The number sixty-five has been established in this country as the designation of old age, mature, senior citizen, third-ager or becoming elderly. Age sixty-five represents a time for retirement and the finishing of one's lifetime tasks. Sixty-five is a convenient way to categorize people into a group, but is not indicative of an individual's mental ability, physical capability or state of overall health. The aging process is affected by many factors such as lifestyle, occupation, heredity and culture.

The population of age 65 and over is increasing in the United States and has tripled since 1900 (Torres 181). In 1986, there were twice as many individuals under age 18 as older people. By 2030 it is estimated that the two groups will be about equal in number. The fastest growing segment of the elderly population in the United States is age 85 and over. From 1960 to 1990, this group increased by 274% (Pfizer 4). Reasons for increased longevity in this country include, but are not limited to, better living conditions, vaccines for infectious disease, isolation of infectious patients, improved nutrition and pasteurization to kill organisms.