Background The HealthNuts study previously reported interim prevalence data showing the highest prevalence of challenge-confirmed food allergy in infants internationally. However, population-derived ...prevalence data on challenge-confirmed food allergy and other allergic diseases in preschool-aged children remain sparse. Objective This study aimed to report the updated prevalence of food allergy at age 1 year from the whole cohort, and to report the prevalence of food allergy, asthma, eczema, and allergic rhinitis at age 4 years. Methods HealthNuts is a population-based cohort study with baseline recruitment of 5276 one-year-old children who underwent skin prick test (SPT) to 4 food allergens and those with detectable SPT results had formal food challenges. At age 4 years, parents completed a questionnaire (81.3% completed) and those who previously attended the HealthNuts clinic at age 1 year or reported symptoms of a new food allergy were invited for an assessment that included SPT and oral food challenges. Data on asthma, eczema, and allergic rhinitis were captured by validated International Study of Asthma and Allergies in Childhood questionnaires. Results The prevalence of challenge-confirmed food allergy at age 1 and 4 years was 11.0% and 3.8%, respectively. At age 4 years, peanut allergy prevalence was 1.9% (95% CI, 1.6% to 2.3%), egg allergy was 1.2% (95% CI, 0.9% to 1.6%), and sesame allergy was 0.4% (95% CI, 0.3% to 0.6%). Late-onset peanut allergy at age 4 years was rare (0.2%). The prevalence of current asthma was 10.8% (95% CI, 9.7% to 12.1%), current eczema was 16.0% (95% CI, 14.7% to 17.4%), and current allergic rhinitis was 8.3% (95% CI, 7.2% to 9.4%). Forty percent to 50% of this population-based cohort experienced symptoms of an allergic disease in the first 4 years of their life. Conclusions Although the prevalence of food allergy decreased between age 1 year and age 4 years in this population-based cohort, the prevalence of any allergic disease among 4-year-old children in Melbourne, Australia, is remarkably high.
Increasing the accuracy of peanut allergy diagnosis by using Ara h 2 Dang, Thanh D., BBiomedSc (Hons); Tang, Mimi, MBBS, PhD, FRACP, FRCPA, FAAAAI; Choo, Sharon, MBBS, FRACP, FRCPA ...
Journal of allergy and clinical immunology,
04/2012, Letnik:
129, Številka:
4
Journal Article
Recenzirano
Odprti dostop
Background Measurement of whole peanut-specific IgE (sIgE) is often used to confirm sensitization but does not reliably predict allergy. Ara h 2 is the dominant peanut allergen detected in 90% to ...100% of patients with peanut allergy and could help improve diagnosis. Objectives We sought to determine whether Ara h 2 testing might improve the accuracy of diagnosing peanut allergy and therefore circumvent the need for an oral food challenge (OFC). Methods Infants from the population-based HealthNuts study underwent skin prick tests to determine peanut sensitization and subsequently underwent a peanut OFC to confirm allergy status. In a stratified random sample of 200 infants (100 with peanut allergy and 100 with peanut tolerance), whole peanut sIgE and Ara h 2 sIgE levels were quantified by using fluorescence enzyme immunoassay. Results By using the previously published 95% positive predictive value of 15 kUA /L for whole peanut sIgE, a corresponding specificity of 98% (95% CI, 93% to 100%) was found in this study cohort. At the equivalent specificity of 98%, the sensitivity of Ara h 2 sIgE is 60% (95% CI, 50% to 70%), correctly identifying 60% of subjects with true peanut allergy compared with only 26% correctly identified by using whole peanut sIgE. We report that when using a combined approach of plasma sIgE testing for whole peanut followed by Ara h 2 for the diagnosis of peanut allergy, the number of OFCs required is reduced by almost two thirds. Conclusion Ara h 2 plasma sIgE test levels provide higher diagnostic accuracy than whole peanut plasma sIgE levels and could be considered a new diagnostic tool to distinguish peanut allergy from peanut tolerance, which might reduce the need for an OFC.
