Validity of self-reported endoscopies of the large bowel and implications for estimates of colorectal cancer risk

Am J Epidemiol. 2007 Jul 15;166(2):130-6. doi: 10.1093/aje/kwm062. Epub 2007 Apr 23.


Large-bowel endoscopy with removal of polyps strongly reduces colorectal cancer risk. In epidemiologic studies, ascertainment of large-bowel endoscopies often relies on self-reports and might be prone to imperfect recall. In 2003-2004, the authors assessed the validity of self-reported colorectal endoscopies in a population-based case-control study including 540 cases and 614 controls from southwest Germany and calculated odds ratios of colorectal cancer risk according to self-reports and medical records. They sought to obtain all medical records for the last self-reported endoscopy and for a subsample of 100 subjects reporting no previous endoscopy. In total, 377 of 483 records could be obtained (78%). Sensitivity of self-reports was 100%, and specificity ranged from 93% to 98% among subgroups defined by age, gender, education, family history of colorectal cancer, and case-control status. The odds ratios for colorectal cancer risk after previous colonoscopy were 0.31 (95% confidence interval: 0.21, 0.45) using self-reports and 0.31 (95% confidence interval: 0.20, 0.47) using medical records. However, agreement between self-reports and medical records was poor regarding type of endoscopy (colonoscopy, sigmoidoscopy, or rectoscopy; kappa = 0.22), moderate concerning polypectomy (kappa = 0.58), and reasonable for year of examination (kappa = 0.70). Self-reports of previous colorectal endoscopies agreed well with medical records, but validation appears to be essential with respect to details of the examination.

Publication types

  • Validation Study

MeSH terms

  • Aged
  • Case-Control Studies
  • Colonic Polyps / complications
  • Colonic Polyps / epidemiology
  • Colonic Polyps / surgery
  • Colonoscopy*
  • Colorectal Neoplasms / diagnosis*
  • Colorectal Neoplasms / etiology
  • Female
  • Germany
  • Humans
  • Male
  • Mass Screening
  • Medical Records*
  • Mental Recall
  • Middle Aged
  • Reproducibility of Results
  • Risk Factors
  • Self Disclosure*
  • Sigmoidoscopy*