A measure of the reduced quality of life caused by disability.

A term coined to signify a drop in testosterone levels in older men, which normally results in reduced sexual desire, erections, and muscle mass. (Also called male menopause.)

The time in middle age, usually around age 50, when a woman’s menstrual periods cease and the production of estrogen, progesterone, and testosterone drops. Strictly speaking, menopause is dated one year after a woman’s last menstrual period, although many months before and after that date are menopausal.

A significant loss of hearing associated with senescence. Presbycusis usually is not apparent until after age 60.

Disease. As a measure of health, morbidity usually refers to the rate of diseases in a given population—physical and emotional, acute (sudden) and chronic (ongoing).

Taking hormones (in pills, patches, or injections) to compensate for hormone reduction. HRT is most common in women at menopause or after removal of the ovaries, but it is also used by men as their testosterone decreases. HRT has some medical uses but also carries health risks.

Death. As a measure of health, mortality usually refers to the number of deaths each year per 1,000 members of a given population.

A way of comparing mere survival without vitality to survival with good health. A full year of health is a full QALY; people with less than full health have a fraction of QALY each year. Thus, their total QALY is less than the total years they live.

The inability to conceive a child after trying for at least a year.

A measure of health that refers to how healthy and energetic—physically, intellectually, and socially—an individual actually feels.

The process of aging, whereby the body becomes less strong and efficient.

Difficulty in performing normal activities of daily life because of some physical, mental, or emotional condition.