Allergic Sensitization In Children Research Articles

Association between dietary antioxidants intake and childhood eczema: results from the NHANES database

BackgroundHigh dietary intake of antioxidants reduces the risk of allergic sensitization in children. However, there was no sufficient evidence for the effect of dietary antioxidants intake on childhood eczema. Herein, this study aimed to explore the roles of different dietary antioxidants in childhood eczema.MethodsData of 2305 children and adolescents aged < 18 years old were extracted from the National Health and Nutrition Examination Survey database in 2005–2006 in this cross-sectional study. The associations between dietary antioxidants intake and childhood eczema were explored using univariate and multivariate logistic regression analyses, with odds ratios (ORs) and confidence intervals (CIs). Subgroup analyses based on age and gender were also performed.ResultsA total of 268 (11.6%) children had eczema. After adjusting for covariates, we found no significant associations between dietary intake of β-carotene, vitamin C, selenium (Se), and retinol and childhood eczema. However, compared with children and adolescents whose dietary zinc (Zn) intake < 7.47 mg, those who had dietary Zn intake level ≥ 11.83 mg seemed to have lower odds of eczema [OR 0.45, 95% CI 0.28–0.73]. In addition, subgroup analysis showed that especially in children and adolescents aged 1–11 years old, whatever the gender, a higher dietary intake level of Zn may benefit childhood eczema (all P < 0.05).ConclusionWe concluded dietary Zn intake was negatively associated with childhood eczema. Further studies are needed to explore the roles of dietary antioxidants intake in childhood eczema.

Exposure to ambient ultrafine particles and allergic sensitization in children up to 16 years

BackgroundFew epidemiological studies so far have investigated the role of long-term exposure to ultrafine particles (UFP) in inhalant and food allergy development. ObjectivesThe purpose of this study was to assess the association between UFP exposure and allergic sensitization to inhalant and food allergens in children up to 16 years old in the Netherlands. Methods2295 participants of a prospective birth cohort with IgE measurements to common inhalant and food allergens at ages 4, 8, 12 and/or 16 were included in the study. Annual average UFP concentrations were estimated for the home addresses at birth and at the time of the IgE measurements using land-use regression models. Generalized estimating equations were used for the assessment of overall and age-specific associations between UFP exposure and allergic sensitization. Additionally, single- and two-pollutant models with NO2, PM2.5, PM2.5 absorbance and PM10 were assessed. ResultsWe found no significant associations between UFP exposure and allergic sensitization to inhalant and food allergens (OR (95% CI) ranging from 1.02 (0.95–1.10) to 1.05 (0.98–1.12), per IQR increment). NO2, PM2.5, PM2.5 absorbance and PM10 showed significant associations with sensitization to food allergens (OR (95% CI) ranging from 1.09 (1.00–1.20) to 1.23 (1.06–1.43) per IQR increment). NO2, PM2.5, PM2.5 absorbance and PM10 were not associated with sensitization to inhalant allergens. For NO2, PM2.5 and PM2.5 absorbance, the associations with sensitization to food allergens persisted in two-pollutant models with UFP. ConclusionThis study found no association between annual average exposure to UFP and allergic sensitization in children up to 16 years of age. NO2, PM2.5, PM2.5 absorbance and PM10 were associated with sensitization to food allergens.

Exposure to ambient ultrafine particles and allergic sensitization in children up to 16 years

