Understanding the Full Spectrum and Burden of Multi-Food Allergies

Announcer:
You’re listening to On the Frontlines of Food Allergy on ReachMD. On this episode, we’ll hear from Dr. Christopher Warren, an Assistant Professor of Preventive Medicine at Northwestern University’s Feinberg School of Medicine and Director of Population Health Research at the Center for Food Allergy and Asthma Research. He will dive into the epidemiology of multifood allergy in the United States.

Here’s Dr. Warren now.

Dr. Warren:
Traditionally, it’s been thought that peanut allergy has been the focus of a lot of treatments and a lot of policies, but the number of Americans living with just a peanut allergy is a very small proportion of the overall affected population. So our data suggests that somewhere around 40‒50 percent of kids and adults with food allergies have at least one food allergy with a fair proportion being allergic to more than five or six trigger foods.

The foods that are often triggers of multi-food allergy—it depends how you categorize it because there are obviously people with allergies to multiple tree nuts, and when you’re allergic to one tree nut, you’re often allergic to additional tree nuts because the proteins are similar, and there’s cross reactivity that’s also possibly due to differential sensitization through the diet as well or other routes; so often, these patients with multi-food allergy have the full spectrum of allergies that you see in the general population, including but not limited to peanut, cow’s milk, hen’s egg, and shellfish. They are probably the most common, and finfish are also present as well.

So we really set out in the study to characterize what we call the population-level burden of food allergy, so that includes the prevalence of food allergies, like what percent of the population is impacted by food allergies. And we acknowledge that there’s a big gap between the people who report that they’re allergic to a food or multiple foods and the people who would actually fail a double-blind placebo-controlled oral food challenge if clinically evaluated, and the truth of who’s genuinely affected by food allergies kind of falls somewhere in between. And so we try to use a number of different case definitions to not totally ignore the people who are living their day-to-day life as if they have a food allergy, whether or not they truly do, and not limiting our estimates to just those who have allergist-confirmed allergy because we know there are a lot of barriers to getting that confirmation clinically. And especially in adults, they have been managing their food allergy more or less fine according to their preferences and they don’t see the need, especially up until recently because there weren’t really FDA-approved treatments until just a couple years ago. So we aim to take a snapshot of over 50,000 US households tabulating the number of food allergies that folks have, their reaction histories, their emergency department utilization, healthcare utilization, quality of life, and all of these different factors. And so we arrived at these estimates of around 8 percent of kids have at least one food allergy with around 40 percent of them having multiple food allergies, and then around 10 percent of adults appear to meet convincingly IgE-mediated criteria for food allergy, and closer to half of those individuals are likely allergic to multiple foods. And so that was the first part.

And then when we went and looked quality of life, which we assess via a well-validated measure that gets at some of the key aspects of impairment of your day-to-day life associated with living with a food allergy, we saw a very clear monotonic relationship where as quality of life burden goes up, the number of food allergies goes up. And vice versa; we found that as you have more food allergies, your lived experience on average is worse. You’re more fearful of the consequences of adverse reactions, you’re more likely to report greater social limitations relating to your food allergy, and more likely to report greater degree of allergen avoidance.

And so all those paint a picture where if we want to prioritize interventions either at the patient level or kind of the public health population level—that kind of get the most bang for our buck—we really should be thinking about how do we really address this very high burden of food allergies in these multi-allergic kids and adults because they appear to be bearing a disproportionate brunt of the disease.

Announcer:
That was Dr. Christopher Warren talking about the epidemiology of multifood allergy in the United States. To access this and other episodes in our series, visit On the Frontlines of Food Allergy on ReachMD.com, where you can Be Part of the Knowledge. Thanks for listening!