title: Impact of Uncertainties in Exposure Assessment on Thyroid Cancer Risk among Persons in Belarus Exposed as Children or Adolescents Due to the Chernobyl Accident.
abstract: BACKGROUND
  The excess incidence of thyroid cancer in Ukraine and Belarus observed a few years after the Chernobyl accident is considered to be largely the result of 131I released from the reactor. Although the Belarus thyroid cancer prevalence data has been previously analyzed, no account was taken of dose measurement error.
  
  
  METHODS
  We examined dose-response patterns in a thyroid screening prevalence cohort of 11,732 persons aged under 18 at the time of the accident, diagnosed during 1996-2004, who had direct thyroid 131I activity measurement, and were resident in the most radio-actively contaminated regions of Belarus. Three methods of dose-error correction (regression calibration, Monte Carlo maximum likelihood, Bayesian Markov Chain Monte Carlo) were applied.
  
  
  RESULTS
  There was a statistically significant (p<0.001) increasing dose-response for prevalent thyroid cancer, irrespective of regression-adjustment method used. Without adjustment for dose errors the excess odds ratio was 1.51 Gy- (95% CI 0.53, 3.86), which was reduced by 13% when regression-calibration adjustment was used, 1.31 Gy- (95% CI 0.47, 3.31). A Monte Carlo maximum likelihood method yielded an excess odds ratio of 1.48 Gy- (95% CI 0.53, 3.87), about 2% lower than the unadjusted analysis. The Bayesian method yielded a maximum posterior excess odds ratio of 1.16 Gy- (95% BCI 0.20, 4.32), 23% lower than the unadjusted analysis. There were borderline significant (p = 0.053-0.078) indications of downward curvature in the dose response, depending on the adjustment methods used. There were also borderline significant (p = 0.102) modifying effects of gender on the radiation dose trend, but no significant modifying effects of age at time of accident, or age at screening as modifiers of dose response (p>0.2).
  
  
  CONCLUSIONS
  In summary, the relatively small contribution of unshared classical dose error in the current study results in comparatively modest effects on the regression parameters.
authors.affiliation: Radiation Epidemiology Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Department of Health and Human Services, Bethesda, Maryland, United States of America.
authors.forename: Mark P
authors.initials: MP
authors.lastname: Little
authors.affiliation: Sylvester Comprehensive Cancer Center, University of Miami, Miami, Florida, United States of America.
authors.forename: Deukwoo
authors.initials: D
authors.lastname: Kwon
authors.affiliation: Department of Epidemiology and Biostatistics, University of California San Francisco, San Francisco, California, United States of America.
authors.forename: Lydia B
authors.initials: LB
authors.lastname: Zablotska
authors.affiliation: Radiation Epidemiology Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Department of Health and Human Services, Bethesda, Maryland, United States of America.
authors.forename: Alina V
authors.initials: AV
authors.lastname: Brenner
authors.affiliation: Radiation Epidemiology Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Department of Health and Human Services, Bethesda, Maryland, United States of America.
authors.forename: Elizabeth K
authors.initials: EK
authors.lastname: Cahoon
authors.affiliation: The Republican Research Center for Radiation Medicine and Human Ecology, Gomel 246040, Belarus.
authors.forename: Alexander V
authors.initials: AV
authors.lastname: Rozhko
authors.affiliation: The Republican Research Center for Radiation Medicine and Human Ecology, Gomel 246040, Belarus.
authors.forename: Olga N
authors.initials: ON
authors.lastname: Polyanskaya
authors.affiliation: Research Institute for Nuclear Problems, Minsk, Belarus.
authors.forename: Victor F
authors.initials: VF
authors.lastname: Minenko
authors.affiliation: Burnasyan Federal Medical Biophysical Center, Moscow, Russian Federation.
authors.forename: Ivan
authors.initials: I
authors.lastname: Golovanov
authors.affiliation: Radiation Epidemiology Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Department of Health and Human Services, Bethesda, Maryland, United States of America.
authors.forename: André
authors.initials: A
authors.lastname: Bouville
authors.affiliation: Radiation Epidemiology Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Department of Health and Human Services, Bethesda, Maryland, United States of America.
authors.forename: Vladimir
authors.initials: V
authors.lastname: Drozdovitch
mesh_terms: D000293:Adolescent; D000328:Adult; D001499:Bayes Theorem; D047852:Chernobyl Nuclear Accident; D002648:Child; D004190:Disasters; D004307:Dose-Response Relationship, Radiation; D004781:Environmental Exposure; D005260:Female; D006801:Humans; D007457:Iodine Radioisotopes / Q000009:adverse effects*; D008297:Male; D008390:Markov Chains; D015233:Models, Statistical; D009010:Monte Carlo Method; D009381:Neoplasms, Radiation-Induced / Q000453:epidemiology*; D009688:Nuclear Reactors; D015995:Prevalence; D015203:Reproducibility of Results; D002094:Republic of Belarus; D012307:Risk Factors; D013269:Stochastic Processes; D013964:Thyroid Neoplasms / Q000453:epidemiology* / Q000209:etiology*; D014455:Ukraine; D035501:Uncertainty; D055815:Young Adult
chemical_list: D007457:Iodine Radioisotopes