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Determinants of Peanut Allergy in an Observational Study (CoFAR2) of Food Allergy
Sunday, March 6, 2016
South Exhibit Hall H (Convention Center)
Scott H. Sicherer, MD FAAAAI, Robert A. Wood, MD FAAAAI, Tamara T. Perry, MD, Brian P. Vickery, MD FAAAAI, Stacie M. Jones, MD, Donald Y. Leung, MD PhD FAAAAI, Beth Blackwell, PhD, Peter Dawson, PhD, A. Wesley Burks, MD FAAAAI, Robert W. Lindblad, MD, Hugh A. Sampson, MD FAAAAI
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 kUA/L, otherwise ≥14 kUA/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.