High prevalence and fast rising incidence of multiple sclerosis in Caltanissetta, Sicily, Southern Italy

Background: Epidemiological studies conducted in Sicily and Sardinia, the two major Mediterranean islands, showed elevated incidence and prevalence of multiple sclerosis (MS) and a recent increase in disease frequency. Objective: To confirm the central highlands of Sicily as areas of increasing MS prevalence and elevated incidence, we performed a follow-up study based on the town of Caltanissetta (Sicily), southern Italy. Methods: We made a formal diagnostic reappraisal of all living patients found in the previous study performed in 1981. All possible information sources were used to search for patients affected by MS diagnosed according to the Poser criteria. We calculated prevalence ratios, for patients affected by MS who were living and resident in the study area on December 31, 2002. Crude and age- and sex-specific incidence ratios were computed for the period from January 1, 1993, to December 31, 2002. Results: The prevalence of definite MS rose in 20 years from 69.2 ( retrospective prevalence rate) to 165.8/100,000 population. We calculated the incidence of definite MS for the period 1970-2000. These rates calculated for 5-year periods increased from 2.3 to 9.2/100,000/year. Conclusion: This survey shows the highest prevalence and incidence figures of MS in the Mediterranean area and confirms central Sicily as a very-high-risk area for MS. Copyright (c) 2007 S. Karger AG, Basel.