The
National Heart, Lung, and Blood Institute (NHLBI) has a longstanding
appreciation of the value of behavioral research. From the earliest
days, when the concept of "coronary prone" behavior was
introduced, to the growing recognition of the need for strategies to
encourage health-promoting behaviors and lifestyles, to more recent
efforts to incorporate health-related quality of life measures into our
clinical studies, behavioral research has contributed much to our
understanding of cardiovascular disease (CVD). Although
still in its infancy, the application of this discipline to lung and
blood diseases, sleep disorders, and transfusion medicine issues
clearly offers much promise for advances in treatment and
prevention.
Acknowledging that many opportunities lie in biobehavioral research, in
November 1995 the NHLBI convened the Task Force on Behavioral Research
in Cardiovascular, Lung, and Blood Health and Disease
to chart a course for future research efforts. Composed of national
experts, it was charged to review the state of knowledge in
biobehavioral research in cardiovascular, lung, and
blood diseases and sleep disorders over the past 5 years; identify
research opportunities; and develop a comprehensive plan, including
scientific priorities, for NHLBI support of research on health and
behavior for the next several years.
During a series of meetings that spanned nearly 2 years, the task
force worked to develop a report of its findings and conclusions. The
report provides a detailed summary of accomplishments to date,
highlights new scientific opportunities, and identifies specific
recommendations for future research. The full text, with graphics, is
available on the NHLBI Web site at
http://www.nhlbi.nih.gov/nhlbi/sciinf/taskforc.htm.
The synopsis that follows was excerpted from the executive summary of
the task force report.
The Institute is very pleased to have this task force report to guide
its activities with respect to research on health and behavior. We are
grateful to the task force chair, Dr Stephen Manuck; the subgroup
chairs, Drs David Krantz and Margaret Chesney; and the task force
members for their valuable contribution to this important and timely
endeavor.
Overview of Behavioral Research
Behavior contributes significantly to health, well-being, and
longevity. Indeed, clinical and epidemiological research supports
numerous behavioral guidelines for the prevention of disease. These
guidelines include regular physical activity and maintenance of
appropriate weight; avoidance of tobacco products; dietary intake
of fruits, vegetables, and fiber, coupled with a low consumption of
fat; moderate use of alcohol; and the ability to cope effectively with
stress. Among persons who suffer from disease, behavior is also often
critical to achieving treatment objectives. For example, patients must
frequently comply with complex and lengthy treatment regimens, as well
as assume significant personal responsibility for managing their
symptoms and monitoring their health status.
If we can aspire to greater health through prudent behavior, reality
abundantly reflects our frequent failure to do so. Many examples may be
cited. Cigarette smoking remains prevalent in American society and is
currently increasing in some segments of the teenage population. Only a
quarter of Americans engage in regular physical exercise, and although
fat consumption has decreased somewhat in recent years, rates of
obesity have risen appreciably over the same period. It is also
estimated that 5 of every 10 patients fail to adhere fully to
prescribed therapies.
Hence, behavior's role in health and disease encompasses both promise
and challenge—the promise of a reduced risk for illness and better
disease management and the challenge of promoting actions that will
contribute significantly to this goal. Behavioral research seeks to
inform both of these objectives. Two of its primary aims are to
elucidate the nature, origins, and effects of health-related behaviors
and to apply behavioral principles to modify individuals'
health-impairing behaviors and lifestyles.
For many decades, clinicians and scientists have also speculated on the
role that emotional stress and personality traits play in the
pathogenesis and clinical expression of various disorders, including
coronary heart disease (CHD), essential hypertension, and
asthma. The rigorous study of such concepts was long hampered by
imprecise definitions of stress and personality and by the absence of
reliable methods of assessing these variables. In recent years,
however, this research has progressed significantly because of the
availability of new measurement techniques and advances in behavioral
science methodologies. Consequently, the increased risk for disease
conferred by psychosocial factors and, with respect to CVD, the
biological processes underlying these associations are much better
understood than they were a decade ago.
