[Principles and problems in the epidemiology of multiple sclerosis].

The problems of epidemiological studies in multiple sclerosis (MS) concern: the (1.) difficulties of diagnostics, the (2.) development and heterogeneity of the disease (manifestation and forms of course), the (3.) peculiarities of ascertainment of patients, the (4.) respective area of investigation (geographical location and size) and the (5.) population (including genetics and sociologic-economical factors). Further components, influencing incidence, prevalence and mortality, were exposed. As for the area of Rostock the onset of illness amounts to 30.9 ( +/- 8.9) years on an average; an incidence rate of 2.9 and prevalence rate of 60.4 (per 100 000 inhibitants) could be determined. Beside informations about the number of cases treated clinically in the several districts (with downward trend from North to South-East) there were given hypothetical data regarding the incidence and prevalence of MS in the GDR.