Analysis of potential predictors of depression among coronary heart disease risk factors including heart rate variability, markers of inflammation, and endothelial function

Aims We investigated the relationship between autonomic nervous system balance, systemic immune activation, endothelial dysfunction, and depression in patients free of coronary heart disease (CHD) with increased CHD risk. Methods and results Depression status (Beck Depression Inventory, BDI), selected CHD risk factors, inflammation markers, measures of heart rate variability (HRV), and indices of endothelial function (flow-mediated dilation, FMD) were evaluated in 415 subjects free of CHD, diabetes mellitus, and other life-threatening conditions, with at least two CHD risk factors among the following: older age, male gender, current smoking, hypertension, and dislipidaemia. Overall, 51.7% of the participants were males, aged 57.6 +/- 8.8 years on average (minimum 30, maximum 70). Almost half were hypertensive, 43.9% were dyslipidemic, 30.4% current smokers, and 23.1% showed a depressive symptomatology (BDI >= 10). Logistic regression showed that, as compared with non-depressed individuals and after adjustment for age, gender, and hypertension, depressive subjects were significantly more likely to be smokers, to have higher total cholesterol, higher C-reactive protein, and Interleukin-6. In addition, depressed subjects were more likely to have altered HRV and their FMD was severely impaired (adjusted odds ratio of 1% increase = 0.72; 95% CI: 0.61-0.86). Conclusion Our data indicate an independent association between depression and impaired HRV, systemic inflammatory, and endothelial function. These mechanisms play a role not only in the complication of advanced forms of disease, but also promote and/or accelerate the early disease and connect depression and CHD.