Prevalence of multiple sclerosis in Ecuador

Introduction: Multiple sclerosis (MS) is less frequent in areas near to the Equator, while the incidence and prevalence rises with increasing distance from this particular area, determining a clear north to south gradient. During the last decade several published reports provide recent data on the prevalence in Latin America. The main objective of this article is to report prevalence data in the three largest cities of Ecuador, a South American Country located on Latitude zero North-South. Methods: In order to determine the prevalence and other epidemiological variables we conducted a cross-sectional, observational study in the three largest cities of Ecuador. Based on capture and recapture methodology we identified patients with MS who received medical care in the 12 state and private hospitals and in the Ecuadorian Foundation of Multiple Sclerosis (FUNDEM-Quito). The main inclusion criteria to determine the diagnosis of MS was based on the criteria proposed by Poser. For the relative and absolute frequencies calculation, as well as the 95% confidence interval, the Epilnfo 6.01 and EpiDat 3.1. programs were used. Results: A total of 159 patients were identified in the three largest cities included in the study. In Quito, the capital city: 5.05/100,000 inhabitants (95% CI, 4.03-6.03), Guayaquil, on the coast: 2.26/100,000 inhabitants (95% CI, 1.62-2.91) and Cuenca in the south: 0.75/100,000 inhabitants (95% CI, 0.024-0.175). Conclusions: Ecuador is a low prevalence country although we believe it is possible that the number of MS cases is underestimated since this is not a population based study. We believe that more studies should be carried out on general populations where the disease has been seldom reported or as non-existent. Important exogenous factors may be involved in the pathogenesis of MS in Ecuador. (C) 2009 Sociedad Espanola de Neurologia. Published by Elsevier Espana, S.L. All rights reserved.