title: Risk of ischemic stroke in patients with Crohn's disease: a population-based nested case-control study.
abstract: BACKGROUND
  Observational studies have linked Crohn's disease (CD) to an increased risk of venous thromboembolic complications. Case reports of ischemic stroke in CD patients have raised the question of a similar association, but data from observational studies are lacking.
  
  
  METHODS
  Using data from the UK General Practice Research Database we conducted a nested case-control analysis within a population-based cohort of 8054 patients with and 161,078 patients without CD. A total of 1748 cases of ischemic stroke were identified to whom 17,348 controls were matched on age, sex, and year of cohort entry. Adjusted odds ratios (ORs) of ischemic stroke associated with CD were calculated by conditional logistic regression. Stratified analyses were performed for age and sex.
  
  
  RESULTS
  While CD was not associated with an overall increased risk of ischemic stroke (OR 1.10, 95% confidence interval [CI] 0.85-1.43), stratified analyses revealed an increase in risk in younger patients (<50 years: OR 2.93; 95% CI 1.44-5.98) but not in elderly patients (> or =50 years: OR 0.99; 95% CI 0.75-1.30; P for interaction <0.01). The interaction with age remained statistically significant even after changing the cutoff value for the younger and older age group to 45, 55, or 60 years in a sensitivity analysis. There was no interaction with sex (P = 0.79).
  
  
  CONCLUSIONS
  The study indicates that younger patients with CD may be under an increased risk of ischemic stroke.
authors.affiliation: Institute for Social Medicine, Epidemiology, and Health Economics, Charité University Medical Center Berlin, Germany. frank.andersohn@charite.de
authors.forename: Frank
authors.initials: F
authors.lastname: Andersohn
authors.forename: Mark
authors.initials: M
authors.lastname: Waring
authors.forename: Edeltraut
authors.initials: E
authors.lastname: Garbe
mesh_terms: D000367:Age Factors; D000368:Aged; D002545:Brain Ischemia / Q000453:epidemiology / Q000209:etiology; D016022:Case-Control Studies; D003424:Crohn Disease / Q000150:complications / Q000453:epidemiology*; D016208:Databases, Factual; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012306:Risk; D020521:Stroke / Q000453:epidemiology* / Q000209:etiology; D006113:United Kingdom / Q000453:epidemiology