Top Risk Factors for Developing Early Childhood Food Allergy

Major and minor risk factors linked with the development of childhood food allergies were identified and clarified in a comprehensive systematic review published in JAMA Pediatrics.¹ The findings provide clinicians with evidence-based guidance for identifying at-risk populations.

“Rather than representing competing paradigms, our findings support a unifying multifactorial model in which food allergy arises from intersecting microbial, genetic, environmental, allergen exposure, and social influences, driven by a major risk factor or a combination of multiple major or minor risk factors,” the authors wrote.

The meta-analysis, which examined 190 studies involving 2.8 million participants across 40 countries, found that approximately 5% of children develop food allergies by age 6. The researchers identified both major and minor risk factors that operate through a multifactorial model rather than a single dominant cause.

Early Allergic Conditions Emerge as Strongest Predictors of Food Allergy

The strongest associations were found with early allergic conditions, often referred to as the "atopic march" or diathesis. Infants with atopic dermatitis within the first year of life showed a 12% absolute risk increase (OR, 3.88; risk difference [RD], 12%; 95% CI, 8.8%-15.7%), while allergic rhinitis (OR, 3.39; RD, 10.1%; 95% CI, 6.7%-14.4%) and early wheezing (OR, 2.11; RD, 5.0%; 95% CI, 2.1%-8.8%) also demonstrated substantial associations.

Severity of atopic dermatitis also played a significant role, with each 5- to 10-point increase on the Scoring Atopic Dermatitis scale associated with a 1% risk increase. Elevated skin transepidermal water loss showed a 10% risk difference (OR, 3.36; RD, 10.0%; 95% CI, 6.3%-14.8%), and filaggrin gene loss-of-function variations carried a 4.2% risk difference (OR, 1.93; RD, 4.2%; 95% CI, 2.4%-6.4%).

Timing of Food Introduction, Antibiotic Use Matters for Allergy Development

The study found that delayed introduction of allergenic foods significantly increased food allergy risk. Introducing peanuts after 12 months was associated with a 6.8% risk increase (OR, 2.55; RD, 6.8%; 95% CI, 1.9%-14.6%), while delayed introduction of fish, eggs, and fruits showed similar patterns.

“Subgroup analysis of incidence suggested possible but uncertain lower incidence of food allergy after early introduction guidelines were issued compared to before,” the authors noted, referring to a guideline shift following the 2015 Learning Early About Peanut Allergy (LEAP) study, which showed a significant decrease in the development of peanut allergy among high-risk infants when peanuts were introduced early.²

Antibiotic use during infancy emerged as a major modifiable risk factor, with timing appearing impactful.¹ Antibiotic exposure within the first month of life showed the strongest association (OR, 4.11; RD, 12.8%; 95% CI, 0.4%-40%), while use within the first year (OR, 1.39; RD, 1.8%; 95% CI, 0.8%-3.1%) or during pregnancy (OR, 1.32; RD, 1.5%; 95% CI, 0.6%-2.5%) showed more modest effects.

Demographic and Social Allergy Risk Factors

The analysis identified several demographic risk factors, including male sex (1.1% risk increase), firstborn status (0.6% risk increase), and family history of allergies. Children with a maternal food allergy history showed a 4.4% risk increase, while having both parents with food allergies increased risk by 4.8%.

Notably, parental migration prior to birth carried a substantial 9.7% risk increase (OR, 3.28; RD, 9.7%; 95% CI, 4.9%-16.3%), while children who identified as Black showed significantly elevated risk compared with White children (OR, 3.93; RD, 12.1%; 95% CI, 5.2%-22.5%) or non-Hispanic White children (OR, 2.23; RD, 5.5%; 95% CI, 3.0%-8.7%).

Birth-related factors showed mixed results. While cesarean delivery was associated with a modest 1% risk increase, factors such as low birth weight, postterm birth, maternal stress during pregnancy, and partial breastfeeding showed no significant risk differences.

Clinical Implications of Allergy Risk Factors

The researchers emphasized that these findings should inform clinical practice by enabling targeted prevention strategies.

The study's comprehensive approach represents the first systematic synthesis examining multiple risk factors together rather than in isolation. The authors noted that future research should focus on harmonizing birth cohorts and ensuring consistent adjustment for core risk factors to better understand how these various elements interact in food allergy development.

"By systematically quantifying and classifying both major and minor predictors, this study reconciles inconsistencies in definitions of at-risk populations for developing food allergy in clinical guidelines and trials," the authors wrote.

This evidence synthesis provides clinicians across multiple specialties—including pediatrics, allergy and immunology, family medicine, and obstetrics—with a framework for identifying high-risk infants who may benefit from targeted prevention interventions.

“The clinical implications of our findings include clarifying which children are at highest risk and therefore enabling targeted prevention strategies,” the authors concluded. “From a practice and policy standpoint, these findings support global consensus on defining high-risk infants. For researchers, the findings highlight key variables to prioritize in future randomized clinical trials and mechanistic studies, helping refine study design and improve intervention development.”

References

1. Islam N, Chu AWL, Sheriff F, et al. Risk factors for the development of food allergy in infants and children: a systematic review and meta-analysis. JAMA Pediatr. Published online February 9, 2026. doi:10.1001/jamapediatrics.2025.6105

2. Du Toit G, Roberts G, Sayre PH, et al. Randomized trial of peanut consumption in infants at risk for peanut allergy. N Engl J Med. 2015;372(9):803-813. doi:10.1056/NEJMoa1414850