Breastfeeding protects against current asthma up to 6 years of age

How maternal factors shape the immune system of breastfed infants to alleviate food allergy: A systematic and updated review

What infants eat early in life may shape the immune system and have long-standing consequences on the health of the host during later life. In the early months post-birth, breast milk serves as the exclusive and optimal nourishment for infants, facilitating crucial molecular exchanges between mother and infant. Recent advances have uncovered that some maternal factors influence breastfed infant outcomes, including the risk of food allergy (FA). To date, accumulated data show that breastfed infants have a lower risk of FA. However, the issue remains disputed, some reported preventive allergy effects, while others did not confirm such effects, or if identified, protective effects were limited to early childhood. The disputed outcomes may be attributed to the maternal status, as it determines the compounds of the breast milk that breastfed infants are exposed to. In this review, we first detail the compounds in breast milk and their roles in infant FA. Then, we present maternal factors resulting in alterations in breast milk compounds, such as maternal health status, maternal diet intake, and maternal food allergen intake, which subsequently impact FA in breastfed infants. Finally, we analyze how these compounds in breast milk alleviated the infant FA by mother-to-infant transmission. Altogether, the mechanisms are primarily linked to the synergetic and direct effects of compounds in breast milk, via promoting the colonization of gut microbiota and the development of the immune system in infants.

GEMA 5.3. Spanish Guideline on the Management of Asthma

The Spanish Guideline on the Management of Asthma, better known by its acronym in Spanish GEMA, has been available for more than 20 years. Twenty-one scientific societies or related groups both from Spain and internationally have participated in the preparation and development of the updated edition of GEMA, which in fact has been currently positioned as the reference guide on asthma in the Spanish language worldwide. Its objective is to prevent and improve the clinical situation of people with asthma by increasing the knowledge of healthcare professionals involved in their care. Its purpose is to convert scientific evidence into simple and easy-to-follow practical recommendations. Therefore, it is not a monograph that brings together all the scientific knowledge about the disease, but rather a brief document with the essentials, designed to be applied quickly in routine clinical practice. The guidelines are necessarily multidisciplinary, developed to be useful and an indispensable tool for physicians of different specialties, as well as nurses and pharmacists. Probably the most outstanding aspects of the guide are the recommendations to: establish the diagnosis of asthma using a sequential algorithm based on objective diagnostic tests; the follow-up of patients, preferably based on the strategy of achieving and maintaining control of the disease; treatment according to the level of severity of asthma, using six steps from least to greatest need of pharmaceutical drugs, and the treatment algorithm for the indication of biologics in patients with severe uncontrolled asthma based on phenotypes. And now, in addition to that, there is a novelty for easy use and follow-up through a computer application based on the chatbot-type conversational artificial intelligence (ia-GEMA).

Treating allergies via skin - Recent advances in cutaneous allergen immunotherapy

Subcutaneous allergen immunotherapy has been practiced clinically for decades to treat airborne allergies. Recently, the cutaneous route, which exploits the immunocompetence of the skin has received attention, which is evident from attempts to use it to treat peanut allergy. Delivery of allergens into the skin is inherently impeded by the barrier imposed by stratum corneum, the top layer of the skin. While the stratum corneum barrier must be overcome for efficient allergen delivery, excessive disruption of this layer can predispose to development of allergic inflammation. Thus, the most desirable allergen delivery approach must provide a balance between the level of skin disruption and the amount of allergen delivered. Such an approach should aim to achieve high allergen delivery efficiency across various skin types independent of age and ethnicity, and optimize variables such as safety profile, allergen dosage, treatment frequency, application time and patient compliance. The ability to precisely quantify the amount of allergen being delivered into the skin is crucial since it can allow for allergen dose optimization and can promote consistency and reproducibility in treatment response. In this work we review prominent cutaneous delivery approaches, and offer a perspective on further improvisation in cutaneous allergen-specific immunotherapy.

Allergen Content and Protease Activity in Milk Feeds from Mothers of Preterm Infants

Rationale: There is little information regarding the allergen content of milk feeds in the preterm population. Previous studies have not performed a broad analysis of the allergenic peptide content and protease activity of milk feeds in this population. Methods: To evaluate feasibility, we initially performed mass spectrometry on 4 human milk (HM) samples (2 term and 2 preterm) from the Mommy's Milk Human Milk Biorepository (HMB) and analyzed the results against the University of Nebraska FASTA database and UniProt for a total of 2,211 protein sequences. We then further analyzed five samples from the Microbiome, Atopy, and Prematurity (MAP) study including peptidomic and protease activity analysis. Results: Each HMB sample had between 806 and 1,007 proteins, with 37-44 nonhuman proteins/sample encompassing 26 plant and animal species. In the preterm MAP samples, 784 digested nonhuman proteins were identified, 30 were nonbovine in origin. Proteins from 23 different species including aeroallergens, food, and contact allergens were identified. Protease activity was highest in HM samples without human milk fortifier and lowest in preterm formula. Conclusions: These findings represent the first preterm milk feed mass spectrometry and protease analysis with identification of known allergenic proteins to food, contact, and aeroallergens. These results raise questions of whether the composition of milk feeds in the neonatal intensive care unit impact the development of atopic disease in the preterm population and whether the complex interaction between allergens, proteases, and other HM components can serve to induce sensitization or tolerance to allergens in infants. Clinical Trial Registration Number: NCT04835935.

