Relationship between migraine and epilepsy in a large population-based cohort: The HUNT Study

Several studies have reported substantial comorbidity between epilepsy and migraine. Most of these were based on clinical cohorts or used unvalidated diagnostic instruments. Our study re-examined this association in a large general population cohort using validated diagnoses for both disorders.

A total of 65,407 participants (≥20 years old) from HUNT (the Trøndelag Health Study) were classified for migraine and nonmigraine headache using a validated questionnaire. Medical record review was used to validate and classify epilepsy in 364 participants (cases), who were compared with 63,298 participants without epilepsy (controls). The association between epilepsy and migraine was analysed using logistic regression adjusted for sex and age.

Patients with epilepsy had no increased prevalence of migraine (odds ratio [OR] = 0.95, 95% confidence interval [CI] = 0.68-1.33) or nonmigraine headache (OR = 1.18, 95% CI = 0.93-1.50) compared to controls. When stratified by headache frequency, epilepsy was associated with a higher prevalence of migraine with highly frequent headache (≥7 days/month; OR = 1.73, 95% CI = 1.08-2.78).

Migraine was equally common in people with and without epilepsy. Patients with epilepsy who suffered from migraine were more prone to having highly frequent migraine.