We often hear that there are more children with peanut and nut allergy today than in the past, but there has been scarce evidence to prove the point. Now, data presented in February at the American Academy of Allergy, Asthma & Immunology annual conference in New Orleans reveal that peanut and tree nut allergy in children has steadily increased in the United States since 1997, as shown by three surveys over those 11 years.
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
Researchers in Canada are moving closer to having solid figures on the number of people with food allergies in Canada. Dr. Moshe Ben-Shoshan presented data at the AAAAI meeting that showed 1.68 per cent of children have “probable” food allergy, while 1.59 per cent have “probable” tree nut allergy.
This represents a significant rate of these two allergies, higher in fact than the new U.S. rates of peanut and tree nut allergies in children, which, in the case of peanut allergy, grew by 250 per cent over 11 years.
Ben-Shoshan and his team are cautious with their statistics, however. He explained to Allergic Living that the term “probable” is used to identify those people who had a convincing history of food allergy, or have been diagnosed by a physician. The survey of close to 10,000 individuals was conducted in 2008 and 2009. After the survey, researchers attempted to contact the doctors of people who said they had a food allergy, to confirm the diagnosis. This proved difficult, as many physicians didn’t respond to the requests.
When including only those people whose doctors confirmed they had a food allergy (and it was tested for in a way the researchers found satisfactory), 1.03 per cent of children had peanut allergy, and 0.69 per cent had tree nut allergy.
Ben-Shoshan believes the “probable” figure is the one that more likely represents the number of people with the allergy, as it is similar to the number of children found to have peanut allergy in a study in Montreal, where all the children were diagnosed using clinical history and confirming tests, including food challenges. Final data is expected to be published later this spring.
|Child (probable allergy)|
|Adult (probable allergy)|
First published in Allergic Living magazine, Spring 2010 edition.
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