Chronic disease: A disease that persists for a long time. A chronic disease is one lasting 3 months or more, by the definition of the U.S. National Center for Health Statistics. Chronic diseases generally cannot be prevented by vaccines or cured by medication, nor do they just disappear. Eighty-eight percent of Americans over 65 years of age have at least one chronic health condition (as of 1998). Health damaging behaviors - particularly tobacco use, lack of physical activity, and poor eating habits - are major contributors to the leading chronic diseases.

Chronic diseases tend to become more common with age. The leading chronic diseases in developed countries include (in alphabetical order) arthritis, cardiovascular disease such as heart attacks and stroke, cancer such as breast and colon cancer, diabetes, epilepsy and seizures, obesity, and oral health problems. Each of these conditions plague older adults in the US (and other developed nations).

Arthritis and related conditions are the leading cause of disability in the US affecting nearly 43 million Americans. Although cost-effective interventions are available to reduce the burden of arthritis, they are underused. Regular, moderate exercise offers a host of benefits to people with arthritis by reducing joint pain and stiffness, building strong muscle around the joints, and increasing flexibility and endurance.

Cardiovascular disease is a growing concern in the US. Heart disease is the nation's leading cause of death. Three health-related behaviors--tobacco use, lack of physical activity, and poor nutrition--contribute markedly to heart disease. Modifying these behaviors is critical for both preventing and controlling heart disease. Modest changes in one or more of these risk factors among the population could have a profound public health impact.