Background and aim: Few epidemiological studies so far have investigated the role of long-term exposure to ultrafine particles (UFP) in allergy development. The purpose of this study was to assess the association between UFP exposure and allergic sensitization to inhalant and food allergens in children up to 16 years old in the Netherlands. Methods: 2295 participants of the prospective PIAMA birth cohort with specific IgE measurements to common inhalant and food allergens at ages 4, 8 or 12 or to common inhalant allergens at age 16 were included in the study. Annual average UFP concentrations were estimated for the home addresses at birth and at the time of the IgE measurements using land-use regression models. Generalized estimating equations were used for the assessment of overall and age-specific associations between UFP exposure and allergic sensitization. Additionally, single- and two-pollutant models with NO2, PM2.5, PM2.5 absorbance and PM10 were assessed. Results: We found no significant associations between UFP exposure and allergic sensitization to inhalant and food allergens (OR (95% CI) ranging from 1.02 (0.95 – 1.10) to 1.05 (0.98 – 1.12), per IQR increment). In contrast, NO2, PM2.5, PM2.5 absorbance and PM10 showed significant associations with sensitization to food allergens (OR (95% CI) ranging from 1.09 (1.00–1.20) to 1.23 (1.06–1.43) per IQR increment) but not with sensitization to inhalant allergens (OR (95% CI) ranging from 0.98 (0.90-1.07) to 1.08 (0.93-1.25) per IQR increment). For NO2, PM2.5 and PM2.5 absorbance, the associations with sensitization to food allergens persisted in two-pollutant models with UFP. Conclusion: This study found no association between annual average exposure to UFP and allergic sensitization in children up to 16 years of age. NO2, PM2.5, PM2.5 absorbance and PM10 were associated with sensitization to food allergens. Key words: ultrafine particles, IgE sensitization, inhalant and food allergens, children, air pollution, allergy

Risk Assessment on Use of Lactobacillus rhamnosus (LGG) as an Ingredient in Infant Formula and Baby Foods (II)

On 10. March 2006 , The Norwegian Food Safety Authority (Mattilsynet) decided that, on the basis of VKM’s previous risk assessment (2005), Nutramigen 1 with Lactobacillus rhamnosus GG (LGG) could not be marketed in Norway as medical foods for infants (0-4 months). In addition, The Norwegian Food Safety Authority (Mattilsynet) decided (08. November 2006) to withdraw permission for marketing of Nutramigen 2 with LGG, which is a milk supplement for infants aged between 4 and 6 months, with cow’s milk and soy protein allergy. On 13. December 2006, Mead Johnson Nutritionals appealed against this decision from The Norwegian Food Safety Authority (Mattilsynet). The Norwegian Food Safety Authority forwarded the appeal from the companies, asked the VKM Panel on biological hazards and the VKM Panel on nutrition, dietetic products, novel food and allergy, for a new risk assessment including the new data provided in the appeal.&#x0D; LGG is one of the most studied probiotic strains. Lactic acid produced by LGG in the human gut results in a decrease in faecal pH, which in turn inhibits colonisation by potentially pathogenic bacteria. Short-term beneficial effects from administration of LGG to infants and young children with infectious diarrhoea have been reported in a number of studies, but a prophylactic effect on diarrhoea has not been documented. Furthermore, whilst some studies have reported a prophylactic, or even a curative, effect of LGG on atopic eczema in young children, more recent studies do not report such effects. Some even suggest an increased incidence of allergic sensitization in children receiving LGG supplemented formula at an early age. There are no published data that demonstrate long-term clinical benefits of infant formula supplemented with LGG for children between 4 months and 3 years, although no immediate deleterious effects of LGG have been found. Possible long-term effects of LGG on intestinal colonisation, and its effects on long-term gastrointestinal and immune functions, are not known.&#x0D; LGG, as an ingredient in infant formula and baby foods, is intended for daily use in the target group, and not for short-term, specific treatment. Furthermore, the targeted consumer group includes children below the age of twelve months. These two aspects demand particular consideration with regard to the unknown effects of long-term treatment with large doses of live bacteria on the ecology of the microbiota of the gastrointestinal tract and on the immune system. Neither of these systems is fully matured in infants and small children, and therefore may be particularly susceptible.&#x0D; There is no documented prophylactic effect of LGG on any disease in children. The effect of treatment with LGG-supplemented formula in small children is questionable, except for a documented short-term effect on infectious diarrhoea. Panel on Biological Hazards and Panel on nutrition, dietetic products, novel food and allergy at the Norwegian Scientific Committee for Food Safety find that the data available are not sufficient to support the suggested beneficial effects, or the safety, of LGG in infant formula and baby foods for children aged between 4 months and 3 years, when the products are intended for daily use.

