Black children more at risk for peanut allergy: Study

By Dr. Ananya Mandal, MDSep 9 2011

Children with African ancestry may be more likely to develop peanut allergy, a new study suggests.

U.S. researchers examined the genetic profiles of more than 1,100 urban children of different races, averaging around 3 years of age, and found that black children were more likely to have allergic antibodies to food allergens. The study also found that African ancestry was linked with levels of allergic antibodies to peanut typically associated with clinical peanut allergies.

“National studies show there are higher rates of allergic antibodies to food in African American individuals,” study leader Dr. Rajesh Kumar, an associate professor of pediatrics at Northwestern University Feinberg School of Medicine and a pediatric allergist at Children's Memorial Hospital, said in a hospital news release.

“We found similar results but we also found that an individual's genetic ancestry (the proportion of one's ancestors which came from each continental group determined by genetic analysis) increased the risk of a person having allergic antibodies to peanut above a level which is often associated with peanut allergy,” Kumar explained. The study appears in the October issue of the journal Pediatrics.

Specific immunoglobulin E (sIgE) levels of 0.35 or more kilo-units of allergen (kUA)/L for any of the eight common food allergens was defined as food sensitization. The correlations of self-identified race and genetic ancestry with food sensitization were assessed. In addition, associations were assessed with the number of food sensitizations (zero, one or two, and at least three foods) and with logarithmically transformed allergen sIgE levels.

The investigators found that 35.5 percent of individuals had food sensitizations. Food sensitization was correlated with self-reported black race and African ancestry (odds ratio [OR], 2.34 and 1.07, respectively), and both were also associated with a high number (at least three) of food sensitizations, (OR, 3.76 and 1.19, respectively). African ancestry was correlated with elevated odds of peanut sIgE levels of 5 or more kUA/L (OR, 1.25) and egg sIgE levels of 2 or more kUA/L (OR, 1.13). Similar, but non significant, associations were found with milk sIgE levels of 5 or more kUA/L.

“The study underlines the need for continued follow up, especially in exploring environmental and genetic factors so we can answer 'why' there this association of peanut allergy with African ancestry,” Kumar said. “Further rigorous research is needed to study the genetic and environmental factors which influence the rates of food allergy in U.S. urban populations,” he added.