Multicenter case-control study of multiple sclerosis and risk factors. Design of study. The Coordinating Center and the Neurological Centers of the Cooperative Group.

We present the design of an Italian multicenter case-control study of multiple sclerosis (MS) promoted by the Neuroepidemiology Section of the Italian Society of Neurology (SIN). The principal objective of the study is to verify the existence of an association between MS and migration from the south to the north of Italy and to assess any such association in causal terms (ethnic origin; environmental factors). A second aim is to explore the association between MS, some viral infections suggested as cause(s) of the disease and other variables reported in the literature. The criteria for case and control definition, for their recruitment and the methods of data collection and analysis are described. To date 1593 subjects, of whom 432 have MS, have been included in the study. The first results will become available early in 1986.