Study Finds Severe Increase in Food Allergy Rates among Black Children in the US

May 16, 2014
Andrew Smith

New research shows that food allergies may have increased more far more quickly among black children than among American children as a whole, leading to increased risk of anaphylaxis.

New research shows that food allergies may have increased more far more quickly among black children than among American children as a whole, leading to increased risk of anaphylaxis.

The study, which was published recently in the Annals of Allergy, Asthma and Immunology, showed that the number of black children with self-reported food allergies nearly doubled in 23 years.

Such allergies, which can lead to a number of serious problems, are the leading cause of anaphylaxis among American children.

In a news release that accompanied publication of the study results, Corinne Keet, MD, MS, assistant professor of pediatrics at Johns Hopkins University and lead author of the study, said “Although African Americans generally have higher levels of IgE, the antibody the immune system creates more of when one has an allergy, it is only recently that they have reported food allergy more frequently than white children.”

“Whether the observed increase is due to better recognition of food allergy or is related to environmental changes remains an open question.”

Keet and her fellow researchers analyzed data for more than 450,000 children. They found that food allergy increased among non-Hispanic black children at a rate of 2.1 percentage points per decade (95% CI, 1.5-2.7), 1.2 percentage points among Hispanics (95% CI, 0.7-1.7) and 1 percentage point among non-Hispanic whites (95% CI, 0.4-1.6).

The overall rate of increase was 1.2 percentage points per decade (95% CI, 0.7-1.6).

The researchers did not use medical records directly. Instead, they used other studies.

They searched Embase, MEDLINE, bibliographies of identified reports, and data from publically available data sets for English-language studies with data from the general pediatric US population.

In all, they found 10,090 publications. From those, they identified 27 different survey administrations, representing 452,237 children and covering the period of 1988 to 2011.

They then used meta-analysis and meta-regression on 20 of the surveys to synthesize estimate the effect of study- and participant-level covariates.

The heterogeneity of estimates about the overall prevalence of food allergies made it impossible to create a summary estimate of that figure, but the trends were clear.

Many prior studies have found that childhood allergies are becoming more common and that such increases have led to subsequent increases in anaphylaxis among children.

The CDC reports that food allergies now result in more than 300,000 ambulatory-care visits each year among American children, largely because of anaphylaxis.

As for the recent study, its authors emphasized that self-reporting introduces the potential for several mistakes.

Laymen, for example, often mistake food intolerance for food allergies. What’s more, an increasing awareness of food allergies could lead to an increase in self-diagnosis and self-reporting, even without any actual rise in allergies.

Still, the authors said, oral food challenges (the general standard of diagnosis) may be unfeasible and unethical in large populations, leaving surveys as the best available tool.

As for why the increase self-reported allergies was so much greater among black children than other kids, Keet and her team identified a number of possible explanations, ranging from biological differences to environmental changes to an unusually large increase in food allergy awareness among the black community.

“Our research,” she said, “found a striking food allergy trend that needs to be further evaluated to discover the cause.”