Abstract
At STS in Kazakhstan, more than 450 nuclear tests were performed between 1949 and 1989. Residents around STS were affected with chronic and repeated long-term exposure to low level mixed (external and internal) radiation. REA has been promoting "Study on Health Effects of Radiation in Residents in and around STS" since 2001, with cooperation of NNC, and CSPRE. Data were collected from Archives, Citizen Registration Office, etc. As of the end of July, 2008, personal data (date of birth, sex, race, etc.) were collected for 117,300 persons, including 46,400 of exposed population. Among this population, number of persons whose residential history between 1948 and 1963 was obtained and thereby whose dose can be calculated, was 18,200. Out of the latter, vital status became clear for 14,800 persons (alive, 7,000; dead, 7,800). Control population was not used in statistical analysis at present, because it has not been long after study of this population had been initiated. Among causes of death in exposed population, circulatory disorders were 42%, followed by neoplasms (21%), mainly of esophagus and stomach. Individual radiation doses were calculated with use of calculating formula advocated by Ministry of Health, Russian Federation. Relationship between radiation dose and ICD-10-coded cause of death was analyzed using data of exposed population. Positive trend between effective dose and mortality from malignant neoplasm and also circulatory disorders was suggested by the statistical analyses. Since period of this study is short, increase of study population and verification of various parameters, confounding factors and biases are needed hereafter. (This study is a part of projects supported by Special Accounts from MEXT, Japan.)
