Objective: To study the incidence, prevalence and clinical characteristics of Behçet's disease (BD) in a defined population in southern Sweden.
Methods: The study area consists of three health-care districts with an adult population (≥15 years) of 809 317 on 1 January 2011 (25% of non-Swedish ancestry), situated in Skåne, the southernmost county in Sweden. Patients were identified using clinical registries in all the five hospitals within the study area. Only patients fulfilling the International Study Group criteria for diagnosis of BD were included.
Results: Forty patients (13 women) fulfilling the diagnosis criteria for BD (70% of non-Swedish ancestry) were identified. The point prevalence of BD on 1 January 2011 was 4.9/100,000 adults (95% CI 3.4, 6.5) and was higher among the population of non-Swedish ancestry (13.6 vs 2.0/100,000, P < 0.001), and higher among men (6.8 vs 3.2/100,000, P = 0.019). There were 20 incident cases (diagnosed in Sweden between 1997 and 2010). The annual incidence rate was 0.2/100,000 adults (95% CI 0.1, 0.3) and was higher among the population of non-Swedish ancestry (0.6 vs 0.1/100,000, P < 0.001). The incidence was 0.3/100,000 adults in men and 0.1/100,000 in women, P = 0.143. During the course of the disease, 100% of the patients developed oral ulceration, 80% genital ulcers, 88% skin lesions, 53% eye disease, 40% arthritis/arthralgia and 20% venous thrombosis.
Conclusion: The prevalence of BD is higher in Sweden than previously reported, mainly due to immigration. The incidence of BD remains elevated for immigrants from high-prevalence regions even long after settling in Sweden.