MIAMI — An AARP study released yesterday challenges the perception that older Americans have been left out of the current real estate crisis because they have built enough home equity to avoid delinquencies and foreclosure.

Research by AARP's Public Policy Institute showed that 684,000 homeowners age 50 and older were either in foreclosure or delinquent on mortgage payments in the last six months of 2007. Homeowners age 50 and older represented about 28 percent of all delinquencies and foreclosures.

Of the 684,000 homeowners, about 50,000 were in foreclosure or already lost their homes, the study showed.

The vast majority of homeowners 50 and older, however, are keeping up with their mortgage payments. The foreclosure rate among older Americans in the sample was 0.24 percent at the end of 2007. That's was half the rate for those younger than 50, who tend to have even less equity than their older counterparts, the study showed.

"Older Americans depend on their homes both for shelter and as a retirement asset," said Susan Reinhard, senior vice president of the Public Policy Institute. "Losing a home jeopardizes long-term financial security, with limited time to recover."

The study also reflects the effect that the subprime mortgage market meltdown had on homeowners 50 and older. Older Americans with subprime mortgages were nearly 17 times more likely to be in foreclosure than those who had prime loans, the study showed.

The states with high foreclosure rates for older Americans include California, Colorado, Florida, Nevada and Michigan.