At the beginning of the 20th century acute diseases, including tuberculosis, pneumonia, and other infectious diseases, were the primary causes of death in the United States. By the end of the 20th century this pattern had undergone a major shift. According to Centers for Disease Control and Prevention (CDC) statistics, chronic and preventable diseases, including heart disease, cancer, stroke, and diabetes, account for 7 of every 10 deaths in the United States. Although multiple factors contribute to these chronic diseases, a survey of the actual causes of these deaths by McGinnis and Foege (1993) identified tobacco, diet and activity patterns, alcohol, microbial agents, toxic agents, firearms, sexual behavior, motor vehicles, and illicit use of drugs as the top 10 contributors. These contributors not only cause death (mortality) but cause illness (morbidity) and compromise positive functioning and well-being. The majority of these contributors involve behavioral choices, and behavior is central to the maintenance of health and prevention of disease.
Health promotion was defined by Green and Kreuter (1991) as “any combination of health education and related organizational, economic, and environmental supports for behavior of individuals, groups or communities conducive to health” and by O’Donnell (1989) as “the science and art of helping people change their lifestyle to move toward a state of optimal health.” The practice of health-promoting and preventative behaviors and the avoidance of health-compromising behaviors are at the core of health promotion.
A key component of health promotion is an understanding of health. At its founding in 1948, the World Health Organization (WHO) offered a landmark definition of health as “a complete state of physical, mental, and social well-being and not merely the absence of disease or infirmity.” This definition moved the focus beyond a negative definition of health as the absence of disease to include positive well-being, and included not only physical health, but also mental and social aspects of health.
Health promotion interventions focus on a wide variety of health behaviors, including smoking prevention and cessation, diet and nutrition, physical activity, weight control, sexual behavior, accidental injury prevention (e.g., seat belt use, bicycle helmet use, firearm safety), alcohol and drug use, stress management, social support, disease screening (e.g., cancer, blood pressure, and human immunodeficiency virus [HIV] screening), vaccinations, dental hygiene, and preventive skin care (e.g., sunscreen use). The majority of these specific health behaviors affect multiple health disease outcomes and pathways (e.g., heart disease, cancer, diabetes, metabolic syndrome, hypertension, hyperlipidemia), both directly and indirectly. For example, physical inactivity directly increases the risks for heart disease, cancer, and stroke, and also indirectly impacts these diseases through its associations with risk factors such as obesity and hypertension.
Many of these deleterious health behaviors occur in significant segments of the American population. Health promotion interventions often target these behaviors at an individual level. Yet because individual health behaviors are influenced by social and environmental factors, health promotion interventions also focus on higher-level efforts to impact health behaviors through environmental changes, systemic interventions, and public policy. On a national level, the U.S. Public Health Service and the Department of Health and Human Services have developed initiatives to define measurable health goals, including Healthy People 2000 and Healthy People 2010. Health promotion interventions are guided by these goals, such as the Healthy People 2010 objectives to increase the quality and years of healthy life and eliminate health disparities, with a focus on 28 specific areas, including cancer, nutrition and overweight, and tobacco use. These goals also provide a measure of the success of healthy promotion interventions. The final report on Healthy People 2000 showed mixed results in meeting similar health objectives, with success in some areas (e.g., reducing cancer deaths) but significant challenges remaining in others (e.g., tobacco use).
Models of Health Behavior and Health Behavior Change
Models and theories of health behavior guide scientific understanding of these behaviors and provide direction for how to effect behavior change. Although a comprehensive discussion of all models and theories of health behavior and health behavior change is beyond the scope of this entry and several are discussed in other entries in this encyclopedia, a few key models and theories are highlighted here.
The WHO definition of health is consistent with a biopsychosocial model of health, which defines health or illness as a consequence of biological, psychological, and social processes, rather than a biomedical model of illness, which explains illness in terms of somatic, biochemical, and neurophysiological processes. This biopsychosocial model underpins health promotion efforts that focus not only on biological mechanisms, but also on psychological, social, and environmental factors that influence health behavior.
