Cooperative Italian study on multiple sclerosis and risk factors: a case-control study. The Coordinating Center and the Neurological Centers of the Cooperative Group.

The main aims of this study were to investigate: the supposed relationship between multiple sclerosis (MS) and migration and consider it in terms of causality (ethnic origin, multiple moves); the possible association of MS with some viral infections supposed to be cause/s of MS (measles, herpes virus type 1 and 2, mononucleosis); the association with some other variables possibly related to the disease (alcohol consumption, occupational exposure to neurotoxic agents, tonsillectomy). The cases were hospitalized MS patients, diagnosed since 1 December 1983, from 19 provinces of Italy, followed up at least every six months. Two sets of controls were recruited randomly: neurological controls from the same department as the cases and non neurological controls from other departments of the same hospital. The history of exposure to risk factors was taken by skilled interviewers using a standardized questionnaire. On 30 September 1985, 1253 patients had been enrolled in the interview study: 280 cases, 581 neurological and 392 non neurological controls. The study is under way.