Knowledge mapping of the links between the microbiota and allergic diseases: A bibliometric analysis (2002-2021)

Background

In recent decades, dramatic changes in modern environmental exposures and lifestyles have resulted in a steep rise in the prevalence of allergic diseases such as asthma, allergic rhinitis, atopic dermatitis and food allergies. Evidence is mounting that the microbiota plays a crucial role in allergic disorder development and evolution. Therefore, a better understanding of allergic diseases within the context of the microbiota is urgently needed. This work aimed to comprehensively outline general characteristics, research hotspots, evolution routes, and emerging trends in this area.

Methods

Relevant publications from January 2002 to December 2021 were obtained from the Web of Science Core Collection on 5 August 2022. Bibliometric and visual analyses were performed using CiteSpace; VOSviewer; an online bibliometric platform; and Microsoft Excel 2019.

Results

In total, 2535 documents met the requirements. The annual number of publications has shown rapid growth in the last two decades. The USA, University of California System, and Isolauri E of the University of Turku were the most productive and influential country, institution, and author, respectively. The Journal of Allergy and Clinical Immunology was the most prolific and most cocited journal. High-frequency keywords included "gut microbiota", "asthma", "atopic dermatitis", "children", and "probiotics". Recent studies have focused on "atopic dermatitis", "skin", "asthma", and "probiotics", according to the cocitation analysis of references. Burst detection analysis of keywords showed that "community", "skin microbiome", "microbiome", "Staphylococcus aureus", and "chain fatty acid" were emerging research frontiers, which currently have ongoing bursts.

Conclusion

In the last 20 years, studies of the microbiota in allergic diseases have been flourishing, and the themes have been increasing in depth. These findings provide valuable references on the current research hotspots and gaps and development trends in the link between the microbiota and allergic diseases.

Investigating the influence of breastfeeding on asthma in children under 12 years old in the UK Biobank

Background

Childhood-onset asthma (COA) has become a major and growing problem worldwide and imposes a heavy socioeconomic burden on individuals and families; therefore, understanding the influence of early-life experiences such as breastfeeding on COA is of great importance for early prevention.

Objectives

To investigate the impact of breastfeeding on asthma in children under 12 years of age and explore its role at two different stages of age in the UK Biobank cohort.

Methods

A total of 7,157 COA cases and 158,253 controls were obtained, with information regarding breastfeeding, COA, and other important variables available through questionnaires. The relationship between breastfeeding and COA were examined with the logistic regression while adjusting for available covariates. In addition, a sibling analysis was performed on 398 pairs of siblings to explain unmeasured family factors, and a genetic risk score analysis was performed to control for genetic confounding impact. Finally, a power evaluation was conducted in the sibling data.

Results

In the full cohort, it was identified that breastfeeding had a protective effect on COA (the adjusted odds ratio (OR)=0.875, 95% confidence intervals (CIs): 0.831~0.922; P=5.75×10^-7). The impact was slightly pronounced in children aged 6-12 years (OR=0.852, 95%CIs: 0.794~0.914, P=7.41×10^-6) compared to those aged under six years (OR=0.904, 95%CIs: 0.837~0.975, P=9.39×10^-3), although such difference was not substantial (P=0.266). However, in the sibling cohort these protective effects were no longer significant largely due to inadequate samples as it was demonstrated that the power was only 23.8% for all children in the sibling cohort under our current setting. The protective effect of breastfeeding on COA was nearly unchanged after incorporating the genetic risk score into both the full and sibling cohorts.

Conclusions

Our study offered supportive evidence for the protective effect of breastfeeding against asthma in children less than 12 years of age; however, sibling studies with larger samples were warranted to further validate the robustness our results against unmeasured family confounders. Our findings had the potential to encourage mothers to initiate and prolong breastfeeding.

The link between atopic dermatitis and asthma- immunological imbalance and beyond

Atopic diseases are multifactorial chronic disturbances which may evolve one into another and have overlapping pathogenetic mechanisms. Atopic dermatitis is in most cases the first step towards the development of the atopic march and represents a major socio-economic burden in the industrialized countries. The treatment of atopic diseases is often long-lasting and in some cases with lower effectiveness than expected.

