title: Indoleamine 2,3-dioxygenase activation and depressive symptoms: results from the Young Finns Study.
abstract: OBJECTIVE
  To examine whether the activation of indoleamine 2,3-dioxygenase (IDO), an enzyme involved in serotonin production, is associated with depressive symptoms.
  
  
  METHODS
  The participants were 544 women and 442 men (aged 24-39 years) from the population-based Young Finns Study who participated in a medical examination in 2001 (including IDO and depression) and 2007 (follow-up assessment for depression).
  
  
  RESULTS
  At baseline, IDO was associated with depressive symptoms (in the total cohort: B = 0.23, p < .001; women: B = 0.20, p = .007; men: B = 0.29, p = .002; p for interaction = .19). IDO at baseline was also associated with depressive symptoms at follow-up in women (B = 0.17, p = .03), which remained significant when adjusting for any of the biologic and behavioral risk factors. Adjusting for body mass index attenuated the association by 6%. In the final model including all baseline variables, none of the risk factors (except for baseline depressive symptoms) were associated with depressive symptoms at follow-up.
  
  
  CONCLUSIONS
  These data suggest that IDO activity may be a risk factor for future depression especially in women. IDO-induced alterations in serotonergic function may offer one biologic explanation to the well-established associations between inflammation and depression.
authors.affiliation: Institute of Behavioural Sciences, University of Helsinki, Helsinki, Finland. marko.elovainio@thl.fi
authors.forename: Marko
authors.initials: M
authors.lastname: Elovainio
authors.forename: Mikko
authors.initials: M
authors.lastname: Hurme
authors.forename: Markus
authors.initials: M
authors.lastname: Jokela
authors.forename: Laura
authors.initials: L
authors.lastname: Pulkki-Råback
authors.forename: Mika
authors.initials: M
authors.lastname: Kivimäki
authors.forename: Mirka
authors.initials: M
authors.lastname: Hintsanen
authors.forename: Taina
authors.initials: T
authors.lastname: Hintsa
authors.forename: Terho
authors.initials: T
authors.lastname: Lehtimäki
authors.forename: Jorma
authors.initials: J
authors.lastname: Viikari
authors.forename: Olli T
authors.initials: OT
authors.lastname: Raitakari
authors.forename: Liisa
authors.initials: L
authors.lastname: Keltikangas-Järvinen
mesh_terms: D000328:Adult; D015992:Body Mass Index; D003863:Depression / Q000150:complications / Q000276:immunology / Q000378:metabolism*; D005260:Female; D006801:Humans; D050503:Indoleamine-Pyrrole 2,3,-Dioxygenase / Q000276:immunology / Q000378:metabolism*; D007249:Inflammation / Q000150:complications / Q000276:immunology / Q000378:metabolism*; D008137:Longitudinal Studies; D008297:Male; D012307:Risk Factors; D012701:Serotonin / Q000276:immunology / Q000378:metabolism*; D012737:Sex Factors
chemical_list: D050503:Indoleamine-Pyrrole 2,3,-Dioxygenase; D012701:Serotonin