[Epidemiologic aspects of multiple sclerosis]

Epidemiology plays a prominent role in the search for environmental risk factors in multiple sclerosis (MS). The basic pattern with the predilection for temperate zones of the globe, whites, females and medium age groups was confirmed throughout. Whether or not MS is increasing in frequency is highly debated. Although no clear risk factors have been demonstrated so far, a certain association of the MS risk with the factors "low temperatures and precipitation", "consumption of animal proteins/fats or meat", "familiar occurrence of MS" and with a late occurrence of common childhood infections became obvious. Many other putative risk factors were not confirmed in most studies.