In order to prevent the development of the atopic march, the links between the atopic diseases have to be understood. The aim of this review is to present some major points outlining the link between atopic dermatitis and asthma, through a research in the medical literature from recent years.

Stratifying patient populations according to the clinical phenotype of their disease and according to specific measurable values (biomarkers) can help to establish the main etiopathogenetic mechanisms of the disease in these populations. This will add predictive value for the evolution of the disease, and will allow the use and research of more targeted therapy in order to stop this evolution and comorbidities.

Association of breastfeeding with tidal breathing analysis in infants with bronchiolitis

BACKGROUND

Tidal breathing flow-volume (TBFV) analysis provides important information about lung mechanics in infants.

AIM

To assess the effects of breastfeeding on the TBFV measurements of infants who recover from acute bronchiolitis.

METHODS

In this cross-sectional study, TBFV analysis was performed in infants with bronchiolitis prior to hospital discharge. The ratio of time to peak expiratory flow to total expiratory time (tPEF/tE) at baseline and after the administration of 400 mcg salbutamol was evaluated.

RESULTS

A total of 56 infants (35 boys), aged 7.4 ± 2.8 mo, were included. Of them, 12.5% were exposed to tobacco smoke and 41.1% were breastfed less than 2 mo. There were no differences in baseline TBFV measurements between the breastfeeding groups; however, those who breastfed longer than 2 mo had a greater change in tPEF/tE after bronchodilation (12% ± 10.4% vs 0.9% ± 7.1%; P < 0.001). Moreover, there was a clear dose-response relationship between tPEF/tE reversibility and duration of breastfeeding (P < 0.001). In multivariate regression analysis, infants who breastfed less (regression coefficient -0.335, P = 0.010) or were exposed to cigarette smoke (regression coefficient 0.353, P = 0.007) showed a greater change in tPEF/tE after bronchodilation, independent of sex, prematurity, and family history of asthma or atopy.

CONCLUSION

Infants who recover from bronchiolitis and have a shorter duration of breastfeeding or are exposed to cigarette smoke, have TBFV measurements indicative of obstructive lung disease.

Breastfeeding and risk of childhood asthma: a systematic review and meta-analysis

OBJECTIVE

To investigate the relationship between breastfeeding and the development of paediatric asthma.

METHODS

A systematic review and meta-analysis was conducted with MEDLINE, Embase, CINAHL and ProQuest Nursing and Allied Health source databases. Retrospective/prospective cohorts in children aged <18 years with breastfeeding exposure reported were included. The primary outcome was a diagnosis of asthma by a physician or using a guideline-based criterion. A secondary outcome was asthma severity.

RESULTS

42 studies met inclusion criteria. 37 studies reported the primary outcome of physician-/guideline-diagnosed asthma, and five studies reported effects on asthma severity. Children with longer duration/more breastfeeding compared to shorter duration/less breastfeeding have a lower risk of asthma (OR 0.84, 95% CI 0.75-0.93; I2 = 62.4%). Similarly, a lower risk of asthma was found in children who had more exclusive breastfeeding versus less exclusive breastfeeding (OR 0.81, 95% CI 0.72-0.91; I2=44%). Further stratified analysis of different age groups demonstrated a lower risk of asthma in the 0-2-years age group (OR 0.73, 95% CI 0.63-0.83) and the 3-6-years age group (OR 0.69, 95% CI 0.55-0.87); there was no statistically significant effect on the ≥7-years age group.

CONCLUSION

The findings suggest that the duration and exclusivity of breastfeeding are associated with a lower risk of asthma in children aged <7 years.

Microbial Glycoside Hydrolases in the First Year of Life: An Analysis Review on Their Presence and Importance in Infant Gut

The first year of life is a crucial period during which the composition and functionality of the gut microbiota develop to stabilize and resemble that of adults. Throughout this process, the gut microbiota has been found to contribute to the maturation of the immune system, in gastrointestinal physiology, in cognitive advancement and in metabolic regulation. Breastfeeding, the “golden standard of infant nutrition,” is a cornerstone during this period, not only for its direct effect but also due to its indirect effect through the modulation of gut microbiota. Human milk is known to contain indigestible carbohydrates, termed human milk oligosaccharides (HMOs), that are utilized by intestinal microorganisms. Bacteria that degrade HMOs like Bifidobacterium longum subsp. infantis, Bifidobacterium bifidum, and Bifidobacterium breve dominate the infant gut microbiota during breastfeeding. A number of carbohydrate active enzymes have been found and identified in the infant gut, thus supporting the hypothesis that these bacteria are able to degrade HMOs. It is suggested that via resource-sharing and cross-feeding, the initial utilization of HMOs drives the interplay within the intestinal microbial communities. This is of pronounced importance since these communities promote healthy development and some of their species also persist in the adult microbiome. The emerging production and accessibility to metagenomic data make it increasingly possible to unravel the metabolic capacity of entire ecosystems. Such insights can increase understanding of how the gut microbiota in infants is assembled and makes it a possible target to support healthy growth. In this manuscript, we discuss the co-occurrence and function of carbohydrate active enzymes relevant to HMO utilization in the first year of life, based on publicly available metagenomic data. We compare the enzyme profiles of breastfed children throughout the first year of life to those of formula-fed infants.

