In 1985, American Richard Bass accomplished an amazing feat. He had set for himself the task of climbing the world’s highest mountains in all seven continents. In that year, at age 55, he completed the climb of the last of his seven mountains, Mount Everest and in doing so became the first person to climb all seven mountains and the oldest person ever to successfully climb Mount Everest.
But now Mr Bass’s record has been eclipsed.
The oldest person to climb Mount Everest is Yuichiro Miura of Japan, who reached the summit of Mount Everest in 2013, at age 80. And the oldest person to have climbed all seven mountains in seven continents is Takao Arayama of Tanzania who climbed the last of those mountains at age 74 in 2010.
Over time, as life expectancy increases and people become healthier, older people can do things which were previously the domain of those younger. Indeed, no one would be surprised if, within the next decade, both the above records were broken.
Well, perhaps not exactly no one.
People who analyze population aging using conventional measures assume that none of the attributes that are important for understanding aging change over time or differ in localities. But a wide variety of attributes can be used to study aging. An important one metric for how 65-year-old age, for example, is their projected remaining life expectancy. Another one is how well those 65-year-olds can remember things.
Our research findings challenge the view that the only thing that matters in the study of aging is chronological age; we also dispute the idea that the attributes of elderly people do not matter.
We believe that it is time for aging measurements to account for the new reality of today’s old age, including how well the elderly actually function.
In the conventional view used by most demographers and policy-makers, it is irrelevant that life expectancy at older ages is increasing. Such views don’t account for the observation that older people are healthier and are achieving ever higher scores on cognitive status tests than in the past.
And many find no relevance in the fact that people in their mid-80s and beyond will be able to climb the world’s highest mountains in the future.
We seek to challenge this misconception. An analysis of population aging has two aspects: first, based on chronological age, most countries of the world are in the process of growing older. The proportions of populations 65+ years old are increasing. The proportions of populations 80-years-old and older are increasing even faster and median ages of the populations are also increasing.
The conventional approach to the study of population aging ends here, but in doing so, it ignores the second and equally important aspect of aging.
The characteristics of people at each age are changing.
For example, in 1950, 65-year-old Swedish men could expect to live 13.5 more years.
In 2011, their additional life expectancy is 18.4 years more, almost 5 years longer.
By contrast, in 2010, 65-year-old Russian men had an additional life expectancy of 11.9 more years, which is less than that of Swedish men in 1900.
By ignoring changes in the attributes of people and looking only at chronological age, the conventional approach provides a misleading picture of the future. In a series of articles we show how to incorporate the changing characteristics of people into measures of population aging, and have defined a new measure called “prospective age.” Prospective age is a measurement based on the average number of years that people have left to live. We categorize people as being “old” not at age 65, but when people at their age have an average of 15 more years to live.
Using this criterion, a Swedish man in 1900 would be considered old at age 60. In 1960, he would have been considered old at age 63, and in 2010 at age 69. Russian men would have been considered old at age 62 in 1960, about the same age at which Swedish men would have been considered old at that time. In 2010, however, Russian men would have been considered old at age 59, 3 years younger than in 1960. This reflects the mortality crisis in Russia after the dissolution of the Soviet Union.
In our article in PLOS ONE, we describe our discovery of a new and counterintuitive aspect of population aging based on those new measures.
Using measures of aging based on prospective age, we found that these measures of aging increase more slowly when life expectancy increase is faster.
For example, we looked at what would happen to measures of aging based on prospective age, if life expectancy were to continue to increase at its current pace in many developed countries of around 1.5 additional years of life per decade. We also looked at what would happen if increases in life expectancy were to stop. We found that our measures of aging were lower in the scenario in which life expectancy was increasing.
In other words, if people lived longer, healthier, and more productive lives, we would have less to worry about, in terms of population aging, than if they if they lived shorter, less healthy, and less productive lives.
When people think about aging from the conventional perspective, they tend to fear rapid increases in life expectancy for four reasons.
First, rapid increases in life expectancy may affect the sustainability of pension systems. But more and more countries are adopting pension systems that automatically adjust for changes in life expectancy. For this growing list of countries, the challenge of sustaining pension systems has already been successfully addressed. The United States, unfortunately, is not one of those countries, but it could be in the future.
The second fear centers on health-care costs. But health-care costs are highest in the last few years of life and these years occur later as life expectancy increases.
The third fear is that there will be so many seriously disabled people in the future that it will be difficult to care for all of them. The evidence, however, tends not to support this concern because the rates of severe disability at each stage of older age tend to decrease with increasing life expectancy.
The last fear is that when life expectancy increases there will be more people not working. However, simultaneous with the increases in the life expectancy and health of Americans, the labor force participation rates of 65- to 69-year-olds has jumped (according to figures from the US Bureau of Labor Statistics) from 21.8% in 1990 to 30.8% in 2010.
The life expectancy of a child born in a wealthy country today could well be 100 years. By the end of the century, the populations of many of those countries could have median ages above 65.
We need to think about a future in which more than half of the population would be older than the age at which most people retire today. Pension systems, tax systems, educational systems, and labor markets will all have to adjust.
Population aging does produce challenges. It does us no good, however, to misunderstand those changes based on insufficient measurements. It is time for us to understand aging not just on the basis of how many years people have lived, but on the basis of how well they function. When we understand this, we will be in a better position to plan for the changes that we will have to make.