(REUTERS/Mike Blake)

The fact that the US population is aging because of the baby boomers isn't exactly news.

But it could have something to do with what's going on in the economy right now.

"The aging population helps explain the relatively modest economic growth and record low interest rates of the past several years," says Ed Keon, a managing director and portfolio manager at QMA, a business of Prudential Financial.

Keon writes that, one, a large population of older folks are earning a greater share of income and wealth in the US, and, two, they are changing investing and spending habits. And he suggests that these two factors have contributed to the current economic state.

While older people have generally had more wealth than younger people, this difference has been amplified by the recent "Great Recession." Keon's team estimates that the proportion of total wealth held by those 55 and older shot up from 61% to 73% between 2007 and 2013. (On the flip side, those numbers dropped from 39.2% down to 27.5% for those age 15-54.)

(US Census)

Additionally, all age groups below 65 saw a drop in mean real income, while the income of those 65 and older went up from 2006 to 2014.

Plus, the income of Americans 55 and over grew by almost $800 billion between 2006 to 2014, while younger Americans saw their income drop in real terms by $400 billion during that time.

On top of that, the wages for older workers have grown faster than those of younger people.

And all of these shifts in wealth and income have implications for the investing world. Keon:

The conventional financial advice for older people ... is straightforward: reduce risk in portfolios by shifting from equities to fixed income. Notably, back "during the bull market of the 1980s and 1990s, when Baby Boomers were in their 30s and 50s, equity funds received the lion's share of flows. But over the past ten years, as Boombers reached or approached ... the ten years prior [to] and the first years of retirement, bonds have seen the big flows.

So basically what's happening is, there's a soaring population of older people who have more of the wealth and income, and they favor bonds over stocks, for the most part.

This has, at least partially, contributed to the milder economic growth we've been seeing — and, subsequently, the lower rates.

As an endnote, Keon suggests that this sort of set up might be the case for a few years to come:

Interest rates, inflation, and economic growth are likely to remain below the typical levels of the past 70 years and the strong growth, high inflation, and high interest rates of the post-WWII years might themselves have been influenced by the Baby Boom. With the maximum impact of the Baby Boomers still ahead, we expect that this post-post crisis period might well last for another five to ten plus years.