NEW ORLEANS (AP) -- Dozens of infants and toddlers who lived in Louisiana's biggest trailer park for those displaced by Hurricane Katrina were anemic because of poor diets, at a rate that health experts said was four times the national average.

About 41 percent of 77 children under the age of 4 suffered from the condition this year, according to a study released Monday by the Children's Health Fund. Most, and possibly all, lived in the Renaissance Village trailer park in Baker.

Iron deficiency anemia can cause fatigue and learning problems. Severe deficiency in young children can delay growth and development and even cause heart murmurs.

The national rate for children that young is below 10 percent. Louisiana has one of the nation's highest anemia rates, with about 24 percent of all children below the age of 5 affected, according to the 2007 Pediatric Nutrition Surveillance survey.

Dr. Irwin Redlener, president of the Children's Health Fund and director of Columbia University's National Center for Disaster Preparedness, said the Renaissance Village rate was double the rate for homeless children the same age in New York City shelters.

The study used records for all 261 babies and children who lived in New Orleans until Katrina and were treated last year at CHF's mobile clinics at the trailer park and Baton Rouge schools, said Roy Grant, the organization's director of applied research and policy analysis.

While most of the affected children were storm evacuees, it was possible that a few were natives of Baton Rouge.

But studying the problem further and providing follow-up care for the children is difficult because the state closed the parks in May.

"Now it's more difficult, because they're no longer in the trailer area. They're dispersed around the state. So it's a little harder to get follow-up," said Dr. Jimmy Guidry, Louisiana's health officer.

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