Evgenia Ostroumova1, Alexander Rozhko2, Maureen Hatch1, Kyoji Furukawa3, Olga Polyanskaya2, Robert J. McConnell4, Eldar Nadyrov2, Sergey Petrenko5, George Romanov2, Vasilina Yauseyenka2, Vladimir Drozdovitch1, Viktor Minenko6, Alexander Prokopovich2, Irina Savasteeva2, Lydia B. Zablotska7, Kiyohiko Mabuchi1, Alina V. Brenner1
07 May 2013
Background: Thyroid dysfunction after exposure to low or moderate doses of radioactive iodine-131 (131I) at a young age is a public health concern. However, quantitative data are sparse concerning 131I-related risk of these common diseases.
Objective: Our goal was to assess the prevalence of thyroid dysfunction in association with 131I exposure during childhood (≤ 18 years) due to fallout from the Chernobyl accident.
Methods: We conducted a cross-sectional analysis of hypothyroidism, hyperthyroidism, autoimmune thyroiditis (AIT), serum concentrations of thyroid-stimulating hormone (TSH), and autoantibodies to thyroperoxidase (ATPO) in relation to measurement-based 131I dose estimates in a Belarusian cohort of 10,827 individuals screened for various thyroid diseases.
Results: Mean age at exposure (± SD) was 8.2 ± 5.0 years. Mean (median) estimated 131I thyroid dose was 0.54 (0.23) Gy (range, 0.001–26.6 Gy). We found significant positive associations of 131I dose with hypothyroidism (mainly subclinical and antibody-negative) and serum TSH concentration. The excess odds ratio per 1 Gy for hypothyroidism was 0.34 (95% CI: 0.15, 0.62) and varied significantly by age at exposure and at examination, presence of goiter, and urban/rural residency. We found no evidence of positive associations with antibody-positive hypothyroidism, hyperthyroidism, AIT, or elevated ATPO.
Conclusions: The association between 131I dose and hypothyroidism in the Belarusian cohort is consistent with that previously reported for a Ukrainian cohort and strengthens evidence of the effect of environmental 131I exposure during childhood on hypothyroidism, but not other thyroid outcomes.