Prospective cohort study of residents near the Semipalatinsk nuclear test site – feasibility assessment (SEMI-NUC)

The former Soviet Union’s Semipalatinsk test site covers an area of 18,500 km² and is named after the city of Semipalatinsk, which is located approximately 150 km east of the test site. The Soviet Union’s first nuclear test was conducted here on August 29, 1949. During the following 40 years, 456 nuclear explosions were carried out, including 111 atmospheric events until 1963. After the onset of the Limited Test Ban Treaty signed in 1963, the tests were restricted to underground shafts and tunnels so that, with a few exceptions, little or no off-site environmental contamination was caused.

The health effects of exposures to fallout from Soviet nuclear weapons testing for the residents living near by the Semipalatinsk nuclear test site in Kazakhstan have been investigated in different studies (Grosche et al. 2015) among them a cohort study in which BfS was involved. This cohort was established in 1963 by today’s Scientific Research Institute of Radiation Medicine and Ecology (NIIRME), Kazakhstan and is called "historical cohort". The most recent analysis was published in 2011 where the relationship between mortality from cardiovascular diseases and radiation exposure from the fall-out was assessed (Grosche et al. 2011). The historical cohort is part of a comprehensive registry with 145,306 persons affected by the nuclear tests and their offspring.

Additionally, a new cohort was established as result of collaboration between Japanese and Kazakh organisations during 2001-2009. To date, there are no results published in the open literature.

The SEMI-NUC project, aimed at investigating the feasibility of setting up a united cohort of residents around the Semipalatinsk site, including preparation for prospective follow-up. The above mentioned register encompasses not only the historical cohort, but also parts of the new cohort. The main difference between the databases is the choice of control regions. The register is well-maintained and regularly updated. Thus, it has the potential for future prospective epidemiological research on the association between radiation and cardiovascular diseases as well as cancer. Record linkage of the databases was tested with test cases and found to be feasible, however, only with intensive work.

A joint approach for individual dose reconstruction was defined. Further, it was identified to what extent biological material (e.g., blood samples) from cohort members is available and can be used for radiobiological research.

With this project, BfS continued its long involvement in Semipalatinsk related studies as a part of an international network on health effects due to Soviet nuclear testing.