Beyond the causes and treatment of disease is the individual's
experience of illness itself. Disease is often accompanied by pain,
apprehension, restricted mobility, and other functional impairments;
difficulties fulfilling personal, family, and financial
responsibilities; and, occasionally, impaired cognitive function.
Diagnostic procedures and medical interventions may affect
behavior in a variety of ways, sometimes eroding (and at other times
enhancing) patients' overall quality of life, even while improving
medical outcomes. Behavioral scientists are currently studying these
effects and defining the dimensions of quality of life for both ill and
healthy individuals.
It is now widely acknowledged that medicine's concerns extend beyond
the biological end points of disease to encompass a wider spectrum of
patients' experiences, including their emotional, cognitive, and
interpersonal functioning. Because heart, lung, and blood diseases are
responsible for a substantial portion of all morbidity and mortality in
the United States, the behavioral and social sequelae of these diseases
and their treatments have become increasingly important areas of
behavioral science research.
With an aging population in the United States, the prevention and
management of chronic illnesses is becoming a topic of significant
concern. Here, behavioral research is enhancing understanding of the
ways patients cope with serious illness and the efficacy of
psychosocial and other environmental interventions to ease patients'
adjustment to illness, promote their recovery, and prevent the
recurrence of disease.
The scope of behavioral research is therefore wide-ranging. For
cardiovascular, pulmonary, and blood diseases
and sleep disorders, it includes 3 main areas:
The term "behavior" is used here in its broadest sense. It
denotes both the external actions of individuals and the more
subjective qualities of individuals' experiences. These subjective
experiences are represented "internally" by feelings,
moods, attitudes, perceptions, and psychological dispositions (eg,
personality traits).
The term "environment" also is defined broadly and
includes both psychosocial and physical environments. Psychosocial
environmental factors, such as socioeconomic status, social isolation,
and networks of social affiliation and support figure prominently in
behavioral research. Other pertinent psychosocial factors include
ethnicity, culture, and occupational and social stress. Physical
environmental factors include geographic areas of residence, quality of
habitat, and substances (eg, allergens) to which individuals may be
exposed in occupational and residential settings.
Behavioral variables affect disease in the context of genetic and
biological predispositions. Thus, genetic variability among
individuals, often in interaction with environmental variables, can
affect both behavior and disease-relevant physiology.
To the extent that some behavioral factors conspire to increase risk
for disease, it also follows that their modification might diminish
risk or aid in the management of disease. Psychological interventions
therefore seek to alter the behaviors of individuals in beneficial
ways, by changing certain aspects of the environment, reinforcing
preferred behaviors, or modifying patients' motivational states,
thoughts, or feelings.
Two Broad Conclusions
The task force reached 2 broad conclusions based on its review of
the state of the science of behavioral research on heart, lung, and
blood diseases and sleep disorders:
Overview of the Report
In Part I, Behavioral Antecedents of Disease, the task
force addressed 2 main topics: the extent to which behavioral factors
increase risk for cardiovascular and lung diseases, and
the influences of these factors on the pathophysiology of disease and
the expression of symptoms. Three types of behavioral variables are
implicated in individuals' risk for disease:
Part I also includes a review of experimental and clinical
research on physiological processes that
link behavior with disease. For example, there is increasing evidence
that behavioral factors exacerbate atherosclerosis,
promote hypertension and related alterations in cardiac structure and
function, induce myocardial ischemia in persons with
coronary artery disease, affect processes involved in
hemostasis and thrombosis, and trigger cardiac arrhythmias.
Many of the lifestyle factors that increase risk for CVD also
appear to aggregate in relation to abnormalities of insulin and glucose
metabolism. In addition, sleep disorders can profoundly
affect cardiovascular and pulmonary conditions.
Studies of individuals with asthma indicate that psychological factors
may also affect airway obstruction and that individual differences in
the ability to perceive diminished airflow in asthma may be related to
the exacerbation of symptoms.
In Part II, Behavioral Interventions: Prevention and Management
of Disease, the report focuses on applied behavioral research.
