Risk of thyroid nodules in residents of Belarus exposed to Chernobyl fallout as children and adolescents.

Risk of thyroid nodules in residents of Belarus exposed to Chernobyl fallout as children and adolescents.

J Clin Endocrinol Metab. 2017 Mar 22;:

Authors: Cahoon EK, Nadirov EA, Polanskaya ON, Yauseyenka VV, Velalkin IV, Yeudachkova TI, Maskvicheva TI, Minenko VF, Liu W, Drozdovitch V, Mabuchi K, Little MP, Zablotska LB, McConnell RJ, Hatch M, Peters KO, Rozhko AV, Brenner AV

Abstract
Context: Although radiation exposure is an important predictor of thyroid cancer upon diagnosis of a thyroid nodule, the relationship between childhood radiation exposure and thyroid nodules has not been comprehensively evaluated.
Objective: To examine the association between internal I-131 thyroid radiation dose and thyroid nodules in young adults exposed during childhood.
Design, setting, and participants: In this cross-sectional study, we screened 11,970 residents of Belarus aged ≤18 years at the time of the Chernobyl nuclear accident (April 1986) for thyroid disease (median age 21 years) with thyroid palpation, ultrasonography, blood and urine analysis, and medical follow-up when appropriate. Eligible participants (N=11,421) had intact thyroid glands and doses based on direct individual thyroid activity measurements.
Main outcome measures: Excess odds ratios per Gray (EOR/Gy, scaled at age 5 years at exposure) for any thyroid nodule and for nodules grouped by cytology/histology, diameter size, and single versus multiple presentation.
Results: Risk of any thyroid nodule increased significantly with I-131 dose and, for a given dose, with younger age at exposure. The EOR/Gy (95%CI) for neoplastic nodules (3.82;0.87, 15.52) was significantly higher than for non-neoplastic nodules (0.32;<0.03, 0.70) and did not vary by size; while the EOR/Gy for non-neoplastic nodules did vary by size (P=0.02) and was 1.55 (0.36, 5.46) for nodules ≥10 mm and 0.02 (<-0.02, 0.70) for nodules <10 mm. EORs/Gy for single and multiple nodules were comparable.
Conclusions: Childhood exposure to internal I-131 is associated with increased risk of neoplastic thyroid nodules of any size and non-neoplastic nodules ≥10 mm.

PMID: 28368520 [PubMed - as supplied by publisher]

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