A Multicenter Study Assessing Risk Factors and Aeroallergens Sensitization Characteristics in Children with Self-Reported Allergic Rhinitis in China.

BackgroundUp to now, epidemiological studies on allergy rhinitis (AR) have primarily focused on determining the risk of disease in Chinese adults, with the majority of them designed by single centers, while cross-sectional and epidemiological data describing allergic sensitization in children with self-reported AR are scarce.ObjectiveThis study was estimating of the latest information about the sensitization patterns and risk factors of clinical AR to develop effective strategies for the prevention and treatment of AR.MethodsWe conducted a cross-sectional survey between January 2020 and June 2021 involving children from seven cities in China who reported AR. A total of 762 children participated in this survey. To evaluate the risk factors and specific sensitization patterns of clinical AR through questionnaires and specific immunoglobulin E to 11 aeroallergens.ResultsOf the 762 patients, 593 (77.8%) had at least one positive IgE level. Aged 7–14 years (OR 1.503, (95% CI 1.058–2.136), P = 0.023); With allergic conjunctivitis (OR 1.843, (95% CI 1.297–2.620), P = 0.001) and living in the Eastern (OR 1.802, (95% CI 1.263–2.573), P = 0.001) all elevated the risk of clinical AR associated with aeroallergens. The sensitization rates of D. pteronyssinus and D. farinae were higher than those of other allergens in the 0–6 and 7–14 years old age groups. The most common aeroallergens among self-reported children with AR in the eastern were D. farinae (74.9%) and D. pteronyssinus (74.3%), while in the western were mugwort (60.0%) and marguerite (56.6%). Majority of sIgE-positive subjects were sensitized to three or more of the tested pollen allergens in the Western (52.1%), compared with 5.7% in the Eastern.ConclusionThere was an apparent geographic variation in childhood allergies in China. Age factors also had strong impacts on the allergen sensitization rate of children, but these impacts differed across regions.

Cord Blood T Cells Expressing High and Low PKCζ Levels Develop into Cells with a Propensity to Display Th1 and Th9 Cytokine Profiles, Respectively.

Low Protein Kinase C zeta (PKCζ) levels in cord blood T cells (CBTC) have been shown to correlate with the development of allergic sensitization in childhood. However, little is known about the mechanisms responsible. We have examined the relationship between the expression of different levels of PKCζ in CBTC and their development into mature T cell cytokine producers that relate to allergy or anti-allergy promoting cells. Maturation of naïve CBTC was initiated with anti-CD3/-CD28 antibodies and recombinant human interleukin-2 (rhIL-2). To stimulate lymphocyte proliferation and cytokine production the cells were treated with Phytohaemagglutinin (PHA) and Phorbol myristate acetate (PMA). Irrespective of the PKCζ levels expressed, immature CBTC showed no difference in lymphocyte proliferation and the production of T helper 2 (Th2) cytokine interleukin-4 (IL-4) and Th1 cytokine, interferon-gamma (IFN-γ), and influenced neither their maturation from CD45RA+ to CD45RO+ cells nor cell viability/apoptosis. However, upon maturation the low PKCζ expressing cells produced low levels of the Th1 cytokines, IFN-γ, IL-2 and tumour necrosis factor-alpha (TNF), no changes to levels of the Th2 cytokines, IL-4, IL-5 and IL-13, and an increase in the Th9 cytokine, IL-9. Other cytokines, lymphotoxin-α (LT-α), IL-10, IL-17, IL-21, IL-22 and Transforming growth factor-beta (TGF-β) were not significantly different. The findings support the view that low CBTC PKCζ levels relate to the increased risk of developing allergic diseases.

