Migraine and Risk of Ocular Motor Cranial Nerve Palsies: A Nationwide Cohort Study.

ABSTRACT

PURPOSE: To determine whether migraine is associated with an increased risk of developing ocular motor cranial nerve palsies (OMCNP). DESIGN: Nationwide retrospective cohort study. PARTICIPANTS: Medical records of patients with migraine who were entered in the National Health Insurance Research Database (NHIRD) between 2005 and 2009 were retrieved from the NHIRD in Taiwan. Two cohorts were selected patients with migraine (n = 138 907) and propensity score-matched controls (n = 138 907). MAIN OUTCOME MEASURES: Cohorts were followed until the end of 2010, death, or occurrence of cranial nerve (CN)3, CN4, or CN6 palsies. A Cox proportional hazards regression model was used to calculate the hazard ratios (HRs) and 95% confidence intervals (CIs), which were used to compare to the risk of developing CN3, CN4, and CN6 palsy between cohorts. RESULTS: After a mean follow-up period of 3.1 years (range, 1-6 years), the migraine cohort exhibited a greater risk of developing subsequent CN3, CN4, and CN6 palsies compared with the control cohort (HR, 2.67, P < 0.001; HR, 4.23, P < 0.001; HR, 3.37; P < 0.001). This finding was maintained after excluding potential confounders during sensitivity tests. Moreover, the significant association between migraine and OMCNP remained after we adjusted for potential risk factors of microvascular ischemia. However, different migraine subtypes showed no significant differences. CONCLUSIONS: Migraine is an unrecognized risk factor for OMCNP development in adults. Further studies are needed to validate our findings and to delineate the exact pathophysiologic mechanisms linking migraine and OMCNP.