title: Childhood thyroid radioiodine exposure and subsequent infertility in the intermountain fallout cohort.
abstract: BACKGROUND
  Above-ground and underground nuclear weapon detonation at the Nevada Test Site (1951-1992) has resulted in radioiodine exposure for nearby populations. Although the long-term effect of environmental radioiodine exposure on thyroid disease has been well studied, little is known regarding the effect of childhood radioiodine exposure on subsequent fertility.
  
  
  OBJECTIVE
  We investigated early childhood thyroid radiation exposure from nuclear testing fallout (supplied predominantly by radioactive isotopes of iodine) and self-reported lifetime incidence of male or female infertility or sterility.
  
  
  METHODS
  Participants were members of the 1965 Intermountain Fallout Cohort, schoolchildren at the time of exposure who were reexamined during two subsequent study phases to collect dietary and reproductive histories. Thyroid radiation exposure was calculated via an updated dosimetry model. We used multivariable logistic regression with robust sandwich estimators to estimate odds ratios for infertility, adjusted for potential confounders and (in separate models) for a medically confirmed history of thyroid disease.
  
  
  RESULTS
  Of 1,389 participants with dosimetry and known fertility history, 274 were classified as infertile, including 30 classified as sterile. Childhood thyroid radiation dose was possibly associated with infertility [adjusted odds ratio (AOR) = 1.17; 95% CI: 0.82, 1.67 and AOR = 1.35; 95% CI: 0.96, 1.90 for the middle and upper tertiles vs. the first tertile of exposure, respectively]. The odds ratios were attenuated (AOR = 1.08; 95% CI: 0.75, 1.55 and AOR = 1.29; 95% CI: 0.91, 1.83 for the middle and upper tertiles, respectively) after adjusting for thyroid disease. There was no association of childhood radiation dose and sterility.
  
  
  CONCLUSIONS
  Our findings suggest that childhood radioiodine exposure from nuclear testing may be related to subsequent adult infertility. Further research is required to confirm this.
authors.affiliation: University of Utah Department of Family and Preventive Medicine, Salt Lake City, Utah 84108, USA.
authors.forename: Mary Bishop
authors.initials: MB
authors.lastname: Stone
authors.forename: Joseph B
authors.initials: JB
authors.lastname: Stanford
authors.forename: Joseph L
authors.initials: JL
authors.lastname: Lyon
authors.forename: James A
authors.initials: JA
authors.lastname: VanDerslice
authors.forename: Stephen C
authors.initials: SC
authors.lastname: Alder
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D007246:Infertility / Q000139:chemically induced*; D007457:Iodine Radioisotopes / Q000633:toxicity*; D008297:Male; D008875:Middle Aged; D009689:Nuclear Warfare; D054043:Nuclear Weapons; D013961:Thyroid Gland / Q000187:drug effects*
chemical_list: D007457:Iodine Radioisotopes