A comprehensive analysis of nearly 3 million participants across 40 countries has identified a cluster of risk factors significantly associated with the development of early-onset food allergies in children, researchers reported this week. The study, a systematic review and meta-analysis published in JAMA Pediatrics, points to early allergic conditions, skin barrier dysfunction, delayed introduction of allergenic foods, and early antibiotic exposure as key contributors.
The research, led by Derek Chu, MD, PhD, of McMaster University, found an overall incidence of childhood food allergy of approximately 5%, rising to 7% in the United States, based on studies utilizing oral food challenges. The findings aim to provide evidence-based guidance for clinicians and families seeking to prevent food allergies, a condition affecting more than 33 million people in the U.S. Alone.
“Before this review, no systematic, evidence-based consensus existed regarding which children are at the highest risk of developing food allergy,” explained Dr. Chu and colleagues in their published work. “That is critical for targeting prevention efforts, patient education, policymaking, and future research.”
The analysis highlighted several factors with a high degree of certainty. Children with atopic dermatitis (eczema) within their first year of life showed a 3.88-fold increased odds of developing a food allergy, representing a 12% increase in risk. Similarly, high transepidermal water loss (TEWL), indicating a compromised skin barrier, was associated with a 3.36-fold increase in odds, and a 10% increase in risk. Genetic variations in the filaggrin gene were also identified as a significant risk factor, with a 1.93-fold increase in odds and a 4.2% increase in risk.
The timing of food introduction also proved crucial. Delaying the introduction of peanut beyond 12 months of age was linked to a 2.55-fold increase in odds, and a 6.8% increase in risk, with similar estimates observed for other common food allergens. Infant antibiotic leverage during the first month of life demonstrated a substantial association, with a 4.11-fold increase in odds and a 12.8% increase in risk.
Beyond these biological and environmental factors, the study also identified demographic associations. Infants who self-identified as Black and families who had recently migrated were found to be at elevated risk, though the underlying reasons for these disparities require further investigation.
Researchers emphasized that food allergy development is likely multifactorial, involving a combination of major and minor risk factors. “Rather than one dominant pathway for developing food allergy in all individuals, our findings present a multifactorial model,” the authors wrote. Other minor risk factors included being firstborn, being male, infant age, and maternal age.
The findings have implications for clinical practice, with researchers urging clinicians to prioritize early identification and management of atopic dermatitis. They also recommend avoiding unnecessary delays in introducing solid foods and allergenic foods, aligning with current guidance emphasizing introduction around 4 to 6 months when infants are developmentally ready. Resources from organizations like the American Academy of Allergy, Asthma and Immunology (AAAAI) are available to support clinicians in managing atopic dermatitis in infants.
The study authors acknowledge the need for further research, particularly large randomized trials, to refine allergy prevention strategies. They also call for better-designed studies with consistent data adjustment and harmonization to improve the interpretation of combined effects. The research team has made their work available at allergyevidence.ca.
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