Despite the mainstream opinion in the Western societies including in Australia, a faster increase in life-spans does not necessarily lead to faster population aging, instead makes people healthier, younger and more capable at their traditional "old age".
According to a new study by the International Institute for Applied Systems Analysis (IIASA) published in the US journal PLOS ONE, old age should be measured not by the number of years a person lived up to date, but by how long people still have left to live ahead of them.
Researchers at IIASA applied new measures of ageing to future population projections for Europe up to the year 2050.
"Age can be measured as the time already lived or it can be adjusted taking into account the time left to live. If you don't consider people old just because they reached age 65 but instead take into account how long they have left to live, then the faster the increase in life expectancy, the less aging is actually going on," said Sergei Scherbov, World Population Program Deputy Director, at IIASA.
The study looked at three scenarios for future population aging in Europe, using three different rates of increase for life expectancy, from no increase to an increase of about 1.4 years per decade.
Researchers compared the proportion of the population that was categorized as “old” using the conventional measure that assumes that people become “old” at age 65 and the proportion based on their new measure of age, which incorporates changes in life expectancy.
“What we think of as old has changed over time, and it will need to continue changing in the future as people live longer, healthier lives,” said Scherbov, adding that “Someone who is 60 years old today, I would argue is middle aged. 200 years ago, a 60-year-old would be a very old person.”
Population in most of the developed countries is considered to be ageing faster as a result of sustained low fertility and increasing life expectancy.
