Is migraine a risk factor for pediatric stroke?

Importance Our understanding of risk factors for childhood stroke is incomplete. In adults, migraine with aura is associated with a two-fold increase in ischemic stroke risk. Objective In this cohort study we examine the association between migraine and stroke among children in Kaiser Permanente Northern California (KPNC). Design, setting, and participants Children ages 2-17 years who were members of KPNC for 6 months between 1997 and 2007 were included. Migraine cohort members had one or more of: an ICD-9 code for migraine, migraine listed as a significant health problem, or a prescription for a migraine-specific medication. The comparison group was children with no evidence of headache. Main outcome measures Main outcome measures included stroke incidence rates and incidence rate ratios (IR). Results Among the 1,566,952 children within KPNC during the study period, 88,164 had migraine, and 1,323,142 had no evidence of headache. Eight migraineurs had a stroke (three (38%) hemorrhagic; five (63%) ischemic). Eighty strokes occurred in children without headache (53 (66%) hemorrhagic; 27 (34%) ischemic). The ischemic stroke incidence rate was 0.9/100,000 person-years in migraineurs vs. 0.4/100,000 person-years in those without headache; IR 2.0 (95% CI 0.8-5.2). A post-hoc analysis of adolescents (12-17 years) showed an increased risk of ischemic stroke among those with migraine; IR 3.4 (95% CI 1.2-9.5). The hemorrhagic stroke incidence rate was 0.5/100,000 person-years in migraineurs and 0.9/100,000 person-years in those without headache; IR 0.6 (95% CI 0.2-2.0). Conclusions There was no statistically significant increase in hemorrhagic or ischemic stroke risk in pediatric migraineurs in this cohort study. A post-hoc analysis found that ischemic stroke risk was significantly elevated in adolescents with migraine. Future studies should focus on identifying risk factors for ischemic stroke among adolescent migraineurs. Based on adult data, we recommend that migraine aura status should be studied as a possible risk factor for ischemic stroke among adolescent migraineurs.