title: The relationship between neuroticism and inflammatory markers: a twin study.
abstract: BACKGROUND
  Neuroticism is an important marker of vulnerability for both mental and physical disorders. Its link with multiple etiological pathways has been studied before. Inflammatory markers have been demonstrated to predict similar mental and physical disorders as neuroticism. However, currently no study has focused on the shared genetic background of neuroticism and inflammatory markers. In the present study we will focus on the phenotypic and genetic relationship between neuroticism and three commonly used inflammatory markers: C-reactive protein (CRP), fibrinogen and Immunoglobulin-G (IgG).
  
  
  METHODS
  The study was conducted in 125 Dutch female twin pairs. For each participant, four different neuroticism scores were available to calculate a neuroticism composite score that was used in the statistical analyses. Blood samples for inflammatory marker determination were taken after an overnight fast. Heritabilities, phenotypic and genetic correlations were estimated using bivariate structural equation modeling.
  
  
  RESULTS
  Heritabilities are fair for neuroticism (0.55), CRP (0.52) and fibrinogen (0.67) and moderate for IgG (0.43). No significant phenotypic or genetic correlations were found between neuroticism and the inflammatory markers. Interaction models yielded no moderation of the genetic and environmental pathways in the regulation of inflammatory markers by neuroticism.
  
  
  CONCLUSIONS
  Substantial heritabilities were observed for all variables. No evidence was found for significant shared (or moderation of) genetic or environmental pathways underlying neuroticism and inflammatory status.
authors.affiliation: University of Groningen,University Medical Center Groningen,Department of Epidemiology,Groningen,The Netherlands.
authors.forename: Arthur A
authors.initials: AA
authors.lastname: Sas
authors.affiliation: Social,Genetic and Developmental Psychiatry Research Center,Institute of Psychiatry,King's College London,London,United Kingdom.
authors.forename: Frühling V
authors.initials: FV
authors.lastname: Rijsdijk
authors.affiliation: University of Groningen,University Medical Center Groningen,Department of Psychiatry,Interdisciplinary Center Psychopathology and Emotion regulation (ICPE),Groningen,The Netherlands.
authors.forename: Johan
authors.initials: J
authors.lastname: Ormel
authors.affiliation: University of Groningen,University Medical Center Groningen,Department of Epidemiology,Groningen,The Netherlands.
authors.forename: Harold
authors.initials: H
authors.lastname: Snieder
authors.affiliation: University of Groningen,University Medical Center Groningen,Department of Epidemiology,Groningen,The Netherlands.
authors.forename: Harriëtte
authors.initials: H
authors.lastname: Riese
mesh_terms: D000328:Adult; D001008:Anxiety Disorders / Q000097:blood* / Q000235:genetics / Q000473:pathology; D015415:Biomarkers / Q000097:blood*; D002097:C-Reactive Protein / Q000378:metabolism; D004200:Diseases in Twins / Q000097:blood* / Q000235:genetics / Q000473:pathology*; D005260:Female; D005340:Fibrinogen / Q000378:metabolism; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood; D007249:Inflammation / Q000097:blood* / Q000235:genetics / Q000473:pathology; D008137:Longitudinal Studies; D000075384:Neuroticism; D010641:Phenotype; D014429:Twins, Dizygotic / Q000235:genetics*; D014430:Twins, Monozygotic / Q000235:genetics*; D055815:Young Adult
chemical_list: D015415:Biomarkers; D007074:Immunoglobulin G; D005340:Fibrinogen; D002097:C-Reactive Protein