Radiation epidemiology of cancer- and non-cancer thyroid diseases in Russia after the ChNPP accident: prognostication and risk estimate

In presented paper the problem of thyroid cancer following the ChNPP accident is considered for the first time on the basis of system approach. The three main tasks are solved: prognostication of immediate and later effects of radiation action comments with the induction of malignant thyroid tumors; determination of radiation risks of non-cancer thyroid diseases; estimation of radiation risks of cancer thyroid diseases. As a result of conducted prognostication estimates it is shown, in particular, that the attributive life time risk for children from the territories of Bryansk oblast contaminated by radionuclides will constitute 44% (i.e., nearly each second cancer will be conditioned by radiation), for children of Kaluga oblast this coefficient will amount to 26%. In the cohort of children and adolescents of Kaluga oblast (5694 people) with individual radiation dose of thyroid gland based on direct radiometry carried out in 1986 the radiation risk estimates of non-cancer thyroid diseases were obtained. In particular, estimation of excess relative risk coefficient at the dose of 1 Gy equal to 0,2 (0,06; 0,34) is in a good agreement with the data published on the basis of AHS-cohort (Japan). The technology "case-control" is realized first for determination of radiation risks of thyroid cancer diseases by children and adolescent (at the moment of the accident) living in Bryansk oblast. The relative risk coefficient of thyroid cancer diseases in the western rayons of Bryansk oblast contaminated by radionuclides at the dose of 1 Gy is equal 7,15 (1,52; 33,8). The principal radiation epidemiological data obtained evidence the necessity of conducting the long-term monitoring the persons exposed to radiation action due to the ChNNP accident.