title: Incidence and risk factors of chronic daily headache in young adolescents: a school cohort study.
abstract: OBJECTIVE
  This study investigated the incidence and risk factors of chronic daily headache (CDH) and its major subtypes in young adolescents.
  
  
  METHODS
  A field cohort of 3342 adolescents aged 13 to 14 was established in 3 middle schools in Taitung, Taiwan, from 2005 to 2007. Participants without CDH at baseline were annually followed up for 1 to 2 years using the same questionnaires, including the Adolescent Depression Inventory and Pediatric Migraine Disability Assessment. The neurologists made the headache diagnoses based on clinical interviews and headache diaries. The person-time incidence rates and risk factors of incident CDH and its subtypes (ie, chronic migraine [CM] and chronic tension-type headache [CTTH]) were calculated by using Cox proportional hazards models.
  
  
  RESULTS
  The cohort completed 5586 person-years (PYs) of follow-up. Sixty-three subjects (21 boys/42 girls) developed incident CDH with an incidence rate of 1.13 per 100 PYs, including 37 with CM (0.66 per 100 PYs) and 22 with CTTH (0.39 per 100 PYs). Thirty-three subjects (52%) had a baseline diagnosis of migraine. The independent risk factors for incident CDH included female gender, acute family financial distress, obesity, higher headache frequency, and a baseline diagnosis of migraine. A higher headache frequency was the only identical risk factor for CDH, CM, and CTTH. A baseline diagnosis of migraine and obesity were significant predictors for both CM and CDH. Female gender was a significant predictor for both CTTH and CDH.
  
  
  CONCLUSIONS
  Incident CDH was common in young adolescents. Some risk factors for incident CM and CTTH were different.
authors.affiliation: Department of Neurology, Kaohsiung Medical University Chung-Ho Memorial Hospital, Kaohsiung, Taiwan.
authors.forename: Shiang-Ru
authors.initials: SR
authors.lastname: Lu
authors.forename: Jong-Ling
authors.initials: JL
authors.lastname: Fuh
authors.forename: Shuu-Jiun
authors.initials: SJ
authors.lastname: Wang
authors.forename: Kai-Dih
authors.initials: KD
authors.lastname: Juang
authors.forename: Shih-Pin
authors.initials: SP
authors.lastname: Chen
authors.forename: Yi-Chu
authors.initials: YC
authors.lastname: Liao
authors.forename: Yen-Feng
authors.initials: YF
authors.lastname: Wang
mesh_terms: D000293:Adolescent; D000367:Age Factors; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D003866:Depressive Disorder / Q000175:diagnosis / Q000453:epidemiology; D004185:Disability Evaluation; D005260:Female; D005500:Follow-Up Studies; D020773:Headache Disorders / Q000453:epidemiology* / Q000209:etiology; D006801:Humans; D015994:Incidence; D008297:Male; D008881:Migraine Disorders / Q000175:diagnosis / Q000453:epidemiology; D009460:Neurologic Examination; D012307:Risk Factors; D012737:Sex Factors; D013624:Taiwan; D018781:Tension-Type Headache / Q000175:diagnosis / Q000453:epidemiology
keywords: adolescence; incidence; migraine headache; risk factors; tension-type headache