Endotype of allergic asthma with airway obstruction in urban children

Black and Hispanic children growing up in disadvantaged urban neighborhoods have the highest rates of asthma and related morbidity in the United States. This study sought to identify specific respiratory phenotypes of health and disease in this population, associations with early life exposures, and molecular patterns of gene expression in nasal epithelial cells that underlie clinical disease. The study population consisted of 442 high-risk urban children who had repeated assessments of wheezing, allergen-specific IgE, and lung function through 10 years of age. Phenotypes were identified by developing temporal trajectories for these data, and then compared to early life exposures and patterns of nasal epithelial gene expression at 11 years of age. Of the 6 identified respiratory phenotypes, a high wheeze, high atopy, low lung function group had the greatest respiratory morbidity. In early life, this group had low exposure to common allergens and high exposure to ergosterol in house dust. While all high-atopy groups were associated with increased expression of a type-2 inflammation gene module in nasal epithelial samples, an epithelium IL-13 response module tracked closely with impaired lung function, and a MUC5AC hypersecretion module was uniquely upregulated in the high wheeze, high atopy, low lung function group. In contrast, a medium wheeze, low atopy group showed altered expression of modules of epithelial integrity, epithelial injury, and antioxidant pathways. In the first decade of life, high-risk urban children develop distinct phenotypes of respiratory health versus disease that link early life environmental exposures to childhood allergic sensitization and asthma. Moreover, unique patterns of airway gene expression demonstrate how specific molecular pathways underlie distinct respiratory phenotypes, including allergic and nonallergic asthma.

Neighbourhood green and blue spaces and allergic sensitization in children: A longitudinal study based on repeated measures from the Generation XXI cohort

Evidence on the effect of natural environments on atopy in children is limited and inconsistent, disregarding the time-varying and cumulative exposures throughout the life course. To assess critical periods of exposure as well as the effect of longitudinal trajectories of exposure to green and blue spaces on the development of allergic sensitization in children at the age of 10 years. A longitudinal study was conducted involving 730 children enrolled in Generation XXI, a population-based birth cohort from the Porto Metropolitan Area (Portugal). Food and aeroallergens sensitization were evaluated at 10 years of age using Phadiatop Infant, Phadiatop fx1 and fx22 ImmunoCAP (Thermo Fisher Scientific, Uppsala, Sweden). Residential Normalized Difference Vegetation Index (NDVI) and distance to the nearest blue space (sea, river) were assessed using a Geographic Information System. Latent class linear mixed models were fitted to determine longitudinal trajectories of exposure. Associations were estimated using Cox proportional hazards regression models and expressed using hazard ratios (HR) and 95% confidence intervals (95% CI). Residing in neighbourhoods surrounded by more vegetation at 10 years, as well as lifetime exposure to a trajectory of higher levels of NDVI, were associated with a lower risk of allergic sensitization [HR (95% CI) = 0.095 (0.011, 0.823) and HR (95% CI) = 0.539 (0.301, 0.965), respectively]. Our findings support a role for both longitudinal, but particularly late-childhood, exposure to green spaces, in the prevention of allergic sensitization in children.

Symptom burden of atopic dermatitis in early childhood assessed from daily monitoring of symptoms and topical steroid use

To our knowledge, diseaseburden of atopic dermatitis (AD) as number of days with symptoms and medical treatment has never been studied as measure of severity. To investigate risk factors for AD burden in the first 3years of life. The Copenhagen Prospective Studies on Asthma in Childhood2010 included 700 children. AD burden was assessed by daily diary entries with information on AD and steroid days measuring 18 possible heritable, prenatal, and postnatal environmental exposures. The children with AD had a median (interquartile range) of 136 symptom days (61-294days) and 72 steroid days (27-145days) during the first 3years of life, with the highest disease burden in the second year of life. The multivariable risk factor analysis showed that maternal AD and childhood allergic sensitization were associated with a higher number of AD days and maternal AD, filaggrin mutation, and allergic sensitization were associated with a higher number of steroid days. Participants with a personal interest in atopic diseases could be more likely to participate. Children's burden of AD, assessed quantitatively as AD and steroid days, demonstrated positive associations with maternal AD, filaggrin mutation, and early-life allergic sensitization, with the highest disease burden in the second year of life.

