Epidemiologic characteristics of the United States elderly population in the 20th century.

In 1900 approximately 25 percent of all deaths occurred in people age 65 years of age and over while by 1980 30 percent of deaths occurred in those over age 80. The greatest declines in age-specific mortality for those 65 and over occurred from 1920 to 1945 and since 1970. Some evidence exists that illness and disability may be rising in all age groups. Understanding the reasons for the declines in mortality for the elderly in this century and basic research in chronic disease causation and prevention are urged.