The effect of diet in infancy on asthma in young adults: the Merthyr Allergy Prevention Study

INTRODUCTION

Early infant diet might influence the risk of subsequent allergic disease.

METHODS

The Merthyr Allergy Prevention Study (MAPS) was a randomised controlled trial in infants at high risk of allergic disease. The trial determined whether a cow's milk exclusion diet for the first 4 months of life decreased the risk of allergic disease including asthma compared with a normal diet. A soya milk preparation was offered to those in the intervention group. A standardised questionnaire for allergic disease was completed at ages 1, 7, 15 and 23 years, with clinical assessment at 1, 7 and 23 years. The effect of the intervention on the risk of atopy, asthma and wheeze at age 23 years was determined.

FINDINGS

487 subjects entered the study; at age 23 years 299 completed the questionnaire, of which 119 attended clinical assessment. Subjects randomised to the intervention group had a significantly increased risk of atopy (adjusted OR 2.97, 95% CI 1.30 to 6.80; p=0.01) and asthma (OR 2.07, 95%CI 1.09 to 3.91; p=0.03) at age 23 years, but not wheeze (OR 1.43, 95%CI 0.87 to 2.37; p=0.16). Earlier exposure to cow's milk was associated with a decreased risk of wheeze and asthma at age 23 years, while earlier exposure to soya milk was associated with an increased risk of atopy and asthma.

INTERPRETATION

In infants at high risk of allergic disease, either cow's milk exclusion or early soya milk introduction for the first 4 months of life increases the risk of atopy, wheeze and asthma in adulthood.

Butyrate: A Link between Early Life Nutrition and Gut Microbiome in the Development of Food Allergy

Increased prevalence of food allergies in the last thirty years has been attributed to lifestyle changes in Westernized countries. Among the environmental factors, nutritional factors and their interaction with the gut microbiome in early life are thought to have an important role in the observed epidemiological change. The gut microbiome synthesizes bacterial metabolites, which represent a link among gut microbiome, nutrition, and immune system. The main metabolites produced by gut microbiome are short-chain fatty acids (SCFAs). SCFAs have multiple beneficial effects on human health including protective effects in autoimmune and inflammatory diseases. Among SCFAs, butyrate is essential for maintaining gut immune homeostasis and exerts a pivotal role in immune tolerance with strong anti-inflammatory effects in allergic diseases. Recent findings suggest that butyrate takes part in the development of immunological tolerance to food, especially in the first 1000 days of life. Herein, we provide a critical review of the scientific literature on the role of butyrate for prevention and treatment of food allergies with focus on the complex interplay among early life nutrition, gut microbiome, and immune system.

Duration of breastfeeding, age at introduction of complementary foods and allergy-related diseases: a prospective cohort study

Background

The influences of breastfeeding and infant diet in the prevention of allergy-related diseases are uncertain and many of the studies conducted on the topic are limited by methodological challenges. Our aim was to assess whether the duration of breastfeeding and age at complementary food introduction affected the prevalence of asthma, wheeze, allergic rhinoconjunctivitis (ARC) and eczema at two and six years of age.

Methods

We used information gathered between 2000 and 2014 through questionnaires in the Prevention of Allergy among Children in Trondheim (PACT) study, a prospective cohort study in Trondheim, Norway. The current study includes 6802 children who submitted questionnaires detailing breastfeeding duration and or age at introduction to complementary foods, as well as at least one of the child health questionnaires completed at two and six years of age. Adjusted odds ratios (aORs) were calculated for each combination of exposure and outcomes and sensitivity analyses were performed to assess the possible influence of recall bias and reverse causality.

Results

The mean duration of breastfeeding was 11 months (SD 5.6) in this study population and 5695 of 6796 (84%) infants had been breastfed for at least 6 months. We did not find any conclusive preventative effect of longer breastfeeding on parental reported doctor-diagnosed asthma, aOR 0.79 (95% CI 0.51, 1.21). However, at 6 years of age we observed a reduction in the less strictly defined outcome wheeze, aOR 0.71 (95% CI 0.53, 0.95). Longer breastfeeding was associated with a reduced risk of ARC at 2 years, aOR 0.65 (95% CI 0.49, 0.86), with a continued protective trend at 6 years, aOR 0.77 (95% CI 0.58, 1.04).