Interventions to reduce the risk of disease or improve disease
management may be targeted to individuals, groups, or communities and
may range from health education to behavior-modification programs,
"skills" training, and some forms of psychotherapy.
The objectives of interventions to modify risk factors for disease
include prevention and cessation of smoking, promotion of regular
exercise and increased physical activity (including physical
rehabilitation of cardiac patients), modification of diet, weight loss,
and control of alcohol use and abuse.
Addressing the behavioral aspects of disease management, the task force
focused on chronic diseases. Topics include prevention of the
progression or recurrence of CVD; behavioral management of
chronic lung diseases (asthma, chronic obstructive pulmonary
disease, cystic fibrosis, and tuberculosis); treatment of sleep
disorders; adjustment to the debilitating symptoms of sickle cell
disease, thalassemia disorders, and hemophilia; and behavioral aspects
of blood donation and transfusion medicine.
Part II of the report also discusses 2 key issues for improving health
outcomes: ensuring adequate adherence to treatment regimens that
frequently are complex, inconvenient, or painful and evaluating the
effect of disease and medical treatments on patients' quality of life.
These cross-cutting issues are highly pertinent to the management of
all cardiovascular, pulmonary, and blood
diseases and sleep disorders.
Recommendations for Future Research
The task force identified more than 100 areas of significant
opportunity for behavioral research. These topics range from risk
factor associations and risk reduction to pathophysiology, expression
of symptoms, and the clinical management of disease. The many specific
recommendations for new research are listed in the report for each of
the research areas addressed by the task force.
Many of the recommendations in the report reflect similar research
concerns, as applied to different diseases and clinical care issues,
and therefore may be expressed as thematic objectives for behavioral
investigation. These objectives, which are viewed by the task force as
representing areas of highest priority for behavioral
research, are summarized below.
1. Foster Interdisciplinary Research and Research Teams
The scientific accomplishments summarized in the report illustrate
that research on the behavioral dimensions of disease and its clinical
management progresses most vigorously when conducted by
interdisciplinary research teams. For example, the best evidence that
psychosocial factors contribute to risk for CVD comes from population
studies joining the expertise of both behavioral scientists and
epidemiologists. Similarly, the experimental and clinical evidence that
behavior influences the pathophysiology of CHD, including
atherosclerosis, myocardial ischemia, and
cardiac arrhythmia, results from extensive research
collaborations among many experts, including psychologists,
neurobiologists, cardiologists, and comparative pathologists.
Because the application of behavioral science to the problems of heart,
lung, and blood diseases and sleep disorders involves
interdisciplinary investigation, the collaborative arrangements
necessary for conducting such research must continue to be
fostered.
2. Encourage Research on Behavioral Factors in Lung and Blood
Diseases
Research on the behavioral aspects of lung and blood diseases must
be expanded. Behavioral scientists have given relatively little
attention to these 2 areas even though lung and blood diseases are
prevalent, disproportionately affect children, and present numerous
challenges for patients' psychosocial adjustment and long-term
clinical management.
Contemporary treatments significantly extend the life expectancy of
patients with diseases such as cystic fibrosis, sickle cell disease,
thalassemia, and hemophilia, but they also create new difficulties for
these patients and their families. These difficulties include adhering
to treatment regimens, which are often painful and complex, and
handling the effects of debilitating symptoms on patients' social and
emotional development, as well as on overall family functioning.
For most of these diseases, even the scope of relevant behavioral
issues remains to be elucidated—such as the cognitive and emotional
sequelae of disease, the determinants of symptom exacerbation,
patients' perceived quality of life, level of treatment adherence, and
problems in disease self-management. Progress in these areas, however,
could lead to significant improvements in clinical care and treatment,
as the barriers to optimal adjustment and disease management are
identified and subjected to targeted behavioral intervention.
3. Promote Investigation of Previously Understudied
Populations
Like other biomedical research, most of the evidence on
behavioral predictors of disease is based on studies of middle-aged
white men. The prevalence of lifestyle and psychosocial risk factors,
however, often varies across different demographic groups. For example,
tobacco use and physical activity vary according to race, gender, and
socioeconomic status. Understanding these differences may assist in
reaching underserved populations and in designing interventions that
will have the greatest benefit.
