Debt for all households in 401(k) plans increased 9 percentage points during the period studied.

The monthly debt obligation for those between 50 and 65 now accounts for 22 cents of every dollar the households earn. That figure was 13 cents in 1992. For all DC plan participants in 1992, it was 20 cents.

Those who are taking on more debt than they save have two years of salary saved up, compared to four years for those who are net savers, the study found.

"Through retirement plans and Social Security taxes, the average 401(k) participant now contributes over 11 percent of their paycheck to retirement savings every month, yet the typical worker near retirement has only about two years of replacement income saved," HelloWallet founder and CEO Matt Fellowes, a former Brookings Scholar who led the study, said in a statement. "The growth in household debt is one big reason why retirement readiness is so stubbornly low."

While the percentage of households spending more than they saved increased during the recession to nearly two-thirds (64 percent), the study found that a substantial portion (46 percent) was already doing so in 2006-2007.

One factor in the increasing debt owed by workers over 40 is that average home ownership lasts nine years. By moving more often, households take on debt each time they purchase a new home rather than building up equity as they near retirement.

Of workers over 50, those who should be doing even more to increase their nest eggs, 41 percent were termed "debt savers" by the report. About half (50 percent) of those in the highest quartile income were likely to be in that group.