ABSTRACT
Increased longevity in humans is one of the great biosocial and biomedical triumphs of the modern era. Globally, we are on average living longer and experiencing a better quality of life than ever before, although large differences between and within national populations remain. Increased longevity and generally declining fertility mean that all countries are experiencing growth in the numbers of older people in the population and, in many, the proportion of older people in the population is also expanding. By 2020 the world population of older people is expected to have trebled, with an estimated seven hundred million people aged sixty-five years and over, of whom 70% will be in developing countries. Of particular significance is the growth of the oldest old in the population.
