title: The associations of high levels of C-reactive protein with depression and myocardial infarction in 9258 women and men from the HUNT population study.
abstract: BACKGROUND
  Elevated levels of circulating C-reactive protein (CRP) have been associated with coronary heart disease and, in some studies, depression. Most studies have been of populations selected by age and/or gender. We investigate these associations with depression, myocardial infarction (MI), or both, in a large general population sample.
  
  
  METHODS
  A cross-sectional population study of 9258 women and men aged ≥ 20 years. The study included clinical examination, self-report of MI and depression and factors known to confound their associations. The Hospital Anxiety and Depression Scale was used to assess severity of depressive symptoms. Elevated high sensitive-CRP was defined as values >2.2 mg/l.
  
  
  RESULTS
  The association of elevated CRP with depression was attenuated towards the null [from odds ratio (OR) 1.28, p=0.001 to OR 1.08, p=0.388] following extensive adjustment, while associations with MI (adjusted OR 1.42, p=0.032) and co-morbid MI and depression (adjusted OR 2.66, p=0.003) persisted. Confounders associated with elevated CRP levels were smoking (OR 1.66; p<0.001), chronic physical illness (OR 1.34, p<0.001), BMI ≥ 30 (OR 1.13, p<0.001), employment (OR 0.70, p<0.001) and high coffee consumption (OR 0.83, p=0.017). Interaction tests indicated a lower effect of old age (OR 0.54, p<0.001) and smoking (OR 0.63, p<0.001) on elevated CRP levels in women compared with men.
  
  
  CONCLUSIONS
  CRP levels were raised in those with MI and co-morbid MI and depression; the positive association with depression was explained by confounding factors. We found new evidence that might help understand gender-specific patterns. Future studies should explore the neurobiological mechanisms underpinning these interrelations and their relevance for treatment of these conditions.
authors.affiliation: Department of Research and Development (RaD), Levanger Hospital, Health Trust Nord-Trøndelag, Norway. ottar.bjerkeset@ntnu.no
authors.forename: O
authors.initials: O
authors.lastname: Bjerkeset
authors.forename: U
authors.initials: U
authors.lastname: Romild
authors.forename: G Davey
authors.initials: GD
authors.lastname: Smith
authors.forename: K
authors.initials: K
authors.lastname: Hveem
mesh_terms: D017677:Age Distribution; D000368:Aged; D015415:Biomarkers / Q000097:blood; D002097:C-Reactive Protein / Q000378:metabolism*; D016022:Case-Control Studies; D015897:Comorbidity; D003430:Cross-Sectional Studies; D003866:Depressive Disorder / Q000453:epidemiology* / Q000378:metabolism; D005260:Female; D006801:Humans; D007249:Inflammation / Q000097:blood; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009203:Myocardial Infarction / Q000453:epidemiology* / Q000378:metabolism; D009664:Norway / Q000453:epidemiology; D012307:Risk Factors; D017678:Sex Distribution
chemical_list: D015415:Biomarkers; D002097:C-Reactive Protein