Central bankers have spent most of the past decade battling short-term challenges from bank crises to recession and their aftermath. They’ll soon need to start worrying again about the long term.

That’s because the graying of the world threatens to undermine the economies and inflation outlooks the policy makers are charged with managing, according to UBS AG economists Andrew Cates and Sophie Constable.

To prove their point, they plotted the 10-year change in dependency ratios, which measure the number of people outside the labor force, against changes in consumption and home prices in more than 60 economies. The result: The retrenchment as workers retire and spend less represents a material brake on economic growth. The U.S., Japan and Germany, the world’s largest industrial economies, are all at risk.

Most central banks will “arguably need to err on the loose side of the ledger for arguably longer than many realize simply in order to fend off the disinflationary thrust from aging populations,” London-based Cates and Constable concluded in an Aug. 21 report.

“With new technologies presently invoking a disinflationary threat to the price of many other goods and services and likely to continue doing so, this conclusion concerning policy clearly carries even more force.”

To John D. Herrmann, director of U.S. rate strategy at Mitsubishi UFJ Securities USA Inc., Europe has the most reason to worry that it faces a fate similar to Japan, which the International Monetary Fund says has the most rapidly aging population in the world and is suffering as a consequence.

He reckons the 10-year German bund yield could even fall beneath 0.70 percent as that risk materializes.

“At some point, policy makers in Europe, Japan and America have to address the need for a modern approach to embolden private risk taking, innovation and economic and employment growth,” said Herrmann. “Until that time, sovereign debt ‘risk free’ yields are likely to stay lower than otherwise.”