The dependence of incidence rates of non-cancer thyroid diseases in the post-natal period at the Kaluga oblast children from term gestation, on which has taken place them in utero irradiation owing to technogenic iodine-131 incorporation

The results of investigation of non-cancer thyroid diseases incidence rates, relative risks and etiologic fractions by cohort study at 420 children from southwest region of the Kaluga oblast for the 12-year's period after irradiation in utero on various terms of gestation at the expense of the technogenic iodine-131 incorporation are presented. Also 150 not exposed children as the control group was observed. It was established that incidence rates of thyroid diseases in the children irradiated in utero was at 2.6 times more than in the control group. The incidence of thyroid diseases among the children irradiated in utero was depended on the period of gestation at which irradiation was occurred. The most high level of the thyroid diseases incidence rate was in two subgroups of irradiated children: in the first subgroup every member was irradiated at the expense of iodine-131 from 4-th to 12-th week of gestation, in the second subgroup - from 16-th to 22-th week of gestation. It is known from radiobiological investigations that at these periods of gestation thyroid of foetus intensively accumulates radioactive iodine.