Multiple Sclerosis in Italy. A reappraisal of incidence and prevalence in Ferrara

Background: Previous descriptive surveys on multiple sclerosis (MS) in the province of Ferrara, northern Italy, carried out by our own epidemiological research group, pointed out that this area was not at lowmedium risk for MS. Objective: To verify the morbidity estimates and update the temporal trend of MS. Design and Methods: We used a complete enumeration approach by reviewing all the possible sources of case collection available in Ferrara for 1965 through 1993. We included all patients with definite and probable MS according to the criteria of Poser et al. Results: The mean annual incidence rate was 2.3 per 100 000 population (95% confidence interval, 2.0-2.6 per 100 000), 3.0 per 100 000 for women and 1.5 per 100 000 for men. On December 31,1993,249 patients (170 women and 79 men) suffering from definite or probable MS were living in the province of Ferrara, giving a crude prevalence rate per 100 000 population of 69.4 (95% confidence interval, 61.2-78.7), 90.8 for women and 46.0 for men. Conclusion: The data confirm that in Ferrara, MS occurs more frequently than previously suggested by the latitude-related epidemiological model, supporting the view that northern Italy is a high-risk area for the disease. While the prevalence rate is much higher than in our previous studies, probably owing to the increasing survival of the patients because of improving supportive care, the incidence rates, similar in magnitude to those observed in high-risk areas of northern and central Europe, have remained relatively stable over time.