That 8 percent finding is considerably higher than previously known. Previous prevalence estimates that have found the range of food allergies as high as 8 percent in children under age 3, but more in the range of 4 percent for older children.

The study, published in the medical journal Pediatrics, finds that teens between the ages of 14 and 17 are most at risk of a severe reaction. It also finds a higher incidence of food allergies in African-American children and those of Asian background. But of concern, children from those two groups were less likely to see an allergist and receive a formal diagnosis than white children.

Key findings:

• 38.7 percent of the children in the survey had a severe or life-threatening allergy
• 30.4 percent had multiple food allergies
• Children with food allergies were most commonly allergic to peanuts (25.2 percent), milk (21.1 percent) and shellfish (17.2 percent), followed by tree nuts (13.1 percent), and egg (9.8 percent)
• Severe reactions were most common among children with a tree nut, peanut, shellfish, soy, or fin fish allergy
• Children aged 14-17 years were most likely to have a severe food allergy
• Food allergies affect children in all geographic regions
• Asian and African American children were more likely to have a convincing history of food allergy, but were less likely to receive a formal diagnosis when compared to white children

Read also:

- FAI’s full media release.
- AL’s Gwen Smith interviews the study author.
- More on Food Allergy Prevalence – U.S. & Canada.

The data from the nation-wide Surveying Canadians to Assess the Prevalence of Common Food Allergies and Attitudes towards Food Labelling and Risk (SCAAALAR) telephone survey, sponsored by Health Canada and the AllerGen research network, was presented at the American Academy of Allergy, Asthma & Immunology’s conference in March, 2009.

While the information is not complete – it reflects about 90 per cent of the 9,000 individuals on whom data was collected: “We do find a greater prevalence of peanut allergy in Canadian children, and a greater prevalence of tree nut allergy overall, and in Canadian children,” says Dr. Ann Clarke, an allergist at the McGill University Health Centre, who discussed the results with Allergic Living.

In Canada, 1.52 per cent of children are allergic to peanuts, based on a history of allergic reaction. The comparable figure in the U.S., from a 2002 survey, is .83 per cent, representing an 83 per cent higher rate in Canada. Similarly, the rate of tree nut allergy is about 120 per cent higher for Canadian children: 1.13 per cent have a history of reaction here, compared to .51 per cent in the United States.

When Clarke and her team looked at the rates of shellfish allergy in both countries, they found a 50 per cent higher rate of the allergy in U.S. adults compared to Canadian adults.

Clarke cautions, however, that the differences come with a few caveats: the Canadian data was collected six years after the U.S. data, and some of the difference could be attributed to an increase in food allergies over that time. Also, the SCAAALAR team has not analyzed the demographics of the Canadian survey respondents yet, so it’s unclear if the studies represent the same socio-economic groups. This analysis will be done before the final results are published next year. (Updated U.S. statistics are also coming next year.)

While the rates of allergy that Clarke and her team used to compare to U.S. figures are based on having a history of food allergy reactions, they also collected data on those who have had a medical diagnosis of food allergy, without a previous reaction. “It might mean that the parent is going in with a child and saying, well, his brother has peanut allergies so I’m concerned he might be allergic, but he’s never eaten it,” says Clarke.

The physician then does a skin or blood test and makes a diagnosis based on the results. The SCAAALAR team is currently contacting all physicians who made the diagnoses in these cases to confirm that yes, that patient is deemed to have a true food allergy.

The final figures for food allergy prevalence in Canada for individual foods, as well as overall incidence figures, will be based on those who have had a history of allergic reaction, as well as those who have a confirmed physician diagnosis.
First published in the Summer 2009 issue of Allergic Living.

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Clarke revealed the new prevalence statistics at the Anaphylaxis Canada Spring Conference in Toronto in May. These figures are calculated from the nationwide SCAAALAR survey (which stands for Surveying Canadians to Assess the Prevalence of Common Food Allergies and Attitudes Towards Food Labelling and Risk), on which Clarke is a lead investigator. SCAAALAR is the first formal national tally of food allergies in Canada, with detailed information from 10,000 individuals.

A few days after Clarke’s Toronto speech, the Journal of Allergy and Clinical Immunology published a follow-up study on the prevalence of peanut and nut allergies in the United States.

In their phone survey of 13,500 individuals, Dr. Scott Sicherer and his colleagues at the Mount Sinai School of Medicine in New York determined that peanut and nut allergies in children more than tripled in 2008 from their comparable study in 1997.

In 2008, 1.4 per cent of American kids had peanut allergy and 1.1 per cent had nut allergy compared to 0.4 and 0.2 per cent respectively in 1997. (The combined rate of these two top allergies was 2.1 percent in 2008, compared to 0.6 percent in 1997.)

The SCAAALAR survey, funded by Health Canada and the AllerGen research network, and also published in JACI,  pegged the probable rate for peanut allergy in Canadian kids at 1.7 per cent in 2008, and 1.6 per cent for tree nuts.

Media Muddy Message

These new statistics arrived just as the question is again being raised in the media about how many people truly have food allergies, compared to how many think they have them. An article in The New York Times sparked the debate: it stated that “only” 8 per cent of children have food allergies and 5 per cent of adults have food allergies, then compared that to 30 per cent of the U.S. population who believe they have such allergies.

While these statistics appeared to come from a study published in the Journal of the American Medical Association (JAMA), Allergic Living obtained a copy of the study and those data are not in the report.

What the JAMA report provides is a review of 72 papers on food allergy diagnosis, management and prevention. In comparing available statistics, the medical article does say that more than 1 to 2 per cent, but fewer than 10 per cent of Americans have food allergies.

The report does not address the question of “perceived” versus true allergy at all, and one of the report’s authors told Allergic Living that the 30 per cent figure cited by The New York Times does not apply to the United States.

JAMA’s study was designed to provide guidance to the National Institute of Allergy and Infectious Diseases as its officials develop guidelines to define food allergies and give criteria for diagnosing and managing patients. The authors found that there isn’t a universally accepted definition of food allergy, and that there’s a lack of well-established guidelines for diagnosis.

“The systematic review of the food allergy literature published in JAMA is helpful in crystallizing the fact that food allergy is common, affecting millions of Americans, but also points out that we need much more research to better understand the exact prevalence, and how to prevent, more easily diagnose and treat this life-changing medical problem,” Sicherer noted.

First published in Allergic Living magazine, Summer 2010 edition.
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Researchers conducted a telephone survey in 2008 of more than 5,300 households and found that 3½ times more children have peanut allergy now than they did 11 years ago. In 1997, 0.4 per cent of children were reported to have peanut allergy, which doubled by 2002, to 0.8 per cent. In 2008, 1.4 per cent of children had peanut allergy.

The rate of tree nut allergy in children has similarly increased: from 0.2 per cent in 1997 to 0.5 per cent in 2002 and 1.1 per cent in 2008.

Dr. Robert Wood, chief of pediatric allergy and immunology at Johns Hopkins Children’s Center in Baltimore, told the conference that the survey, conducted using random digit dialing, could slightly overestimate the numbers because, “people might think they have an allergy but really don’t.”

But since the same same methodology was used in all three surveys, Wood notes: “We’re pretty confident that the increase that was seen, now in an 11-year period from 0.4 to 1.4 [per cent of children having peanut allergy], has to be real.”

Dr. Hugh Sampson, chief of allergy and immunology in the pediatrics department of the Mount Sinai School of Medicine in New York and one of the study’s authors, pointed out that questions were also asked to determine if the patient truly did have food allergy, such as whether the person experienced hives.

Next: Canadian Statistics