Traditional learning theories, including classical conditioning described by Ivan Pavlov in the 1920s and operant conditioning described by B. F. Skinner in the 1930s, help explain a variety of behaviors, including health behaviors, and form the early basis on which health promotion has subsequently developed. These theories emphasize the unidirectional impact of the environment on behavior and learning, and do not include cognitive factors. Subsequent theories have emphasized the importance of individual cognitive and social factors. Social cognitive theory, a version of social learning theory developed by Albert Bandura in the 1980s, has been one of the most influential theories guiding research. Social cognitive theory emphasizes the reciprocal relationship among behavior, environment, and personal factors (including cognitive processes related to self-efficacy and outcome expectations, i.e., beliefs that one can successfully undertake a behavior change and that doing so will result in valued outcomes or benefits).
Other models include the health belief model developed by Irwin Rosenstock and colleagues in the 1950s. This model defines four beliefs that influence the likelihood of engaging in a health behavior: (1) the perceived susceptibility to a disease, (2) the perceived severity of the disease, (3) the perceived benefits to action, and (4) the perceived barriers to action. The transtheoretical model developed by James Prochaska and Carlo DiClemente in the 1970s and 1980s describes the stages and processes of change that people may move through when changing a health behavior. The five stages are precontemplation (not intending to change behavior), contemplation (thinking about changing behavior), preparation (beginning to make behavior changes), action (actively changing a behavior), and maintenance (maintaining a successful behavior change). These models and theories—and others, including the relapse prevention model, the self-determination theory, and the updated theory of reasoned action and planned behavior—focus on intrapersonal, behavioral, and microenvironmental processes.
In addition, health promotion draws upon meso- and macroenvironmental and community approaches. For example, social ecology models focus on the macroenvironment, specifically on transactional interactions between people and their physical, social, institutional, and cultural environments. Applying these macroenvironmental models to health promotion emphasizes environmental factors that contribute to health behaviors and provides an opportunity to intervene at these macro levels (i.e., through urban planning and neighborhood design).
Target Populations and Settings
The prevalence of specific diseases and the practice of health behaviors often vary according to sociodemographic characteristics (e.g., age, education, income level, ethnicity). For example, according to the CDC, low-income adults are more likely to be overweight and older adults are more likely to be injured by accidental falls than those in other age groups. As a result health promotion interventions often target specific populations, making use of tailored approaches to effectively meet their needs.
Where do health promotion interventions take place? This question is intricately tied to the issue of the target population. To reach a wide variety of audiences from the general healthy population to specific high-risk populations, health promotion interventions typically occur in a variety of settings, including health care settings, schools, work sites, communities, state and local legislatures, and the consumer marketplace. Depending on the intervention setting, different behavior change theories, models, and intervention strategies drive successful health promotion interventions. For example, a work site intervention may rely on a social ecology model, a community approach may use mass media campaigns, and an individual counseling approach in a health care setting may use specific behavior modification techniques such as behavioral self-monitoring or individualized goal setting.
Contributions of Health Promotion Interventions and Evidence for Effectiveness
Health promotion interventions have focused on a range of risk and protective behaviors that contribute to disease and health, especially smoking prevention and cessation, diet and nutrition, physical activity, weight control, sexual behavior, and accidental injury prevention. In addition to excellent reviews of the literature and meta-analyses, several national panels have convened in the past decade to examine the evidence and propose national guidelines (e.g., the National Heart, Lung, and Blood Institutes 1998 Clinical Guidelines on the Identification, Evaluation, and Treatment of Overweight and Obesity in Adults). These evaluation efforts have been enhanced by efforts to obtain representative national data (e.g., the Behavioral Risk Factor Surveillance System [BRFSS] and the National Health and Nutrition Examination Survey [NHANES]), not only on disease prevalence, but also on preclinical conditions (e.g., blood pressure) and specific health behaviors.
Smoking Prevention and Cessation
Mass consumption of tobacco began in the 1920s in the United States and increased until the 1960s. Following the release of the first Surgeon General’s report on the health consequences of smoking in 1964, the percentage of smokers began to decline. This decline lasted until 1991, when smoking prevalence failed to decrease. In 2000 over 23 percent of U.S. adults smoked cigarettes. Tobacco use remains the leading cause of preventable morbidity and mortality, contributing to more than 450,000 deaths annually from a variety of diseases including heart disease and cancer. Both psychosocial and physiological mechanisms are involved in the initiation of regular smoking, active continued smoking, smoking cessation, and cessation maintenance.
