In today's Health Matters, thousands of children in the U.S. end up in the hospital as a result of child abuse, and researchers believe the numbers they've seen are only "the tip of the iceberg."

A team from Yale University analyzed information from a 2006 kids inpatient database. They determined the rate of hospitalizations for children due to serious physical abuse.

Infants less than a year old were at the highest risk for child abuse-related hospitalizations.

Health experts believe these numbers are just a small sample of the amount of abuse cases nationwide since many abused children don't end up in the hospital.

Poverty appears to be a risk factor for child abuse. Children covered by medicaid were about six times more likely to be victims of serious abuse.

Findings appear online and in the March issue of the journal "Pediatrics."