Incidence of ALS in Northern and Southern Italy: Comparison of the results from two population-based registries

Introduction. Previous studies show that the incidence of amyothrophic lateral sclerosis (ALS) varies according to latitude but comparison of different studies might be difficult if different methods are used for the detection of cases. Methods. Two registries were established at the same time in two Italian regions, one in the North and one in the South. Both registries used the same protocol and the same classification of cases (EL-Escorial Criteria 1994). The population of Lombardia was 3,897,642 in seven provinces (Lecco, Lodi, Pavia, Varese, Sondrio, Bergamo and Brescia): the population of Puglia was 4.021.124 (ISTAT 1991) for all provinces. The incidence was calculated for 1998. Results. In Lombardia we detected 64 cases (35 defined, 15 probable, 3 possible, 11 suspected): the overall incidence was 1.6 per 100,000 inhabitants. In Puglia we detected 66 cases (20 defined, 23 probable, 25 possible, 8 suspected): the overall incidence was 1.6\100,000 inhabitants. Conclusions. Incidence of ALS does not vary in Italy according to latitude gradient. The reported incidence is similar to the incidence reported in other studies. In both registries suspected ALS is about 15%.