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Background: In regions with a high prevalence of peanut allergy (PA), there is a consensus that the introduction of peanuts in early infancy is preventive against the development of PA. However, few studies have investigated whether the introduction of peanuts to infants is associated with PA in regions with a low prevalence of PA, including Japan. Methods: We used data from 74,240 mother--child pairs who participated in the Japan Environment and Children's Study, a prospective birth cohort recruited between January 2011 and March 2014. A logistic regression model was used to analyze the association between infantile peanut introduction and PA at the age of 4 years with non-infantile peanut introduction as the reference group, adjusted for potential confounders. Results: The percentage of infantile peanut introduction was 4.9% (n = 3,294), and 286 (0.4%) participants had allergic symptoms to peanuts at 4 years of age. Of all participants, 129 (0.2%) had PA at 4 years of age, which was defined as allergic symptoms and sensitization to peanuts. Those with infantile peanut introduction had a lower prevalence of PA than those without infantile peanut introduction, although this did not reach statistical significance (adjusted odds ratio 0.53; 95% confidence interval, 0.17-1.68). Sensitivity analysis using IgE-mediated symptoms caused by peanuts as the outcome showed a similar result in relation to infantile peanut introduction. Conclusion: In countries with a low prevalence of PA, the effect of infantile peanut introduction on PA prevention was unclear. [ABSTRACT FROM AUTHOR]

The apparent increase in atopic disease, particularly food allergy, over the past 2 decades has resulted in reconsideration of prevention strategies aimed at the infant’s diet. Early advice to have atopy-prone infants delay ingestion of potential food allergens, such as egg, cow’s milk, and peanut, was rescinded, as new evidence emerged that did not support these approaches. More recently, randomized controlled trials have provided data to support an opposite strategy, promoting early ingestion of allergens as a means of food allergy prevention. Specifically, new guidelines suggest early ingestion of peanut as a means to prevent peanut allergy. Additional dietary approaches regarding breastfeeding, early introduction of other types of food allergens, formula feeding, dietary nutrients, and probiotics are also under scrutiny as potential preventative strategies. This review focuses on the timing of food introduction as a preventative strategy for food allergy and also discusses other aspects of the infant diet that may provide opportunities for prevention of atopic disease. [ABSTRACT FROM AUTHOR]

Background Peanut allergy is one of the most severe food allergies. Whether breastfeeding induces tolerance to peanuts or on the contrary, pre-disposes at risk-babies to occult allergic sensitization to peanuts is still a matter of discussion. We sought to investigate the transfer of the most potent peanut allergen Ara h 2 into human breast milk in a German breast milk study and to shed light on the time kinetics of Ara h 2 appearance. Methods We recruited 32 lactating, non-peanut-allergic women and collected breast milk samples at different time points after consumption of 100 g dry roasted peanuts. Breast milk samples were investigated for Ara h 2 with different immunological methods: by 2D immunoblotting with a patient's serum, by affinity enrichment using a monoclonal antibody against Ara h 2 followed by LC- MS/ MS-based detection and by a competitive inhibition ELISA for the detection of Ara h 2 and its digestion-resistant peptides ( DRP-Ara h 2). Results In a qualitative analysis, Ara h 2 could be identified in a breast milk sample by 2D immunoblot by means of a patient's serum and furthermore by immunoaffinity enrichment followed by LC- MS/ MS analysis. In a semi-quantitative analysis, Ara h 2 and its digestion-resistant peptides were detected in the breast milk of 9 of 32 subjects. Evidence suggests that Ara h 2 is excreted individually either rapidly (after 1, 2, 3 or 4 h) or delayed (after 8 or 12 h) and in different concentrations. Conclusions Time and concentration of secreted Ara h 2 in breast milk appears to be individually regulated. The identification of Ara h 2 in breast milk is the prerequisite for the investigation of its sensitizing or tolerogenic properties. [ABSTRACT FROM AUTHOR]

