Epidemiology of multiple sclerosis in Sicily

From epidemiological data obtained over more than 20 years by surveys condu cted in different parts of Sicily, it is evident that Sicily is a high-risk area for multiple sclerosis (MS). This is in sharp contrast with the gradi ent hypothesis. High frequencies have been found in different parts of the island having different geoclimatic features, but at least two cities (Monr eale and Enna) had had a prolonged Norman domination. This is in agreement with the hypothesis that MS originated in Northern Europe and spread around the world throughout the raids of the northern peoples. The increase in fr equency estimated by follow-up and incidence studies is well established an d is only in part linked to the improvement in diagnostic techniques. Final ly, it is noteworthy that in the islands of Malta, a few sea miles away fro m Sicily, the MS prevalence rates are in the range of 4-8 cases per 100 000 persons. This occurrence represents a natural model to investigate MS etio logy through analytic studies and genetic analyses.