Early introduction of peanuts in children at high risk for allergy not associated with an increased prevalence of peanut allergy: The LEAP-On Trial


1. Peanut allergy at 72 months, after a 12-month period of avoidance, was significantly greater in the peanut-avoidance group compared to the peanut-consumption group.

2. Strengths of the study included high number of participants and high adherence to the intervention.

Evidence Rating Level: 1 (Excellent)      

Study Rundown: Peanut allergy is a potentially life-threatening food allergy which is extremely common. The Learning Early About Peanut Allergy (LEAP) trial demonstrated that for infants at high risk for allergy, the sustained consumption of peanut, starting in the first 11 months of life, resulted in 81% lower allergy prevalence at 60 months of age compared to those children who avoided it. The Persistence of Oral Tolerance to Peanut (LEAP-On) study investigated the mechanisms of loss of protection from allergic responses by asking participants from the LEAP program, irrespective of which group they were part of in the original trial, to avoid peanuts for 12-months and then assessed whether the allergic response changed based on the original group they had been placed in. Peanut allergy at 72 months was significantly higher in the peanut-avoidance group compared to the peanut-consumption group. A 12-month period of peanut avoidance was not associated with an increase in the prevalence of peanut allergy. Overall, 4 years of consuming peanut was sufficient to induce stable unresponsiveness to peanut, irrespective of subsequent consumption.

Click to read the study in NEJM

Relevant Reading: Randomized trial of peanut consumption in infants at risk for peanut allergy

In-Depth [randomized controlled trial]: This follow-up study was a two-group comparison that involved participants from the original LEAP trial at 72 months of age. The primary outcome in the follow-up trial was the percentage of participants with peanut allergy, after 12 months of peanut avoidance. A total of 550 participants who had already completed the LEAP trial completed the LEAP-On study. A total of 79.1% of the participants from the peanut-avoidance group and 46.4% of the peanut-consumption group adhered to the study protocol and avoided peanut consumption during this 12-month follow-up study. At 72 months there was a significantly higher prevalence of peanut allergy in the peanut-consumption group compared to the peanut-avoidance group (18.6% vs. 4.8%, p<0.001). Furthermore, at the endpoint, 19.2% of the participants in the peanut-avoidance group had peanut allergy and 2.1% of those in the peanut-consumption group had peanut allergy (p<0.001). Peanut-avoidance group reported more adverse events during the follow-up study than the peanut-consumption group (89.4% vs. 80.7%).

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