Background Asian infants born in Australia are three times more likely to develop nut allergy than non-Asian infants, and rates of challenge-proven food allergy in infants have been found to be unexpectedly high in metropolitan Melbourne. To further investigate the risk factors for nut allergy, we assessed the whole-of-state prevalence distribution of parent-reported nut allergy in 5-year-old children entering school. Methods Using the 2010 School Entrant Health Questionnaire administered to all 5-year-old children in Victoria, Australia, we assessed the prevalence of parent-reported nut allergy (tree nut and peanut) and whether this was altered by region of residence, socio-economic status, country of birth or history of migration. Prevalence was calculated as observed proportion with 95% confidence intervals ( CI). Risk factors were evaluated using multivariable logistic regression and adjusted for appropriate confounders. Results Parent-reported nut allergy prevalence was 3.1% (95% CI 2.9-3.2) amongst a cohort of nearly 60 000 children. It was more common amongst children of mothers with higher education and socio-economic index and less prevalent amongst children in regional Victoria than in Melbourne. While children born in Australia to Asian-born mothers ( aOR 2.67, 95% CI 2.28-3.27) were more likely to have nut allergy than non-Asian children, children born in Asia who subsequently migrated to Australia were at decreased risk of nut allergy ( aOR 0.1, 95% CI 0.03-0.31). Conclusion Migration from Asia after the early infant period appears protective for the development of nut allergy. Additionally, rural regions have lower rates of nut allergy than urban areas. [ABSTRACT FROM AUTHOR]

The LEAP randomized controlled trial provides the first direct evidence that delayed introduction of peanut in an infant's diet significantly increases the risk of peanut allergy. However, as often is the case in ground-breaking research, the LEAP study raises almost as many questions as it resolves. Although the quality of design and excellence in study execution is unquestioned, the particular difficulty this study raises is how to generalize results from a trial of high-risk infants, which screened infants for the presence of peanut allergy prior to peanut introduction, to the general population. Although many existing infant feeding guidelines already allow for the introduction of allergenic foods from 4 to 6 months of age irrespective of co-existent risk factors for peanut allergy, these will now need to be revised to more strongly state that avoidance may be harmful. Interim guidelines have already been published which incorporate these recommendations. However, the question as to how to achieve timely introduction of peanut into an infant's diet in a safe and cost-effective way, particularly in high-risk infants, remains unresolved. [ABSTRACT FROM AUTHOR]

Background: Asian infants appear to be over-represented among patients with clinical food allergy in Australia, but this has not been formally examined at the population level. Any difference in prevalence according to parental country of birth may be secondary to modifiable lifestyle factors. We aimed to quantify (i) differences in the prevalence of peanut allergy by parental country of birth and (ii) contribution of measured environmental exposures to these differences. Methods: The population-based HealthNuts study in Melbourne, Australia, screened 5276 infants (74% participation) with skin prick tests and sensitized infants underwent food challenge. Of these, 535 had a parent born in East Asia and 574 in UK/Europe. Associations between parents' country of birth and offspring peanut allergy were examined using multiple logistic regression. Results: Compared to infants with two Australian-born parents, peanut allergy was more common among infants with parent/s born in East Asia (OR 3.4, 95% CI 2.2-5.1) but not those with parent/s born in the UK/Europe (OR 0.8, 95% CI 0.4-1.5). Paradoxically rates of allergic disease were lower among Asian parents. A higher prevalence of eczema among infants of Asian parents explained around 30% of the increase in peanut allergy, while differences in dog ownership explained around 18%. Conclusions: The high peanut allergy prevalence among infants of Asian-born parents appears to have occurred in a single generation and was not present among infants with parents migrating from other countries, suggesting gene-environment interactions are important. The role of eczema and microbial exposure in food allergy prevention warrants exploration. [ABSTRACT FROM AUTHOR]

