Consumption of Peanut Products During Infancy May Reduce the Incidence of Peanut Allergy Compared to Peanut Avoidance in High Risk Children

EBM Focus - Volume 10, Issue 9

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Reference: LEAP Trial (N Engl J Med 2015 Feb 26;372(9):803) (level 2 [mid-level] evidence)

Peanut allergies in children are on the rise world-wide, with an increase in self-reported childhood peanut allergies in the United States from 0.4% in 1997 to 1.4% in 2008 (World Allergy Organ J 2013 Dec 4;6(1):21, J Allergy Clin Immunol 2010 Jun;125(6):1322). In 2000, the American Academy of Pediatrics recommended excluding peanuts from the diets of pregnant and nursing mothers of infants at high risk for developing allergies and excluding peanuts from the child’s diet until 3 years of age (Pediatrics 2000 Aug;106(2 Pt 1):346). This recommendation was removed in 2008, however, with the increasing prevalence of peanut allergies and new studies finding elimination of food allergens from diet did not prevent the development of food allergies (Pediatrics 2008 Jan;121(1):183, N Engl J Med 2003 Mar 13;348(11):977, Pediatrics 2006 Feb;117(2):401), but the questions surrounding timing of food introduction for the prevention of food allergies remain. A recent randomized trial of 640 infants aged 4-11 months at high risk for developing allergies compared peanut consumption vs. peanut avoidance until age 60 months. High risk infants were defined as those with severe eczema, egg allergy, or both.

Prior to randomization, all infants were tested for peanut allergy by skin-prick test and stratified into groups based wheal size. Infants with no measurable wheal (negative) or a 1-4 mm wheal diameter (positive) were randomized, while infants with a wheal diameter > 4 mm were excluded for safety reasons. All infants randomized to peanut consumption were given a baseline unblinded food challenge. Seven infants with a positive food challenge were instructed to avoid peanut products, but were included in peanut consumption group in the intention-to-treat analysis. All other infants with a negative baseline food challenge received at least 6 g of peanut protein (Bamba snack or smooth peanut butter) divided across at least 3 meals each week. Peanut allergy was assessed at 60 months by oral food challenge.

The intention-to-treat analysis included 98% of randomized infants and results are shown in the table below. The table also shows the analysis by baseline stratification of skin-prick test results. There were no significant differences in hospitalization rates or adverse events between groups.

This trial suggests that early peanut consumption may decrease the development of peanut allergies in high risk children and moreover the length of this study provides particularly compelling evidence that the reduced risk of allergy is not a transient effect. These results highlight the importance of basing clinical recommendations on evidence from clinical trials whenever possible, since clinical outcomes have often proven to be counter-intuitive. Further studies are required to determine if early peanut exposure would prevent the development of peanut allergies in low-risk children showing early peanut sensitization on skin-prick test or if these results could be generalized to other common food allergens.

For more information, see the Food allergy topic in DynaMed.


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