Risk of endemic non toxic goiter in Chernobyl liquidators and nuclear industry employees

Estimates of radiation risk of non-toxic goiter (ICD 10: E04-E04.9) in Chernobyl liquidators were given from the information database of the Sectoral register of persons exposed to radiation as a result of the Chernobyl accident for 1989-2018. Used dosimetry information contained liquidators radiation doses were measured during their work inside the Chernobyl exclusion zone, and the employees’ occupational radiation dose. The study used information about men - 12663 people, of which 1327 workers have an occupational exposure dose. At the first stage, the excess relative risk per 1 Sv (ROR/Sv) of non-toxic goiter was estimated for four groups depending on age at the time of participation in work in the Chernobyl accident zone. At the second stage of the study, a Poisson process with an intensity parameter was chosen as a statistical model of morbidity. Based on the obtained individual non-stratified data, an analytical likelihood function for the Poisson process was built and the value of the excess relative risk (RRR) of the disease with nontoxic goiter was calculated. The nature of the dose dependence of the IOR was studied, for which the Amfit module of the Epicure statistical software package was used. A cohort study of liquidators 1986-1990 was carried out. for 1989-2018 depending on the dose of external exposure received during the liquidation of the consequences of the Chernobyl accident, and with the total dose received in the 30-km zone of the Chernobyl nuclear power plant with the dose during professional work. The values of the radiogenic risk of non-toxic goiter in liquidators of the consequences of the Chernobyl accident are shown. A significant increase in the risk of IOR disease per dose unit for doses received during the liquidation of the consequences of the Chernobyl accident was not found. A significant increase in risk was noted when using total doses for its calculation only for liquidators in the age group of 50-59 years. The use of doses from various types of exposure in assessing the radiogenic risk of non-toxic goiter in liquidators of the consequences of the Chernobyl accident gives different values of the excess relative risk of developing this nosology. For a correct assessment of the radiation risk of non-toxic goiter, it is necessary to collect data on the doses of all types of exposure (occupational, emergency, medical and natural), and only the use of the total dose can give the true risk necessary to calculate the radiation safety standards.