Analysis of maternal and perinatal determinants of allergic sensitization in childhood

BackgroundNon-communicable diseases, such as allergies, are influenced by both genetic and epigenetic factors. Perinatal determinants conceivably modify the epigenetic makeup of the developing fetal immune system preventing or predisposing the development of allergies. The aim of this study therefore was to identify independent perinatal factors associated with allergic sensitization in childhood.MethodsIn a single center retrospective case-cohort study electronic obstetric medical records and available skin prick testing results of children were analyzed. For the analysis 286 skin prick test positive (sensitized) children [median (IQR): 3.47 (1.70–7.34) years] were compared with data from all remaining live births in the obstetric cohort (n = 66,583).ResultsSensitized children more frequently had a mother born in Asia (19.1% vs. 10.2%; P < 10–6). Applying backward elimination logistic regression, seven out of 23 initially entered perinatal factors remained in the model. High maternal age (> 35 years; OR: 1.912; P < 0.001), male offspring sex (OR: 1.423; P < 0.01) and assisted conception (OR: 1.771; P < 0.05) increased the risk for allergic sensitization. In contrast, maternal smoking (OR: 0.469; P < 0.005), increasing parity (OR: 0.881; P < 0.05), maternal pre-pregnancy overweight (OR: 0.742; P < 0.005) and preterm birth (OR: 0.484; P < 0.05) decreased the risk for allergic sensitization.ConclusionsIn addition to supporting previous findings, this study is first to report an increased risk of allergic sensitization after assisted conception. Beyond this finding’s potential implementation in preventative strategies, exploration of this association could further pathophysiological understanding of allergic disease.

Sensitization to indoor allergens in children with bronchial asthma

BACKGROUND: Children with asthma have a high prevalence of environmental allergies. Sensitization to various allergens, especially to indoor allergens is crucial for effective measures for asthma management. Indian data on allergic sensitization in children is scarce, necessitating the need of the study. METHODS: A Cross-sectional study was conducted to determine the indoor allergen sensitization in 100 asthmatic children aged 5 to 15 yrs. They underwent skin prick test for indoor allergen house dust mite cockroach, cat, dog dander, house fly, candida, aspergillus, and mosquito. RESULTS: In the study sensitization to house dust mite was 93%. 39% were sensitized to Candida 36% to cockroach,23% housefly and 22%to dog dander and Aspergillus and 13% to mosquito and cat dander. Allergen sensitivity rate for atleast one allergen was 94% which was significant. Mean No. of allergens for which sensitization was seen is 2.57±1.77. Comorbidities were present in 35% of cases.7% had urticarial and allergic conjunctivitis each. CONCLUSION: Asthmatic children showed high sensitization to indoor allergen and the most common allergen found was house dust mite

Asthma and allergic rhinitis risk depends on house dust mite specific IgE levels in PARIS birth cohort children

BackgroundThe natural history of allergic sensitization in childhood, and its impact on allergic disease development, needs to be clarified. This study aims to identify allergic sensitization and morbidity patterns during the first 8 years of life. MethodsThe study was conducted in the on-going population-based prospective Pollution and Asthma Risk: an Infant Study (PARIS) birth cohort. Sensitization profiles were identified by k-means clustering based upon allergen-specific IgE levels measured at 18 months and 8/9 years. Allergic morbidity profiles were identified by latent class analysis based on symptoms, symptom severity, treatments, and lifetime doctor-diagnoses of asthma, allergic rhinitis, and atopic dermatitis and on lower respiratory infections before 2 years. ResultsFive sensitization and 5 allergic morbidity patterns were established in 714 children. Children not sensitized or with isolated and low allergen-specific sensitization were grouped together (76.8%). A profile of early and transient sensitization to foods that increased the risk of asthma later in childhood was identified (4.9%). Children strongly sensitized (≥3.5 kUA/L) to house dust mite at 8/9 years (9.0%) had the highest risk of asthma and allergic rhinitis. Finally, timothy grass pollen at 8/9 years sensitization profile (5.3%) was related to respiratory allergic diseases, as was early onset and persistent sensitization profile (4.1%), this latter being also strongly associated with atopic dermatitis. Conclusions & Clinical RelevanceWe show that accurate assessment of the risk of allergic disease should rely on earliness and multiplicity of sensitization, involved allergens, and allergen-specific IgE levels, and not considering solely allergic sensitization as a dichotomous variable (allergen-specific IgE ≥0.35 kUA/L), as usually done. This is particularly striking for house dust mite. We are hopeful that, pending further confirmation in other populations, our findings will improve clinical practice as part of an approach to allergic disease prevention.

