Abstract
BACKGROUND: Late life depression, including patients with vascular depression, has been associated with higher levels of intima-media thickness (IMT). Although individuals with vascular depression tend to report a later onset of depression, the relationship of IMT and age of first depressive episode is uncertain in younger adults. We therefore investigated the relationship between IMT and age of first depressive episode in a sample of 202 adults (age range 40-81 years) with major depression (MDD). METHODS: Depression status was assessed using the Structured Clinical Interview Schedule and the Hamilton Depression Rating Scale. Patients underwent a physical examination in which a medical history was obtained. IMT was measured from the left and right common carotid arteries. Simple regression analyses were used to investigate the association between IMT and self-reported age of first depressive episode. RESULTS: IMT was associated with a later onset of first major depressive episode (b=.225, P=.0005) and this association remained significant after controlling for age, Framingham Stroke Risk Profile, smoking pack years, physical activity, high- and low-density lipoprotein, body mass index, triglyceride levels, and history of chronic medical conditions (b=.142, P=.028). Each .10mm increase in IMT was associated with a 2.6-year later reported occurrence of first major depressive episode (MDE). Similarly, higher levels of IMT were associated with fewer previous MDEs (b=-.149, P=.020) and this effect remained significant in our multivariate model (b=-.140, P=.030). In contrast, IMT was not associated with current depressive severity (b=-.024, P=.720). CONCLUSIONS: Greater levels of IMT are associated with a later onset of depression and fewer previous depressive episodes among middle-aged and older adults, independent of cardiovascular co-morbidities. These findings provide preliminary evidence that increased vascular burden may be associated with a later onset of depression.