Randomized clinical trials showed that earlier peanut introduction can prevent peanut allergy in select high-risk populations. This led to changes in infant feeding guidelines in 2016 to recommend ...early peanut introduction for all infants to reduce the risk of peanut allergy.
To measure the change in population prevalence of peanut allergy in infants after the introduction of these new guidelines and evaluate the association between early peanut introduction and peanut allergy.
Two population-based cross-sectional samples of infants aged 12 months were recruited 10 years apart using the same sampling frame and methods to allow comparison of changes over time. Infants were recruited from immunization centers around Melbourne, Australia. Infants attending their 12-month immunization visit were eligible to participate (eligible age range, 11-15 months), regardless of history of peanut exposure or allergy history.
Questionnaires collected data on demographics, food allergy risk factors, peanut introduction, and reactions.
All infants underwent skin prick tests to peanut and those with positive results underwent oral food challenges. Prevalence estimates were standardized to account for changes in population demographics over time.
This study included 7209 infants (1933 in 2018-2019 and 5276 in 2007-2011). Of the participants in the older vs more recent cohort, 51.8% vs 50.8% were male; median (IQR) ages were 12.5 (12.2-13.0) months vs 12.4 (12.2-12.9) months. There was an increase in infants of East Asian ancestry over time (16.5% in 2018-2019 vs 10.5% in 2007-2011), which is a food allergy risk factor. After standardizing for infant ancestry and other demographics changes, peanut allergy prevalence was 2.6% (95% CI, 1.8%-3.4%) in 2018-2019, compared with 3.1% in 2007-2011 (difference, -0.5% 95% CI, -1.4% to 0.4%; P = .26). Earlier age of peanut introduction was significantly associated with a lower risk of peanut allergy among infants of Australian ancestry in 2018-2019 (age 12 months compared with age 6 months or younger: adjusted odds ratio, 0.08 05% CI, 0.02-0.36; age 12 months compared with 7 to less than 10 months: adjusted odds ratio, 0.09 95% CI, 0.02-0.53), but not significant among infants of East Asian ancestry (P for interaction = .002).
In cross-sectional analyses, introduction of a guideline recommending early peanut introduction in Australia was not associated with a statistically significant lower or higher prevalence of peanut allergy across the population.
Background A recent randomized trial (the Learning Early About Peanut Allergy LEAP study) provided evidence that earlier dietary peanut introduction reduces peanut allergy prevalence in high-risk ...infants. However, questions remain as to how to identify and target the “at-risk” population to facilitate timely introduction of peanut. Objective We sought to use population-based infant peanut allergy data to understand feasibility and implications of implementing the LEAP trial intervention. Methods Using the HealthNuts study cohort (n = 5276) of 1-year-old infants, we explored the impact of using various criteria to identify infants at high risk of developing peanut allergy, and the implications of skin prick test (SPT) screening before peanut introduction. Results Screening all infants with early onset eczema and/or egg allergy could require testing 16% of the population and would still miss 23% of peanut allergy cases; 29% of screened infants would require clinical follow-up because of being SPT-positive. Around 11% of high-risk infants were excluded from the LEAP study because of an SPT wheal size of more than 4 mm to peanut at baseline; data from the HealthNuts study suggest that 80% of these would be peanut allergic on food challenge. There were no life-threatening events among either low- or high-risk infants whose parents chose to introduce peanut at home in the first year of life, or in 150 peanut-allergic infants during hospital-based challenges. Conclusions Based on this large epidemiological study, a population program aiming to identify and screen all infants at risk of peanut allergy would pose major cost and logistic challenges that need to be carefully considered. Further research might be required to provide data for low-risk infants.
Randomized controlled trials demonstrate that timely introduction of peanut to infants reduces the risk of peanut allergy. However, much debate remains regarding how to best achieve earlier peanut ...introduction at the population level. Our previous study in 2007-2011 (HealthNuts, n = 5300) indicated that few infants were consuming peanut in the first year. Australian infant feeding guidelines were updated in 2016 to recommend introducing peanut before 12 months for all infants. There were no data available on the subsequent effect on peanut introduction or peanut reactions.
We sought to assess the consequences of a nonscreening approach to allergenic food introduction in a population-based sample of infants in their first year of life.
EarlyNuts is a population-based, cross-sectional study of 12-month-old infants in Melbourne, Australia, recruited by using an identical sampling frame and methods to HealthNuts (72% response rate vs 73% response rate in HealthNuts). We report here on the first 860 participants recruited between November 2016 and October 2018.
Most infants (88.6%; 95% CI, 86.1% to 90.7%) had introduced peanut by 12 months (median age, 6 months), an increase from 28.4% (95% CI, 27.2% to 29.7%) in the HealthNuts study. By 12 months, the majority of these (76.4%) had consumed peanut more than 4 times, and 28% were eating peanut more than once per week. Preliminary results on parent-reported reactions show that 4.0% of those consuming peanut by 12 months had possible IgE-mediated reactions.
There has been a striking shift toward earlier peanut introduction, with a 3-fold increase in peanut introduction by age 1 year in 2018 compared with 2007-2011.
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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.
