Associations between affective traits and endothelial function in depressed adults

Abstract

Depressed adults are at increased risk of developing atherosclerotic cardiovascular disease (CVD). However, heterogeneity in the depressed population engenders a key question: Are there subgroups of depressed adults at greater risk of developing CVD? Because other affective traits – i.e., anxiety, hostility/anger, and low trait positive affect – have also been associated with increased CVD risk, depressed adults with higher levels of these co-occurring affective traits may have an elevated risk of developing CVD. Consequently, the present study’s first aim was to examine, in depressed adults, which affective traits (depression, anxiety, hostility/anger, or low positive affect) are associated with endothelial function, a marker of cumulative CVD risk. In addition, because the other affective traits overlap with depressive symptom severity, this study’s second aim was to investigate which components of pairs of affective traits (shared versus unique) are related to endothelial function. Finally, given that the mechanisms underlying affective trait-endothelial function relationships in depressed adults are unknown, this study’s third aim was to explore traditional CVD risk status as a candidate mediator of observed relationships. To achieve these aims, I combined pre-treatment, cross-sectional data from three randomized controlled trials involving 138 depressed primary care patients with no history of clinical CVD. Assessments included validated self-report questionnaires for affective traits, brachial artery flow-mediated dilation (FMD) for endothelial function, and 10-year Framingham risk score for traditional CVD risk status. I conducted structural equation modeling (SEM) with confirmatory factor analysis to examine the relationships of interest after adjusting for age, sex, race/ethnicity, education, and baseline arterial diameter. Although the shared variance between each affective trait pair could not be modeled due to poor fit, adequate fitting models revealed that hostility/anger and the unique components of hostility/anger were associated with poorer endothelial function (standardized coefficients = -.18 and -.22, respectively). All of the other affective traits and their components (depression, anxiety, positive affect, unique depression, unique anxiety, and unique positive affect) were not related to endothelial function (all ps > .08). Traditional CVD risk status did not partially explain the relationship between the unique components of hostility/anger and endothelial function (standardized coefficient for the indirect effect = .00; p = .89). If my results are supported by future findings, it would suggest that depressed adults with hostility/anger (a) may be a subgroup of the depressed population at greater risk of developing CVD and (b) may be in need of earlier, more intense, and/or different CVD primary prevention efforts. Future studies are needed to confirm this relationship and identify underlying mechanisms.