Determinants of Peanut Allergy in an Observational Study (CoFAR2) of Food Allergy

Sicherer, Scott

Rationale: To determine baseline demographic, clinical, and serum/skin test parameters that predict an eventual diagnosis of peanut allergy (PNA) in a cohort of 3-15 month olds with likely egg/milk allergy but no known PNA.

Methods: The primary endpoint was confirmed/convincing PNA at any time or last classified as serologic PNA (<2 yrs, ≥5 kU_A/L, otherwise ≥14 kU_A/L) among 511 participants followed to a median age of 8 years (range: 0.5-9.8). Univariable logistic regression was used to explore associations of potential factors with PNA, and factors with p<0.05 were analyzed in a stepwise multiple logistic regression (MLR) model.

Results: 203/511 (39.7%) had an eventual diagnosis of PNA. Baseline factors associated with PNA (p<0.05) included: lack of breastfeeding, atopic dermatitis, egg and peanut SPT, milk, egg, and peanut IgE, race and peanut consumption during pregnancy and breastfeeding. The stepwise model (n=490) identified three key factors (p<0.01): lack of breastfeeding, peanut SPT, and IgE. The odds of PNA decreased for those breastfeeding at enrollment (OR: 0.3, 95% CI: 0.1-0.5) or those ever breastfed (OR=0.4, 95% CI: 0.2-0.8) compared to those never breastfed. The odds of PNA increased 10% (OR=1.1, 95% CI: 1.0-1.2) for a 1 mm increase in peanut SPT wheal size, and by 70% (OR=1.7, 95% CI: 1.4-2.1) for a 10 fold increase in peanut IgE.

Conclusions: We identified a number of risk factors associated with PNA including key factors (lack of breastfeeding, peanut SPT size, peanut IgE level) via multivariable analysis that can be used for a predictive model for outcomes.