ORLANDO – Reports of U.S. children with a food allergy jumped by a third between 2003-2004 and 2007-2008.
The finding is based on survey responses collected by the Centers for Disease Control and Prevention from more than 90,000 patients during each of the two time periods. An analysis of other data collected by the surveys implicated younger age, lack of health insurance, and eczema as three factors associated with the increased prevalence of food allergies in children, Dr. Karen A. DeMuth said during a poster presentation at the meeting (J. Allergy Clin. Immunol. 2012 [doi:10.1016/j.jaci.2011.12.147]).
Other possible factors not accounted for in the survey results might also have played a role in the sharp rise, such as an increased level of awareness about food allergies among parents, and an increased rate of testing children for food allergies, she acknowledged in an interview. The telephone surveys conducted by the CDC relied exclusively on parents’ reports of allergies in their children, and so the rates do not reflect allergy rates documented by physician examinations or food-challenge tests. But the fact that these limitations applied in both survey periods – 2003-2004 and 2007-2008 – makes it less likely that they played a major role in explaining the increased food allergy prevalence.
"These data show us how many parents think their kids have a food allergy," Dr. DeMuth said.
She and her associate used data collected in the first two National Surveys of Children’s Health. During 2003-2004, the CDC completed telephone surveys with 102,353 U.S. households, and during 2007-2008, the agency obtained responses from 91,642 families. During each survey, the CDC collected data for a single child aged 0-17 years from each responding family.
During the first survey, parents reported a food allergy in their child at a rate of 3,566 cases/100,000 children, a prevalence rate of 3.6%. By the second survey, the prevalence rose to 4,848 cases/100,000 children, a rate of 4.8%, a 33% relative increase that was statistically significant, reported Dr. DeMuth, an allergist and immunologist at Emory University in Atlanta.
The prevalence rates increased by an absolute rate of more than 2% in eight states: Arkansas, Delaware, Georgia, Hawaii, Maryland, Ohio, Oklahoma, and New Hampshire. The greatest absolute rise in percent terms was in Oklahoma, where the prevalence rate jumped by 3.2 percentage points. During 2007-2008, the highest overall reported prevalence rate for pediatric food allergies was in New Hampshire, where 6.7% of families reported having a child with a food allergy. The lowest prevalence rate during 2007-2008 was in Wisconsin, with a 3.3% rate. Between 2003-2004 and 2007-2008, a statistically significant increase in the prevalence of pediatric food allergies occurred in 17 states.
Three factors were linked on a statistically significant level with the increased rate of food allergies: Age of 0-5 years boosted the food allergies rate by 33%, compared with older children; having no health insurance was linked with a 48% higher rate of food allergy increase; and having eczema or atopic dermatitis was linked with a 4.7-fold higher rate of food-allergy increase, compared with children without skin atopy.
Results from two other studies reported in posters at the meeting further documented recent prevalence rates of pediatric food allergies in U.S. populations.
A survey of randomly-selected U.S. families was conducted during June 2009-February 2010 and collected information on 38,480 children aged 0-17. The results found that 3,218 parents (8%) said they had a child with a food allergy, reported Dr. Ruchi S. Gupta and her associates from Northwestern University in Chicago (J. Allergy Clin. Immunol. 2012 [doi:10.1016/j.jaci.2011.12.145]).
The parents said that 70% of these children had been identified as having a food allergy by a physician, and that 20% of the children had their food allergy documented by an oral food-challenge test. The allergens that the responding parents reported were peanut, milk, tree nut, shellfish, egg, fin fish, wheat, soy, and sesame. The most common presenting symptom was urticaria, reported for roughly half of the children with a food allergy.
The second report included data from a retrospective chart review done at a single, hospital-based Medicaid clinic in the East Harlem section of New York City. During July 1, 2008-July 1, 2010, the clinic saw 9,314 children, of whom 331 (3.6%) had a physician-diagnosed food allergy, reported Dr. Sarah A. Taylor-Black and her associate from Mount Sinai Medical Center in New York (J. Allergy Clin. Immunol. 2012 [doi:10.1016/j.jaci.2011.12.148]). The patients’ average age at diagnosis was 1.7 years, with a range of 4 months to 10 years old. The most common allergy was to peanut, followed by shellfish, egg, tree nut, milk, fruit, fish, soy, vegetable, seed, and wheat. Allergy prevalence was 5.6% among black children, compared with 3.0% among Hispanic children, a statistically significant difference. Skin symptoms were the most common presentation in children with allergies to peanut, shellfish, egg, milk, and fish.