August 15, 2014
High Rate of Food Allergies in Inner-City Children
NIH funded study finds 1 in 10 were allergic to milk, egg or peanut
MILWAUKEE, WI – Experts found that even within an already high-risk birth cohort, the cumulative incidence of food allergy is much higher than expected.
A team of researchers led by Emily C. McGowan, MD, and Robert A. Wood, MD, FAAAAI, followed children enrolled in an ongoing birth cohort who were at high risk for allergies in Baltimore, Boston, New York and St. Louis. Household exposures, diet, clinical history and physical examinations were assessed every year while sensitization to milk, egg and peanut were measured at ages 1, 2, 3 and 5 years.
“Even given that this was designed to be a high-risk cohort, the cumulative incidence of food allergy is extremely high, especially considering the strict definition of food allergy that was applied and that only three common allergens were included,” McGowan noted in the report.
Researchers classified children as food allergic, possibly allergic, sensitized but tolerant or not allergic/sensitized based on both specific-IgE testing and complete clinical history over the five years. From the over 500 children included in the study, 55.4 percent were sensitized while 9.9 percent were categorized as food allergic (6.0% were allergic to peanut, 4.3% to egg, and 2.7% to milk). Another 3.5 percent reported reactions to foods other than milk, egg or peanut.
“This cumulative incidence estimate of 9.9 percent is higher than the recent prevalence estimate of 6.5 percent for self-reported food allergy,” McGowan said.
Food allergies were found to be associated with recurrent wheeze, eczema, aeroallergen sensitization, male gender, breastfeeding and lower endotoxin exposure during the child’s first year. Curiously, there was a significant protective effect of endotoxin exposure for the development of food allergies and researchers believe this shows some support for the hygiene hypothesis.
While race/ethnicity, income, tobacco exposure, maternal stress or early introduction of foods were not found to influence the development of food allergies, the researchers noted that the study was largely homogeneous in terms of race/ethnicity and poverty level, so there may not be enough variation in these measures to draw any significant conclusions.
The study, funded by National Institute of Allergy and Infectious Diseases (NIAID) of the National Institutes of Health (NIH), was published by The American Academy of Allergy, Asthma & Immunology (AAAAI) and will appear in The Journal of Allergy and Clinical Immunology.
More information on food allergies and the hygiene hypothesis is available at the AAAAI website.
The AAAAI represents allergists, asthma specialists, clinical immunologists, allied health professionals and others with a special interest in the research and treatment of allergic and immunologic diseases. Established in 1943, the AAAAI has more than 6,800 members in the United States, Canada and 72 other countries. The AAAAI’s Find an Allergist / Immunologist service is a trusted resource to help you find a specialist close to home.