Multiple sclerosis and migration in Italy: a case/control study. Preliminary reports.

The present study was performed on Milan residents, in order to evaluate the risk of acquiring multiple sclerosis between patients born in Milan and patients born in Southern Italy. For this purpose, 216 consecutive subjects with definite or probable multiple sclerosis, inmates of the Neurological Institute C. Besta (Milan) from 1968-1976, were matched with 216 controls, uniform as regards age, sex, profession and residence, who were hospitalized at the same time for other neurological diseases. Comparing the case/control pairs of the migration, we observed that the North-Centre born had a relative risk of acquiring the disease significantly superior to one (RR = 1.9; P = 0.01) as compared to migrants from the Southern regions of Italy.