Adult onset epilepsy incidence in Finland over 34 years: A nationwide registry study.

BACKGROUND AND PURPOSE

The incidence of epilepsy is decreasing among the working-aged in high-income countries, but previous studies have reported conflicting results in Finland.

METHODS

A nationwide population-based cross-sectional analysis was made of annual epilepsy drug reimbursement rights frequency data from the Social Insurance Institution of Finland, the national authority, between 1986 and 2019. All persons at least 20 years of age living in Finland during the study period were included.

RESULTS

Based on the analysis of 77,939 new reimbursement rights, crude incidence was 57.4/100,000 (95% confidence interval [CI] = 57.0-57.8) person-years, and age-standardized (to the European Standard Population 2013) incidence was 51.6/100,000 person-years. Both crude (r = 0.62, p = 0.00009) and standardized (r = 0.65, p = 0.00003) incidence increased over time. Incidence increased in both men (from 66.4 to 71.6/100,000, r = 0.51, p = 0.002) and women (from 51.5 to 55.3/100,000, r = 0.68, p < 0.00001). The mean male to female incidence rate ratio was 1.28 (95% CI = 1.26-1.30, range = 1.15-1.41), but decreased during the study period (r = -0.47, p = 0.006). Incidence decreased in those 20-59 years old but increased in all older age groups. This development was similar between sexes.

CONCLUSIONS

The incidence of adult onset epilepsy in Finland increased in people older than 60 years and decreased in the 20-59-year age group during the study period. These trends were similar between sexes. Therefore, etiological epilepsy trends in the elderly need to be studied further to plan public health measures to prevent epilepsy in this age group.