Depression and inflammation in patients with coronary heart disease: findings from the Heart and Soul Study.
BACKGROUND
Depression and inflammation independently predict adverse cardiovascular outcomes in patients with coronary heart disease (CHD). Depression has been associated with elevated levels of inflammation in otherwise healthy patients without known CHD. However, studies investigating the link between depression and inflammation in patients with established CHD have produced inconclusive results.


METHODS
We sought to examine the association of major depression with inflammation in 984 outpatients with established CHD from the Heart and Soul Study. We assessed current major depression with the Computerized Diagnostic Interview Schedule and collected venous blood samples for measurement of five inflammatory biomarkers (white blood cell count, CD40 ligand, C-reactive protein [CRP], fibrinogen, and interleukin-6 [IL-6]). We used multivariate analysis of variance to examine the association of current depression with inflammatory markers, adjusted for potential confounding variables.


RESULTS
Of the 984 participants, 217 (22%) had current major depression. Depression was not associated with increased levels of any inflammatory marker. Contrary to our hypothesis, depression was associated with lower levels of CRP (p = .09), fibrinogen (p = .006), and IL-6 (p = .007) in both unadjusted and adjusted models.


CONCLUSIONS
We found no evidence that current depression is associated with greater inflammation in outpatients with CHD. Inflammation is unlikely to explain the adverse cardiovascular outcomes associated with depression in patients with established CHD.
Whooley
Mary A
MA
Department of Veterans Affairs Medical Center, San Francisco, California; University of California, San Francisco, CA 94121, USA. mary.whooley@ucsf.edu
Caska
Catherine M
CM
Hendrickson
Bethany E
BE
Rourke
Meghan A
MA
Ho
Joseph
J
Ali
Sadia
S
D000368:Aged; D015415:Biomarkers / Q000097:blood; D002097:C-Reactive Protein / Q000032:analysis*; D023201:CD40 Ligand / Q000097:blood; D016009:Chi-Square Distribution; D015331:Cohort Studies; D003327:Coronary Disease / Q000097:blood / Q000150:complications / Q000276:immunology* / Q000523:psychology; D003430:Cross-Sectional Studies; D003865:Major Depressive Disorder / Q000097:blood / Q000150:complications / Q000276:immunology*; D005260:Female; D005340:Fibrinogen / Q000032:analysis*; D006801:Humans; D007249:Inflammation / Q000097:blood / Q000150:complications / Q000276:immunology; D015850:Interleukin-6 / Q000097:blood*; D007958:Leukocyte Count; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012720:Severity of Illness Index
D015415:Biomarkers; D015850:Interleukin-6; D023201:CD40 Ligand; D005340:Fibrinogen; D002097:C-Reactive Protein