Smoking cessation and prevention interventions utilize both clinical and public health approaches. National panels (e.g., the Surgeon General’s report on reducing tobacco use and tobacco cessation guidelines) have concluded that intensive clinical intervention programs, including psychosocial interventions, have demonstrated efficacy. Meta-analyses have revealed that success of psychosocial interventions is associated with time spent in counseling, social support (both in treatment and outside treatment), problem solving (including skills training, relapse prevention, and stress management), and aversive smoking procedures.
The vast majority of smokers who quit do so on their own or with minimal assistance. As opposed to intensive clinical interventions that may be costly and reach a smaller percentage of people, public health approaches target the broad population. Because the majority of smokers begin smoking in their teens, early prevention efforts are critical. As evidenced by the decline in smoking spurred by the initial Surgeon General’s report, public health efforts can have a definitive impact. Public health approaches are employed in a variety of domains; both work site and community-level interventions have demonstrated some efficacy. Health-care setting interventions, such as having a primary health care provider ask about smoking and advise quitting, are efficacious but not necessarily widely adopted. Other multipronged public health approaches, including directed advertising, tobacco taxes, and legislation banning smoking in particular settings (e.g., restaurants), appear to be effective in decreasing the prevalence of smoking.
Diet and Nutrition
Poor diet is a risk factor for heart disease and cancer and is central to weight control and eating disorders. For example, high saturated fat intake is associated with increased serum cholesterol levels. On the other hand, increased consumption of fruits and vegetables protects against multiple cancers including colon and breast cancer. Thus dietary change is a primary target of health promotion interventions. The first Surgeon General’s recommendations for nutrition were published in 1988. Guidelines from the National Academy of Sciences suggest that adults should consume 45-65 percent of their calories from carbohydrates, 20-35 percent from fat, and 10-35 percent from protein, and 21-38 g of fiber daily. Dietary guidelines also suggest consuming at least five servings of fruits and vegetables per day. Few Americans, however, comply with these guidelines. For example, according to the BRFSS, less than 25 percent consume the recommended number of fruits and vegetables.
Health promotion interventions targeting individuals can successfully impact dietary composition. Individual and group counseling approaches often involve self-monitoring (e.g., keeping food diaries) and receiving regular feedback on progress. Less intensive community interventions (e.g., providing self-help materials in health care centers) have also shown a significant though usually smaller impact. The National Cancer Institute has sponsored a number of community interventions as part of the “5 A Day” program to increase consumption of fruits and vegetables, including mass media campaigns and the use of lay advocates in churches. Work site interventions have shown some effectiveness in reducing dietary composition through the use of multiple strategies, including health education and environmental changes in food availability or nutritional composition. Finally, several states have undertaken legislative approaches similar to those used with tobacco through the use of so-called “fat taxes” to tax less nutritious, “snack” foods.
Physical Activity
Although physical activity affects multiple health and disease outcomes including heart disease, cancer, hypertension, and diabetes, and the benefits of engaging in regular physical activity are generally accepted, the first Surgeon General’s report documenting the health benefits was not published until 1996. The CDC and American College of Sports Medicine recommend that adults accumulate 30 min or more of at least moderate-intensity physical activity on 5 or more days a week, and the National Academy of Sciences suggests 60 min of daily moderate-intensity physical activity to prevent weight gain and realize other health benefits. Yet, according to the Surgeon General, more than 60 percent of Americans are not active enough to get health benefits, and more than 25 percent are completely sedentary. Several target groups have an even greater percentage of sedentary behavior, including women, ethnic minorities, and low-educated, low-income, and older adults.
Because physical activity habits often begin in childhood, youth are frequently targeted for intervention. Successful youth interventions have been implemented in school environments and have included an active physical activity or physical education curriculum. Adult interventions have used a variety of approaches including structured group-based activities, home-based activities supervised through periodic face-to-face or mediated approaches (e.g., the telephone), interventions that target routine activities undertaken throughout the day, and environmental interventions. Interventions using behavior modification principles have been shown to have significant effects on physical activity, at least during the period when the intervention was being actively delivered. Tailored telephone and print-mail interventions have also proven effective for increasing physical activity.
Weight Control
Obesity rates rose dramatically over the second half of the 20th century. Based on 1999 NHANES data, 61 percent of U.S. adults are overweight or obese, and these rates are even higher in specific sociodemographic groups such as African-American and Mexican-American women. Since the late 1970s obesity rates have doubled in adults and children and tripled in adolescents. Overweight and obesity are associated with an increase in risk factors for cardiovascular disease and diabetes such hypertension, hyperlipidemia, and physical inactivity. In fact, weight is intricately linked to both diet and physical activity, and health promotion interventions targeting diet and/or physical activity often target weight control as well.
