RESUMEN
BACKGROUND: It is common that the epidemiology of multiple sclerosis (MS) varies with geography and ethnicity. Recent studies show a continuous growth of incidence and prevalence in Sicily, despite the controversial "latitude gradient theory." OBJECTIVES: The aim of our study is to ascertain incidence and prevalence rates of MS in the city of Biancavilla, Sicily, Southern Italy. METHOD: Case ascertainment approach and a clinical database collecting data of MS cases to Biancavilla, according to McDonald 2011 and Thompson 2018 criteria, from 1992 to 2018, have been used to the study. We further collected information regarding the familiarity of patients with Mesothelioma, highly incident in this geographic area. RESULTS: The results showed an increase of the mean annual incidence for the period 2012-2018 (16.8/100,000) compared to 1992-1996 (4.5/100,000), and a standardized incidence ratio of 1.41 (95% CI 0.74-2.45). On December 31, 2018, 70 patients suffering from definite MS and living in Biancavilla yielded a crude prevalence of 292.3 per 100,000 (198.2/100,000 for men; 380.7/100,000 for women) with a standardized morbidity ratio of 2.3 (95% CI 1.8-2.9). CONCLUSIONS: Our data confirmed Biancavilla is an area at high risk for MS, ascribable to increased survival, improved ascertainment, or maybe related to a genetic or environmental risk. At the time, any relation with mesothelioma was excluded.