Incidence of diffuse toxic goiter in children irradiated as a result of the Chernobyl accident

Time course of incidence of diffuse toxic goiter (DTG) was studied in 1986-1999 in the cohort of subjects who were aged under 15 years in the year of the Chernobyl accident and lived at radionuclide contaminated iodine deficient territories of Central Russia (Belgorod, Voronezh, and Orel regions, a total of 34 territories, n = 215,294). Control cohort (3-fold more numerous) consisted of age-matched residents of the same region, but from non-contaminated territories (45 territories, n = 665,987). During 5 years after the accident the morbidity was the same in both groups and lower than in children of Europe, Americas, Asia living in regions with normal and excess iodine consumption (0.279 per 100,000 annually in the main cohort and 0.390 in the control vs. 3-4 in foreign countries). The values remained low during subsequent 4 years (0.697 and 0.526 - the increases are insignificant). During recent 5 years the incidence of DTG sharply increased at all territories, most drastically in the cohort of irradiated subjects (1.579 and 0.841). The morbidity increased 2- fold in the control vs. the initial level (the relative risk being 2.1 (1.1-4. l,p < 0.03) and almost 6-fold in the main cohort (relative risk = 5.7 (1.7-19.3, p < 0.004). On the whole, 10-15 years after the accident, the risk of DTG for children exposed to low-intensive radiation surpassed the estimated level 1.9 times ([1.1-3.4], p < 0.04).