Life expectancy is increasing dramatically throughout the world, more visibly in developed countries, where unprecedented falls in mortality have led to increasing numbers and proportions of elderly people. Although the increase in life expectancy during the first half of the 20th century has been attributed to public health measures rather than to medical interventions (the McKeown hypothesis), many experts believe that the continuing increases in life expectancy in the second half of the century are due to advances in medical science and health care. Whatever the reasons, people live longer and many of them have more years of healthy, active, and independent life. For this group and their carers, maintaining vigour and independence is a therapeutic goal at least as important as further reductions in mortality.1

Britain's Medical Research Council recently reviewed the health of elderly people to identify opportunities and priorities for further research.2 Elderly' was defined as over 65; the report did not stratify people by age beyond this. Examining separately the young old (<=75), the old old, and the oldest old (>85)3 would have had important implications for policy because by the researchers' own analysis some dramatic demographic and epidemiological differences exist between them. …