ABSTRACT
The progressive gain in mean human life expectancy is possibly one of the great biomedical achievements of modern times. The United Nations estimates that by the year 2050, individuals aged 60 years or older will represent 22% of the world’s population, or about 2 billion people (up from 10% or 600 million people in 2000). The growth in the population of the proportion of the “oldest old” is of particular signicance: the number of individuals aged 80 years or older is projected to more than triple in the period 2000-2050, from 73 million people (1.2%) to 400 million people (4.3%).1 Declining fertility together with increased survival of infants and young children translates, for virtually all countries, to a rapid growth in the absolute number and in most cases also in the proportion of people reaching or surpassing 65 years of age. However, the promise of extending the upper limits of human life span remains largely unfullled; the fountain of eternal youth, a human quest since ancient times, is more an inspiration for fables than an evidence-based proposition.
