Contribution to the epidemiology of multiple sclerosis in Poland.

An epidemiological survey of multiple sclerosis was carried out in western Poland. Uneven local distribution of MS was found within 198 communes making up the territory. The disease was less frequent in 1981 than in 1965. A marked increase of population in age classes under 20 during the last decade may account for the observed differences in the prevalence rate. In the town of Gniezno, a new MS cluster was discovered.