Just when they need it least, a growing number of people at or near retirement are experiencing higher debt levels. According to a study published by the Employee Benefit Research Institute (EBRI), one of the main culprits is rising housing debt, and that's a particular problem for the lower-income elderly.

Using data from the Federal Reserve's Survey of Consumer Finance, the EBRI survey found the percentage of American families headed by someone 55 or older who have some debt level was 63% in 2007, up nearly 10 percentage points since 1992. In addition, the average total debt level for the 55-and-older group ballooned almost 120% during this timeframe, to $70,370, while the median debt level zoomed 170%, to $43,000.

Credit card debt played a role in the uptick, though the largest contributor by far came from housing debt attributed to mortgage refinancing, people cashing out equity in their home or those who bought homes priced at peak levels during the housing boom. The biggest increase in housing debt occurred in families headed by someone ages 65 to 74, which rose 23% between 2004 and 2007, to almost $66,000.

On the whole, the largest debt increases occurred in families headed by someone between ages 55-64, and whose incomes were in the lower three of the four quartile income groups measured by EBRI. The survey notes that debt by itself doesn't necessarily spell trouble for elderly or near-elderly families if they have high incomes. But high housing debt can be a problem because housing is often the biggest asset for many elderly families. And carrying hefty housing debt later in life could drain money needed to fund an adequate retirement.

According to EBRI, the percentage of families with debt payments greater than 40% of income grew significantly between 2004 and 2007, from 7.3% to 9.9%. The upshot: more people are facing retirement insecurity.