Health Behavior

The major causes of death in the United States and other developed countries are chronic diseases such as heart disease, cancer, and stroke. Behavioral factors are related to all 12 leading causes of death, and behavioral factors are thought to contribute to almost half of the deaths in the United States. According to Mokdad and others, the most common behavioral contributors to mortality, or death, in 2000 were tobacco use, poor diet and physical inactivity, and alcohol use; other significant causes of death include firearms, sexual behavior, motor vehicle crashes, and illicit use of drugs. These behaviors were responsible for nearly 1 million deaths in just a single year. The resurgence of infectious diseases, including foodborne illness and tuberculosis, and the emergence of new infectious diseases such as antibiotic-resistant infections, HIV/AIDS, hepatitis C, and human papillomavirus (HPV) are also largely affected by human behaviors. The social and economic costs related to these behaviors can all be greatly reduced by changes in individuals’ behaviors.

Understanding and improving health behavior is key to improving public health and individual wellbeing. This entry reviews definitions of health behavior, health trends in the United States, and some of the methods used to identify and assess them. It also examines the determinants of health behavior and ways in which such behavior can be improved. In general, behavioral interventions will be more effective if they are adapted to the audiences or communities they are intended for, if they are theoretically based, and if they are carefully crafted and properly pretested. To gain an understanding of health behaviors and to inform the development of behavioral interventions, researchers over the past decade have most frequently made use of the health belief model, the theory of reasoned action and the theory of planned behavior, social-cognitive theory, social ecological models, and the transtheoretical model (or stages of change model). This entry briefly describes these theories and models.