Conclusions

Longer breastfeeding resulted in a reduced risk of wheeze and a trend towards a protective effect on ARC up until school age. No conclusive associations were seen between the duration of breastfeeding or age at introduction to complementary foods and prevention of asthma, wheeze, ARC and eczema.

Trial registration

The trial is registered in Current Controlled Trials as ISRCTN28090297.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13006-020-00352-2.

Do Human Milk Oligosaccharides Protect Against Infant Atopic Disorders and Food Allergy?

Atopic disorders (AD), often coexistent with food allergy (FA), start developing in early life and have lifelong health consequences. Breastfeeding is thought to be protective against AD and FA, but the data are controversial, and mechanisms are not well understood. Human milk oligosaccharides (HMOs) are complex carbohydrates that are abundant in human milk. These are thought to contribute to the development of the infant immune system by (i) promoting healthy microbiome, (ii) inhibiting pathogen binding to gut mucosa and (iii) modulating the immune system. Differences in microbiome composition between allergic and healthy infants have been observed, regardless of breastfeeding history. To date, limited studies have examined the preventive effects of HMOs on AD and FA in infants and current data relies on observation studies as trials of varying HMO intake through randomising individuals to breastfeeding are unethical. There is evidence for beneficial effects of breastfeeding on lowering the risks of FA, eczema and asthma but there are inconsistencies amongst studies in the duration of breastfeeding, diagnostic criteria for AD and the age at which the outcome was assessed. Furthermore, current analytical methods primarily used today only allow detection of 16-20 major HMOs while more than 100 types have been identified. More large-scale longitudinal studies are required to investigate the role of HMO composition and the impact of changes over the lactation period in preventing AD and FA later in life.

Respiratory Health of Pacific Youth: An Observational Study of Associated Risk and Protective Factors Throughout Childhood

BACKGROUND

Respiratory disease is the third most common cause of death in New Zealand, with Pacific people living in New Zealand bearing the greatest burden of this type of disease. Although some epidemiological outcomes are known, we lack the specifics required to formulate targeted and effective public health interventions. The Pacific Islands Families (PIF) birth cohort study is a study that provides a unique source of data to assess lung function and current respiratory health among participants entering early adulthood and to examine associations with early life events during critical periods of growth.

OBJECTIVE

This paper aims to provide an overview of the design, methods, and scope of the Respiratory Health of Pacific Youth Study, which uses the overall PIF study cohort aged 18-19 years.

METHODS

From 2000-2019, the PIF study has followed, from birth, the growth, and the development of 1398 Pacific children born in Auckland, New Zealand. Participants were nested within the overall PIF study (at ages 18-19 years) from June 2018, and assessments were undertaken until mid-November 2019. The assessments included respiratory and general medical histories, a general physical examination, assessment of lung function (forced expiratory volume and forced vital capacity), self-completed questionnaires (St George's Respiratory Questionnaire, European Quality of Life 5 Dimensions-3 Level, Epworth Sleepiness Scale for Children and Adolescents, and Leicester Cough Questionnaire), blood tests (eosinophils, Immunoglobulin E, Immunoglobulin G, Immunoglobulin A, Immunoglobulin M, and C-reactive protein), and chest x-rays. Noninferential analyses will be carried out on dimensionally reduced risk and protective factors and confounders.

RESULTS

Data collection began in June 2018 and ended in November 2019, with a total of 466 participants recruited for submission of the paper. Collection and collation of chest x-ray data is still underway, and data analysis and expected results will be published by November 2020.

CONCLUSIONS

This is the first longitudinal observational study to address the burden of respiratory disease among Pacific youth by determining factors in early life that impose long-term detriments in lung function and are associated with the presence of respiratory illness. Identifying risk factors and the magnitude of their effects will help in adopting preventative measures, establishing whether any avoidable risks can be modified by later resilient behaviors, and provide baseline measurements for the development of respiratory disease in later adult life. The study results can be translated into practice guidelines and inform health strategies with immediate national and international impact.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/18916.

The Interplay Between Eczema and Breastfeeding Practices May Hide Breastfeeding's Protective Effect on Childhood Asthma

BACKGROUND

Longer duration of breastfeeding may be protective against asthma. However, early manifestations of allergic disease, such as eczema, are risk factors for asthma and can influence the duration of breastfeeding, and hence, may bias observable associations.

OBJECTIVE

To examine the relationship between breastfeeding ever and duration and the development of asthma and allergic asthma phenotypes, stratified by a diagnosis of eczema during or after the breastfeeding period.

METHODS

A total of 3663 children participated in the 6-year-old follow-up of the HealthNuts study, a population-based, longitudinal study of allergic diseases in Australia. At age 1 year, breastfeeding and eczema data were collected and at age 6 years, information on wheeze, medication use, and parental report of doctor-diagnosed asthma were obtained, both via questionnaire. Skin prick test responses to food and aeroallergens at age 6 years further distinguished asthmatic children into allergic and nonallergic phenotypes.

