Lead author Dr. Ruchi Gupta -- an assistant professor of pediatrics at Northwestern University Feinberg School of Medicine, and a physician at the Ann & Robert H. Lurie Children's Hospital of Chicago -- and colleagues said the study involved 38,465 children age 18 and under, a representative sample of U.S. households.
The subjects' food allergies were mapped by ZIP code.
The study, scheduled to be published in the July issue of Clinical Pediatrics, found in urban centers, 9.8 percent of children have food allergies, compared to 6.2 percent in rural communities.
Peanut allergies are twice as prevalent in urban centers as in rural communities, with 2.8 percent of children having the allergy in urban centers compared to 1.3 percent in rural communities, the study found.
"We have found for the first time that higher population density corresponds with a greater likelihood of food allergies in children," Gupta said in a statement. "This shows that environment has an impact on developing food allergies. Similar trends have been seen for related conditions like asthma. The big question is -- what in the environment is triggering them? A better understanding of environmental factors will help us with prevention efforts."