title: The potential impact of primary headache disorders on stroke risk.
abstract: BACKGROUND
  Headache such as migraine is associated with stroke. Studies focused on primary headache disorders (PHDs) as a risk factor for stroke are limited. The purpose of this population-based cohort study was to explore whether patients with PHDs were at a high risk for developing stroke.
  
  
  METHODS
  A total of 1346 patients with PHDs were enrolled and compared with 5384 age-, gender- and co-morbidity-matched control cohorts. International Classification of Diseases, Clinical Modification codes were administered for the definition of PHDs, stroke, and stroke risk factors. Cox proportional-hazards regressions were performed for investigating hazard ratios (HR).
  
  
  RESULTS
  PHDs patients exhibited a 1.49 times (95% CI :1.15-1.98, p < 0.01) higher risk for developing ischaemic stroke compared with that of control cohorts. Both migraine (HR = 1.22, 95% CI :1.13-1.97, p < 0.05) and tension-type headache (HR = 2.29, 95% CI :1.22-2.80, p < 0.01) were associated with an increased risk of ischemic stroke. Females with PHDs were at greater risk of developing ischaemic stroke (HR = 1.49, 95% CI :1.13-1.90, p < 0.01) than those without PHDs. PHDs patient aged 45 to 64 years displayed significantly higher risk to develop ischaemic stroke (HR = 1.50, 95% CI: 1.11-2.10, p < 0.05) than the matched controls. The impact of PHDs on ischaemic stroke risk became gradually apparent by different following time intervals beyond 2 years after first diagnosis.
  
  
  CONCLUSIONS
  PHDs is suggestive of an incremental risk for ischaemic stroke with gender-dependent, age-specific and time-dependent characteristics.
authors.affiliation: Department of Neurology, Tri-Service General Hospital, National Defense Medical Center, No.325, Sec. 2, Cheng-Kung Road, 11490, Taipei, Taiwan, Republic of China.|Graduate Institute of Medical Sciences, National Defense Medical Center, Taipei, Taiwan, ROC.
authors.forename: Chia-Lin
authors.initials: CL
authors.lastname: Tsai
authors.affiliation: Department of Neurology, Tri-Service General Hospital, National Defense Medical Center, No.325, Sec. 2, Cheng-Kung Road, 11490, Taipei, Taiwan, Republic of China.|Graduate Institute of Medical Sciences, National Defense Medical Center, Taipei, Taiwan, ROC.
authors.forename: Chung-Hsing
authors.initials: CH
authors.lastname: Chou
authors.affiliation: Departments of Nursing, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan, ROC.
authors.forename: Pei-Jung
authors.initials: PJ
authors.lastname: Lee
authors.affiliation: Department of Neurology, Tri-Service General Hospital, National Defense Medical Center, No.325, Sec. 2, Cheng-Kung Road, 11490, Taipei, Taiwan, Republic of China.|Division of Neurology, Department of Medicine, Cheng Hsin General Hospital, Taipei, Taiwan, ROC.
authors.forename: Jiu-Haw
authors.initials: JH
authors.lastname: Yin
authors.affiliation: Department of Neurology, Cardinal Tien Hospital, New Taipei City, Taiwan, ROC.|Department of Hyperbaric Medicine, Cardinal Tien Hospital, New Taipei City, Taiwan, ROC.|School of Medicine, Fu-Jen Catholic University, New Taipei City, Taiwan, ROC.
authors.forename: Shao-Yuan
authors.initials: SY
authors.lastname: Chen
authors.affiliation: Department of Neurology, Tri-Service General Hospital, National Defense Medical Center, No.325, Sec. 2, Cheng-Kung Road, 11490, Taipei, Taiwan, Republic of China.
authors.forename: Chun-Chieh
authors.initials: CC
authors.lastname: Lin
authors.affiliation: Department of Neurology, Tri-Service General Hospital, National Defense Medical Center, No.325, Sec. 2, Cheng-Kung Road, 11490, Taipei, Taiwan, Republic of China.
authors.forename: Yueh-Feng
authors.initials: YF
authors.lastname: Sung
authors.affiliation: Department of Neurology, Tri-Service General Hospital, National Defense Medical Center, No.325, Sec. 2, Cheng-Kung Road, 11490, Taipei, Taiwan, Republic of China.
authors.forename: Fu-Chi
authors.initials: FC
authors.lastname: Yang
authors.affiliation: Taiwanese Injury Prevention and Safety Promotion Association, Taipei, Taiwan, ROC.|School of Public Health, National Defense Medical Center, Taipei, Taiwan, ROC.|Department of Medical Research, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan, ROC.
authors.forename: Chi-Hsiang
authors.initials: CH
authors.lastname: Chung
authors.affiliation: School of Public Health, National Defense Medical Center, Taipei, Taiwan, ROC.|Department of Medical Research, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan, ROC.
authors.forename: Wu-Chien
authors.initials: WC
authors.lastname: Chien
authors.affiliation: Department of Neurology, Tri-Service General Hospital, National Defense Medical Center, No.325, Sec. 2, Cheng-Kung Road, 11490, Taipei, Taiwan, Republic of China.
authors.forename: Chia-Kuang
authors.initials: CK
authors.lastname: Tsai
authors.affiliation: Department of Neurology, Tri-Service General Hospital, National Defense Medical Center, No.325, Sec. 2, Cheng-Kung Road, 11490, Taipei, Taiwan, Republic of China. jiunntay@gmail.com.|Graduate Institute of Medical Sciences, National Defense Medical Center, Taipei, Taiwan, ROC. jiunntay@gmail.com.
authors.forename: Jiunn-Tay
authors.initials: JT
authors.lastname: Lee
mesh_terms: D000328:Adult; D000368:Aged; D015331:Cohort Studies; D015897:Comorbidity; D005260:Female; D051270:Headache Disorders, Primary / Q000175:diagnosis* / Q000453:epidemiology*; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D008881:Migraine Disorders / Q000175:diagnosis / Q000453:epidemiology; D011159:Population Surveillance / Q000379:methods; D011897:Random Allocation; D012307:Risk Factors; D020521:Stroke / Q000175:diagnosis* / Q000453:epidemiology*; D013624:Taiwan / Q000453:epidemiology; D018781:Tension-Type Headache / Q000175:diagnosis / Q000453:epidemiology
keywords: Ischaemic stroke; Migraine; Non-migrainous headache; Risk factor; Tension-type headache