Geriatrics refers to medical care for the elderly, an age group that is not easy to define precisely. “Older people” is sometimes preferred but is equally imprecise; > 65 is the age often used. Gerontology is the study of aging, including biologic, sociologic, and psychologic changes.

Around 1900 in the US, people > 65 accounted for 4% of the population; now, they account for > 13% (38 million, with a net gain of > 1000/day). In 2026, when post–World War II baby boomers begin to reach age 80, estimates suggest that > 20% (almost 80 million) will be > 65. Mean age of those > 65 is now a little ore than 75, and the proportion of those > 85 is predicted to increase.

Life expectancy is an additional 16 yr at age 65 and 9 yr at age 75 for men and an additional 19 yr at age 65 and 12 yr at age 75 for women. Overall, women live about 5 yr longer than men, probably because of genetic, biologic, and environmental factors. These differences in survival have not changed, despite changes in women's lifestyle (eg, increased smoking, increased stress).

Last full review/revision June 2009 by Richard W. Besdine, MD

Content last modified February 2012