Associations between depressive symptoms, cigarette smoking, and cardiovascular health: Longitudinal results from CARDIA

Introduction: Depression is associated with increased risk of incident and recurrent cardiovascular disease, while the association between depression and cardiovascular health ( CVH) remains unknown. Because the natural course of depression varies widely, different patterns of depression, as well as co-occurring factors such as cigarette smoking, may influence this relationship. We examined potential interactions between longitudinal patterns of depression and smoking with CVH. Methods: Using data from the Coronary Artery Risk Development in Young Adults (CARDIA) study, we modeled trajectories of depression (Center for Epidemiologic Studies Depression scale scores; Years 5, 10, 15, 20) and smoking (cigarettes/day; Years 0, 2, 5, 7, 10, 15, 20). We calculated a modified American Heart Association (AHA) CVH Score (weight, blood glucose, cholesterol, blood pressure, physical activity, and diet; Year 20); higher scores indicate better CVH. Generalized linear models evaluated associations between depression trajectories, smoking trajectories, and their interaction with CVH Score. Results: The depression trajectory x smoking trajectory interaction was not associated with CVH Score, but main effects of depression trajectory (p < .001) and smoking trajectory (p < .001) were observed. Participants with patterns of subthreshold depression (beta = - 0.26, SE = 0.08), increasing depression (beta = - 0.51 SE = 0.14), and high depression (beta = -0.65, SE = 0.32) had lower CVH Scores than those without depression. Compared to never smokers, participants who quit smoking had higher CVH Scores (beta = 0.38, SE = 0.11), while participants with the greatest smoking exposure had lower CVH Scores (beta = -0.49, SE = 0.22). Limitations: CVH Scores were adapted from the AHA guidelines based on the available CARDIA data. Conclusions: Deleterious depression and smoking trajectories are independently but not synergistically associated with worse CVH.