Chicago ? Nearly half of all U.S. children and 90 percent of black youngsters will be on food stamps at some point during childhood, and fallout from the current recession could push those numbers even higher, researchers say.

The estimate comes from an analysis of 30 years of national data, and it bolsters other recent evidence on the pervasiveness of youngsters at economic risk. It suggests that almost everyone knows a family who has received food stamps, or will in the future, said lead author Mark Rank, a sociologist at Washington University in St. Louis.

The analysis was released Monday in the November issue of Archives of Pediatrics and Adolescent Medicine. The authors say it’s a medical issue pediatricians need to be aware of because children on food stamps are at risk for malnutrition and other ills linked with poverty.

Food stamps are a Department of Agriculture program for low-income individuals and families, covering most foods although not prepared hot foods or alcohol. For a family of four to be eligible, their annual take-home pay can’t exceed about $22,000.