Demographic determinants and speed of population ageing

Population ageing, which entails an increasing share of older persons in the population, is a major global demographic trend which will intensify during the twenty-first century. For statistical purposes, and unless otherwise specified, in this report older persons are considered to be those aged 60 years or older. Ageing results from the demographic transition, a process whereby reductions in mortality are followed by reductions in fertility. Together, these reductions eventually lead to smaller proportions of children and larger proportionate shares of older people in the population. Ageing is taking place almost everywhere, but its extent and speed vary. In most developed countries, the population has been ageing for many decades, while in developing countries, population ageing has taken place relatively recently, as their mortality and fertility levels have fallen. Currently, the most aged populations are in the developed countries, but the majority of older persons reside in developing countries. Given that the rate of growth of the older population in developing countries is significantly higher than in developed countries, the older population of the world will increasingly be concentrated in the less developed regions.

Related Subject(s): Population and Demography