[Demographic evolution, aging and frailty]

The 20th century will be remembered for its technological and scientific discoveries and for the exceptional changes in the demographic structure brought about by these and the improved economic and social conditions; in fact, the reduction in the birth rate and a fall in the death rate have caused an increase in the population of the elderly. Today the elderly population represents about 20% of the total and is much more heterogeneous than in the past, with several classes of the elderly: the young elderly from 64 to 74; the old elderly from 75 to 84, the very old from 85 to 100 and the oldest old who are living around a century. The aging of the population has brought out several problems of the elderly, among the "frailty", the effects of which increase as the years pass and which regards about one half of the very old. Frailty is a reduction of the body's ability to maintaine global homeostasis and is caused by a reduction of the functional reserves of all the organs and apparatus which occurs with aging. Screening the frail elderly with a careful multidimensional assessment is important to prevent health problems and to promote good health and it is a good parameter in evaluating the management of the geriatric assistance network and thus health and social costs.