“Rigor” Mortis: Post Mortem on an Airborne Allergy Article

By Jessica Martin, PhD

The Conversation is a publication touting articles that have “academic rigor” and “journalistic flair.” As far as I can tell, the most recent article – “The myth of flying peanuts: not so deadly after all” by Tim Spector, Professor of Genetic Epidemiology at King’s College, London – is long on flair and short on rigor. Would it have passed muster in actual peer-review? Here is my not-so-anonymous “peer” review (I promise to be nice, unlike these actual anonymous peer-reviewers).

1. The article is egregiously mis-titled. In reality, the main thesis of the article, as indicated prominently by the last paragraph, is that food allergies may be prevented by promoting a rich diverse diet, including common allergens from an early age. The article title should reflect this point, which is independent from how those managing existing food allergies mitigate anaphylactic reactions. While the article itself never makes an explicit link between preventing food allergies and mitigating reactions for those already allergic, the author’s Twitter feed suggests that banning peanuts may cause others to develop peanut allergies because they “unnecessarily” restrict their diet. I disagree. Quite apart from the fact that by school age, peanut allergies are already firmly established for most, if we assume that 1 meal is consumed in school for 5 days a week, then this means only 5 out of 21 meals (assuming 3 meals a day) during the week are consumed in the school environment. Don’t the 76% of meals outside of school per week (even fewer on airplanes) provide ample opportunity to incorporate common, potential allergens in a diet? Why does this diet expansion have to come with risk to the truly allergic? In the LEAP study, which showed significant prevention of peanut allergy in infants at risk of allergy, the minimum baseline consumption of peanut was at least 6 g of peanut protein (equivalent to about 24 peanuts) per week, distributed in three or more meals per week. Infants are not going to get that on airplanes.

2. Focusing on airborne-mediated allergic reactions misses the greater risk. The risk of anaphylactic allergic reactions by inhaling allergens is low, yet it also isn’t well studied. In fact, one of the references given that tested for airborne peanut protein under various conditions states, “Small amounts of airborne peanut protein were detected in the scenario of removing shells from roasted peanuts; however, Ara h 1 and Ara h 2 proteins were unable to be consistently detected. Although airborne peanut proteins were detected, the concentration of airborne peanut protein that is necessary to elicit a clinical allergic reaction is unknown.” But the real point is that the author fails to acknowledge additional, more common, avenues for allergic reactions. Severe allergic reactions can occur by touching a contaminated surface followed by putting hands in the mouth, as one possible example. Whether the reaction to nuts for the 4 year-old on the airplane was due to airborne exposure or not, it still cannot be dismissed that an airplane was forced to land because of anaphylaxis. Will airlines dismiss the symptoms because it is a theoretical improbability? A major concern for parents of young children with life-threatening food allergies is through inadvertent contact of lingering, invisible food proteins in the environment in general, followed by unknown ingestion, more so than allergen ingestion through the air.

3. Statistics on food allergies referenced are inconsistent, and should refer to primary sources. While pinning down the actual prevalence of food allergies is challenging for researchers, statistics do fall within a certain range, predicted between 1-10%. Spector’s article says “up to 10%” and follows it by saying “1 in 50 children in the UK and Australia is affected” (2%), but the source for these numbers is not the original article but a King’s College press release based on the research. It needs to be clarified that 1 in 50 refers to only peanut allergy. Furthermore, statistics should refer to primary sources or comprehensive reviews and not university press releases, which are known to be unreliable sources. An academic researcher should know to be cautious when referencing statistics and always verify the primary source. Later in the article, it is mentioned that the real prevalence of food allergy is closer to 1% – this is the bottom end of the range currently predicted in the literature. The author needs to use a range from the most robust recent studies, such as those reviewed recently by leading food allergy experts, Drs. Scott Sicherer and Hugh Sampson of Mount Sinai. There is too much room for misinterpretation by an unknowing reader.

4. Focusing on the societal “hype” and “misunderstanding” of food allergies does not negate risk for those with a history of anaphylactic food allergies. Does epidemiology only count when diseases are infectious, but not when food antigens threaten individuals? The fact that there is so much societal misunderstanding of allergies may heighten the risk for those living with the threat of anaphylactic reactions. This makes risk reduction through preventative strategies (like wiping down airplane surfaces) all the more pressing.