In 2001 the Surgeon General issued a call to action to prevent and decrease overweight and obesity in the United States. Behavioral weight-loss interventions, specifically group-based interventions using behavior-modification principles and focusing on improving eating (e.g., type and amount of food eaten) and physical activity behaviors (e.g., frequency, duration, and types of activity), have proven to be effective in facilitating weight loss. In children, family-based behavioral treatments can produce long-term weight reductions. Although weight losses can be achieved in adults, weight losses are typically not maintained over time, with weight increasing over longer term follow-up. Traditionally, weight-loss treatments sought to reach ideal weights; however, panels have suggested the importance of losing and maintaining more modest weight losses (e.g., 5-15 percent of body weight) that can still confer significant health benefits. Indeed, in addition to promoting weight loss, weight control interventions also target maintenance of weight losses and prevention of weight gain, although much work remains to be done in these areas.
Because obesity is such a prevalent problem, large-scale interventions, including the school, community, and legislative dietary and physical activity interventions, have produced some results. Although these results are typically smaller than those seen in more intensive, clinical approaches, they have the potential to have a significant impact on weight at a population level. More research is needed on the effectiveness of these interventions for weight control.
Sexual Behavior
Twelve million American are infected with sexually transmitted diseases (STDs) every year, and 800,000-900,000 people are infected with HIV. In 2001 the Surgeon General issued a call to action to promote sexual health and responsible sexual behavior. Unsafe sexual practices increase the risk for contracting multiple STDs including HIV. Health promotion interventions in this area are aimed at preventing and altering high-risk sexual behaviors (e.g., having sex without using a condom) and maintaining these changes over time. Intervention involves accurately educating individuals about the mechanisms of contraction, increasing motivation for change, and changing social norms. The success of these specific approaches often depends on the target population. Among youth, regular school attendance and community-based youth development programs have a proven effect on sexual behavior. Some clinic- and school-based programs have also been effective. Targeting adolescents and adults, a number of com-munity curriculum-based prevention programs, in addition to some clinic-based programs, have shown success in preventing infection.
Accidental Injury Prevention
In 1999 accidents were the fifth leading cause of death in the United States. Health promotion interventions have targeted behaviors to minimize both the prevalence and the adverse impact of accidental injury and include individual, community, and legislative approaches. Motor vehicle accidents are the most common cause of accidental injury, and alcohol is often involved in these accidents. Legislative approaches requiring mandatory seat belt use and limiting legal blood alcohol content have been effective in reducing motor vehicle fatalities. Because specific types of accidental injuries are more common in different age groups, interventions often target specific populations. Parents are usually targeted to decrease accidental injuries in children. For example, communitywide interventions using mass media advertising and health-care provider interventions aimed at encouraging increased bicycle helmet use in children have had success. Injurious falls are a major cause of accidental injury among the elderly, due in part to high rates of osteoporosis along with other aging-related risk factors (e.g., increasing difficulties with vision and motoric balance). In another example of the interconnection between health behaviors, the development of bone loss and osteoporosis has been linked with inadequate diet and physical activity behaviors, and can be impacted by interventions in these areas.
Conclusions
This entry provides an overview of the breadth of impact health promotion interventions can have on a range of diseases and conditions across the life span. Although research aimed at intervention development and evaluation has been reasonably promising, it is clear that expanded scientific as well as public health efforts will be required if national public health goals are to be reached. Among the areas that deserve future attention to reach these goals are building theories that continue to include a broader transdisciplinary perspective (i.e., discussion and interaction among a greater number of scientific, health, and environmental disciplines); emphasizing multilevel approaches to intervention that recognize the interplay among individual, organizational, environmental, and policy domains; tailoring preventive interventions to meet the needs of population segments at particular risk; evaluating methods for systematically combining health behaviors to facilitate physical and behavioral synergy; exploring technological advances in the delivery of health promotion interventions in greater depth; and attending to methods for translating and disseminating successful health promotion interventions to a broader segment of the American public. Given the significant health challenges that Americans face, systematic attention to all of these areas will likely be necessary to achieve population-wide successes.
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