Epigenome-wide association study reveals methylation pathways associated with childhood allergic sensitization

ABSTRACTEpigenetic mechanisms integrate both genetic variability and environmental exposures. However, comprehensive epigenome-wide analysis has not been performed across major childhood allergic phenotypes. We examined the association of epigenome-wide DNA methylation in mid-childhood peripheral blood (Illumina HumanMethyl450K) with mid-childhood atopic sensitization, environmental/inhalant and food allergen sensitization in 739 children in two birth cohorts (Project Viva–Boston, and the Generation R Study–Rotterdam). We performed covariate-adjusted epigenome-wide association meta-analysis and employed pathway and regional analyses of results. Seven-hundred and five methylation sites (505 genes) were significantly cross-sectionally associated with mid-childhood atopic sensitization, 1411 (905 genes) for environmental and 45 (36 genes) for food allergen sensitization (FDR<0.05). We observed differential methylation across multiple genes for all three phenotypes, including genes implicated previously in innate immunity (DICER1), eosinophilic esophagitis and sinusitis (SIGLEC8), the atopic march (AP5B1) and asthma (EPX, IL4, IL5RA, PRG2, SIGLEC8, CLU). In addition, most of the associated methylation marks for all three phenotypes occur in putative transcription factor binding motifs. Pathway analysis identified multiple methylation sites associated with atopic sensitization and environmental allergen sensitization located in/near genes involved in asthma, mTOR signaling, and inositol phosphate metabolism. We identified multiple differentially methylated regions associated with atopic sensitization (8 regions) and environmental allergen sensitization (26 regions). A number of nominally significant methylation sites in the cord blood analysis were epigenome-wide significant in the mid-childhood analysis, and we observed significant methylation – time interactions among a subset of sites examined. Our findings provide insights into epigenetic regulatory pathways as markers of childhood allergic sensitization.

Glucocorticoid Receptor Binding Inhibits an Intronic IL33 Enhancer and is Disrupted by rs4742170 (T) Allele Associated with Specific Wheezing Phenotype in Early Childhood.

Interleukin 33 (IL-33) is a cytokine constitutively expressed by various cells of barrier tissues that contribute to the development of inflammatory immune responses. According to its function as an alarmin secreted by lung and airway epithelium, IL-33 plays a significant role in pathogenesis of allergic disorders. IL-33 is strongly involved in the pathogenesis of asthma, anaphylaxis, allergy and dermatitis, and genetic variations in IL33 locus are associated with increased susceptibility to asthma. Genome-wide association studies have identified risk “T” allele of the single-nucleotide polymorphism rs4742170 located in putative IL33 enhancer area as susceptible variant for development of specific wheezing phenotype in early childhood. Here, we demonstrate that risk “T” rs4742170 allele disrupts binding of glucocorticoid receptor (GR) transcription factor to IL33 putative enhancer. The IL33 promoter/enhancer constructs containing either 4742170 (T) allele or point mutations in the GR-binding site, were significantly more active and did not respond to cortisol in a pulmonary epithelial cell line. At the same time, the constructs containing rs4742170 (C) allele with a functional GR-binding site were less active and further inhibitable by cortisol. The latter effect was GR-dependent as it was completely abolished by GR-specific siRNA. This mechanism may explain the negative effect of the rs4742170 (T) risk allele on the development of wheezing phenotype that strongly correlates with allergic sensitization in childhood.

Excess Free Fructose Beverages and Allergy in Children and Adolescents: Results From NHANES 2005-2006.

