title: Long-term effects of migraine on cognitive function: a population-based study of Danish twins.
abstract: OBJECTIVE
  To investigate the cognitive functioning of migraineurs vs nonmigraineurs in a large population-based sample of middle-aged twins where headache diagnoses were established by neurologists.
  
  
  METHODS
  Twins identified through the population-based Danish Twin Registry participated in face-to-face structured interviews, which included cognitive tests and two previously validated questions screening for migraine. Twins who screened positive for migraine and their co-twins were invited to participate in a telephone-based interview conducted by neurologists, who established headache diagnoses according to the International Headache Society criteria. Cognitive scores on fluency, digit span, delayed word recall, and symbol digit substitution test were compared between migraineurs and nonmigraineurs. Comparisons within monozygotic and dizygotic same sex twin pairs discordant for migraine were also performed.
  
  
  RESULTS
  Of the 1,789 twins who were eligible for inclusion in the present study, 1,393 (77.8%) were interviewed. A diagnosis of migraine was established in 536 twins (migraine without aura n = 347; migraine with aura n = 157). Average scores on cognitive tests in twins with migraine or one of the migraine subtypes did not differ from those of nonmigraineurs in any of the tests. Comparisons within twin pairs discordant for migraine produced highly comparable results. Adjustment for possible confounders and stratification by cumulated number of lifetime attacks did not influence the results.
  
  
  CONCLUSIONS
  A lifetime diagnosis of migraine was not associated with cognitive deficits in middle-aged subjects.
authors.affiliation: Danish Twin Register & Epidemiology, Institute of Public Health, University of Southern Denmark. dg@dadlnet.dk
authors.forename: D
authors.initials: D
authors.lastname: Gaist
authors.forename: L
authors.initials: L
authors.lastname: Pedersen
authors.forename: C
authors.initials: C
authors.lastname: Madsen
authors.forename: I
authors.initials: I
authors.lastname: Tsiropoulos
authors.forename: S
authors.initials: S
authors.lastname: Bak
authors.forename: S
authors.initials: S
authors.lastname: Sindrup
authors.forename: M
authors.initials: M
authors.lastname: McGue
authors.forename: B Krogh
authors.initials: BK
authors.lastname: Rasmussen
authors.forename: K
authors.initials: K
authors.lastname: Christensen
mesh_terms: D000368:Aged; D003071:Cognition; D003072:Cognition Disorders / Q000453:epidemiology; D015331:Cohort Studies; D015986:Confounding Factors, Epidemiologic; D003718:Denmark / Q000453:epidemiology; D004200:Diseases in Twins / Q000453:epidemiology; D004522:Educational Status; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D008881:Migraine Disorders / Q000453:epidemiology / Q000523:psychology*; D011581:Psychological Tests; D012737:Sex Factors; D011795:Surveys and Questionnaires; D014429:Twins, Dizygotic; D014430:Twins, Monozygotic