Cardiovascular diseases remain the leading cause of death and a major cause of disability and lowered quality of life for both men and women in the United States. An estimated 13 million people have coronary heart disease (CHD). Each year there are an estimated 1.5 million myocardial infarctions (MI) and 500,000 deaths from MIs. The cost of heart disease in the United States, both direct and indirect, exceed $180 billion per year. Lung and blood diseases add more than $80 billion in costs.
Behavioral and psychological factors contribute a large share to the burden of these diseases. With the help of psychological science, we at the National Institutes of Health (NIH) have made significant strides toward understanding some of these, but we have a long way to go. Since its creation in 1948, NIH’s National Heart, Lung, and Blood Institute (NHLBI) has made behavioral science research an important component of the Institute’s research agenda. As the NHLBI approaches its 50th anniversary, I’d like to share with you some of the significant findings over the years and give you an overview of the current program.
Depression and Social Support
A few years ago, strong evidence became available showing that heart attack patients who are depressed or have few people to count on for social support are more likely to die or to experience another heart attack.
These findings were troubling but suggested that treating depression and enhancing social support might extend life and reduce future heart attack risk for these patients. Recently, the Institute launched a major clinical trial, Enhancing Recovery in Coronary Heart Disease Patients (ENRICHD), to determine whether treating depression and social isolation will prolong life or reduce the risk of another heart attack.
Other psychosocial factors contributing to cardiovascular diseases are also being investigated, including the influence of personality on risk of coronary heart disease and the effects of chronic and acute stress.
Socio-economic Status and Health
There is substantial epidemiological evidence that health is directly related to socio-economic status (SES). Therefore, it is not surprising that there is a strong link between cardiovascular disease and SES. However, traditional risk factors and access to health care do not fully explain the effects of SES on health. Other contributing factors include personality variables, differential availability of social support or other coping mechanisms, and excess environmental stress. Some studies have found that limited decision latitude at work is associated with increased incidence of cardiovascular disease. It is likely that several or all of these influences act simultaneously but to a different extent in different individuals. Effective disease prevention will depend on an improved understanding of the relationships between SES and health.
Mental Stress and Myocardial Ischemia
In recent years, it has become clear that mental stress can trigger episode of myocardial ischemia. Although the mechanisms through which mental stress provokes ischemia are not well understood, characteristic changes in sympathetic response and in blood circulation have been described. These changes are hemodynamically different from changes observed during exercise stress testing, and may help to identify patients who are at risk for cardiac events triggered by mental stress.
Research is needed on why hemodynamic changes observed in patients during exercise do not predict their responses to mental stress, the serotonergic and dopaminergic systems, and the response of the coronary endothelium to stress-related neurohormones.
Mechanisms Precipitating Acute Cardiac Events
The study of mechanisms that precipitate or trigger heart attacks, arrhythmias, or sudden death has been limited by the fact that they occur when the affected individual is not available for observation or study. Nevertheless, we have important clues about these mechanisms. For example, the well-documented morning increase in all major cardiovascular events indicates an important role of the patient’s physiology, activities, and behavior. Emotions such as anger may confer increased risk directly through neural and neuroendocrine pathways and may lower the threshold at which other triggers become effective.
Heart Disease in Women
Studies have found that women have a worse prognosis, both medical and psychosocial, than men following certain CHD events and treatments, but the reasons are not fully understood. For example, a recent study of bypass surgery patients found that women have less favorable physical and psychosocial risk profiles at the time of surgery.
Gender differences in susceptibility to stress-provoked myocardial ischemia are also thought to be important factors in the understanding of heart disease in women. Gender differences in cardiovascular reactivity are well documented, but not well understood. In part, these are the result of neuroendocrine influences, but also could be related to differences in receptor density or distribution, hemodynamic control variables, or psychological characteristics.
After taking into consideration all risk factors present in an individual, a history of CHD in the family adds a statistically significant additional amount of risk. Genetic research is not a new area of the behavioral sciences. Behavior genetics studies have helped us understand the extent to which cognitive, behavioral and psychological characteristics are inherited. However, we still need to learn more about the role of psychosocial and behavioral factors as moderators of phenotypic expression in cardiovascular disease.
Health-related Quality of Life
Health care professionals have become increasingly interested in the effects of medical treatments on the quality of patients’ lives. The NHLBI routinely includes assessments of patients’ quality of life in clinical trials and other studies of heart, lung, and blood diseases. These assessments have led to a number of important findings that have benefitted patients. For example, NHLBI trials have found that weight loss, either alone or in combination with drug therapy, improves quality of life and may, in fact, attenuate sexual dysfunction in men treated with certain antihypertensive drugs, such as chlorthalidone. Evidence suggests that reducing blood pressure itself may have beneficial effects on quality of life. Thus, in most individuals, hypertension can be treated with few, if any, effects on individuals’ quality of life, encouraging adherence to treatment.
The Institute supports a substantial research effort for primary and secondary prevention of disease including, among others, major commitments to community-based risk factor reduction studies, studies of diet and physical activity in children and adults, nonpharmacological interventions for hypertension, and prevention of smoking. Some of these efforts are specifically designed for minorities, in whom the incidence and prevalence of many diseases is higher than among non-minorities. Each of these areas presents unique challenges to behavioral research, as age, culture, socioeconomic status, and community variables exact their own requirements for optimal success.
Nowhere is the need for research more urgent than in the area of smoking cessation and prevention of smoking. Currently, the NHLBI funds several dozen smoking-related studies. These studies primarily address patients at risk for or suffering from cardiovascular and respiratory diseases. The recognition that cigarette smoking can affect us early in life has influenced the direction of NHLBI research. The effects of smoking during pregnancy, on perinatal outcomes, and on newborns are being assessed as are the effects of exposure to environmental tobacco smoke on children with and without asthma. Further research is needed to help prevent smoking in children and adolescents and to reach certain subgroups in which smoking is most prevalent.
The management of asthma in both children and adults is affected by socio-cultural, financial, and ethnic factors. For example, this chronic disease affects a disproportionate number of African Americans and Latinos. Current research efforts focus on identifying which behavioral elements, such as peak-flow monitoring, are most effective in day-to-day asthma management. Psychologists play a major role in developing adherence plans and retaining patients in clinical trials.
An estimated 70 million Americans at all stages of life have a sleep problem or disorder. The National Center for Sleep Disorders Research, located within the NHLBI, coordinates research, training, and education programs on sleep, sleep disorders, sleep deprivation, and sleepiness with other NIH institutes, other federal agencies and public organizations. Ongoing research includes studies of sleep disturbances and the natural patterns of sleep to determine the effects on productivity, cognitive performance, quality of life and relationship to cardiovascular and pulmonary health.
Task Force on Behavioral and Social Sciences Research
In 1995, the NHLBI convened a task force of leading scientists in psychology, public health, and medicine to review the Institute’s health and behavior research programs. The task force’s report, expected by the end of this year, promises to be an important resource for all scientists. With this report to help guide us-and the interest and commitment of behavioral scientists-we’re hopeful that the next 50 years at NHLBI will bring great advances in health and behavior research on heart, lung, and blood diseases.