Eczema, delayed allergen introduction, and early antibiotics top list of childhood food allergy risk factors

Eczema, delayed introduction of allergenic foods, and early-life antibiotic exposure are among the strongest predictors of childhood food allergy, according to a systematic review and meta-analysis of 190 studies encompassing 2.8 million children published in JAMA Pediatrics.¹ The analysis, which pooled data from 40 countries and evaluated 342 candidate risk factors, found that no single factor explains the rise in pediatric food allergy.

“Our study highlights that genetics alone cannot fully explain food allergy trends, pointing to interactions—or a ‘perfect storm’—between genes, skin health, the microbiome, and environmental exposures,” said Derek Chu, MD, PhD, senior author of the study and assistant professor in the Departments of Medicine and Health Research Methods, Evidence, and Impact at McMaster University.²

Meta-analysis design and scope in food allergy risk factor research

Investigators searched MEDLINE and Embase through January 2025 for cohort, case-control, and cross-sectional studies of children 6 years or younger, then ran random-effects meta-analyses to pool adjusted odds ratios (ORs) and calculate risk differences (RDs) for each factor.¹ Of the 190 included studies, 156 were cohort studies, 22 were case-control studies, and 12 were cross-sectional, with a median sample size of 1184 participants.¹ Risk of bias was assessed with the Quality in Prognosis Studies tool, and certainty of evidence was graded using GRADE; two-thirds of studies were judged to be at high or probably high risk of bias for at least 1 domain.¹

Key risk factors identified for childhood food allergy development

Among 176 studies reporting 342 risk factors, 38 were supported by high-certainty evidence and 69 by moderate-certainty evidence.¹ Atopic dermatitis within the first year of life carried nearly 4-fold higher odds of food allergy (OR, 3.88; RD, 12.0%; 95% CI, 8.8%-15.7%), and allergic rhinitis (OR, 3.39; RD, 10.1%) and wheeze (OR, 2.11; RD, 5.0%) showed similar patterns.¹ Markers of skin barrier dysfunction, including elevated transepidermal water loss (OR, 3.36; RD, 10.0%) and filaggrin gene loss-of-function variants (OR, 1.93; RD, 4.2%), were also linked to higher risk.¹ Delayed introduction of peanut after age 12 months nearly tripled the odds of food allergy (OR, 2.55; RD, 6.8%), while infant antibiotic use in the first month of life was associated with a 4-fold increase in odds (OR, 4.11; RD, 12.8%).¹ Demographic and birth-related factors—including male sex, firstborn status, family history of allergic disease, parental migration before birth, self-identified Black race, and cesarean delivery—each carried smaller but statistically meaningful associations.¹

Food allergy incidence and regional variation in the meta-analysis

Across 16 studies confirming diagnosis by oral food challenge, the pooled incidence of IgE-mediated food allergy by age 6 years was 4.7% (95% CI, 3.2%-6.9%), rated as moderate-certainty evidence.¹ Incidence varied by region, from an estimated 10.2% in Australia to 1.8% in Africa, a pattern the authors attribute to both genuine epidemiologic variation and differences in study methodology and health care access.¹

Clinical context: food allergy burden and prevention guidance

Food allergy affects an estimated 33 million people in the United States and can cause life-threatening anaphylaxis, yet clinicians have lacked a consensus, evidence-based framework for identifying at-risk infants.¹ The National Academies of Sciences, Engineering, and Medicine previously flagged this gap as a research and policy priority.⁴ The findings are intended to inform an evidence-based definition of high-risk populations for prevention counseling, building on existing guidance supporting early introduction of allergenic foods, particularly peanut, in infants with risk factors such as eczema.¹

Interpretation: a multifactorial model of food allergy risk

Rather than attributing risk to eczema or allergen-introduction timing alone, the authors propose that food allergy arises from the convergence of genetic, microbial, environmental, and social factors, often driven by 1 major risk factor combined with several minor contributors.¹ Migration before birth, for example, may simultaneously alter allergen exposure timing, worsen eczema, and shift the infant microbiome—illustrating how these pathways intersect rather than act independently.¹

Limitations and next steps for food allergy risk research

The authors caution that many of the 342 factors were supported only by low- or very low-certainty evidence, often from single small studies, and that inconsistent adjustment across studies limits conclusions about how identified factors interact with one another.¹ Most included studies were conducted in higher-income countries, limiting generalizability to low- and middle-income settings, and causality for most factors remains unconfirmed pending randomized trial data.¹ The investigators note that the ongoing SunBEAm birth cohort, which uses protocolized food challenges, may help close evidence gaps in modern US populations.¹

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. 2026;180(5):486-499. doi:10.1001/jamapediatrics.2025.6105

2. JAMA Network. What drives food allergies? New study pinpoints early-life factors that raise risk [news release]. EurekAlert. Published February 9, 2026. Accessed August 12, 2026. https://www.eurekalert.org/news-releases/1115635

3. McMaster University Faculty of Health Sciences. What drives food allergies? New study pinpoints early-life factors that raise risk. Published February 18, 2026. Accessed August 12, 2026. https://healthsci.mcmaster.ca/what-drives-food-allergies-new-study-pinpoints-early-life-factors-that-raise-risk/

4. National Academies of Sciences, Engineering, and Medicine; Health and Medicine Division; Food and Nutrition Board; Committee on Food Allergies. Finding a Path to Safety in Food Allergy: Assessment of the Global Burden, Causes, Prevention, Management, and Public Policy. National Academies Press; 2016.