The number of children hospitalized with serious abuse-related injuries increased slightly from 1997 to 2009, new data show.

Researchers analyzed U.S. hospital statistics from the Kids Inpatient Database. During this 12-year period, the incidence of serious injuries from child abuse - including fractures and abusive head trauma - increased by 4.9 percent. By contrast, child protective service records showed a 55 percent decrease in child abuse injuries in that time period.

The new findings appear online Oct. 1 and in the November print issue of Pediatrics.

Many reasons could account for the apparent disconnect, said study co-author Dr. John Mishel Leventhal, a professor of pediatrics at the Yale School of Medicine.

For starters, "we were looking at the most serious injuries that require hospital stays, while others have looked at child abuse rates overall," he said. There may also have been changes in reporting and injury coding as well as the criteria for who is admitted to the hospital.

The new data show that serious abuse-related hospitalizations are more common in infants under 1 year old and tend to disproportionately affect families on Medicaid, the U.S. health program for low-income individuals and families. "Rates of stress may be high in poorer families, and stress is linked to risk of abuse," Leventhal said.

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