S. V. Kasl and S. Cobb identified three types of health behavior: preventive health behavior, illness behavior, and sick-role behavior. Preventive health behavior is "any activity undertaken by an individual who believes himself to be healthy for the purpose of preventing or detecting illness in an asymptomatic state" (Kasl and Cobb 1966, p.246). Illness behavior and sick-role behavior, on the other hand, are concepts that encompass behaviors that occur in response to specific symptoms or illness. These behaviors are aimed at minimizing the effects of illness.
Preventive health behavior generally follows from a belief that such behavior will benefit health. An obvious example is quitting smoking to reduce the chances of early morbidity and mortality. It does not follow, of course, that all beliefs on which preventive behaviors are based are well founded, nor that the resulting behaviors will have the desired outcomes. Many preventive behaviors have never been demonstrated to be effective, such as megadoses of vitamin C to prevent the common cold.
Preventive actions can reduce, but not eliminate, the chances of acquiring a disease or illness. The strength of the cause and effect relationship between a certain behavior and the health problem one is trying to prevent will determine the impact performing the behavior will have on reducing the risk. This impact is measured in terms of attributable risk. Attributable risk is a measure of the chance of acquiring a disease if the risk factors for it are eliminated or preventive health behavior is engaged in. The chances are influenced by the relationship of the preventive behavior to the etiology of the disease. Most people are aware that if you smoke you have an increased risk of getting lung cancer. Data indicate that almost 90 percent of lung cancer cases in males and 79 percent in females can be attributed to smoking, according to the Office on Smoking and Health. Some people who do not smoke get lung cancer, of course, but the numbers are small. Similarly, wearing a seat belt reduces the chance of dying in an automobile crash, yet it does not guarantee that the individual involved will not be seriously hurt.
TYPOLOGY OF PREVENTIVE HEALTH BEHAVIORS
Although individual actions contribute to a person's health behavior, preventive health behavior is not totally volitional. Sociocultural and environmental aspects of a person's life influence preventive health behavior, and these factors can have minimal to great effect in determining whether a preventive health behavior is performed.
Some preventive health-related behaviors occur for reasons unrelated to health. Cultural traditions, attitudes, and beliefs can play an important role in the ways in which people behave. In Mediterranean countries, the traditional diet has been found to be an important preventive diet. The traditional meal is often cooked in olive oil, which may help in preventing heart disease.
Social, economic, and cultural determinants of behaviors are closely linked. For many years it was unfashionable for women to smoke cigarettes. In the decades since this taboo was removed, there have been substantial gender-related changes in the overall burden of smoking-related diseases. Between 1981 and 1996 the per-person mortality burden of smoking-related diseases such as lung cancer and chronic obstructive pulmonary disease decreased by 15 percent and 16 percent, respectively, for males, but increased by 62 percent and 70 percent for females. Currently, 24.2 percent of adult men and 20.9 percent of adult women smoke cigarettes, according to the Centers for Disease Control and Prevention (CDC).
Preventive health-related behaviors are also undertaken specifically to improve or enhance health. These types of behavior include both primary prevention and early detection. Primary prevention behaviors aim to prevent the incidence of disease (the number of new cases occurring within a given time frame). Exercise to improve aerobic fitness and prevent cardiovascular disease is an example of a primary preventive behavior. People who increase their levels of physical activity have been found to have reduced levels of risk factors such as high blood pressure, high blood cholesterol, and excess body fat. Early detection (or secondary prevention) behaviors aim to prevent early forms of disease from progressing. This involves people who have already developed preclinical disease or risk factors for disease but in whom the disease has not yet become clinically apparent. Behaviors such as having a breast screen (mammogram) or a pap test for cervical cancer are intended to detect disease early so it can be treated promptly.
Some preventive health-related behaviors may, or may not, improve health outcomes. It is becoming increasingly common for people to use a range of complementary and alternative medicines to improve their health. The 1995 Australian National Health Survey estimated that almost 26 percent of the population used vitamin or mineral supplements, and over 9 percent used herbal or natural medications. Females used these therapies more than males. These behaviors are undertaken with the hope of improving health without clear evidence that the practice has beneficial effects for individuals or populations.
UNDERSTANDING PREVENTIVE HEALTH BEHAVIORS
There is no one theory or concept that explains why people perform certain behaviors. Many theories have been developed to describe, understand, explain, and influence health-related behavior. Although these theories contribute substantially to our understanding of individual behavior, they are often limited because the broader social and environmental context in which an individual lives is not taken into account. It is becoming increasingly recognized that individual unhealthful behaviors reflect the social, cultural, and environmental contexts within which they occur.
