The Prevalence of Food Sensitization Appears Not to Have Changed between 2 Melbourne Cohorts of High-Risk Infants Recruited 15 Years Apart

BACKGROUND: Although food allergy has probably risen over recent decades, recent reports suggest that the prevalence of food sensitization in the general population has not changed. However, this has not been analyzed in infants at high risk of food allergy. OBJECTIVE: The objective of this study was to compare the prevalence of food sensitization in high-risk infants from 2 cohorts recruited 15 years apart in the same region. METHODS: This study includes 620 high-risk infants with a family history of allergy (Melbourne Atopy Cohort Study [MACS]) born 1990-1994, and a subgroup of high-risk infants from the population-based HealthNuts study (n = 3,661/5,276), born 2006-2010. Both studies undertook skin prick tests (SPT) to peanut, egg, and milk at age 12 months. A logistic regression model generated adjusted prevalences to account for differences in sampling frame. SPT >= 95% positive predictive values (PPVs) for food allergy were used as proxies for food allergy. RESULTS: The adjusted prevalence of sensitization in MACS was similar to the observed prevalence of sensitization in the high-risk subgroup of HealthNuts: 7.9% (95% confidence interval 6.8-8.9) and 7.9% (7.0-8.8) respectively for peanut, 15.0% (13.4-16.6) and 14.5% (13.4-15.7) respectively for egg, and 2.4% (1.6-3.1) and 2.6% (2.0-3.4) respectively for cow's milk. The prevalence of SPT >= 95% PPVs was similar between the 2 studies. CONCLUSIONS: The prevalence of food sensitization among high-risk infants has remained stable in Australia since the 1990s, despite the reported increase in food-related anaphylaxis in the same period. This discrepancy could be due to increased food allergy in the low-risk population, increased conversion of food sensitization to allergy, or increased number of high-risk infants. Alternatively, increased awareness or severity of reactions may have led to an apparent increase in food allergy. (C) 2017 American Academy of Allergy, Asthma & Immunology