title: Parental and comorbid migraine in individuals with bipolar disorder: A nationwide register study.
abstract: Genetic studies imply a shared genetic etiology between bipolar disorder (BD) and migraine. Epidemiological studies have demonstrated elevated comorbidity between these disorders, but haven't controlled for parental psychopathology. No previous nationally representative studies exist on familial clustering of BD and migraine. This study examines the association between parental and comorbid migraine and BD, controlling for potential confounders.
  
  
  
  We identified 1861 cases aged ≤25 years, 3643 matched controls, and their parents from Finnish national registers. Conditional logistic regression was used to calculate odds ratios (ORs) with 95% confidence intervals (CIs) and two-sided significance limits of p<0.05.
  
  
  
  Parental migraine, controlling for parental BD, was associated with offspring BD diagnosed at age ≥18 years (OR 1.52, 95%CI: 1.08-2.14). Associations between BD and comorbid migraine persisted following adjustment for parental BD and parental migraine in all subjects (OR=2.46, 95% CI: 1.76-3.42), both age groups of BD-diagnosis (<18 years,≥18 years) and both sexes.
  
  
  
  The diagnoses were register-based, not directly ascertained.
  
  
  
  This study indicates that parental migraine, even in the absence of parental BD, is a risk factor for offspring BD. Thus, a genetic link between BD and migraine could potentially explain some of the elevated comorbidity between these disorders. However, BD shows a stronger association with comorbid migraine than with parental migraine, suggesting that much of the elevated comorbidity is related to non-genetic factors. Increased understanding of mechanisms underlying the comorbidity of BD and migraine is important since it is associated with poorer health-related outcomes compared with BD alone.
authors.affiliation: Research Centre for Child Psychiatry, University of Turku, Turku, Finland. Electronic address: dansuc@utu.fi.
authors.forename: Dan
authors.initials: D
authors.lastname: Sucksdorff
authors.affiliation: Department of Psychiatry, Columbia University Medical Center, New York State Psychiatric Institute, New York, USA; Department of Epidemiology, Columbia University Mailman School of Public Health, New York, USA.
authors.forename: Alan S
authors.initials: AS
authors.lastname: Brown
authors.affiliation: Research Centre for Child Psychiatry, University of Turku, Turku, Finland.
authors.forename: Roshan
authors.initials: R
authors.lastname: Chudal
authors.affiliation: Department of Psychiatry, University of Turku, Turku, Finland.
authors.forename: Markus
authors.initials: M
authors.lastname: Heinimaa
authors.affiliation: Research Centre for Child Psychiatry, University of Turku, Turku, Finland.
authors.forename: Auli
authors.initials: A
authors.lastname: Suominen
authors.affiliation: Research Centre for Child Psychiatry, University of Turku, Turku, Finland; Department of Child Psychiatry, University of Turku, Turku, Finland.
authors.forename: Andre
authors.initials: A
authors.lastname: Sourander
mesh_terms: D000293:Adolescent; D000328:Adult; D001714:Bipolar Disorder / Q000453:epidemiology*; D016241:Child of Impaired Parents / Q000706:statistics & numerical data*; D015897:Comorbidity; D005260:Female; D005387:Finland / Q000453:epidemiology; D006801:Humans; D016247:Information Storage and Retrieval; D016015:Logistic Models; D008297:Male; D008881:Migraine Disorders / Q000453:epidemiology*; D016017:Odds Ratio; D010290:Parents; D012042:Registries; D012307:Risk Factors; D055815:Young Adult
keywords: Bipolar disorder; Epidemiology; Migraine; Population-based study; Register