Epidemiology of aging.

Over the past century, truly remarkable changes have been observed in the health of older persons throughout the world, and these changes have strongly impacted society. The growth of the older population has resulted mostly from a general increase in the overall population size but is also strongly influenced by major declines in leading causes of mortality. These demographic transformations reverberate in society, increasing medical care and social needs, which are expected to increase steeply in the years to come. Based on demographic and epidemiologic perspectives, these changes were already detectable decades before and should have prompted radical changes in the structure and function of our system of health and social protection at that time. We come to this enormous challenge unprepared.