The nature and strength of associations between risk factors and
disease outcomes may also differ among population groups. For example,
some evidence suggests that behavioral factors predict CVD more
strongly in men than in women. However, such findings are difficult to
evaluate because of a dearth of investigations in this area and the
methodological deficiencies of existing studies. Thus, reported gender
differences in behavior-disease associations may be erroneous,
resulting from reliance on psychosocial measures that are validated
only for men or, possibly, from inadequate statistical power due to the
lower incidence of cardiac events in middle-aged women. Another
possibility is that behavioral factors are equally important among
women and men, but the specific variables that predispose to
disease in women may differ from those that are predictive in men.
Similar issues may also pertain to studies of minority populations.
Behavioral risk factors may vary in these populations because of
different cultural and learning experiences, exposure to different
environments, and different genetic backgrounds. Current understanding
of the behavioral aspects of disease across all segments of the
population must be increased.
4. Incorporate Behavioral Science into Existing Epidemiological
and Clinical Studies
The effect of behavioral factors on risk for disease must be
better understood. However, establishing associations between putative
risk factors and subsequent development of new or recurrent disease
usually requires large-scale investigations, often involving population
sampling or extensive recruitment of patients and repeated observations
over several years. Incorporation of behavioral measurements into
existing studies offers a cost-effective means of evaluating the
disease relevance of newly hypothesized risk factors and the usefulness
of new techniques or instruments to measure specific variables of
interest.
For example, research indicates that enhanced
cardiovascular responsiveness to stress may increase an
individual's risk for CHD and essential hypertension. To clarify this
possible association, the NHLBI recently supported development of a
psychophysiological test battery that has high
reliability and may be applied in population-based epidemiological
investigations. Incorporating such instruments into ongoing,
prospective studies of risk factors for CVD is now appropriate.
Similarly, inclusion of ambulatory blood pressure monitoring in
longitudinal studies can enhance understanding of behaviorally evoked
variations of blood pressure and the influence of this variability on
the development of hypertension and its end-organ effects.
In addition, behavioral research should be integrated into studies of
the occurrence of CHD events. Such work can help illuminate the onset,
triggers, and course of myocardial infarction, myocardial
ischemia, and malignant arrhythmias. Psychological
measures could also be included usefully in studies identifying
precipitants of clinical asthma. Also, other instruments for assessing
psychosocial risk factors, such as socioeconomic status, should now be
incorporated routinely in epidemiological investigations, as should
measures of treatment adherence and health-related quality of life in
studies of patient populations and major clinical trials.
5. Identify Further the Biological Mechanisms that Underlie
Behavior-Disease Associations
Recent research has linked individuals' behavior not only to the
incidence of disease, but also to important
pathophysiological processes, especially those
related to CHD. This research must now be followed by more intensive
investigations of the biological mechanisms that mediate behavioral
influences on clinical disease.
Recent research efforts point to potentially promising areas of study.
For example, experiments on nonhuman primates have identified some of
the neuroendocrine factors that promote
atherosclerosis. This work should lead to more detailed
studies of pathophysiology and mechanisms, focusing on such
disease-relevant events as early changes in the function of
arterial endothelium; the proliferation of
cells in the intima of the artery; and processes involved in plaque
formation, complication and rupture.
Both clinical research and experimental research are also needed to
establish the hemodynamic, neuroendocrine, hemostatic,
and neural mechanisms for behavioral influences on acute cardiac
events, including infarction, coronary thrombosis, myocardial
ischemia, ventricular fibrillation, and sudden
death in susceptible individuals, as well as the development of
behaviorally induced hypertension. Studies of sleep-disordered patients
should similarly seek to determine how sleep apnea affects myocardial
perfusion and cardiac electrical stability; in addition, they should
look to clarify the circadian mechanisms that may underlie diurnal
variations in morbidity and mortality from
cardiovascular and pulmonary disease.
