title: Tumors of the nervous system and pituitary gland associated with atomic bomb radiation exposure.
abstract: BACKGROUND
  The risk of developing nervous system tumors following exposure to ionizing radiation is not well quantified. We characterized the incidence of nervous system tumors among atomic bomb survivors as a function of radiation dose.
  
  
  METHODS
  Tumors of the nervous system and pituitary gland diagnosed between 1958 and 1995 among 80 160 atomic bomb survivors were ascertained using the Hiroshima and Nagasaki tumor registries, medical records, and death certificates. Pathologists reviewed slides and medical records to provide histologic diagnoses. Poisson regression analyses were used to characterize radiation effects on tumor incidence, which are expressed as excess relative risk per sievert (ERR(Sv)). All statistical tests were two-sided.
  
  
  RESULTS
  A statistically significant dose-related excess of nervous system tumors was observed in the cohort (ERR(Sv) = 1.2, 95% confidence interval [CI] = 0.6 to 2.1). The highest ERR(Sv) was seen for schwannoma (4.5, 95% CI = 1.9 to 9.2). The risk for all other nervous system tumors as a group is also statistically significantly elevated (ERR(Sv) = 0.6, 95% CI = 0.1 to 1.3). Risk increases, although not statistically significant, were seen for meningiomas (ERR(Sv) = 0.6, 95% CI = -0.01 to 1.8), gliomas (ERR(Sv) = 0.6, 95% CI = -0.2 to 2.0), other nervous system tumors (ERR(Sv) = 0.5, 95% CI = <-0.2 to 2.2), and pituitary tumors (ERR(Sv) = 1.0, 95% CI = <-0.2 to 3.5). The dose-response relationships were linear. For nervous system tumors other than schwannoma, excess risks were higher for men than for women and for those exposed during childhood than for those exposed during adulthood.
  
  
  CONCLUSIONS
  A statistically significant dose response was observed for all nervous system tumors combined and for schwannoma considered separately, indicating that exposure to even moderate doses (i.e., <1 Sv) of radiation is associated with an elevated incidence of nervous system tumors.
authors.affiliation: Department of Statistics, Radiation Effects Research Foundation, Hiroshima, Japan. preston@rerf.or.jp
authors.forename: Dale L
authors.initials: DL
authors.lastname: Preston
authors.forename: Elaine
authors.initials: E
authors.lastname: Ron
authors.forename: Shuji
authors.initials: S
authors.lastname: Yonehara
authors.forename: Toshihiro
authors.initials: T
authors.lastname: Kobuke
authors.forename: Hideharu
authors.initials: H
authors.lastname: Fujii
authors.forename: Masao
authors.initials: M
authors.lastname: Kishikawa
authors.forename: Masayoshi
authors.initials: M
authors.lastname: Tokunaga
authors.forename: Shoji
authors.initials: S
authors.lastname: Tokuoka
authors.forename: Kiyohiko
authors.initials: K
authors.lastname: Mabuchi
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D004307:Dose-Response Relationship, Radiation; D005260:Female; D005910:Glioma / Q000453:epidemiology / Q000209:etiology; D006801:Humans; D015994:Incidence; D007564:Japan / Q000453:epidemiology; D016014:Linear Models; D008297:Male; D008579:Meningioma / Q000453:epidemiology / Q000209:etiology; D008875:Middle Aged; D009381:Neoplasms, Radiation-Induced / Q000453:epidemiology* / Q000209:etiology; D009423:Nervous System Neoplasms / Q000453:epidemiology* / Q000209:etiology*; D009442:Neurilemmoma / Q000453:epidemiology / Q000209:etiology; D010911:Pituitary Neoplasms / Q000453:epidemiology* / Q000209:etiology*; D012042:Registries; D012306:Risk; D017741:Survivors / Q000706:statistics & numerical data