Theories, that assist our understanding of preventive health behaviors, can be divided into three categories:
Theories that describe the health behavior and behavior change of individuals. Commonly used theories include the health belief model; the theory of reasoned action; the transtheoretical (or stages of change) model; and social cognitive theory.
Theories that describe the behavior of communities and environmental changes, such as the diffusion of innovation theory and the communication-behavior change model.
Theories that help people understand different approaches to societal change, such as community organization theories.
These and other theories help to explain "why we do what we do when we do it." Their common thread is the belief that if a person performs a health-related behavior, the chances of acquiring a disease or an illness will decrease.
MAJOR TRENDS
Despite the general good health of people in developed countries, there is still considerable scope for improvement in preventive health behaviors. Unfortunately, the last years of the twentieth century saw only modest improvements in this area. The number of people using seat belts went from 67 percent in 1995 to 69 percent in 1997. This period also saw a reduction in the number of people reporting driving while over the blood alcohol limit and a reduction in alcohol-related motor vehicle deaths. The proportion of women aged forty years and over who received a mammogram increased from 56 percent in 1995 to almost 60 percent in 1998 (CDC). One of the most marked changes was in tobacco use among adults; the adult smoking rate in 1999 was 23 percent—the lowest it had been in forty years. In the United States, smoking rates among adolescents decreased in 1999 to 34.8 percent, equal to the adolescent smoking rate in 1995. This may be an indication of a reversal of the upward trend of the 1990s (CDC). However, this does not appear to be the case in other countries such as Australia.
Although there is a strong association between dietary behavior and many chronic illnesses, there has been little change in terms of people following dietary guidelines or eating fresh fruits and vegetables. Obesity has continued to increase, with no real change in physical activity.
CONCLUSION
It is clear that individual preventive behaviors such as eating healthful foods, exercising regularly, moderation in the use of alcohol, and the avoidance of tobacco and tobacco products can contribute greatly to a person's health. However, preventive health behavior is but one element within a complex range of influences on health. Biological, social, environmental, and economic factors also play a role. Together these influence the health outcomes for individuals as well as for populations.
Ajzen, I., and Fishbein, M. (1980). Understanding Attitudes and Predicting Social Behavior. Englewood Cliffs, NJ: Prentice Hall.
Australian Institute of Health and Welfare (2000). Australia's Health 2000: The Seventh Biennial Health Report of the Australian Institute of Health and Welfare. Canberra: Author.
Bandura, A. (1986). Social Foundations of Thought and Action: A Social Cognitive Theory. Englewood Cliffs, NJ: Prentice Hall.
Glanz, K.; Lewis, F.; and Rimer, B. (1997). Health Behavior and Health Education: Theory, Research and Practice. San Francisco: Jossey Bass.
Kasl, S. V., and Cobb, S. (1966). "Health Behavior, Illness Behavior, and Sick Role Behavior." Archives of Environmental Health 12:246–266,531–541.
McGuire, W. J. (1989). "Theoretical Foundations of Campaigns." In Public Communication Campaigns, eds. R. E. Rice and C. Atkin. Thousand Oaks, CA: Sage.
Office on Smoking and Health (1989). Reducing the Health Consequences of Smoking: A Report of the Surgeon General. Washington, DC: U.S. Department of Health and Human Services.
Prochaska, J. O., and DiClimente, C. C. (1984). The Transtheoretical Approach: Crossing Traditional Boundaries of Therapy. Homewood, IL: Dow Jones Irwin.
Rogers, E. M. (1983). Diffusion of Innovations, 3rd edition. New York: Free Press.
Strecher, V. J., and Rosenstock, I. M. (1997). "The Health Belief Model." In Health Behavior and Health Education: Theory, Research and Practice, ed. K. Glanz et al. San Francisco: Jossey-Bass.
U.S. Department of Health and Human Services (1995). Healthy People 2000 Review: 1994. USDHHS publication no. PHS 95–12561. Washington, DC: U.S. Government Printing Office.
Westberg, J., and Jason, H. (1996). "Influencing Health Behavior." In Health Promotion and Disease Prevention in Clinical Practice, eds. S. H. Woolfe, S. Jonas, and R. Lawrence. Baltimore, MD: Williams and Wilkins.