Our purpose was to investigate the relationship between intake of excess free fructose beverages and allergy among children and adolescents. We analyzed data of 860 children (aged 6 to 12 years) and 1,142 adolescents (aged 13 to 19 years) from the National Health and Nutrition Examination Survey 2005-2006. Logistic regression analyses were performed to determine the associations between consumption of excess free fructose beverages and allergic symptoms or allergic sensitization. The pattern of findings was not entirely consistent, but some analyses supported the hypothesis of an association between intake of excess free fructose beverages and allergy. After controlling for the potential confounders, children who consumed nondiet fruit drinks at least 5 times per week had a nearly 2.5-fold greater odds of allergic sensitization than did those who consumed such drinks only 1 to 3 times per month (OR = 2.446; 95% CI, 1.583-3.780). Adolescents who consumed excess free fructose beverages at least 5 times per week or 1 to 4 times per week had about fivefold greater odds of presence of allergic symptoms than did those who seldom consumed these beverages (OR = 5.164; 95% CI, 1.866-14.297 and OR = 4.112; 95% CI, 1.857-9.107, respectively). Adolescents who consumed apple juice at least 5 times per week had a twofold greater odds of presence of allergic sensitization than did the seldom consumers (OR = 2.215; 95% CI, 1.178-4.164). These findings provide some support for the hypothesis of a link between intake of excess free fructose beverages and allergic symptoms or allergic sensitization in children and adolescents.

Nasal Colonization with S. aureus is Associated with Allergic Sensitization in Children with Chronic Rhinitis

Nasal Colonization with S. aureus is Associated with Allergic Sensitization in Children with Chronic Rhinitis

Allergenic food introduction and risk of childhood atopic diseases.

BackgroundThe role of timing and diversity of allergenic food introduction in the development of childhood allergic sensitization and atopic diseases is controversial.ObjectiveTo examine whether timing and diversity of allergenic food introduction are associated with allergic sensitization, allergy and eczema in children until age 10 years.Materials and methodsThis study among 5,202 children was performed in a population-based prospective cohort. Timing (age ≤6 months vs. >6 months) and diversity (0, 1, 2 and ≥3 foods) of allergenic food (cow's milk, hen's egg, peanut, tree nuts, soy and gluten) introduction were assessed by questionnaires at ages 6 and 12 months. At age 10 years, inhalant and food allergic sensitization were measured by skin prick tests, and physician-diagnosed inhalant and food allergy by questionnaire. Data on parental-reported physician-diagnosed eczema were obtained from birth until age 10 years.ResultsChildren introduced to gluten at age ≤6 months had a decreased risk of eczema (aOR (95% CI): 0.84 (0.72, 0.99)), compared with children introduced to gluten at age >6 months. However, timing of allergenic food introduction was not associated with allergic sensitization or physician-diagnosed allergy. Children introduced to ≥3 allergenic foods at age ≤6 months had a decreased risk of physician-diagnosed inhalant allergy (0.64 (0.42, 0.98)), compared with children not introduced to any allergenic food at age ≤6 months. However, diversity of allergenic food introduction was not associated with allergic sensitization, physician-diagnosed food allergy or eczema.ConclusionNeither timing nor diversity of allergenic food introduction was consistently associated with childhood allergic sensitization, allergy or eczema.

Duration and exclusiveness of breastfeeding and risk of childhood atopic diseases.

Breastfeeding may have immune modulatory effects that influence the development of childhood allergic sensitization and atopic diseases. We aimed to examine the associations of breastfeeding with childhood allergic sensitization, inhalant or food allergy and eczema, and whether any association was affected by disease-related modification of the exposure or modified by maternal history of allergy, eczema, or asthma. This study among 5828 children was performed in a population-based prospective cohort from fetal life onwards. We collected information on duration (<2months, 2-4months, 4-6months, and ≥6months) and exclusiveness (nonexclusive vs exclusive for 4months) of breastfeeding in infancy by postal questionnaires. At age 10years, inhalant allergic sensitization and food-allergic sensitization were measured by skin prick tests, and physician-diagnosed inhalant and food allergy by a postal questionnaire. Data on parental-reported eczema were available from birth until age 10years. We observed no association of breastfeeding with any allergic sensitization, physician-diagnosed allergy, or combination of these outcomes. Shorter breastfeeding duration was associated with an overall increased risk of eczema (P-value for trend <.05). Nonexclusively breastfed children had an overall increased risk of eczema (adjusted odds ratio [95% confidence interval]: 1.11 [1.01, 1.23]), compared with children exclusively breastfed for 4months. Risk period-specific sensitivity analyses, additional adjustment for ointment use for eczema at age 2months, and cross-lagged modeling showed no consistent results for disease-related modification of the exposure. Results were not modified by maternal history of allergy, eczema, or asthma (lowest P-value for interaction=.13). Shorter duration or nonexclusiveness of breastfeeding is associated with a weak overall increased risk of eczema but not allergic sensitization or physician-diagnosed allergy at age 10years.

