title: Gestational maternal C--reactive protein and risk of bipolar disorder among young individuals in a Nationwide Birth Cohort.
abstract: C-reactive protein (CRP) is a well-established general marker of inflammation from both infectious and noninfectious exposures. Previous studies have shown that maternal CRP is associated with an increased risk of autism and schizophrenia. The aim of this study was to examine the association between early to mid-gestational serum CRP levels, prospectively assayed in maternal sera, and the risk of bipolar disorder (BPD).
  
  
  
  This study is derived from the Finnish Prenatal Study of Bipolar Disorder (FIPS-B), based on a nested case-control study design. A total of 378 BPD cases and 378 controls, matched on date of birth and sex, with available maternal sera were identified from Finnish nationwide registers. Maternal CRP levels were assessed using a latex immunoassay from archived maternal serum specimens, collected primarily during the first and second trimesters of pregnancy.
  
  
  
  Increasing maternal CRP, examined as a continuous variable, was not associated with BPD (OR=0.92, 95% CI: 0.81-1.05, p=0.24). The result did not change appreciably following adjustment for potential confounders. There were no associations between CRP in the highest quintile or decile, compared with their respective reference groups, and BPD.
  
  
  
  The limitations of the study include: relative young age of the cohort and availability only of a single marker of inflammation.
  
  
  
  In contrast to previous findings on schizophrenia and autism, gestational maternal serum CRP levels were not associated with an increased risk of BPD. It is likely that maternal inflammation may be an additional factor that differentiates schizophrenia from BPD.
authors.affiliation: Department of Child Psychiatry, University of Turku and Turku University Hospital, Finland. Electronic address: roschu@utu.fi.
authors.forename: Roshan
authors.initials: R
authors.lastname: Chudal
authors.affiliation: Department of Child Psychiatry, University of Turku and Turku University Hospital, Finland.
authors.forename: Andre
authors.initials: A
authors.lastname: Sourander
authors.affiliation: National Institute for Health and Welfare, Oulu, Finland.
authors.forename: Heljä-Marja
authors.initials: HM
authors.lastname: Surcel
authors.affiliation: Department of Child Psychiatry, University of Turku and Turku University Hospital, Finland.
authors.forename: Dan
authors.initials: D
authors.lastname: Sucksdorff
authors.affiliation: Department of Child Psychiatry, University of Turku and Turku University Hospital, Finland.
authors.forename: Susanna
authors.initials: S
authors.lastname: Hinkka-Yli-Salomäki
authors.affiliation: Department of Psychiatry, Columbia University College of Physicians and Surgeons, New York State Psychiatric Institute, New York, NY, USA; Department of Epidemiology, Columbia University, Mailman School of Public Health, New York, NY, USA.
authors.forename: Alan S
authors.initials: AS
authors.lastname: Brown
mesh_terms: D000328:Adult; D015415:Biomarkers / Q000097:blood; D001714:Bipolar Disorder / Q000097:blood* / Q000150:complications; D002097:C-Reactive Protein / Q000032:analysis*; D016022:Case-Control Studies; D005260:Female; D005387:Finland; D006801:Humans; D008297:Male; D011247:Pregnancy; D011248:Pregnancy Complications / Q000097:blood*; D011262:Pregnancy Trimester, Second; D012307:Risk Factors; D012559:Schizophrenia / Q000097:blood
chemical_list: D015415:Biomarkers; D002097:C-Reactive Protein
keywords: Bipolar disorder; CRP; Epidemiology; Nationwide cohort; Prenatal inflammation