Background The incidence of hospital admissions for food allergy-related anaphylaxis in Australia has increased, in line with world-wide trends. However, a valid measure of food allergy prevalence and risk factor data from a population-based study is still lacking. Objective To describe the study design and methods used to recruit infants from a population for skin prick testing and oral food challenges, and the use of preliminary data to investigate the extent to which the study sample is representative of the target population. Methods The study sampling frame design comprises 12-month-old infants presenting for routine scheduled vaccination at immunization clinics in Melbourne, Australia. We compared demographic features of participating families to population summary statistics from the Victorian Perinatal census database, and administered a survey to those non-responders who chose not to participate in the study. Results Study design proved acceptable to the community with good uptake (response rate 73.4%), with 2171 participants recruited. Demographic information on the study population mirrored the Victorian population with most the population parameters measured falling within our confidence intervals (CI). Use of a non-responder questionnaire revealed that a higher proportion of infants who declined to participate (non-responders) were already eating and tolerating peanuts, than those agreeing to participate (54.4%; 95% CI 50.8, 58.0 vs. 27.4%; 95% CI 25.5, 29.3 among participants). Conclusion A high proportion of individuals approached in a community setting participated in a food allergy study. The study population differed from the eligible sample in relation to family history of allergy and prior consumption and peanut tolerance, providing some insights into the internal validity of the sample. The study exhibited external validity on general demographics to all births in Victoria. Cite this as: N. J. Osborne, J. J. Koplin, P. E. Martin, L. C. Gurrin, L. Thiele, M. L. Tang, A.-L. Ponsonby, S. C. Dharmage, K. J. Allen for the HealthNuts Study Investigators, Clinical & Experimental Allergy, 2010 (40) 1516–1522. [ABSTRACT FROM AUTHOR]

This JAMA Clinical Guidelines Synopsis summarizes the 2016 National Institute of Allergy and Infectious Diseases guideline on peanut allergy prevention among infants. [ABSTRACT FROM AUTHOR]

The author comments on a single-center study by G. Du Toit and colleagues, published in the "New England Journal of Medicine" about the risk for peanut allergy among infants. Topics discussed include the study of infants with egg allergy or eczema, the increase in the prevalence of peanut allergy among children, and the recommendation that mothers exclude peanuts from their food during pregnancy and breastfeeding.

Background: Epidemiological evidence has shown that pediatric food allergy is more prevalent in regions further from the equator, suggesting that vitamin D insufficiency may play a role in this disease. Objective: To investigate the role of vitamin D status in infantile food allergy. Methods: A population sample of 5276 one-year-old infants underwent skin prick testing to peanut, egg, sesame, and cow’s milk or shrimp. All those with a detectable wheal and a random sample of participants with negative skin prick test results attended a hospital-based food challenge clinic. Blood samples were available for 577 infants (344 with challenge-proven food allergy, 74 sensitized but tolerant to food challenge, 159 negative on skin prick test and food challenge). Serum 25-hydroxyvitamin D levels were measured by using liquid chromatography tandem mass spectrometry. Associations between serum 25-hydroxyvitamin D and food allergy were examined by using multiple logistic regression, adjusting for potential risk and confounding factors. Results: Infants of Australian-born parents, but not of parents born overseas, with vitamin D insufficiency (≤50 nmol/L) were more likely to be peanut (adjusted odds ratio [aOR], 11.51; 95% CI, 2.01-65.79; P = .006) and/or egg (aOR, 3.79; 95% CI, 1.19-12.08; P = .025) allergic than were those with adequate vitamin D levels independent of eczema status. Among those with Australian-born parents, infants with vitamin D insufficiency were more likely to have multiple food allergies (≥2) rather than a single food allergy (aOR, 10.48; 95% CI, 1.60-68.61 vs aOR, 1.82; 95% CI, 0.38-8.77, respectively). Conclusions: These results provide the first direct evidence that vitamin D sufficiency may be an important protective factor for food allergy in the first year of life. [Copyright &y& Elsevier]