Household pet exposure, allergic sensitization, and rhinitis in the U.S. population.

The effect of animal dander exposure on allergic sensitization may be age-dependent. A comparison between the association of the levels of exposure to pet allergen with rhinitis symptoms and allergic sensitization in children and adults is yet to be performed in the U.S. Cross-sectional study of 3034 adults (age, 20 to 85 years) and 2104 children (age, 6 to 19 years) in the National Health and Nutrition Examination Survey, 2005-2006. Samples of household dust were collected to measure the amounts of indoor allergens in the participants' homes. Self-reported rhinitis was based on symptoms during the past 12 months, and allergen sensitization was defined as a positive response to any of the 19 specific immunoglobulin E (IgE) antigens tested. Higher levels of exposure to dog dander were associated with a higher prevalence of any allergic sensitization in adults (prevalence ratio [PR] 1.19; 95% confidence interval [CI], 1.01 to 1.39), but a lower prevalence in children (PR 0.84; 95% CI, 0.73 to 0.096), p-interaction by age group 0.02. Cat exposure was associated with an increased prevalence of rhinitis symptoms in adults (PR for the 3rd vs lowest tertile of cat dander concentrations: 1.14; 95% CI, 1.05 to 1.23) but not in children (PR for the 3rd vs lowest tertile of cat dander IgE concentrations: 0.86; 95% CI, 0.70 to 1.07), p-interaction 0.01. Allergic sensitization and symptomatic response to pet dander exposure may vary based on age. Further studies are necessary to assess the mechanisms for these apparent differences.

Climate and Allergic Sensitization to Airborne Allergens in the General Population: Data from the French Six Cities Study

Background: The results of international epidemiological surveys show large geographical variations in skin test reactivity but do not provide a rationale for such variations. Objective: To assess the relationship between climate and allergic sensitization in schoolchildren. Methods: In the present study, we analyzed data from a multicenter, epidemiological survey that included 6,461 schoolchildren, aged 9-11 years, living in 6 French cities scattered around France. The protocol also included a battery of skin prick tests to common airborne allergens. The crude prevalence of sensitization to each allergen was estimated for each city and then adjusted for potential confounding factors. This analysis was repeated for monosensitization and for allergens grouped into 2 categories: indoor allergens, i.e., house dust mite (HDM), cat, and cockroach allergens, and outdoor allergens, i.e., birch pollen, grass pollen, and Alternaria. We also grouped cities according to their location on the coast, i.e., Marseille and Bordeaux, or inland, i.e., Créteil, Clermont-Ferrand, Reims, and Strasbourg. Results: A difference in prevalence of sensitization to each airborne allergen or allergens grouped into indoor and outdoor categories was found between cities, even after adjusting for potential confounding factors. Also, a higher prevalence of sensitization to HDM, cat dander, and, broadly speaking, indoor allergens, was found in children living on the coast than in those living inland, whereas they showed a lower prevalence of sensitization to birch pollen. Between-city differences in the prevalence of monosensitization were also statistically significant. Children living in coastal cities had a higher rate of monosensitization to indoor allergens and a lower prevalence of sensitization to birch pollen. The higher prevalence of allergic sensitization in children from coastal cities is most likely due to climatic conditions, such as proximity from sea and humidity. Differences in sensitization to birch allergens could be due to differential exposure to these pollen. Conclusion: These results indicate a role of environmental exposure in sensitization to perennial as well as seasonal allergens.