Why Your Birthday Cake Might Have Too Many Candles

Perhaps the number of candles on your birthday cake is wrong.

Instead of celebrating the number of years you’ve been alive, you could tell people your biological age. In fact, some economists think we should be paying more attention to our biology and less to chronology.

Aging Populations

Chronological Age

Because we are living longer and having fewer babies, the average age of most populations is going up. Japan’s median age was 26 in 1952 and now it’s 46. For the United States, we moved from 29.5 in 1960 to 38.2 now.

The UN reports that everywhere the 60 and older population is growing. But the really big increase in aging populations is in the less developed countries:

Below you can see the actual numbers.  The last column, for example, says that 61.2% of the world’s oldest people will live in Asia. Currently it’s 57.1 percent:

So yes, many of us are chronologically older. But we are also biologically younger because of longer life expectancy.

Biological Age

One Yale Medical School professor, Morgan Levine, says we can calculate our biological age with nine biomarkers. She told CNN last year that they included, “blood sugar, kidney and liver measures, and immune and inflammatory measures.”

A paper that Dr. Levine co-authored quantifies the decrease in our biological age. For example, between the two time periods, 1988-1994 and 2007-2010, the decrease for women aged 60-79 was 3.63 years:

As we would expect, she takes us beyond the averages to the differences and policy implications that relate to age, gender, genes, health habits, disease…the list is long. All though remind us of the difference between chronology and biology.

Our Bottom Line: Age Inflation

In previous posts, we’ve used an old-age dependency ratio, the OADR (number of people 65 and over as a percent of the labor force) to convey the impact of a growing elderly population. The basic idea has been that an increasingly larger older population will impede economic growth because of a proportionally smaller labor force. In other words, more young people will have to work harder because of all of those old folks who don’t work.

Maybe not.

Based on biology, dependencies will vary considerably. Our health and vigor could be a more accurate indication of an economic contribution. The World Economic Forum even calls the phenomenon “age inflation.” Sort of like a dollar might have the same purchasing power as 90 cents, a 65-year-old could be as productive as a 55-year-old.

So is 65 the new 55? And that means we have too many candles on the cake.

My sources and more: The World Economic Forum looked at aging populations last year. Their discussion of the two age metrics led me to this CNN story. It also took me to a UN report on population and to Brookings for OADRs. However, if you really want to learn more about biological age, this paper is a start.