Epidemiological analysis of primary dystonia in Szczecin and Gdańsk regions

: The aim of the study was to determine the prevalence of primary dystonia in Szczecin Region (total population of 995,000 individuals) and Gdansk Region (total population of 149,000 individuals). We identified on the prevalence day 31.12.2000--98 patients with primary dystonia in Szczecin Region (SR) and 130 in Gdansk Region (GR) and crude rate of 98 per million (CI 81-121) in SR and 87(CI--71-108) in GR. The rates per million for the main types of dystonia were as follows: focal: in SR (n = 84) 84 (CI--69-105), in GR (n = 125) 84 (CI--68-104), segmental: in SR (n = 8) 8 (CI--4-16), in GR (n = 5) 3 (CI--1-9) and multi-focal: in SR (n = 6) (CI--3-13). The prevalence rates per million for the more common types of dystonia were: cervical dystonia: in SR 44 (CI--33-66), in GR 50 (CI--38-69), blepharospasm: in SR 22 (CI-15-34), in GR 27 (CI--18-39) writer's cramp: in SR 10 (CI--5-19), in GR-4 (CI--2-10) laryngeal: in SR-8 (CI--4-16), in GR-3 (CI--1-8). The female predominance was been noted for all subtypes of focal dystonia in both regions. In focal dystonia mean patient's age at onset was: for cervical dystonia in SR--37.86, in GR--39.53, for blepharospasm in SR--54.00, in GR--57.44, for laryngeal dystonia in SR--53.12, in GR--66.25 and for writer's cramp in SR--24.50, in GR--34.75. Our study provide the first data on the prevalence of primary dystonia and its subtypes in two similar Regions in Poland.