title: Comparison of documented and recalled histories of exposure to diagnostic x-rays in case-control studies of thyroid cancer.
abstract: Most information concerning possible cancer risks attributable to lifetime exposure to diagnostic x-rays comes from studies in which x-ray history was ascertained by interview or questionnaire, but little is known about the accuracy of such information. The authors assessed agreement between medical x-ray histories obtained through interview and by review of medical records from thyroid cancer case-control studies conducted in Sweden (1985-1992; 123 cases and 123 controls) and from members of a prepaid health plan in the United States (1986-1991; 50 cases and 50 controls). In both studies, substantial disagreement was found between the numbers of x-ray examinations reported in the interview and in the medical records. There was an indication of relatively poorer reporting among controls, particularly for certain types of x-ray examinations and for large numbers of such examinations. Estimates of the risk associated with exposure to diagnostic x-rays were similar, regardless of whether interview or medical record data were used, even though ordinal dose classifications based on the two sources differed considerably. In populations with a high frequency of exposure, spurious associations with numbers of x-ray examinations or estimated thyroid dose might arise because of differences in recall. However, in the present data, reporting errors by cases and controls seemed to be largely nondifferential.
authors.affiliation: Cancer Research UK Epidemiology Unit, University of Oxford, Oxford, United Kingdom.
authors.forename: Amy
authors.initials: A
authors.lastname: Berrington de Gonzalez
authors.forename: Anders
authors.initials: A
authors.lastname: Ekbom
authors.forename: Andrew G
authors.initials: AG
authors.lastname: Glass
authors.forename: Maria Rosaria
authors.initials: MR
authors.lastname: Galanti
authors.forename: Lars
authors.initials: L
authors.lastname: Grimelius
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Allison
authors.forename: Peter D
authors.initials: PD
authors.lastname: Inskip
mesh_terms: D000328:Adult; D017677:Age Distribution; D000368:Aged; D016022:Case-Control Studies; D004282:Documentation; D005260:Female; D006801:Humans; D008297:Male; D008499:Medical Records; D011939:Mental Recall; D008875:Middle Aged; D011832:Radiation Injuries / Q000453:epidemiology*; D012042:Registries; D015203:Reproducibility of Results; D017678:Sex Distribution; D013548:Sweden / Q000453:epidemiology; D013964:Thyroid Neoplasms / Q000453:epidemiology / Q000209:etiology*; D014481:United States / Q000453:epidemiology