Hospital admissions for child abuse have risen in the past decade, and the increase might be related to the housing crisis of the late-2000s, a new study suggests.

Researchers found that between 2000 and 2009, admissions for physical abuse at pediatric hospitals hit a peak in 2008 - right about the time housing foreclosures were taking off in many parts of the country.

And in general, as a local area's rate of delinquent mortgages and housing foreclosures rose, so did its rate of child abuse admissions.

That doesn't prove the housing crisis is to blame. "This type of study can't demonstrate causation. It can only show an association," said lead researcher Dr. Joanne N. Wood of Children's Hospital of Philadelphia.

But she said it's possible that housing foreclosures signal the "serious end result" of families' economic hard times - when, for example, they've been out of work for a long time, and their savings and "safety net" benefits have run out.

And that could put more kids at risk.

What's more, Wood said, the study conflicts with some past studies indicating that child abuse is declining in the U.S.

"This suggests that maybe the problem is not getting better," Wood said.

Thousands of admissions per year

The findings, reported in the journal Pediatrics, are based on a database that tracks discharges from pediatric hospitals in major metropolitan areas.

Between 2000 and 2009, there were just over 11,800 admissions for physical abuse in children younger than six at 38 hospitals. That accounted for 0.28 percent of the nearly 4.2 million admissions overall.

Over the years, that rate fluctuated, peaking at 0.3 percent in 2008.

Then the researchers looked at each metropolitan area's unemployment rates and housing woes. They found that for each percentage increase in an area's foreclosure rate, admissions for physical abuse rose 6.5 percent the following year. There was a similar pattern when Wood's team looked at 90-day mortgage delinquency rates.

In contrast, there was no link between unemployment and child abuse admissions.

The reason for that discrepancy isn't clear. But Wood speculated that unemployment is a less-extreme marker of a family's economic problems than mortgage delinquencies and foreclosures are.

The results do paint a different picture than some past research that has suggested child abuse is declining in the U.S., Wood and her colleagues say.

But the reason may be the data source, Wood said. Those past studies have looked at reports to child protective services, which cover varying degrees of abuse. On the other hand, children admitted to the hospital would be victims of the most severe physical abuse.

There is "reasonable evidence" that other forms of child maltreatment are declining, said Dr. Kristine A. Campbell, a pediatrician at the University of Utah in Salt Lake City who has studied the issue.

"But there are still huge problems in terms of kids who are being severely abused," said Campbell, who was not involved in the new study.

Complex relationship

Like Wood, she said it's impossible to tell from this study whether housing foreclosures led to some severe abuse cases. "We don't know that economic stress causes child abuse," Campbell said.

There could be complex reasons for the relationship, according to Campbell. It's possible, for example, that when a family loses their home, they may end up living with someone else who is not used to having children around, and that's when the abuse occurs.

Still, Campbell said, "this study adds to a large body of evidence that economic downturns are bad for families and bad for children."

That includes negative effects on kids' nutrition, school work and general health.

"Economic downturns are exactly the time when we should not be cutting services to families," Campbell said. She pointed to government programs like WIC, which gives nutrition assistance to low-income women who are pregnant or have young children.

On the brighter side, Wood's team did see evidence of a dip in physical abuse admissions in 2009 - even though the housing crisis continued.

Campbell said that further research should try to uncover the possible reasons.

"There are hints of an improvement," she said. "Wouldn't it be nice if we could show that something we're doing is working?"