title: Childhood interleukin-6, C-reactive protein and atopic disorders as risk factors for hypomanic symptoms in young adulthood: a longitudinal birth cohort study.
abstract: There are no existing longitudinal studies of inflammatory markers and atopic disorders in childhood and risk of hypomanic symptoms in adulthood. This study examined if childhood: (1) serum interleukin-6 (IL-6) and C-reactive protein (CRP); and (2) asthma and/or eczema are associated with features of hypomania in young adulthood.
  
  
  
  Participants in the Avon Longitudinal Study of Parents and Children, a prospective general population UK birth cohort, had non-fasting blood samples for IL-6 and CRP measurement at the age of 9 years (n = 4645), and parents answered a question about doctor-diagnosed atopic illness before the age of 10 years (n = 7809). These participants completed the Hypomania Checklist at age 22 years (n = 3361).
  
  
  
  After adjusting for age, sex, ethnicity, socio-economic status, past psychological and behavioural problems, body mass index and maternal postnatal depression, participants in the top third of IL-6 values at 9 years, compared with the bottom third, had an increased risk of hypomanic symptoms by age 22 years [adjusted odds ratio 1.77, 95% confidence interval (CI) 1.10-2.85, p < 0.001]. Higher IL-6 levels in childhood were associated with adult hypomania features in a dose-response fashion. After further adjustment for depression at the age of 18 years this association remained (adjusted odds ratio 1.70, 95% CI 1.03-2.81, p = 0.038). There was no evidence of an association of hypomanic symptoms with CRP levels, asthma or eczema in childhood.
  
  
  
  Higher levels of systemic inflammatory marker IL-6 in childhood were associated with hypomanic symptoms in young adulthood, suggesting that inflammation may play a role in the pathophysiology of mania. Inflammatory pathways may be suitable targets for the prevention and intervention for bipolar disorder.
authors.affiliation: Division of Psychiatry,UCL,London,UK.
authors.forename: J F
authors.initials: JF
authors.lastname: Hayes
authors.affiliation: Department of Psychiatry,University of Cambridge,Cambridge,UK.
authors.forename: G M
authors.initials: GM
authors.lastname: Khandaker
authors.affiliation: Institute of Health and Wellbeing,University of Glasgow,Glasgow,UK.
authors.forename: J
authors.initials: J
authors.lastname: Anderson
authors.affiliation: Institute of Health and Wellbeing,University of Glasgow,Glasgow,UK.
authors.forename: D
authors.initials: D
authors.lastname: Mackay
authors.affiliation: Institute of Psychological Medicine and Clinical Neurosciences,Cardiff University School of Medicine,Cardiff,UK.
authors.forename: S
authors.initials: S
authors.lastname: Zammit
authors.affiliation: Division of Psychiatry,UCL,London,UK.
authors.forename: G
authors.initials: G
authors.lastname: Lewis
authors.affiliation: Institute of Health and Wellbeing,University of Glasgow,Glasgow,UK.
authors.forename: D J
authors.initials: DJ
authors.lastname: Smith
authors.affiliation: Division of Psychiatry,UCL,London,UK.
authors.forename: D P J
authors.initials: DP
authors.lastname: Osborn
mesh_terms: D000293:Adolescent; D000328:Adult; D001249:Asthma / Q000453:epidemiology; D001714:Bipolar Disorder / Q000453:epidemiology / Q000209:etiology*; D002097:C-Reactive Protein; D002648:Child; D004485:Eczema / Q000453:epidemiology; D006801:Humans; D015850:Interleukin-6 / Q000097:blood*; D008137:Longitudinal Studies; D012307:Risk Factors; D006113:United Kingdom / Q000453:epidemiology; D055815:Young Adult
chemical_list: C508600:IL6 protein, human; D015850:Interleukin-6; D002097:C-Reactive Protein
keywords: Atopic disorders; cohort studies; hypomania; inflammation