Early Introduction of Peanut Reduces Peanut Allergy Across Risk Groups in Pooled and Causal Inference Analyses

To study the effect of early peanut introduction on peanut allergy prevention by using the individual-level data from Learning Early About Peanut allergy (LEAP) and Inquiring About Tolerance (EAT) studies.

Investigators performed a pooled analysis of the population data from LEAP and EAT studies. The EAT study was composed of exclusively breastfed infants from England and Wales. Exclusion criteria included infants who were premature, who were not exclusively breastfed, or those with history of serious medical conditions. The LEAP study included 640 infants with severe eczema, egg allergy, or both who were between 4 through 11 months of age.

This study was a European Union-funded iFAAM project that included pooled data from 1943 children from the randomized control trials, LEAP and EAT studies. Data collected included evidence of sensitization, peanut allergy, family history of atopy, and demographic information. Outcomes measured included prevalence of peanut allergy by 3 years of age (EAT) and by 5 years of age (LEAP), sensitization to peanut by skin testing, or specific IgE level. Other endpoints measured included the development of eczema.

Investigators noted that 4.8% of patients were found to be allergic to peanut at 3 to 5 years of age and the intention-to-treat (ITT) analyses showed a 75% reduction in peanut allergy. Those with eczema had a higher prevalence of peanut allergy (8.7% vs 0.9%). Early peanut introduction showed a significant reduction in peanut allergy prevalence in the ITT analysis. This protective effect on peanut allergy was evident across all severities of eczema, with an 85% risk reduction in mild eczema, 87% in moderate eczema, and 67% in severe eczema. Additionally, peanut sensitization by skin prick testing was reduced at 12 months of age in the groups with early peanut introduction. There was no significant difference found between IgE levels in early introduction versus control groups. In the ITT population, those with elevated IgE to peanut, showed a 75% reduction in prevalence of peanut allergy by 3 to 5 years of age. This finding was also noted in patients without evidence of elevated IgE to peanut. A significant reduction in peanut allergy was also noted across all ethnic groups.

Significant reductions in peanut allergy were noted in the early peanut introduction groups. These reductions in peanut allergy were further seen in those with eczema regardless of severity, as well as regardless of ethnicity or history of sensitization to peanut.

Investigators pooled data from LEAP and EAT trials to assess individual-level data and noted a significant reduction in peanut allergy prevalence with early introduction, including patients with eczema, regardless of severity. Although this study shows a reduction in peanut allergies with early peanut introduction, the data of pooled analyses should be interpreted with caution, as the analysis of pooled individual data may not account for the selection criteria outlined in the different randomized control trials, possibly introducing bias in the interpretation of data.