Risk of Thyroid Diseases Associated with Iodine Deficiency of Liquidators of the Consequences of the Accident at the Chernobyl NPP ‒ Employees of Nuclear Industry Enterprises

Abstract

Purpose: Assessment of thyroid disease risk associated with iodine deficiency, liquidators of the Chernobyl accident consequences, employees of nuclear industry enterprises depending on the doses of different types of exposure. Material and methods: The dose-risk assessment study included 12663 men, 1327 of whom had occupational exposure data. A Poisson’s process with intensity parameter was chosen as a statistical model of morbidity risk. The statistical package of epidemiological data analysis EPICURE was used for the estimation of excess relative risk (ERR) of thyroid diseases related to iodine deficiency. There was conducted a cohort epidemiological study of a group of liquidators who worked in the 30-km zone in 1986‒1990 over a period of more than thirty years depending on the dose received both during liquidation of the Chernobyl accident consequences and during professional work with radioactive substances (RS) and ionizing radiation sources (IRS). Results: As a result of the study direct estimates of radiogenic risk of thyroid diseases associated with iodine deficiency in the liquidators of the Chernobyl accident consequences were obtained for the first time using the data on doses of Chernobyl and the sum of these doses with the doses of occupational exposure. It is shown that the risk of disease per unit dose (ERR/Zv) for dose loads received both at liquidation of Chernobyl accident consequences and for total doses give different results. Conclusion: Assessment of the risk of thyroid diseases associated with iodine deficiency, liquidators of the Chernobyl NPP accident consequences and workers of nuclear industry enterprises, serviced by FMBA health care institutions of Russia using the doses of different types of exposure gives different results. Correct results of assessing the risk of radiation-related diseases can only be given by the register using the total radiation dose (occupational, accidental, medical, natural), as required by the directive documents.