Background Several indicators suggest that food allergy in infants is common and possibly increasing. Few studies have used oral food challenge to measure this phenomenon at the population level. ...Objective To measure the prevalence of common IgE-mediated childhood food allergies in a population-based sample of 12-month-old infants by using predetermined food challenge criteria to measure outcomes. Methods A sampling frame was used to select recruitment areas to attain a representative population base. Recruitment occurred at childhood immunization sessions in Melbourne, Australia. Infants underwent skin prick testing, and those with any sensitization (wheal size ≥1 mm) to 1 or more foods (raw egg, peanut, sesame, shellfish, or cow's milk) were invited to attend an allergy research clinic. Those who registered a wheal size ≥1 mm to raw egg, peanut, or sesame underwent oral food challenge. Results Amongst 2848 infants (73% participation rate), the prevalence of any sensitization to peanut was 8.9% (95% CI, 7.9-10.0); raw egg white, 16.5% (95% CI, 15.1-17.9); sesame, 2.5% (95% CI, 2.0-3.1); cow's milk, 5.6% (95% CI, 3.2-8.0); and shellfish, 0.9% (95% CI, 0.6-1.5). The prevalence of challenge-proven peanut allergy was 3.0% (95% CI, 2.4-3.8); raw egg allergy, 8.9% (95% CI, 7.8-10.0); and sesame allergy, 0.8% (95% CI, 0.5-1.1). Oral food challenges to cow's milk and shellfish were not performed. Of those with raw egg allergy, 80.3% could tolerate baked egg. Conclusion More than 10% of 1-year-old infants had challenge-proven IgE-mediated food allergy to one of the common allergenic foods of infancy. The high prevalence of allergic disease in Australia requires further investigation and may be related to modifiable environmental factors.
Background Infant feeding guidelines have long recommended delaying introduction of solids and allergenic foods to prevent allergy in high-risk infants, despite a paucity of evidence. Objective We ...aimed to determine whether confirmed egg allergy in 12-month-old infants is associated with (1) duration of breast-feeding and (2) ages of introducing egg and solids. Methods In a population-based cross-sectional study (HealthNuts) parents reported on infant feeding and potential confounding factors before skin prick testing for egg white. Egg-sensitized infants were then offered an egg oral food challenge. Multiple logistic regression was used to investigate associations between diet and egg allergy adjusted for possible confounding factors. Results A total of 2589 infants (73% response) participated. Compared with introduction at 4 to 6 months, introducing egg into the diet later was associated with higher risks of egg allergy (adjusted odds ratios ORs, 1.6 95% CI, 1.0-2.6 and 3.4 95% CI, 1.8-6.5 for introduction at 10-12 and after 12 months, respectively). These findings persisted even in children without risk factors (OR, 3.3 95% CI, 1.1-9.9; 10-12 months). At age 4 to 6 months, first exposure as cooked egg reduced the risk of egg allergy compared with first exposure as egg in baked goods (OR, 0.2 95% CI, 0.06-0.71). Duration of breast-feeding and age at introduction of solids were not associated with egg allergy. Conclusions Introduction of cooked egg at 4 to 6 months of age might protect against egg allergy. Changes in infant feeding guidelines could have a significant effect on childhood egg allergy and possibly food allergy more generally.