RESULTS

Breastfeeding initiation was not associated with current asthma at age 6 years (adjusted odds ratio, 0.76; 95% CI, 0.45-1.29) when compared with never breastfeeding. Results were similar for length of exclusiveness and overall duration of breastfeeding, and allergic and nonallergic asthma phenotypes. However, increased duration of breastfeeding among children without eczema in infancy was associated with reduced odds of asthma (per month increase, adjusted odds ratio, 0.98; 95% CI, 0.95-1.0; P = .05), which equates to 0.86 (95% CI, 0.74-1.0) reduced odds of asthma for a 6-month increase in breastfeeding. This association was not apparent in children who were diagnosed with eczema during breastfeeding (adjusted odds ratio, 1.03; 95% CI, 0.98-1.08; P = .3).

CONCLUSIONS

Longer duration of breastfeeding was associated with a reduced odds of asthma among children without eczema in the first year of life; this association was masked before stratification by eczema in infancy. Future studies examining breastfeeding practices and the risk of allergic outcomes in later childhood need to consider the presence of early-life allergic manifestations impacting on breastfeeding behavior.

Contrasting microbiotas between Finnish and Estonian infants: Exposure to Acinetobacter may contribute to the allergy gap

BACKGROUND

Allergic diseases are more common in Finland than in Estonia, which-according to the biodiversity hypothesis-could relate to differences in early microbial exposures.

METHODS

We aimed at defining possible microbial perturbations preceding early atopic sensitization. Stool, nasal and skin samples of 6-month-old DIABIMMUNE study participants with HLA susceptibility to type 1 diabetes were collected. We compared microbiotas of sensitized (determined by specific IgE results at 18 months of age) and unsensitized Estonian and Finnish children.

RESULTS

Sensitization was differentially targeted between populations, as egg-specific and birch pollen-specific IgE was more common in Finland. Microbial diversity and community composition also differed; the genus Acinetobacter was more abundant in Estonian skin and nasal samples. Particularly, the strain-level profile of Acinetobacter lwoffii was more diverse in Estonian samples. Early microbiota was not generally associated with later sensitization. Microbial composition tended to differ between children with or without IgE-related sensitization, but only in Finland. While land-use pattern (ie green areas vs. urban landscapes around the children's homes) was not associated with microbiota as a whole, it associated with the composition of the genus Acinetobacter. Breastfeeding affected gut microbial composition and seemed to protect from sensitization.

CONCLUSIONS

In accordance with the biodiversity hypothesis, our results support disparate early exposure to environmental microbes between Finnish and Estonian children and suggest a significant role of the genus Acinetobacter in the allergy gap between the two populations. The significance of the observed differences for later allergic sensitization remains open.

Exclusive breastfeeding for the first 3 months of life may reduce the risk of respiratory allergies and some asthma in children at the age of 6 years

AIM

We examined the associations between breastfeeding and respiratory allergies and types of asthma in American children.

METHODS

This longitudinal study used data from mother-infant pairs who took part in the Infant Feeding Practices Study II in 2005-2007 and the Year 6 Follow-Up Study in 2012. The mothers reported breastfeeding practices on a monthly basis for the first year of life, childhood asthma and allergies at age 6 years, and associated factors. Generalised linear models were used in statistical analyses.

RESULTS

Overall, 1177 mother-infant pairs were included in the sample. A third (32.9%) of the children were exclusively breastfed until the age of 3 months and by the age of 6 years 20.8% had been diagnosed with respiratory allergies and 11.3% with asthma. In the multivariable analyses, exclusive breastfeeding for 3 months was associated with a reduced relative risk of respiratory allergies of 0.77 at the age of 6 years. It also reduced the relative risk of asthma to 0.66, but only if the children did not have a family history of asthma.

CONCLUSION

This longitudinal study provided evidence that exclusive breastfeeding for the first 3 months may reduce the risk of respiratory allergies and asthma in children 6 years of age, but concerning asthma, statistical significance was reached only in children without a family predisposition to asthma.

Gut Microbiome Modulation for Preventing and Treating Pediatric Food Allergies

The increasing prevalence and severity of pediatric food allergies (FA) demands innovative preventive and therapeutic strategies. Emerging evidence suggests a pivotal role for the gut microbiome in modulating susceptibility to FA. Studies have demonstrated that alteration of gut microbiome could precede FA, and that particular microbial community structures early in life could influence also the disease course. The identification of gut microbiome features in pediatric FA patients is driving new prevention and treatment approaches. This review is focused on the potential role of the gut microbiome as a target for FA prevention and treatment.

