Prevalence, Incidence, and Disease Characteristics of Takayasu Arteritis by Ethnic Background: Data From a Large, Population-Based Cohort Resident in Southern Norway.

Objective: To study the epidemiology and clinical characteristics of Takayasu arteritis (TAK) in southeast Norway (population 2.8 million).

Methods: All study area hospital databases were screened to capture every potential TAK case between 1999 and 2012. These cases were manually chart reviewed, and only patients fulfilling either the 1990 American College of Rheumatology classification or the 1995 Ishikawa diagnostic criteria were included.

Results: Inclusion criteria were met by 78 patients (68 female, 10 male). Point prevalence (by 2012) segregated by ethnic origin was 22.0 per 10 (95% confidence interval [95% CI] 17-29) in northern Europeans compared to 78.1 (95% CI 38-152) in Asian whites and 108.3 (95% CI 46-254) in Africans (P < 0.001). The incidence rate increased from 1 to 2 per 10 in the first to last 5-year period of the study (P = 0.03). Northern Europeans were mean age 32.3 years at onset, and 47% had involvement confined to aortic arch branches (angiographic type I), while 24% had extensive type V disease. Mean onset age in Asian and African cases was 20.3 years and 47% had type V disease. Coexisting inflammatory bowel disease was observed in 8% and ankylosing spondylitis in 7%.

Conclusion: We report 2-4 times higher population prevalence than previously observed, and the highest prevalence ever found in Norwegians of Asian and African descent. The results support the idea that TAK in northern Europeans is marked by limited arterial involvement and older age at onset.