Twenty seventeen was another banner year when it comes to food allergy research, and peanut allergy research, in particular. There have been hundreds of studies published over the past year in the allergy realm, and there certainly has been a growing interest and focus on peanuts. After reviewing several dozen studies about peanut, I wanted to focus on the most pertinent new data from the year.
A new study published in May of 2017 out of Brigham and Women’s Hospital in Boston looked at medical records from more than 2.7 million patients, and for the first time we have much more vetted knowledge about the prevalence of food allergies in the US. Previously, studies looking at prevalence have used telephone surveys and similar tools – relying on the historical accuracy and hindsight of the patients spoken to. Now we have more rigorous data from this EHR (electronic health record) study, findings which include:
- Food allergy or intolerance were documented for 3.6% of the populations studied
- Shellfish was the most commonly reported food allergy
- The highest rates of food allergies or intolerance were among females and Asians
The overall rate of allergy prevalence that the team found – 3.6% – is consistent with previous estimates using oral food challenges. Of the approximately 97,000 with food allergy or intolerance, 13,000 reported allergy or intolerance to peanut.
There are some limitations to this study, including that some of the data (specifically the PEAR data) included some unverified allergies, intolerances or adverse reactions to foods; such data may be inaccurate due to self-diagnosis or food preferences, not true allergies. Increased awareness about food allergies may have also skewed the data by leading to overdiagnosis or over-reporting, which is another limitation. Finally, this data may not be generalized because the patient population is from only one large health system in Massachusetts and may not be representative of the entire population. This study adds to the current literature available about the prevalence of food allergies.
A study conducted by Ruchi Gupta, MD, MPH and colleagues, presented as an abstract in October at American Academy of Allergy, Asthma, and Immunology (AAAAI), suggested that peanut allergy in children has increased 21% since 2010 and that nearly 2.5% of US children may have allergy to peanuts. A major limitation of this study is that the data was self-reported, which can lead to over-reporting of food allergies. . More than 53,000 U.S. households were surveyed between October 2015 and September 2016 for the study. The research suggests that rates of peanut, tree nut, shellfish, fin fish, and sesame allergies are increasing. Allergy to tree nuts, for example, increased 18 percent from 2010 when data were last collected, and allergy to shellfish increased 7 percent. Also evident was a greater increase in occurrence in black children compared to white children.
“Because peanut allergies are very challenging for both children and their families, the good news”, according to Dr. Gupta in a recent article, “is that parents now have a way to potentially prevent peanut allergy by introducing peanut products to infants early (after assessing risk with their pediatrician and allergist.”
FOOD ALLERGY PREVENTION
Early Introduction of Peanut and other Food Allergens
As a result of the 2015 landmark study Learning Early About Peanut (LEAP), which demonstrated that inclusion of peanut in the diet of infants at high risk for food allergy resulted in a greater than 80% decreased risk of developing a peanut allergy (if fed early and consistently for the first 5 years of life), a logical question was asked: “would early introduction of other food allergens result in the same benefit as the LEAP study?” Thus, the EAT study was born.
Enquiring About Tolerance (EAT), found that introducing a variety of potential allergens (wheat, dairy, egg, peanut, fish and sesame) into an infant’s diet was safe. In fact, amongst those infants who were consistently fed these foods, the risk of any food allergy was reduced by two-thirds!
So, “dietary diversity” has become a new buzzword, when it comes to prevention of food allergies.
In fact, because of the LEAP study, our feeding paradigm in the US has made a 180 degree shift since January 2017 when a consensus panel of experts published the NAIAD Guidelines which now advocate early introduction of peanut to infants in an effort to reduce the incidence of peanut allergy in children. The guidelines walk parents (and practitioners) through the process of introducing peanut-containing foods to infants that are at high, medium, and low risk for developing peanut allergies. Those at highest risk, those with severe eczema or existing egg allergy, should see their pediatrician for an evaluation and potential referral to an allergist before introducing peanut foods. Those at medium and low risk can introduce age-appropriate peanut foods (such as thinned peanut butter) at home around 6 months of age and should keep it in the diet regularly in accordance with the family’s preferences.
But what about the siblings of those with peanut allergies? What is their risk for developing the same?
From Canada, just on the heels of 2017 in November 2016, Begin, Graham, et al looked at 154 kids whose siblings had peanut allergy. The study’s goal was to look at the rate of peanut allergy in siblings of children with documented allergy to peanut. As anticipated, the results showed that brothers and sisters of children with peanut allergy have an increased risk of anaphylaxis upon peanut introduction – with a potentially higher risk for older children for whom introduction was delayed. The study also noted increased anxiety levels of parents, especially if introduction was recommended without prior skin testing or supervision by a health practitioner.
Limitations of the study include selection bias for parents who are less tolerant of risk, since they self-selected to participate in the study. A second limitation is that the older siblings did not undergo oral food challenges to confirm their allergy, therefore may not have actually had true peanut allergy. Even with these limitations, the study gives interesting insight into this important topic.
HOW ARE PRACTITIONERS DOING WITH THE NEW NAIAD GUIDELINES?
In a nutshell, not well. A survey, the results of which were disclosed at AAAAI in October, revealed that 11% of primary health providers are following the NAIAD Guidelines for early introduction of peanut. However, the great majority of those practitioners surveyed show that guidelines to help parents introduce peanut-containing products to infant simply aren’t being discussed. Pediatricians are not only not having the discussion, they’re not referring high-risk babies for testing prior to peanut introduction. This study is limited by a small sample size.
As stated in this article, “We recognize the idea of introducing peanut-containing foods to infants between 4-6 months is scary – especially for parents,” said allergist David Stukus, MD, American College of Allergy, Asthma and Immunology (ACAAI) member. “We need to work with pediatricians – the first physicians who care for most babies – to help them become comfortable putting the guidelines into practice. We need to overcome the current barriers so all physicians who deal with infants understand that early introduction could lead to a new generation of children who have far less peanut allergy.”
A Mayo Clinic study published in in JACI in Practice examined ER visits for anaphylaxis from 2005-2014. A total of 56,212 ER visits for anaphylaxis were identified with 27% of visits definitely associated with food and close to 57% with an unidentified trigger. But more striking, was that there was a 101% increase in ER visits for anaphylaxis, with the greatest increase in children under the age of 17 and adults over 65. The highest rate increase for both food-related anaphylaxis and anaphylaxis overall was in children aged 5-17 – accounting for a striking and disproportionate increase in anaphylaxis amounting to 196%.
The limitations of this study include potential errors in coding. Additionally, this data is region specific and may not be generalizable to the population. The data may also include inaccurately identified triggers or even unknown confounders.
What we do know is that giving epinephrine early and appropriately when anaphylaxis is suspected results in less hospitalizations and less morbidity. In my opinion, perhaps the reluctance to give epinephrine in the field, either because of lack of availability, prohibitive costs, or fear of administration may account for some of the ER data we see above.
All that said, in 2018, health practitioners and advocates have their work cut out for them. Given that science continues to affirm that early introduction of food allergens, especially peanut, has the potential to reduce the incidence of peanut allergies in this next generation, we must continue to spend time educating primary healthcare practitioners. An effort to help them understand and trust the science will lead them to return to their patients with confidence and a willingness to change old habits into new practices.
This is a team effort of pretty epic proportions, and all of the amazing professionals who sit on the Food Allergy Education Advisory Council of the National Peanut Board also are carrying these messages to their colleagues and various platforms. With their help, and the help of all those who care for children, we will achieve the goal of reducing the prevalence of peanut allergy. To get there, we are committed to being part of the solution by funding research, continuing education and outreach, and communicating evidence-based data and solid science.