The dynamics of thyroid diseases incidence in the period before puberty at children from southwest region of the Kaluga oblast irradiated in utero owing to technogenic iodine-131 incorporation

Cohort study of dynamics of non-cancer thyroid diseases incidence rates during 12-year follow-up of prepubertal 420 children exposed to incorporated iodine-131 in utero and 150 unexposed children of the same age resided in the iodine-deficient southwest rayon of the Kaluga oblast was carried out. Both difference in frequency of thyroid diseases development in these two groups of children and changes in thyroid diseases cumulative incidence with maturation of the children were found. Non-cancer thyroid diseases cumulative incidence increased gradually with maturation of unexposed children, the highest incidence was at the last stage of the follow-up, whereas the frequency of thyroid diseases development in the children exposed in utero increased sharply at the younger age, the highest incidence was at the age of 7-9 years; however, at the age of 10-12 years thyroid diseases incidence in this group was a little lower, than that in unexposed children of the same age.