Prevalence of amyotrophic lateral sclerosis in the city of Porto Alegre, in Southern Brazil.

OBJECTIVE: To determine the prevalence of amyotrophic lateral sclerosis (ALS) in the city of Porto Alegre, Brazil. METHOD: We conducted an extensive investigation in clinics and hospitals that provide specialized assistance to these patients, contacted neurologists and the regional association of people with ALS. RESULTS: On July 31, 2010, 70 patients were alive and diagnosed with amyotrophic lateral sclerosis. Considering the population living in the city in the same period (1,409,351), the estimated prevalence was 5.0 cases per 100,000 people (95% CI, 3.9-6.2), being higher for men (5.2/100,000 95% CI, 3.6-7.2) than for women (4.8/100,000 95% CI, 3.4-6.5). The prevalence increased with age peaking in the age group 70-79 years in both genders. CONCLUSION: The prevalence of ALS in the city of Porto Alegre is similar to that reported in other parts of the world.