By Scott Simon and Ina Jaffe, NPR |

One-fifth of the U.S. population will be 65 or older in 15 years. NPR’s Ina Jaffe talks with NPR’s Scott Simon about the aging of the population worldwide and the challenges it presents.

SIMON: The U.S. population is aging, but it’s not just the U.S., is it?

JAFFE: Oh, no, not at all. In fact, some other countries are ahead of us. Japan, for example, a quarter of the population there is already 65 years of age or more, and the populations of some Western European countries are already at that 1-in-5 level that the U.S. is headed for.

SIMON: Whatever else happens in this discussion, should we remind ourselves it’s the result of some good news – that people are living longer?

JAFFE: Well, it is a result of people living longer, but only in part. In North America and Western Europe, people are living longer. But there’s a bigger reason for the aging of populations and that’s that people are having fewer children. That’s what you see in Eastern Europe and Russia and Turkey. And sub-Saharan Africa is not aging as quickly as other places because reproduction rates are higher there.