The ageing of the population is unprecedented in human history and still continuing. Average life expectancy has doubled in most human populations over past 20th century. The number of people aged 60 years and over in the UK is projected to increase from 12 million (20% of the population) in 2001 to 18 million in 2031 (30% of the population).
The societal consequences are substantial. Issues include employment, for example, duration of active working life and duration of post retirement years, education, taxation and savings, pensions, and social structures. Health in an older population is a major issue, as this will influence the ability of older people to continue making active contributions as well as the amount and duration of dependency and need for long term care at the end of life.
The risk of disability and ill health tends to increase with increasing age. By age 75 or so about half the population have some limitation in activity and about a fifth are unable to carry out some major activity. Much current debate concerns how best to treat, support, and care for, the projected great increase in persons with impairments, disability and handicap resulting from the ageing of the population. These numbers are projected to increase two to threefold over the next few decades. However, such morbidity projections are highly sensitive to small changes in incidence and prevalence of disability.
Large international variations and secular trends indicate a large proportion of disability associated with ageing is potentially preventable or at least postponeable and research indicates that modifiable environmental factors, particular lifestyle factors such as diet, physical activity and smoking and infection may play a major role. A central challenge must be how we ensure optimal physical and psychological functioning at older ages in as many people as possible and identify policies that help maintain health and independence in an ageing population.