Prevalence of Multiple Sclerosis in the City of Volta Redonda - Rio De Janeiro, Brazil Using the Capture-Recapture Method.

Abstract : Multiple sclerosis (MS) prevalence in Latin America was estimated in some regions and it was found to range from 0.75 to 30/100,000. The reasons for variation in rates of prevalence around the world still are not clear, but there are environmental and genetic explanations to this phenomenon. This study aimed at estimating the MS prevalence in Volta Redonda, Brazil. Three sources of cases ascertainment were used and the method of capture-recapture was applied for assessing the corrected prevalence in the city of Volta Redonda in November 2012. The capture-recapture method uses data from incomplete lists and allows calculating the number of unregistered cases. Data were analyzed using a log-linear model. A total of 40 MS cases was found by withdrawing overlaps of sources and it was estimated that a total number of 40 cases (95% CI 13.5-118.8) were not detected by the sources. The corrected prevalence of MS was, then, 30.7/100,000. Our study was the first in Brazil to use the capture-recapture method to assess the prevalence of MS, demonstrating the highest prevalence rate so far. It is necessary to perform other similar studies and in other regions of the country using the same method for a better evaluation of the true prevalence of MS our country.