Aiming to identify the most strongly associated risk factors. Food allergy in children can affect nutritional status, growth, and development; however, this large global review focused specifically on its incidence and early-life predictors.
Study
The review included 190 studies with 2.8 million participants across 40 countries. Incidence estimates were derived from all studies that confirmed food allergy by food challenge. Risk factor analyses focused on various types of study, including case-control and cross-sectional studies of children below the age of six years, and included studies using both food-challenge-confirmed and other physician- or history-based definitions of food allergy.
The researchers performed random-effects meta-analyses to estimate pooled incidence rates and adjusted odds ratios, and also examined absolute risk differences when available. They also evaluated the certainty of evidence and the risk of bias in each included study.
The likely pooled incidence of food allergy was 4.7%, based solely on studies that used food challenges. However, Australia had a ~10% incidence, vs ~1.8% in Africa.
The risk analysis included 176 studies, evaluating 342 risk factors for food allergy in infants and children. The level of certainty varied across factors. The following risk factors had the strongest associations and the highest certainty of evidence. These include major factors, linked to twofold or higher odds of food allergy, and minor factors, with smaller increases in odds.
Findings
Among the major risk factors related to allergic history, a prior history of wheezing or allergic rhinitis/conjunctivitis more than doubled or tripled the odds of food allergy, respectively, patterns consistent with the atopic march or diathesis. Atopic dermatitis in the first year of life was associated with a fourfold increase in odds. Higher transepidermal water loss, reflecting impaired skin barrier function, was associated with roughly a 3-fold increase in odds. Late introduction of solid foods, specifically peanuts, after 12 months of age was associated with more than twice the odds.
Regarding antibiotic exposure, systemic antibiotic use in the first month of life was associated with approximately fourfold higher odds of food allergy. Antibiotic exposure before birth was associated with about 30% higher odds, and exposure during the first year of life with about 40% higher odds.
Social and genetic factors were also strongly associated. A family history of allergy doubled the odds when the mother or both parents had food allergy, increased the odds by more than twofold when siblings were affected, and raised the odds by about 70% when the father had food allergy. Parental migration prior to the child’s birth was associated with more than a 3-fold increase in odds.
In addition, children self-reported as Black had approximately fourfold higher odds compared with White children and about twofold higher odds compared with non-Hispanic White children, although the authors note that such associations likely reflect complex social and environmental influences rather than biological race alone.
Conclusion
The study’s limitations primarily reflect those related to the existing literature. These include low-certainty evidence and the lack of uniform and/or comprehensive adjustment for confounders. This may limit risk inferences and the estimation of independent effects. These limitations emphasize the need to use birth cohorts with standardized adjustment for confounding factors.
Causality could not be established, and the studies included mostly those from developed countries, limiting their generalizability.
The current study identified the major and minor risk factors that are associated with early-life food allergy. While these findings improve risk stratification and understanding of potential pathways, they do not establish causation. This could shape preventive strategies and future research.
Source:
https://www.news-medical.net/news/20260212/Top-early-life-factors-driving-childhood-food-allergy.aspx