Baby boomers aren't saving enough for retirement because they are spending too much on mortgage debt—and carrying that and other debts into their near-retirement years, says a new study from the National Center for Policy Analysis.

"Unfortunately, a greater percentage of pre-retirees will be dragging mortgage debt into their retirement years," says National Center for Policy Analysis Senior Fellow Pam Villarreal. "This is a time when major debts should be pared down. Instead, many are taking out longer mortgages and home-equity loans."

In the report "How Are Baby Boomers Spending Their Money?," Villarreal found that for 55- to 64-year-olds in particular, mortgage interest comprises a larger share of their expenditures than for the same age group 20 years ago, despite the fact that interest rates have fallen over time.

Additionally, education expenditures have increased significantly for 45- to 64-year-olds, some of this resulting from loans of their adult children.

"Baby boomers need to recognize their limitations when it comes to spending on their adult children," says Villarreal. "Fifty-nine percent of these parents are providing financial support to adult children who are no longer in school."