The prevalence of multiple sclerosis in the city of São Paulo, Brazil, 1997.

July 1, 1997 was stipulated as the day for estimating the prevalence of multiple sclerosis within the city of São Paulo. The patients were identified via various sources, including associated universities and magnetic resonance services of the city of São Paulo. The area covered by the study has a population of 9,380,000, mainly white and of European origin, with a large number of immigrants from Spain and Portugal. The patients were classified in accordance with the criteria of Poser et al. (1983), and only those with defined multiple sclerosis were registered. The study gave a prevalence of 15.0/10(5) inhabitants, or three times the value obtained in a similar study in 1990. This increase reveals the larger number of cases encompassed by the study, and is attributed to the use of more detailed recording methods, improvements in diagnosis, and better conditions for treatment.