Children living in urban centers are far more likely to have food allergies than those living in rural areas, according to a new study.
The research, published in the journal Clinical Pediatrics, found kids living in big cities are more than twice as likely to have peanut and shellfish allergies as those in rural communities. The finding, by Northwestern University Feinberg School of Medicine researchers, is the first to map children's food allergies by geographical location in the United States.
"We have found for the first time that higher population density corresponds with a greater likelihood of food allergies in children," said lead researcher Dr. Ruchi Gupta, a pediatric specialist at Northwestern and a physician at the Ann & Robert H. Lurie Children's Hospital of Chicago. "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."
The study involved 38,465 children, 18 years and under, whose food allergies were mapped by ZIP code. Among the key findings:
• In cities, 9.8 percent of children have food allergies, compared to 6.2 percent in rural communities, almost a 3.5 percent difference.
• About 2.8 percent of city kids have peanut allergies, compared to 1.3 percent in rural communities. About 2.4 percent of children in urban areas have shellfish allergies, compared to 0.8 percent in rural communities.
• Food allergies are equally severe regardless of where a child lives. Nearly 40 percent of food-allergic children in the study had already experienced a severe, life-threatening reaction to food.
• The states with the highest overall prevalence of food allergies are Nevada, Florida, Georgia, Alaska, New Jersey, Delaware, Maryland and the District of Columbia.
An estimated 5.9 million children under age 18 -- one out of every 13 children -- have a potentially life-threatening food allergy. A severe allergic reaction can cause a drop in blood pressure, trouble breathing and swelling of the throat. A food-allergic reaction sends an American to the hospital every three minutes, according to a recent study published in the Journal of Allergy and Clinical Immunology.
Past research has shown city dwellers are more likely to suffer asthma, eczema, allergic rhinitis and conjunctivitis than residents of rural communities. Some studies have suggested exposure early in life to pollutants encountered in urban areas may trigger the development of allergies.