The greying world: a challenge for the twenty-first century.

As we approach the next millennium, an unprecedented rapid increase of total and relative numbers of older persons in both the developed and the developing world is being observed. The total aged population (aged more than 60 years) world-wide will rise from 605 million in the year 2000 to 1.2 billion in 2025. Population ageing is due to two factors: increased life expectancy and decreasing fertility rates. Public health interventions are major contributor to both. A significant consequence of ageing is the shift from communicable to non-communicable diseases. The World Health Organization (WHO) is addressing the multiple challenges posed by population ageing through integrated activities that include consolidation of databases, capacity building (research and training), advocacy and policy development. These are all approached through WHO perspectives on ageing and health: life-course, health promotion, socio-economic, community based, intergenerational, cultural, gender and ethical.