[South-Eastern France, a high risk area for multiple sclerosis?].

A questionnaire-based prevalence study was conducted in the Chalon-sur-Saône and Avignon areas, in the Rhône-Saône valley, France, to determine the frequency of multiple sclerosis. These areas are 300 km apart and lie on the 47 degrees and 44 degrees North parallels respectively. Age-adjusted prevalence rates on March 20, 1984 were 58.5 and 48.6 per 100,000 inhabitants respectively. There was no significant difference between the two areas. These preliminary data suggest that south-eastern France, as represented by Avignon, may fall within the high risk area for multiple sclerosis.