Young children from urban areas have a disproportionately high risk of developing food allergies, according to a study funded by the National Institutes of Health and published online by the Journal of Allergy and Clinical Immunology on August 13.
Led by FARE Medical Advisory Board member Robert A. Wood, MD, of Johns Hopkins Children’s Center (Baltimore, Md.), researchers followed 516 inner-city children from four cities – Baltimore, Boston, New York and St. Louis – from birth through age five.
The team tracked the children’s exposure to household allergens, conducted physical exams, and reviewed their diets and health histories. They also periodically analyzed blood samples to measure the presence of IgE antibodies to milk, eggs and peanuts.
More than half the children in the study had been sensitized to milk, egg or peanuts, meaning that they had food-specific IgE in their blood and were more likely to develop allergic symptoms. Nearly 10 percent had full-blown food allergies, evidenced by elevated IgE and clinical symptoms. Peanut was the most common allergy, followed by eggs and milk. In this study, breastfed children seemed to be at a higher risk for food allergies.
Children living in homes with higher levels of endotoxin, a molecule released by certain types of bacteria, were less likely to have food allergies, suggesting that early-life exposure to certain microbes may protect against asthma and allergies. Children with food allergies were also more likely to suffer from environmental allergies, wheezing and eczema.
In a press release issued by Johns Hopkins, the researchers described their findings as a “wake-up call” to further investigate the high prevalence of food allergies “among an already vulnerable group.”