title: Increased risk of Bell palsy in patients with migraine: a nationwide cohort study.
abstract: OBJECTIVE
  To evaluate the association between migraine and Bell palsy and to examine the effects of age, sex, migraine subtype, and comorbid risk factors for Bell palsy.
  
  
  METHODS
  This nationwide cohort study was conducted using data from the Taiwan National Health Insurance Research Database. Subjects aged 18 years or older with neurologist-diagnosed migraine from 2005 to 2009 were included. A nonheadache age- and propensity score-matched control cohort was selected for comparison. All subjects were followed until the end of 2010, death, or the occurrence of a Bell palsy event. Cox proportional hazards regression was used to calculate the adjusted hazard ratios and 95% confidence intervals to compare the risk of Bell palsy between groups.
  
  
  RESULTS
  Both cohorts (n = 136,704 each) were followed for a mean of 3.2 years. During the follow-up period, 671 patients (424,372 person-years) in the migraine cohort and 365 matched control subjects (438,677 person-years) were newly diagnosed with Bell palsy (incidence rates, 158.1 and 83.2/100,000 person-years, respectively). The adjusted hazard ratio for Bell palsy was 1.91 (95% confidence interval, 1.68-2.17; p < 0.001). The association between migraine and Bell palsy remained significant in sensitivity analyses, and tests of interaction failed to reach significance in all subgroup analyses.
  
  
  CONCLUSIONS
  Migraine is a previously unidentified risk factor for Bell palsy. The association between these 2 conditions suggests a linked disease mechanism, which is worthy of further exploration.
authors.affiliation: From the Department of Internal Medicine (K.-P.P.), Taipei Veterans General Hospital, Taoyuan Branch, Taoyuan; Institute of Brain Science (K.-P.P., S.-J.W.), National Yang-Ming University, Taipei; Faculty of Medicine (K.-P.P., Y.-T.C., J.-L.F., S.-J.W.), National Yang-Ming University School of Medicine, Taipei; Department of Nephrology (Y.-T.C.), Institute of Internal Medicine, Taipei City Hospital Heping Fuyou Branch, Taipei; Department of Neurology (J.-L.F., S.-J.W.), Neurological Institute, Taipei Veterans General Hospital, Taipei; and School of Health Care Administration (C.-H.T.), Taipei Medical University, Taipei, Taiwan.
authors.forename: Kuan-Po
authors.initials: KP
authors.lastname: Peng
authors.affiliation: From the Department of Internal Medicine (K.-P.P.), Taipei Veterans General Hospital, Taoyuan Branch, Taoyuan; Institute of Brain Science (K.-P.P., S.-J.W.), National Yang-Ming University, Taipei; Faculty of Medicine (K.-P.P., Y.-T.C., J.-L.F., S.-J.W.), National Yang-Ming University School of Medicine, Taipei; Department of Nephrology (Y.-T.C.), Institute of Internal Medicine, Taipei City Hospital Heping Fuyou Branch, Taipei; Department of Neurology (J.-L.F., S.-J.W.), Neurological Institute, Taipei Veterans General Hospital, Taipei; and School of Health Care Administration (C.-H.T.), Taipei Medical University, Taipei, Taiwan.
authors.forename: Yung-Tai
authors.initials: YT
authors.lastname: Chen
authors.affiliation: From the Department of Internal Medicine (K.-P.P.), Taipei Veterans General Hospital, Taoyuan Branch, Taoyuan; Institute of Brain Science (K.-P.P., S.-J.W.), National Yang-Ming University, Taipei; Faculty of Medicine (K.-P.P., Y.-T.C., J.-L.F., S.-J.W.), National Yang-Ming University School of Medicine, Taipei; Department of Nephrology (Y.-T.C.), Institute of Internal Medicine, Taipei City Hospital Heping Fuyou Branch, Taipei; Department of Neurology (J.-L.F., S.-J.W.), Neurological Institute, Taipei Veterans General Hospital, Taipei; and School of Health Care Administration (C.-H.T.), Taipei Medical University, Taipei, Taiwan.
authors.forename: Jong-Ling
authors.initials: JL
authors.lastname: Fuh
authors.affiliation: From the Department of Internal Medicine (K.-P.P.), Taipei Veterans General Hospital, Taoyuan Branch, Taoyuan; Institute of Brain Science (K.-P.P., S.-J.W.), National Yang-Ming University, Taipei; Faculty of Medicine (K.-P.P., Y.-T.C., J.-L.F., S.-J.W.), National Yang-Ming University School of Medicine, Taipei; Department of Nephrology (Y.-T.C.), Institute of Internal Medicine, Taipei City Hospital Heping Fuyou Branch, Taipei; Department of Neurology (J.-L.F., S.-J.W.), Neurological Institute, Taipei Veterans General Hospital, Taipei; and School of Health Care Administration (C.-H.T.), Taipei Medical University, Taipei, Taiwan.
authors.forename: Chao-Hsiun
authors.initials: CH
authors.lastname: Tang
authors.affiliation: From the Department of Internal Medicine (K.-P.P.), Taipei Veterans General Hospital, Taoyuan Branch, Taoyuan; Institute of Brain Science (K.-P.P., S.-J.W.), National Yang-Ming University, Taipei; Faculty of Medicine (K.-P.P., Y.-T.C., J.-L.F., S.-J.W.), National Yang-Ming University School of Medicine, Taipei; Department of Nephrology (Y.-T.C.), Institute of Internal Medicine, Taipei City Hospital Heping Fuyou Branch, Taipei; Department of Neurology (J.-L.F., S.-J.W.), Neurological Institute, Taipei Veterans General Hospital, Taipei; and School of Health Care Administration (C.-H.T.), Taipei Medical University, Taipei, Taiwan. sjwang@vghtpe.gov.tw.
authors.forename: Shuu-Jiun
authors.initials: SJ
authors.lastname: Wang
mesh_terms: D000328:Adult; D020330:Bell Palsy / Q000453:epidemiology* / Q000209:etiology; D016022:Case-Control Studies; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D008881:Migraine Disorders / Q000150:complications / Q000453:epidemiology; D020325:Migraine with Aura / Q000150:complications / Q000453:epidemiology*; D020326:Migraine without Aura / Q000150:complications / Q000453:epidemiology*; D057216:Propensity Score; D016016:Proportional Hazards Models; D012307:Risk Factors; D013624:Taiwan / Q000453:epidemiology