Also, preliminary evidence that psychological stress can exacerbate the
symptoms of asthma should prompt research aimed at identifying
immunological and autonomic–neuroendocrine mechanisms by which
behavioral and emotional states might influence inflammatory and
bronchomotor processes in clinical asthma.
6. Identify Psychological Factors Responsible for the Aggregation
of Behavioral Risk Factors
Many behavioral risk factors for disease often aggregate within
individuals. That is, people who have one lifestyle risk factor such as
smoking, obesity, physical inactivity, or high alcohol consumption, are
also likely to have other health-impairing habits. Also, psychosocial
risk factors for CVD often occur together. Hostile individuals, for
example, are more likely to have symptoms of depression and fewer
sources of social support than nonhostile persons.
This clustering of disease-predictive attributes suggests that a more
limited set of psychological variables may underlie the diversity
of behavioral risk factors documented in epidemiological research.
Attempts to identify these variables may yield a more parsimonious
understanding of the behavioral origins of disease risk and suggest new
directions for designing preventive and therapeutic programs for risk
reduction.
7. Develop Interventions to Promote Sustained Improvements in
Lifestyle Risk Factors
Behavioral researchers have made substantial progress in
developing and evaluating interventions to modify lifestyle risk
factors. These interventions include programs for smoking cessation,
weight loss, physical exercise, and diet modification. However,
individuals' initial successes in altering their high-risk behaviors
are commonly followed by relapse or failure to maintain the lifestyle
changes achieved during the intervention.
A related problem is the lack of empirical guidelines for selecting
appropriate treatment goals. For example, the amount, duration, and
intensity of exercise needed to best protect against CVD is not clear.
In the case of obesity, even a modest reduction in weight will improve
other risk factors, but whether this benefit also reduces an
individual's risk for morbidity and mortality is not known. These
examples illustrate the importance of establishing the relationship
between degrees of risk factor change and relevant health outcomes, in
addition to encouraging long-lasting changes, in efforts to improve the
health of individuals and populations.
8. Develop Interventions to Improve Patients' Adherence to
Treatment
In addition to maintaining long-term changes in lifestyle risk
factors, patients who are being treated for
cardiovascular, lung, and blood diseases often have
difficulty adhering to the treatments prescribed. Failures in adherence
are ubiquitous, affecting nearly all categories of treatment and
thereby undermining much of the therapeutic enterprise. Although many
interventions have been developed to promote improved adherence (some
of generic design and others tailored to specific treatment
modalities), the efficacy of these approaches needs to be established
in controlled clinical studies and randomized trials. In addition, ways
to enhance patients' adherence within managed care settings and to
improve the adherence-counseling skills of primary care physicians,
nurses, and paraprofessionals need to be developed and evaluated.
9. Develop Efficient Preventive Interventions for Reducing Risk
for Disease
Trial programs to prevent smoking and to help individuals develop
healthful dietary and activity patterns have been somewhat successful.
However, recent trends such as increased smoking among some adolescent
groups and population-wide increases in obesity underscore the
deleterious effects that larger cultural influences can have on
individuals' adoption of healthful behaviors.
The effect of the broader environment (eg, mass-media messages, popular
role models) on children's and adolescents' adoption of dietary
patterns, physical activity, and use of alcohol and tobacco needs to be
better understood. This knowledge should be used to develop more
effective policies and interventions for primary prevention, making use
of existing social institutions and medical resources.
10. Foster Development of New Research Methodologies and
Measurement Techniques
Like all areas of science, behavioral research is constrained by
the methodologies and measurement tools available. As new research
methods and techniques become available, behavioral science will
advance more rapidly. Some of the methodologies of the future
may come from other sciences but will nonetheless benefit behavioral
research.
Examples of recent technological developments include ultrasound
techniques for noninvasively evaluating extracranial carotid artery
disease and various imaging techniques for assessing changes in cardiac
function and myocardial perfusion. The first of these techniques is now
being used to evaluate behavioral influences on the development and
progression of atherosclerosis; imaging techniques have
already figured prominently in the study myocardial ischemia
induced by mental stress.
