Unified cohort enhances radiation studies
Residents of villages around the SNTS were exposed to varying doses of moderate to low ionising radiation. Until now, a limited number of studies have tried to assess possible health effects in this population, but results were conflicting, possibly due to differences in dosimetric methods and selection of control groups. The EU-funded SEMI-NUC (Prospective cohort study of residents near the Semipalatinsk nuclear test site - Feasibility) project assessed the feasibility of establishing a unified cohort to quantify effects of ionising radiation exposure. The project brought together scientists from Europe, Japan and Kazakhstan to establish long-term, prospective follow-up studies to determine potential detrimental health effects from radiation exposure. Project partners conducted several site visits to the SNTS and familiarised with a registry which includes individuals who lived or continue to live in the areas contaminated from nuclear bomb testing radioactive fallout(s) as well as their offspring. Researchers reviewed the registry to assess data collection mechanisms as well as quality of information on cancer and non-cancer disease incidence and mortality. A report on cohort unification was completed and two other reports on the follow-up mechanisms of exposed population and ascertainment of health outcomes were prepared. In addition, biological samples, such as whole blood, DNA of exposed people and their offspring, and teeth, and their potential for use in future studies were evaluated. Based on these reports, researchers were able to make recommendations on what health outcomes to study, with particular emphasis on thyroid cancer and non-cancer diseases. Exposure pathways, mechanisms of cumulative dose formation, information required for dose reconstruction, remaining gaps and possible solutions to overcome those were reported in detail. Furthermore, three villages near the SNTS were selected in order to validate selected methodologies and compare the results of various methods of dose reconstruction. SEMI-NUC activities will help to reduce duplication of efforts and resources and facilitate future studies, thereby improving understanding of the health risks associated with low and moderate chronic doses of radiation. Moreover, an improved quantification of risks from low and protracted doses will help in the regulation of exposure due to planned, existing or emergency exposure situations such as Chernobyl and Fukushima. It will also serve as a valuable reference to make decisions on designing long-term medical follow-up programmes of affected populations.
Keywords
Semipalatinsk nuclear test site, ionising radiation, SEMI-NUC, radiation exposure, cancer
