title: Differential association of somatic and cognitive symptoms of depression and anxiety with inflammation: findings from the Netherlands Study of Depression and Anxiety (NESDA).
abstract: OBJECTIVE
  Depression and anxiety have been suggested to be associated with systemic inflammation upregulation. However, results are not always consistent, which may be due to symptom heterogeneity of depression and anxiety. There are some indications that associations with inflammation are mainly driven by somatic symptoms of depression and anxiety. We therefore set out to evaluate the differential association of somatic and cognitive symptoms of depression and anxiety with inflammation, while adjusting for demographic, health related, and lifestyle related variables.
  
  
  METHODS
  We evaluated baseline data from 2861 participants from the Netherlands Study of Depression and Anxiety (NESDA). The Inventory of Depressive Symptomatology and the Beck Anxiety Inventory were used to assess depressive symptoms and anxiety symptoms. For both scales somatic and cognitive symptoms scales were calculated. Baseline blood samples were collected to determine high sensitivity C-Reactive Protein (CRP), interleukin (IL)-6, and Tumor Necrosis Factor (TNF)-α. We used linear regression to analyze the associations adjusting for demographics and health indicators and markers for an unhealthy lifestyle.
  
  
  RESULTS
  After adjustment for sociodemographic and health indicators, depressive symptoms were associated with higher levels of CRP, IL-6 and TNF-α. This association was mainly driven by somatic symptoms. For anxiety, somatic symptoms were associated with higher levels of CRP, IL-6 and TNF-α, whereas cognitive anxiety symptoms were associated with CRP (men only). Markers of an unhealthy lifestyle explained the significant associations.
  
  
  CONCLUSIONS
  Especially somatic symptoms of depression and anxiety are associated with inflammation. However, this association was mostly mediated through unhealthy lifestyles among depressed and anxious individuals.
authors: CoRPS-Center of Research on Psychology in Somatic Diseases, Tilburg University, Tilburg, The Netherlands.
authors: Hester E
authors: HE
authors: Duivis
authors: Nicole
authors: N
authors: Vogelzangs
authors: Nina
authors: N
authors: Kupper
authors: Peter
authors: P
authors: de Jonge
authors: Brenda W J H
authors: BW
authors: Penninx
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000428:Alcohol Drinking / Q000453:epidemiology; D000893:Anti-Inflammatory Agents / Q000627:therapeutic use; D000928:Antidepressive Agents / Q000627:therapeutic use; D001007:Anxiety / Q000097:blood / Q000453:epidemiology / Q000503:physiopathology*; D015415:Biomarkers; D015992:Body Mass Index; D002097:C-Reactive Protein / Q000032:analysis; D015897:Comorbidity; D003863:Depression / Q000097:blood / Q000453:epidemiology / Q000503:physiopathology*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors / Q000627:therapeutic use; D007249:Inflammation / Q000097:blood / Q000503:physiopathology / Q000523:psychology*; D015850:Interleukin-6 / Q000097:blood; D008019:Life Style; D008297:Male; D008875:Middle Aged; D009426:Netherlands / Q000453:epidemiology; D025341:Principal Component Analysis; D012720:Severity of Illness Index; D012907:Smoking / Q000453:epidemiology; D012959:Socioeconomic Factors; D063189:Symptom Assessment; D014409:Tumor Necrosis Factor-alpha / Q000097:blood; D055815:Young Adult
chemical_list: D000893:Anti-Inflammatory Agents; D000928:Antidepressive Agents; D015415:Biomarkers; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors; C508600:IL6 protein, human; D015850:Interleukin-6; D014409:Tumor Necrosis Factor-alpha; D002097:C-Reactive Protein
keywords: Anxiety symptoms; Cognitive; Cohort study; Depressive symptoms; IL-6; Inflammation; Somatic; TNF-α; hsCRP