral arterial atherosclerosis. A dose of 100–500 mSv increased the risk of mortality from CVD by 3.14 times, and a dose of >600 mSv increased it by 7.05 times. Conclusions: A link has been established between long-term exposure to ionizing radiation and increased risks of mortality from CVD in the population of areas contaminated with radiation as a result of nuclear testing.