In this paper, we present simple demonstrations aimed at explaining the fundamental principles of the photoacoustic effect. To display the audible phenomenon that occurs as laser radiation gets ...absorbed by ethene gas, an optical chopper was used to modulate the power of a continuous-wave laser whose beam was directed into a gas. The absorbed pulses of laser light resulted in time, harmonic, temperature, and pressure perturbations that excited the resonator, eliciting an acoustic response at its fundamental resonance frequency and harmonics. Multiple variables were changed to determine their effect on the photoacoustic signal and to replicate similar factors that influence the tones produced by musical instruments. Videos of the oscilloscope were recorded for various musical notes and then assembled into a combined demonstration video. This demonstration can be used to generate greater interest in the sciences as well as explain fundamental concepts that are at work in this experiment to students. The results of the student survey in General Chemistry 2 lectures show that the demonstration videos were useful resources.
Background Ninety-five percent positive predictive values (PPVs) provide an invaluable tool for clinicians to avoid unnecessary oral food challenges. However, 95% PPVs specific to infants, the age ...group most likely to present for diagnosis of food allergy, are limited. Objective We sought to develop skin prick test (SPT) and allergen-specific IgE (sIgE) thresholds with 95% PPVs for challenge-confirmed food allergy in a large population-based cohort of 1-year-old infants with challenges undertaken irrespective of SPT wheal size or previous history of ingestion. Methods HealthNuts is a population-based, longitudinal food allergy study with baseline recruitment of 1-year-old infants. Infants were recruited from council-run immunization sessions during which they underwent SPTs to 4 allergens: egg, peanut, sesame, and cow’s milk/shrimp. Any infant with a detectable SPT response was invited to undergo oral food challenge and sIgE testing. Results Five thousand two hundred seventy-six infants participated in the study. Peanut SPT responses of 8 mm or greater (95% CI, 7-9 mm), egg SPT responses of 4 mm or greater (95% CI, 3-5 mm), and sesame SPT responses of 8 mm or greater (95% CI, 5-9 mm) had 95% PPVs for challenge-proved food allergy. Peanut sIgE levels of 34 kUA /L or greater (95% CI, 14-48 kUA /L) and egg sIgE levels of 1.7 kUA /L or greater (95% CI, 1-3 kUA /L) had 95% PPVs for challenge-proved food allergy. Results were robust when stratified on established risk factors for food allergy. Egg SPT responses and sIgE levels were poor predictors of allergy to egg in baked goods. Conclusion These 95% PPVs, which were generated from a unique dataset, are valuable for the diagnosis of food allergy in young infants and were robust when stratified across a number of different risk factors.
Background
IgE‐mediated egg allergy presents as one of the most common food allergies in children. Measurement of egg white specific IgE (sIgE) levels in serum or skin prick test has been shown to be ...a poor predictor of clinical allergy to raw egg white, and also to baked or cooked egg. Recent developments in component resolved diagnostic (CRD) technology have enabled us to improve the way in which we diagnose and predict peanut allergy by examining IgE specificity to individual peptides.
Objectives
We aimed to investigate whether egg CRD could improve current methods to diagnose various egg allergy phenotypes as well as predict the development of tolerance to egg.
Methods
Using the HealthNuts cohort of food challenge‐proven egg allergic and egg‐sensitized and egg‐tolerant, age‐matched 12‐month infants with longitudinal follow‐up at 2 and 4 years (n = 451), we measured serum egg white, Gal d 1, 2, 3 and 5 sIgE using ImmunoCAP.
Results
Gal d 1 sensitization increased the risk of persistent egg allergy by 2.5‐fold. The production of sIgE to all four egg allergens (Gal d 1, 2, 3 or 5) increased the risk of having persistent raw egg allergy fourfold (OR 4.19 (95% CI: 1.25‐14.07). We did not find any improvements of using Gal d 1, 2, 3 or 5 to diagnose current egg allergy compared to egg white sIgE.
Conclusion
Sensitization to multiple egg allergens Gal d 1, 2, 3 or 5 may be a prognostic marker that could be useful for patient management and identifying individuals at risk of developing persistent egg allergy.
Sensitisation to Gal d 1 increases the risk of persistent egg allergy later in life (OR 2.5). Sensitisation to any of the 3 or 4 major egg allergens Gal d 1, 2, 3 or 5, increases the risk of persistent egg allergy (OR 4.19). The use of egg CRD does not improve the accuracy of egg allergy diagnosis compared to current whole egg sIgE 95% PPV.
IgE-mediated peanut allergic is common, often serious, and usually lifelong. Not all individuals who produce peanut-specific IgE will react upon consumption of peanut and can eat the food without ...adverse reactions, known as sensitized tolerance. Here, we employ high-dimensional mass cytometry to define the circulating immune cell signatures associated with sensitized tolerance and clinical allergy to peanut in the first year of life. Key features of clinical peanut allergic are increased frequency of activated B cells (CD19
HLADR
), overproduction of TNFα and increased frequency of peanut-specific memory CD4 T cells. Infants with sensitized tolerance display reduced frequency but hyper-responsive naive CD4 T cells and an increased frequency of plasmacytoid dendritic cells. This work demonstrates the utility and power of high-dimensional mass cytometry analysis to interrogate the cellular interactions that are associated with allergic sensitization and clinical food allergy in the first year of life.
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