Behavioral and Psychosocial Factors and CAD Risk
Certain behavioral lifestyle factors, such as cigarette smoking, dietary intake, and physical activity, have been strongly linked to risk of CAD events and are common targets for therapeutic lifestyle change recommendations. These and other traditional CAD risk factors, such as family history of CAD and diabetes, are thought to explain up to 70% to 80% of CAD risk. Other factors, including various psychosocial and novel biologic factors, may help explain the remaining 20% to 30% of CAD risk variability.
Psychosocial factors are generally not included in multivariate predictive models of CAD risk prediction, such as those from the Framingham Heart Study, despite the fact that the strength of their association with CAD is similar to the risk factors included in CAD risk prediction equationsÔÇöhypertension, smoking, diabetes, and hyperlipidemia. Psychosocial factors associated with CAD risk include some with negative and others with positive relationships to CAD (see Table 1). Psychosocial factors that have a negative influence on CAD risk include depression, anxiety, anger, hostility, and chronic stressors such as social isolation, low socioeconomic status, and chronic strain from difficult interpersonal relationships and/or responsibilities (occupational and caregiver roles, for example). Depression has been identified for many years as perhaps the strongest negative psychosocial risk factor for CAD risk, increasing the risk of morbidity and mortality by more than two-fold in people with existing CAD.
Negative psychosocial factors are thought to directly affect CAD risk through a variety of pathophysiologic mechanisms, including alterations in autonomic nervous system activity and heart rate variability, blood pressure reactivity, endothelial reactivity, inflammation, coagulation factors, arrhythmias, and atherosclerotic plaque stability. Indirectly, psychosocial factors may also affect CAD risk by exerting a negative influence on adherence to healthy behavioral lifestyle habits (healthy nutrition habits, regular exercise, and tobacco avoidance, for instance).
A number of positive psychosocial factors are associated with reduced CAD risk, including optimism, sense of humor, forgiveness, social support, religious faith, vitality, forgiveness, gratitude, altruistic behavior, emotional flexibility, and coping flexibility. The risk of CAD associated with these positive psychosocial factors is reduced by up to half of that observed in people without these positive factors. Positive factors, such as optimism, are thought to exert beneficial effects on CAD risk through physiologic mechanisms that generally run opposite those associated with the previously mentioned negative psychosocial factors. For instance, positive psychosocial factors have been associated with beneficial effects on autonomic nervous reactivity, and immune system protection against infection. They might also help to reduce CAD risk by reinforcing a personÔÇÖs desire and ability to adhere to healthy lifestyle habits and to preventive medications, such as anti-platelet, anti-hypertension, and lipid-lowering drugs.