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.