Autonomic nervous system, inflammation and preclinical carotid atherosclerosis in depressed subjects with coronary risk factors

ObjectivesWe investigated the relationship between intima-media thickening (IMT) as an expression of preclinical atherosclerosis and coronary risk factors, including the autonomic nervous system and inflammation markers, in depressed subjects free from coronary artery disease.MethodsWe studied 391 asymptomatic subjects with a cluster of risk factors, and we evaluated depression using the Beck Depression Inventory. IMT of the common carotid artery was determined by B-mode ultrasound imaging. Traditional risk factors for atherosclerosis were recorded. Markers of inflammation (C-reactive protein, CRP; interleukin 6, IL-6) and heart rate variability (time domain) were determined.ResultsA total of 90 (23.0%) subjects showed a depressive symptomatology. The average IMT was increased in depressed subjects (0.87 ± 0.35 mm) at risk for CHD but free from disease as compared to controls (0.77 ± 0.19 mm; p < 0.001). Heart rate variability was reduced in depressed subjects. Levels of SDNN (103 ± 14 ms) and SDANN (93 ± 20 ms) were decreased in depressed subjects as compared to non-depressed subjects (SDNN 113 ± 22 ms and SDANN 108 ± 35 ms; p < 0.001). Subjects with depression had higher CRP (1.14 ± 0.65 mg/dl) and IL-6 (2.00 ± 0.40 pg/ml) than subjects without depression (CRP: 0.79 ± 0.34 mg/dl; IL-6: 1.6 ± 0.6 pg/ml; p < 0.001, respectively). In multivariate analysis, depression was positively correlated with CRP and IL-6 and IMT, and inversely associated with levels of SDANN.ConclusionsIMT is higher in depressed subjects, indicating that atherosclerosis is accelerated in this sub-group of patients. This is mainly due to patho-physiological mechanisms which connect depression and coronary artery disease, such as inflammation and imbalance of the autonomic nervous system.