In other areas, there is a need to improve or expand the measurement of
disease-relevant psychosocial and behavioral variables. For
example, validated instruments are needed to assess individuals'
functional health status and perceived well-being, 2 important aspects
of health-related quality of life. Similarly, the availability of
improved, cost-effective methods for measuring visceral obesity and
consumption of fat and other dietary components would enhance studies
of obesity and diet modification.
Researchers who are studying the psychosocial and socio-environmental
predictors of disease would benefit from the availability of scales
having established validity in demographically
heterogeneous populations. This research would also be
enhanced by the availability of multidimensional instruments capable of
capturing the diverse features of such broadly defined concepts as
socioeconomic status, social integration, and psychological stress.
In addition, ambulatory techniques for "real-time" assessment of
behavioral and psychological states in natural environments need to be
further refined. Such techniques promise to assist in understanding the
behavioral triggers for episodic symptoms and events related to
pulmonary and cardiovascular diseases. Finally,
documenting treatment compliance would be improved substantially by the
development of adherence measures that are objective, valid,
practical for use in customary clinical settings, and applicable to a
variety of patient and research populations.
11. Integrate Behavioral and Pharmacological Approaches to the
Reduction of Risk Factors
Medications to redress lifestyle risk factors such as smoking,
obesity, and unhealthy dietary preferences, are emerging as important
components of risk management. For example, nicotine replacement
therapies are a new and effective means for promoting and maintaining
smoking cessation, and new drugs to suppress appetite and reduce food
intake are now widely used to help individuals lose weight and control
obesity. These medications, however, do not offer sufficient benefit to
justify their use as the only means of treatment. This is not
surprising given the important role that environmental, social, and
learning factors play in the initiation and maintenance of
health-impairing behaviors. Indeed, preliminary evidence suggests that
medication may be most effective when it is prescribed in conjunction
with a broader program of behavioral modification and counseling.
12. Incorporate Genetic Research Strategies into Behavioral
Research on Heart, Lung, and Blood Diseases
In addition to abundant evidence that genetic differences among
individuals account for a substantial portion of population variability
in many disease risk factors, it is now well established that most
complex behavioral traits result from a combination of genetic and
environmental influences. Therefore, both the independent and
interactive effects of genes and environments must be identified to
fully understand the development of behavioral risk factors for
disease.
It is already known that many of the behavioral variables
implicated in CVD have significant heritability. These variables
include patterns of physical activity, smoking, obesity, diet-induced
weight gain, certain dietary preferences,
physiological responsiveness to stress, hostile
personality characteristics, and depression. Quantitative genetic
studies also enable researchers to estimate environmental influences on
individual differences in behavior and to distinguish between those
environmental effects (eg, shared family environments) which cause
related persons to be either similar or different. Future behavioral
genetics research should be directed toward clarifying the nature of
genetic and environmental influences on the development of behavioral
risk factors and, possibly, elucidating the common origins of risk
factors that often tend to cluster within individuals.
Recent advances in the molecular genetics of disease and disease risk
can also be incorporated fruitfully into behavioral research. The
identification of major genes regulating lipid metabolism
and body weight, for instance, provides specific markers of genetic
vulnerability, in the context of which behavioral interventions (such
as diet modification or weight loss programs) should be evaluated.
Studies of this type may identify who would be expected to benefit from
a particular form of treatment and to what degree.
Genetic technologies also are producing new animal models that may be
useful in behavioral research on the pathogenesis of disease. For
example, the creation of transgenic and "knockout" mouse strains
that are susceptible to human-like atherosclerosis
offers the opportunity for studying social effects on atherogenesis
using an animal model that is much less expensive, and therefore more
feasible, than nonhuman primates. Such models may also lead to a better
understanding of the physiological mechanisms that
underlie effects of behavioral risk factors on disease.
© 1998 American Heart Association, Inc.
Cardiovascular News
Task Force on Behavioral Research in Cardiovascular, Lung, and Blood Health and Disease
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