geriatrics (jĕrēă´trĬks), the branch of medicine concerned with conditions and diseases of the aged. Many disabilities in old age are caused by or related to the deterioration of the circulatory system (see arteriosclerosis), e.g., mental deterioration and disturbances of motor and sensory function are often associated with an insufficient blood supply. Older persons are more prone to gastrointestinal disturbances, partly because of a reduced blood supply to the gastrointestinal tract and partly for other reasons, such as poor dentition. Changes in bone tissue, primarily osteoporosis in postmenopausal women, create susceptibility to fractures. There may also be diminished pulmonary function due to degenerative changes in the lungs. Elderly males may suffer from prostatic enlargement (see prostate gland), often accompanied by urinary obstruction. Obesity, causing increased strain on the heart and blood vessels, is also a serious problem of the aged.
The exact cause of aging is unknown, but genetic factors are known to influence longevity. Moreover, it is believed that highly reactive substances called free radicals can cause cumulative damage to body cells and tissues, and that aging cells are more susceptible to malignant changes. These factors have made geriatrics an important specialty, particularly since the proportion of elderly persons in the population is increasing steadily. Geriatrics is one of the fields included in the general study of old age, or gerontology, which covers psychological, economic, and social factors as well. Both public and private institutions are spending large sums of money for research in geriatrics and gerontology.
See R. Andres et al., ed., Principles of Geriatric Medicine (1985); W. Cunningham and J. Brookbank, Gerontology (1987); L. Hayflick, How and Why We Age (1994); J. Carter, The Virtues of Aging (1998).