Greenlandic women´s lifestyle and diet during pregnancy and child risk for asthma, eczema and allergy: an ACCEPT-substudy

Persistent Organic Pollutants (POPs) are environmental chemicals bio-accumulating through the food chain. POPs can affect the foetal development of the immune, the neural and the reproductive system. POPs are endocrine disruptors and shown to interfere with child vaccination responses. Our hypothesis is that POPs interfere with the immune system increasing the risk of asthma, allergy and eczema. In a pilot cross-sectional study, we sent 120 questionnaires to Inuit mothers to elucidate the relation between smoking during pregnancy and the risk of child asthma, allergy and eczema, and the possible modifying effect of breastfeeding. Fifty-one mothers responded. We found that the risk of getting allergy among the offspring was higher when the mother had been smoking during pregnancy and the child being breastfed <12 months (OR = 5.67, 95% CI: 0.754; 42.58, p = 0.092). Furthermore, we found that children with eczema were predisposed of having asthma (OR = 19.6, 95% CI: 2.19; 176, p = 0.008), also allergy when breastfed >12 months (OR = 17.0, 95% CI: 1.02; 283, p = 0.048).

Abbreviation: ACCEPT (Adaptation to Climate Change, Environmental Pollution, and Dietary Transition).

Are mothers less likely to breastfeed in harsh environments? Physical environmental quality and breastfeeding in the Born in Bradford study

We use the United Kingdom's Born in Bradford study to investigate whether women in lower quality environments are less likely to breastfeed. We use measures of physical environmental quality (water disinfectant by-products [DBPs], air pollution, passive cigarette smoke, and household condition) alongside socio-economic indicators, to explore in detail how different exposures influence breastfeeding. Drawing on evolutionary life history theory, we predict that lower environmental quality will be associated with lower odds of initiating, and higher hazards of stopping, breastfeeding. As low physical environmental quality may increase the risk of adverse birth outcomes, which may in turn affect breastfeeding chances, we also test for mediation by gestational age, birthweight, head circumference, and abdominal circumference. Our sample is composed of mothers who gave birth at the Bradford Royal Infirmary in West Yorkshire between March 2007 and December 2010 for whom breastfeeding initiation data was available. Analyses were stratified by the two largest ethnic groups: White British (n = 3,951) and Pakistani-origin (n = 4,411) mothers. After controlling for socio-economic position, Pakistani-origin mothers had lower chances of initiating and higher chances of stopping breastfeeding with increased water DBP exposure (e.g., OR for 0.03-0.61 vs. <0.02 μg/day dibromochloromethane exposure 0.70 [0.58-0.83], HR 1.16 [0.99-1.36]), greater air pollution exposure predicted lower chances of initiation for both ethnic groups (e.g., OR for 10 μg/m³ increase in nitrogen dioxide 0.81 [0.66-0.99] for White British mothers and 0.79 [0.67-0.94] for Pakistani-origin mothers) but also a reduced hazard of stopping breastfeeding for White British mothers (HR 0.65 [0.52-0.80]), and exposure to household damp/mould predicted higher chances of breastfeeding initiation amongst White British mothers (OR 1.66 [1.11-2.47]). We found no evidence that physical environmental quality effects on breastfeeding were mediated through birth outcomes amongst Pakistani-origin mothers and only weak evidence (p < 0.10) amongst White British mothers (exposure to passive cigarette smoke was associated with having lower birthweight infants who were in turn less likely to be breastfed whereas greater air pollution exposure was associated with longer gestations and in turn reduced hazards of stopping breastfeeding). Overall, our findings suggest that there is differential susceptibility to environmental exposures according to ethnicity. Although the water DBP results for Pakistani-origin mothers and air pollution-initiation results for both ethnic groups support our hypothesis that mothers exhibit reduced breastfeeding in poorer quality environments, several physical environmental quality indicators showed null or positive associations with breastfeeding outcomes. We consider physiological explanations for our findings and their implications for life history theory and public health policy.

Elevated faecal 12,13-diHOME concentration in neonates at high risk for asthma is produced by gut bacteria and impedes immune tolerance

Neonates at risk of childhood atopy and asthma exhibit perturbation of the gut microbiome, metabolic dysfunction and increased concentrations of 12,13-diHOME in their faeces. However, the mechanism, source and contribution of this lipid to allergic inflammation remain unknown. Here, we show that intra-abdominal treatment of mice with 12,13-diHOME increased pulmonary inflammation and decreased the number of regulatory T (T_reg) cells in the lungs. Treatment of human dendritic cells with 12,13-diHOME altered expression of PPARγ-regulated genes and reduced anti-inflammatory cytokine secretion and the number of T_reg cells in vitro. Shotgun metagenomic sequencing of neonatal faeces indicated that bacterial epoxide hydrolase (EH) genes are more abundant in the gut microbiome of neonates who develop atopy and/or asthma during childhood. Three of these bacterial EH genes (3EH) specifically produce 12,13-diHOME, and treatment of mice with bacterial strains expressing 3EH caused a decrease in the number of lung T_reg cells in an allergen challenge model. In two small birth cohorts, an increase in the copy number of 3EH or the concentration of 12,13-diHOME in the faeces of neonates was found to be associated with an increased probability of developing atopy, eczema or asthma during childhood. Our data indicate that elevated 12,13-diHOME concentrations impede immune tolerance and may be produced by bacterial EHs in the neonatal gut, offering a mechanistic link between perturbation of the gut microbiome during early life and atopy and asthma during childhood.