Background There is a paucity of data examining the natural history of and risk factors for egg allergy persistence, the most common IgE-mediated food allergy in infants. Objective We aimed to assess ...the natural history of egg allergy and identify clinical predictors for persistent egg allergy in a population-based cohort. Methods The HealthNuts study is a prospective, population-based cohort study of 5276 infants who underwent skin prick tests to 4 allergens, including egg. Infants with a detectable wheal were offered hospital-based oral food challenges (OFCs) to egg, irrespective of skin prick test wheal sizes. Infants with challenge-confirmed raw egg allergy were offered baked egg OFCs at age 1 year and follow-up at age 2 years, with repeat OFCs to raw egg. Results One hundred forty infants with challenge-confirmed egg allergy at age 1 year participated in the follow-up. Egg allergy resolved in 66 (47%) infants (95% CI, 37% to 56%) by 2 years of age; however, resolution was lower in children with baked egg allergy at age 1 year compared with baked egg tolerance (13% and 56%, respectively; adjusted odds ratio, 5.27; 95% CI, 1.36-20.50; P = .02). In the subgroup of infants who were tolerant to baked egg at age 1 year, frequent ingestion of baked egg (≥5 times per month) compared with infrequent ingestion (0-4 times per month) increased the likelihood of tolerance (adjusted odds ratio, 3.52; 95% CI, 1.38-8.98; P = .009). Mutation in the filaggrin gene was not associated with the resolution of either egg allergy or egg sensitization at age 2 years. Conclusion Phenotyping of egg allergy (baked egg tolerant vs allergic) should be considered in the management of this allergy because it has prognostic implications and eases dietary restrictions. Randomized controlled trials for egg oral immunotherapy should consider stratifying at baseline by the baked egg subphenotype to account for the differential rate of tolerance development.
To the Editor: Oral food challenges (OFCs) remain the gold standard for diagnosing food allergy.1 However, to date, most studies describing the use of OFCs for the purposes of diagnosing food allergy ...have been retrospective clinical audits that have not clearly described crucial methodological characteristics, such as eligibility for challenge and exclusion and inclusion criteria.2,3 Study outcomes from these retrospective audits are difficult to generalize to other clinic or population cohorts because undeclared physician and parent selection bias is likely to significantly affect the inclusion or exclusion of, for instance, a child with a history of anaphylaxis. ...we thank ALK-Abelló, Spain, for donating food allergens for skin prick tests.
Background It is unknown whether population infant feeding practices have changed since recently revised Australian allergy guidelines removed recommendations to delay allergenic solids. Objectives ...We sought to determine whether updated 2008 guidelines were associated with changes in feeding practice and to determine whether sociodemographic factors influenced this response. Methods In a population-based, cross-sectional study (HealthNuts) of 5276 infants recruited between 2007 and 2011 in Melbourne, Australia, parents reported on infant feeding practices. Multinomial logistic regression was used to investigate the associations between recruitment year and feeding practices and whether these associations were modified by sociodemographic factors. Results Compared with participants recruited in 2007-2009, those recruited in 2009-2011 were more likely to introduce solids at age 4 months (adjusted multinomial odds ratio aMOR, 1.21; 95% CI, 1.02-1.45; P = .032) and less likely to introduce solids at age 6 months (aMOR, 0.80; 95% CI, 0.69-0.92; P = .002), egg after 6 months (aMOR, 0.82; 95% CI, 0.71-0.94; P = .004), and peanut after 12 months (aMOR, 0.70; 95% CI, 0.49-0.98; P = .037). Although parents recruited in 2009-2011 were less likely to formula feed (aMOR, 0.84; 95% CI, 0.72-0.98; P = .023), formula-fed infants were more likely to be given a partially hydrolyzed formula (aMOR, 1.37; 95% CI, 1.12-1.70; P = .003). These changes were significantly stronger among families with a higher socioeconomic status and those without a family history of allergies. Conclusion Updated national allergy guidelines are associated with reduced delay in introduction of solids, egg, and peanut and an increase in partially hydrolyzed formula use among formula-fed infants. Higher socioeconomic status and absence of family history of allergies were associated with better uptake of feeding guidelines.
A structured questionnaire on peanut intake and reactions, peanut skin prick test (SPT) and/or double-blind placebo-controlled food challenge (cumulative 4g peanut protein after 8 weeks peanut ...elimination) were offered.
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