title: Population-based prevalence study of Behçet's disease: differences by ethnic origin and low variation by age at immigration.
abstract: OBJECTIVE
  To estimate the prevalence of Behçet's disease (BD) in a multiethnic population living in France, with particular focus on disease risk among immigrants.
  
  
  METHODS
  The study was conducted in a county in the Paris metropolitan area that is home to 1,094,412 adults (ages > or =15 years), of whom 26% are of non-European ancestry. Patients with BD living in this area during 2003 were identified using 3 sources (hospitals, community physicians, and the National Health Insurance database), and diagnoses were verified using the International Study Group criteria. Standardized, year-2003 prevalence rates were computed for the overall population and for each ethnic group. Stratified prevalence rates according to age at immigration to France were calculated to investigate the relationship between age at immigration and BD risk.
  
  
  RESULTS
  Seventy-nine subjects fulfilled our search criteria. The overall prevalence per 100,000 adults was 7.1 (95% confidence interval [95% CI] 3.5-14.4), and the prevalence for populations of European, North African, and Asian ancestry was 2.4 (95% CI 0.6-7.2), 34.6 (95% CI 24.4-47.5), and 17.5 (95% CI 10.7-27.2), respectively. Within the migrant population of either North African or Asian ancestry, BD prevalences were similar for residents born in France, residents <15 years old at immigration, and residents > or =15 years old at immigration.
  
  
  CONCLUSIONS
  Our findings indicate that the prevalence of BD among immigrants of North African or Asian ancestry is significantly higher than that in the European-origin population, and comparable with rates reported from North Africa and Asia. Moreover, our results suggest that BD risk is not related to age at immigration. These findings support the hypothesis that BD has a primarily hereditary basis.
authors.affiliation: Department of Internal Medicine, Université Paris 5-René Descartes, Hôpital Cochin, Assistance Publique Hôpitaux de Paris, Paris, France. alfred.mahr@cch.aphp.fr
authors.forename: Alfred
authors.initials: A
authors.lastname: Mahr
authors.forename: Linda
authors.initials: L
authors.lastname: Belarbi
authors.forename: Bertrand
authors.initials: B
authors.lastname: Wechsler
authors.forename: Dominique
authors.initials: D
authors.lastname: Jeanneret
authors.forename: Robin
authors.initials: R
authors.lastname: Dhote
authors.forename: Olivier
authors.initials: O
authors.lastname: Fain
authors.forename: François
authors.initials: F
authors.lastname: Lhote
authors.forename: Jacky
authors.initials: J
authors.lastname: Ramanoelina
authors.forename: Joël
authors.initials: J
authors.lastname: Coste
authors.forename: Loïc
authors.initials: L
authors.lastname: Guillevin
mesh_terms: D000328:Adult; D000352:Africa, Northern / Q000208:ethnology; D017677:Age Distribution; D001208:Asia / Q000208:ethnology; D001528:Behcet Syndrome / Q000208:ethnology*; D003430:Cross-Sectional Studies; D054242:Emigrants and Immigrants / Q000706:statistics & numerical data*; D005260:Female; D005602:France / Q000453:epidemiology; D006801:Humans; D008297:Male; D015995:Prevalence; D012307:Risk Factors; D055815:Young Adult