Depressive symptom clusters are differentially associated with atherosclerotic disease

BACKGROUND: Depression increases the risk of subsequent vascular events in both cardiac and non-cardiac patients. Atherosclerosis, the underlying process leading to vascular events, has been associated with depression. This association, however, may be confounded by the somatic-affective symptoms being a consequence of cardiovascular disease. While taking into account the differentiation between somatic-affective and cognitive-affective symptoms of depression, we examined the association between depression and atherosclerosis in a community-based sample. METHOD: In 1261 participants of the Nijmegen Biomedical Study (NBS), aged 50-70 years and free of stroke and dementia, we measured the intima-media thickness (IMT) of the carotid artery as a measure of atherosclerosis and we assessed depressive symptoms using the Beck Depression Inventory (BDI). Principal components analysis (PCA) of the BDI items yielded two factors, representing a cognitive-affective and a somatic-affective symptom cluster. While correcting for confounders, we used separate multiple regression analyses to test the BDI sum score and both depression symptom clusters. RESULTS: We found a significant correlation between the BDI sum score and the IMT. Cognitive-affective, but not somatic-affective, symptoms were also associated with the IMT. When we stratified for coronary artery disease (CAD), the somatic-affective symptom cluster correlated significantly with depression in both patients with and patients without CAD. CONCLUSIONS: The association between depressive symptoms and atherosclerosis is explained by the somatic-affective symptom cluster of depression. Subclinical vascular disease thus may inflate depressive symptom scores and may explain why treatment of depression in cardiac patients hardly affects vascular outcome.