5. Misuse of several original research articles to support claims; sloppy use of words.
There are reasons why peer-reviewed articles are tedious. They cite other articles in the spirit of what they actually say because there’s always a chance someone will look them up. In Spector’s article, the following statement is wrongly supported using the LEAP study, “Paradoxically, peanut allergy looks like it could be cured by reintroducing tiny amounts of peanuts slowly early in life.” You can’t “reintroduce” something that hasn’t been introduced to begin with. The same corresponding author of the LEAP study proposes in a different study that is is “plausible” that peanut sensitization comes through skin contact, not ingestion. Does that constitute “introduction”? Loose diction abounds: The subjects in this study did not have a peanut allergy at the time they were enrolled, so you can’t “cure” something, you don’t have. Those already judged allergic were excluded from “treatment.” Perhaps the author meant to say we may be able to fight the allergy epidemic at a population level by introducing allergens earlier in life?The truth about LEAP was buried at the end of the same paragraph: “[B]abies at high-risk of developing peanut allergy are protected from peanut allergy at the age of five if they eat peanut frequently, starting within their first 11 months.” Protection is not “cure.”

Another statement is also incorrectly supported: “Early studies also suggest microbes can help prevent the allergy as introducing probiotics has also helped.” The Australian study by Mimi Tang et al, tested whether probiotics can be combined with oral immunotherapy (OIT) for those who are already allergic. This was not a prevention study, nor did it test for improvement of OIT outcomes, since the researchers did not compare OIT alone to OIT + probiotics (they only tested OIT + probiotics against control). Furthermore, the original research should be referenced because the media report provided overstates the study conclusions (previous analysis of this article).

For the reasons above, I would not have published this article “as is.” There is building evidence to support allergy prevention through early introduction of allergenic foods as well as the involvement of the microbiome. The author should have developed this further and completely left off airborne allergies and peanut bans. I can only conclude that this unrelated emphasis constitutes too much journalistic flair intended to drive “clicks” over a socially charged topic, i.e., peanut bans, rather than the scientifically solid, well-supported thesis of allergy prevention. It may be the editor’s judgment to give it this button-pushing emphasis, but the editor’s byline doesn’t appear. Even then, the misrepresented science on the microbiome and allergy prevention suggests the author needs to develop further understanding of the science itself before being critical and dismissive to those dealing with anaphylactic allergies.

P.S. – I’m going to give the author some grace and assume that this article wasn’t deliberately published at the same time U.S. legislation is being introduced to assess airline procedures for allergies.

P.P.S. – It’s bad enough when equivocal studies, as most of them are, are rehashed in the popular press to fit the prejudices of the editors and distort the findings. In this case, The Conversation has given other publications a head start on making things worse. The Daily Mail republished Dr. Spector’s article with the following, shiny new headline – “‘Airborne peanut allergies on flights are a MYTH’: Leading scientist claims it’s impossible for a reaction to be triggered this way.” Dr. Spector has not done any scientific studies of airborne allergens (as the title implies). Misconceptions spread like ripples on a pond, and the further they spread, the less they have to do with the original story and more to do with those telling the tale.

Jessica Martin earned a Ph.D. in Neuroscience from Oregon Health and Science University in 2011. She lives in the Portland, Oregon area with her husband Jason and their sons where she teaches undergraduate biology and anatomy and physiology at Portland Community College. Although not currently engaged in cutting-edge laboratory science, she continues to actively research current findings in allergy and immunology, where she writes about some of those findings on her blog, The Food Allergy Sleuth. She aspires to eventually return to the trenches of doing laboratory science in allergy and immunology, but for now, her life is happily filled to the brim with being a Mom, an educator, a writer, and as most food allergy sufferers and parents already know, part-time cook.

Graphic: Johannes Hevelius – Prodromus Astronomia – Volume III “Firmamentum Sobiescianum, sive uranographia” – Tavola T – Pegasus.jpg