title: Thyroid cancer study among Ukrainian children exposed to radiation after the Chornobyl accident: improved estimates of the thyroid doses to the cohort members.
abstract: In collaboration with the Ukrainian Research Center for Radiation Medicine, the U.S. National Cancer Institute initiated a cohort study of children and adolescents exposed to Chornobyl fallout in Ukraine to better understand the long-term health effects of exposure to radioactive iodines. All 13,204 cohort members were subjected to at least one direct thyroid measurement between 30 April and 30 June 1986 and resided at the time of the accident in the northern parts of Kyiv, Zhytomyr, or Chernihiv Oblasts, which were the most contaminated territories of Ukraine as a result of radioactive fallout from the Chornobyl accident. Thyroid doses for the cohort members, which had been estimated following the first round of interviews, were re-evaluated following the second round of interviews. The revised thyroid doses range from 0.35 mGy to 42 Gy, with 95% of the doses between 1 mGy and 4.2 Gy, an arithmetic mean of 0.65 Gy, and a geometric mean of 0.19 Gy. These means are 70% of the previous estimates, mainly because of the use of country-specific thyroid masses. Many of the individual thyroid dose estimates show substantial differences because of the use of an improved questionnaire for the second round of interviews. Limitations of the current set of thyroid dose estimates are discussed. For the epidemiologic study, the most notable improvement is a revised assessment of the uncertainties, as shared and unshared uncertainties in the parameter values were considered in the calculation of the 1,000 stochastic estimates of thyroid dose for each cohort member. This procedure makes it possible to perform a more realistic risk analysis.
authors.affiliation: *State Institution "National Research Centre for Radiation Medicine," National Academy of Medical Sciences of Ukraine, 53 Melnikova Street, 04050 Kyiv, Ukraine; †Institute for Safety Problems of Nuclear Power Plants, National Academy of Sciences of Ukraine, 12/106 Lysogirska Street, 03028 Kyiv, Ukraine; ‡MJP Risk Assessment, Inc., P.O. Box 200937, Denver, CO 80220-0937; §Division of Cancer Epidemiology and Genetics, National Cancer Institute, NIH, DHHS, 9609 Medical Center Drive, Bethesda, MD 20892; **U.S. National Cancer Institute (retired).
authors.forename: Ilya
authors.initials: I
authors.lastname: Likhtarov
authors.forename: Lina
authors.initials: L
authors.lastname: Kovgan
authors.forename: Sergii
authors.initials: S
authors.lastname: Masiuk
authors.forename: Mykola
authors.initials: M
authors.lastname: Talerko
authors.forename: Mykola
authors.initials: M
authors.lastname: Chepurny
authors.forename: Olga
authors.initials: O
authors.lastname: Ivanova
authors.forename: Valentina
authors.initials: V
authors.lastname: Gerasymenko
authors.forename: Zulfira
authors.initials: Z
authors.lastname: Boyko
authors.forename: Paul
authors.initials: P
authors.lastname: Voillequé
authors.forename: Vladimir
authors.initials: V
authors.lastname: Drozdovitch
authors.forename: André
authors.initials: A
authors.lastname: Bouville
mesh_terms: D000293:Adolescent; D047852:Chernobyl Nuclear Accident; D002648:Child; D015331:Cohort Studies; D006801:Humans; D009381:Neoplasms, Radiation-Induced / Q000453:epidemiology*; D011829:Radiation Dosage; D013964:Thyroid Neoplasms / Q000453:epidemiology*; D014455:Ukraine / Q000453:epidemiology