title: The observed association between maternal anxiety and adolescent asthma: children of twin design suggest familial effects.
abstract: BACKGROUND
  Previous studies indicate that maternal anxiety is associated with asthma in the adolescent child, but mechanisms are unclear.
  
  
  OBJECTIVE
  To investigate the association between maternal anxiety and maternal, self- and register-based report of asthma in the adolescent child, and whether the association remains after control of familial confounding (shared environmental and genetic factors).
  
  
  METHODS
  From the Twin and Offspring Study of Sweden, 1691 mothers (1058 twins) and their adolescent child were included. The association between maternal self-reported anxiety (Beck Anxiety Inventory (BAI) and Karolinska Scales of Personality (KSP) somatic or psychic anxiety) and asthma based on subjective (maternal or child report) or objective (register-based diagnosis and medication) measures were analysed using logistic regression. The children-of-twins design was used to explore whether genes or environment contribute to the association.
  
  
  RESULTS
  Maternal BAI anxiety (OR 2.02, CI 1.15-3.55) was significantly associated with adolescent asthma reported by the mother. Maternal KSP somatic anxiety (OR 1.74, CI 1.04-2.91) and psychic anxiety (OR 1.74, CI 1.05-2.86) was significantly associated with breathlessness reported by the adolescent child. In contrast, maternal anxiety was not associated with increased risk for the register-based outcomes of asthma diagnosis or medication. The results remained also after adjusting for covariates and the children-of-twins analyses which indicate that the association was due to familial confounding.
  
  
  CONCLUSIONS
  We found some associations between maternal anxiety and subjectively reported offspring asthma or breathlessness which may be due to familial effects. A likely candidate for explaining this familial confounding is heritable personality traits associated with both anxiety and subjective measures of asthma.
authors.affiliation: Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Ida
authors.initials: I
authors.lastname: Havland
authors.forename: Cecilia
authors.initials: C
authors.lastname: Lundholm
authors.forename: Paul
authors.initials: P
authors.lastname: Lichtenstein
authors.forename: Jenae M
authors.initials: JM
authors.lastname: Neiderhiser
authors.forename: Jody M
authors.initials: JM
authors.lastname: Ganiban
authors.forename: Erica L
authors.initials: EL
authors.lastname: Spotts
authors.forename: Hasse
authors.initials: H
authors.lastname: Walum
authors.forename: David
authors.initials: D
authors.lastname: Reiss
authors.forename: Catarina
authors.initials: C
authors.lastname: Almqvist
mesh_terms: D000293:Adolescent; D000328:Adult; D001007:Anxiety / Q000150:complications*; D001249:Asthma / Q000453:epidemiology* / Q000209:etiology*; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D006801:Humans; D016015:Logistic Models; D009034:Mother-Child Relations; D009035:Mothers / Q000523:psychology*; D016017:Odds Ratio; D057566:Self Report; D013548:Sweden / Q000453:epidemiology; D014427:Twins / Q000523:psychology*