Chronic stress, inflammation, and progression of carotid artery atherosclerosis: A mediation model.

摘要

Psychosocial stress might account for some of the variance in cardiovascular disease (CVD) risk that is not explained by traditional risk factors. Most studies of stress and CVD have focused on (a) stress in a single life domain, and (b) clinical CVD outcomes. Few studies have examined physiologic mechanisms that might explain the association between stress and CVD. The primary aim of the present study was to examine whether: (1) chronic stress predicts changes in carotid artery intima-media thickness (IMT) and plaque; and (2) the association between chronic stress and changes in these surrogate CVD endpoints is mediated by inflammatory processes. A secondary aim was to investigate whether individual differences in cardiovascular reactivity (CVR) moderates the association between stress and changes in IMT and plaque. The sample (n&barbelow;=276; M&barbelow; age=60.5), was a subset of the Pittsburgh Healthy Heart Project, a longitudinal investigation of the effects of psychosocial and biological risk factors on surrogate CVD endpoints among healthy older adults. Chronic stress was assessed at baseline with the Chronic Stress Scale (CSS; Norris & Uhl, 1993), a self-report survey that measures stress in 7 life domains during the preceding 6 months. Chronic stress was computed in terms of (a) scores on the 7 CSS subscales and (b) average score across all 7 subscales. Ultrasound IMT measures were taken at baseline and 3 years later. Mean IMT was derived by taking the bilateral average of far wall common, internal and bulb measures. IMT change was computed as the arithmetic difference between follow-up and baseline values. Plaque change was computed as the number of visible lesions at follow-up less the number of lesions at baseline. Blood draws for inflammatory markers and CVR testing were conducted at separate baseline visits. Results failed to support the mediation model. Only the CSS physical stress subscale was an independent predictor of IMT change (b&barbelow;=.02, t&barbelow;=2.13, p&barbelow;=.03). CSS scores were unrelated to plaque, or to inflammatory marker levels. Results did not differ according to CVR. Findings question the importance of chronic stress, as measured by global self-report, as a predictor of change in IMT and plaque.