Frequency of multiple sclerosis in Menorca, Balearic islands, Spain

Abstract

Objective: To establish prevalence and incidence of multiple sclerosis (MS) in Menorca (Balearic Islands, Spain; population: 67,009).

Methods: An extensive epidemiological study was undertaken using all available information sources. Patients were classified according to Poser's criteria.

Results: The prevalence rate of definite and probable MS was 68.6/100,000 (95% confidence interval 50.3-91.6). The incidence rate was 3.4/100,000/year (95% CI 2.2-5.3). The time lag between the first symptom and diagnosis was 10.2 years for patients with disease onset before 1987 and 2.1 years for patients with onset between 1987 and 1996.

Conclusion: Menorca's population has a moderately high MS risk, with a prevalence rate the highest reported for a Spanish region.