Prevalence and incidence of epilepsy in the Nordic countries.

BACKGROUND Updated knowledge on the prevalence of epilepsy is valuable for planning of health services to this large and complex patient group. Comprehensive epidemiological research on epilepsy has been undertaken, but because of variations in methodology, the results are difficult to compare. The objective of this article is to present evidence-based estimates of the prevalence and incidence of epilepsy in the Nordic countries. METHOD The article is based on a search in PubMed with the search terms epilepsy and epidemiology, combined with each of the Nordic countries separately. RESULTS Altogether 38 original articles reported incidence and/or prevalence rates of epilepsy in a Nordic country. Four studies had investigated the prevalence of active epilepsy in all age groups, with results ranging from 3.4 to 7.6 per 1,000 inhabitants. Only two studies had investigated the incidence of epilepsy in a prospective material that included all age groups. The reported incidence amounted to 33 and 34 per 100,000 person-years respectively. A prospective study that only included adults reported an incidence of 56 per 100,000 person-years. INTERPRETATION We estimate that approximately 0.6% of the population of the Nordic countries have active epilepsy, i.e. approximately 30,000 persons in Norway. Epilepsy is thus one of the most common neurological disorders. The incidence data are more uncertain, but we may reasonably assume that 30-60 new cases occur per 100,000 person-years.