Increasing frequency of multiple sclerosis in Catania, Sicily: a 30-year survey

BACKGROUND AND OBJECTIVE: The objective of this study was to determine the prevalence and incidence of multiple sclerosis (MS) and its temporal profiles from 1975 to 2005 in the city of Catania. METHODS: The incidence of MS from 1975 to 31 December 1999 had been previously investigated by the same group. The frequency of MS in the community of Catania from 1 January 2000 to 31 December 2004 was studied in a population of 313,110 inhabitants (2001 census). All patients who satisfied Poser's criteria were considered as prevalent and incident cases. RESULTS: Three hundred and ninety-eight patients with MS who had experienced the clinical onset of the disease before 31 December 2004 were found in a population of 313,110 inhabitants. The prevalence rate was 127.1/100,000 [95% confidence interval (CI) 115.1-140.4]. From 2000 to 2004, 108 patients with MS had clinical onset of the disease. The mean annual incidence was 7.0/100,000 (95% CI 5.7-13.7) and was higher in women (8.4/100,000; 95% CI 6.4-10.5) than in men (5.3/100,000; 95% CI 3.7-7.2). The mean length of time between the date of clinical onset and the date of the diagnosis was 1.4 ± 1.7 years. During the last 30 years the incidence of MS in this population increased from 1.3/100,000 during the first quinquennium (1975-9) to 7.0/100,000 during 2000-4. CONCLUSIONS: Incidence rates have further increased in this population, suggesting that the risk of MS is still increasing.