Incidence and prevalence of epilepsy in Denmark.

PURPOSE

To estimate the occurrence of epilepsy in Denmark between 1977 and 2002, taking gender, age, and secular trends into consideration.

METHODS

We used the Danish Civil Registration System to identify all persons born in Denmark and the Danish National Hospital Register to identify persons registered with epilepsy between 1977 and 2002.

RESULTS

Between 1977 and 2002 the average incidence of epilepsy was 68.8 new epilepsy patients per 100,000 person-years at risk. However, the incidence changed with calendar time and increased steeply from 1990 to 1995, probably due to changes in diagnostic system and inclusion of outpatients. From 1995 to 2002 the incidence rate was reasonable constant with an average of 83.3 new cases per 100,000 person-years at risk, except for patients over 60 years of age where we observed an increase in incidence with calendar time. The age-specific incidence rates declined from a high level in children to a low level between 20 and 40 years of age, and thereafter a gradual increase was seen. The incidence rate was slightly higher in men than in women except for the age range 10-20 years. About 2% of the population was diagnosed with epilepsy at some point during the first 25 years of life. The overall 5-year prevalence proportion of epilepsy was 0.6% with a slight variation with age and gender between 0.4 and 0.8% of the population.

CONCLUSION

The occurrence of epilepsy is age and gender specific. The estimated incidence rate of epilepsy furthermore increased over time for persons older than 60 years of age.