Thyroid Autoantibodies (Ata) and Thyroid Function in Subjects Exposed to Chernobyl Fallout During Childhood: Evidence for a Transient Radiation-Induced Elevation of Serum Thyroid Antibodies without an Increase in Thyroid Autoimmune Disease

摘要

Context: An increase in the prevalence of thyroid autoantibodies (ATAs) was reported 6–8 yr after\udthe Chernobyl accident in radiation-exposed children and adolescents.\udObjective: Our objective was to reassess the effects of childhood radiation exposure on ATAs and\udthyroid function 13–15 yr after the accident.\udDesign and Setting: We measured the antithyroglobulin (TgAbs) and antithyroperoxidase (TPOAbs)\udantibodies and TSH in 1433 sera collected between 1999 and 2001 from 13- to 17-yr-old\udadolescents born between January 1982 and October 1986 in paired contaminated and noncontaminated\udvillages of Belarus, Ukraine, and Russia.Atotal of 1441 sera was collected from age- and\udsex-matched controls living in Denmark and Sardinia (Italy). Free T4 and free T3 were measured\udwhen TSH was abnormal.\udResults: TPOAb prevalence was higher in contaminated than in noncontaminated Belarusian children\ud(6.4 vs. 2.4%; P r0.02) but lower than previously reported (11%) in a different contaminated Belarus\udvillage.Nodifference inTPOAbprevalencewasfound in UkrainianandRussian villages.TgAbsshowed\udno difference between contaminated and noncontaminated Belarus and Ukraine, whereas in Russia\udthey showed a relative increase in the exposed subjects with respect to the unexposed, who showed\udan unexpectedly lower prevalence of TgAbs. Besides radiation exposure, female gender was the only\udvariable significantly correlated with ATAs in all groups. ATA prevalence in nonexposed villages of\udBelarus, Ukraine,andRussian Federation did not differ from that found in SardiniaandDenmark. With\udfew exceptions, thyroid function was normal in all study groups.\udConclusions: TPOAb prevalence in adolescents exposed to radioactive fallout was still increased in\udBelarus 13–15 yr after the Chernobyl accident. This increase was less evident than previously reported\udand was not accompanied by thyroid dysfunction. Our data suggest that radioactive fallout elicited a\udtransient autoimmune reaction, without triggering full-blown thyroid autoimmune disease. Longer\udobservation periods are needed to exclude later effects.