title: The inflammatory marker GDF-15 is not independently associated with late-life depression.
abstract: OBJECTIVE
  Growth differentiation factor-15 (GDF-15) is an inflammatory molecule that reacts to cell stress. Since major depression is associated with inflammation, we examined whether GDF-15 levels are elevated in patients with late-life depression.
  
  
  METHODS
  Plasma GDF-15 levels were analyzed in 350 patients diagnosed with major depressive disorder in the last six months and 128 non-depressed controls from the Netherlands Study of Depression in Older persons (age ≥ 60 years). Major depressive disorder and age of onset were assessed with the Composite International Diagnostic Interview. Severity of depressive symptoms was measured with the Inventory of Depressive Symptoms (IDS-30). Multiple linear regression models were applied to study depression (diagnosis, onset age, severity, antidepressant drug use) as determinant of GDF-15 level, adjusted for demographic and clinical variables.
  
  
  RESULTS
  Plasma GDF-15 levels were 22% higher in patients with major depression compared to controls. Within the depressed group, levels were higher in patients with older age of onset. GDF-15 levels showed a small, positive correlation to the levels of the inflammatory mediators IL-6 and C-reactive protein (r=0.23, and 0.24, p<0.05). This increase was independent from comorbidities, such as cardiovascular disease, rheumatism and diabetes, and anti-inflammatory drugs. However, this increase was dependent on lifestyle factors as smoking, physical activity and alcohol use. Within the depressed subgroup, neither depression severity or antidepressant drug use was associated with GDF-15 levels in the fully adjusted models.
  
  
  CONCLUSIONS
  The inflammatory factor GDF-15 does not seem to be an independent inflammatory marker for late-life major depressive disorder.
authors.affiliation: Dept. of Clinical Chemistry, Neuroscience Campus Amsterdam, VU University Medical Center Amsterdam, The Netherlands. Electronic address: c.teunissen@vumc.nl.
authors.forename: C E
authors.initials: CE
authors.lastname: Teunissen
authors.affiliation: Dept. of Clinical Chemistry, Neuroscience Campus Amsterdam, VU University Medical Center Amsterdam, The Netherlands.
authors.forename: S
authors.initials: S
authors.lastname: Durieux-Lu
authors.affiliation: Dept. of Clinical Chemistry, Neuroscience Campus Amsterdam, VU University Medical Center Amsterdam, The Netherlands.
authors.forename: M A
authors.initials: MA
authors.lastname: Blankenstein
authors.affiliation: University of Groningen, University Medical Center Groningen, Interdisciplinary Center for Psychopathology of Emotion Regulation (ICPE), Groningen, The Netherlands.
authors.forename: R C
authors.initials: RC
authors.lastname: Oude Voshaar
authors.affiliation: GGZ inGeest/Department Psychiatry, EMGO Institute for Care and Health Research, VU University Medical Center, Amsterdam, The Netherlands.
authors.forename: H C
authors.initials: HC
authors.lastname: Comijs
mesh_terms: D000328:Adult; D000368:Aged; D000428:Alcohol Drinking / Q000009:adverse effects; D000928:Antidepressive Agents / Q000627:therapeutic use; D015415:Biomarkers / Q000097:blood; D002097:C-Reactive Protein / Q000378:metabolism; D015897:Comorbidity; D003863:Depression / Q000097:blood / Q000175:diagnosis; D003865:Major Depressive Disorder / Q000097:blood* / Q000175:diagnosis* / Q000188:drug therapy; D005260:Female; D055436:Growth Differentiation Factor 15 / Q000097:blood*; D006801:Humans; D007249:Inflammation / Q000097:blood* / Q000175:diagnosis; D015850:Interleukin-6 / Q000097:blood; D008019:Life Style; D008297:Male; D008875:Middle Aged; D009426:Netherlands; D010555:Personality Inventory; D012720:Severity of Illness Index; D012907:Smoking / Q000009:adverse effects
chemical_list: D000928:Antidepressive Agents; D015415:Biomarkers; C526140:GDF15 protein, human; D055436:Growth Differentiation Factor 15; D015850:Interleukin-6; D002097:C-Reactive Protein
keywords: GDF-15; Inflammation; Late life depression; Life-style; Plasma