Population-based prevalence study of Behçet's disease: differences by ethnic origin and low variation by age at immigration.

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.