The effect of age at onset of type 1 diabetes mellitus on epilepsy vulnerability.

AIMS: To examine whether type 1 diabetes age onset correlates with epilepsy incidence. METHODS: We used type 1 diabetes longitudinal data with onset age ≤ 40 years enrolled in Taiwan National Health Insurance program to examine type 1 diabetes onset age effect on epilepsy occurrence. RESULTS: In 6,165 type 1 diabetes patients, onset age groups included 3,571 patients (58%) ≤ 18 years (childhood-onset) and 2,594 patients (42%) > 18 years (adulthood-onset). After 8.6 years median follow-up following type 1 diabetes onset, epilepsy incidence rate in adulthood-onset group was 2.26-fold higher than that in childhood-onset group. Epilepsy incidence rate ratio was lowest in those with onset age 6-12 years in comparison to that in patients with onset age ≤ 6 years, but was highest in onset age of 30-40 years. Longer follow-up duration correlates with higher epilepsy risk in adulthood-onset group. Multiple logistic regression analysis showed that onset age 30-40 years, male, more than one diabetic ketoacidosis episode, and unprovoked seizure events were independent risk factors for epilepsy following type 1 diabetes onset. CONCLUSIONS: There is age-related vulnerability to epilepsy following type 1 diabetes onset. Adulthood-onset type 1 diabetes is an independent risk factor for epilepsy susceptibility after type 1 diabetes.