Prevalence of multiple sclerosis in Bulgaria.

The previously reported prevalence of multiple sclerosis in Bulgaria is considerably lower than that reported for neighbouring countries. The aim of this study was to perform a detailed epidemiological investigation in well-defined populations in this country to obtain an accurate estimate of the frequency of multiple sclerosis. An epidemiological study was conducted in two small areas of the country. All patients with clinically or laboratory-supported, definite multiple sclerosis according to Poser's criteria were personally interviewed. The study was begun in January, 1993 and December 31, 1995 was selected as prevalence day. The prevalence ratio of multiple sclerosis per 100,000 population was 39.3 in the first community and 39.1 in the second. Thus, the prevalence ratio of multiple sclerosis in Bulgaria is not significantly different from that reported in bordering countries.