Depression symptoms and the progression of carotid intima-media thickness: a 5-year follow-up study

Background: Only a few studies have investigated the changes in carotid intima-media thickness (IMT) over time, and uncertainties remain on the underlying mechanisms linking depression and subclinical atherosclerosis. We carried out a prospective cohort study to evaluate whether depression is associated with changes in carotid IMT in subjects with cardiac risk factors but free from coronary heart disease (CHD), and to what extent the atherogenicity of depression can be explained by inflammatory markers and autonomic nervous system dysfunction. Methods and results: During baseline and follow-up visits: all participants were asked to provide blood samples and compile a structured questionnaire; trained physicians assessed depression symptoms using Beck Depression Inventory (BDI); altered cardiac autonomic tone was measured using time-domain components of heart rate variability in 24h Holter recordings; measurements of carotid IMT were carried out using B-mode ultrasound image acquisition. Logistic and linear regression analyses were used to adjust for potential confounders and explore potential mediators. A total of 381 subjects completed the 5-year follow-up. The mean carotid IMT significantly increased in all subjects but the amount of increase was significantly larger among subjects with depression symptoms: mean IMT increased by 0.16±0.14 mm; 0.31±0.28 mm and 0.61±0.54 mm among the subjects with no, mild and moderate/severe depression, respectively (all p<0.01). The association between moderate/severe depression and IMT increase remained highly significant even after controlling for all the variables considered, however when both IL-6 and CRP were included in multivariate models the regression coefficient decreased by 42.3%. Some of the inflammation markers and autonomic nervous system dysfunction were also independently correlated with carotid IMT increase. Conclusion: Depression symptoms are independently associated with an accelerated progression of carotid IMT in subjects with CHD risk factors, and inflammation may substantially modulate the association between depression and carotid IMT progression.