Environmental risk factors and multiple sclerosis: a community-based, case-control study in the province of Ferrara, Italy.

The frequency of multiple sclerosis (MS) in Italy and in other areas of the world seems to have increased over time, suggesting that some environmental factors operate in its etiology. We performed a retrospective, community-based case-control study on MS in order to verify the etiologic role of selected environmental factors. We found an association between MS and higher educational level, employment in public administration, past history of allergies, and infection at an early age with measles, rubella and whooping cough. Our data seem to confirm that exogenous factors play a role in the etiology of MS although some confounding variables could have accounted for the associations.