The crosstalk between microbiome and asthma: Exploring associations and challenges

With the advancement of high‐throughput DNA/RNA sequencing and computational analysis techniques, commensal bacteria are now considered almost as important as pathological ones. Understanding the interaction between these bacterial microbiota, host and asthma is crucial to reveal their role in asthma pathophysiology. Several airway and/or gut microbiome studies have shown associations between certain bacterial taxa and asthma. However, challenges remain before gained knowledge from these studies can be implemented into clinical practice, such as inconsistency between studies in choosing sampling compartments and/or sequencing approaches, variability of results in asthma studies, and not taking into account medication intake and diet composition especially when investigating gut microbiome. Overcoming those challenges will help to better understand the complex asthma disease process. The therapeutic potential of using pro‐ and prebiotics to prevent or reduce risk of asthma exacerbations requires further investigation. This review will focus on methodological issues regarding setting up a microbiome study, recent developments in asthma bacterial microbiome studies, challenges and future therapeutic potential.

Prevention of allergy with diverse and healthy microbiota: an update

PURPOSE OF REVIEW

Microbiota consist of symbiotic microscopic neighbors that interact on and within our bodies in diverse and incompletely understood ways throughout our lifetime. Though various associations with allergic disease have been described, clear effective therapeutic interventions to prevent allergy have been elusive.

RECENT FINDINGS

The human microbiome is influenced by multiple factors, including: mode of infant delivery (vaginal vs. cesarean section), breastfeeding, diet, presence of siblings and pets, exposure to antibiotics and other medications (particularly antacids), lifestyle, and developmental context. Microbial species promoting atopic responses and tolerance have been described. Specific microbiota likely act through distinct metabolic pathways to promote the health of their human hosts, optimally directing the developing immune system away from pro-allergic, Th2-dominated responses to more T-regulatory-influenced behaviors.

SUMMARY

Evidence suggests that specific healthy infant microbiome signatures may influence development of some components of the allergic march of childhood by decreasing atopic dermatitis, asthma, and food allergy. Further understanding of factors that influence healthy microbiota may lead to specific strategies tailored for early intervention and disease prevention.

Infant milk-feeding practices and food allergies, allergic rhinitis, atopic dermatitis, and asthma throughout the life span: a systematic review

BACKGROUND

During the Pregnancy and Birth to 24 Months Project, the USDA and Department of Health and Human Services initiated a review of evidence on diet and health in these populations.

OBJECTIVES

The aim of these systematic reviews was to examine the relation of 1) never versus ever feeding human milk, 2) shorter versus longer durations of any human milk feeding, 3) shorter versus longer durations of exclusive human milk feeding prior to infant formula introduction, 4) feeding a lower versus higher intensity of human milk to mixed-fed infants, and 5) feeding a higher intensity of human milk by bottle versus breast with food allergies, allergic rhinitis, atopic dermatitis, and asthma.

METHODS

The Nutrition Evidence Systematic Review team conducted systematic reviews with external experts. We searched CINAHL, Cochrane, Embase, and PubMed for articles published between January 1980 and March 2016, dual-screened the results according to predetermined criteria, extracted data from and assessed the risk of bias for each included study, qualitatively synthesized the evidence, developed conclusion statements, and graded the strength of the evidence.

RESULTS

The systematic reviews numbered 1-5 above included 44, 35, 1, 0, and 0 articles, respectively. Moderate, mostly observational, evidence suggests that 1) never versus ever being fed human milk is associated with higher risk of childhood asthma, and 2) among children and adolescents who were fed human milk as infants, shorter versus longer durations of any human milk feeding are associated with higher risk of asthma. Limited evidence does not suggest associations between 1) never versus ever being fed human milk and atopic dermatitis in childhood or 2) the duration of any human milk feeding and allergic rhinitis and atopic dermatitis in childhood.

CONCLUSIONS

Moderate evidence suggests that feeding human milk for short durations or not at all is associated with higher childhood asthma risk. Evidence on food allergies, allergic rhinitis, and atopic dermatitis is limited.

Gut Microbiome as Target for Innovative Strategies Against Food Allergy

The dramatic increase in food allergy prevalence and severity globally requires effective strategies. Food allergy derives from a defect in immune tolerance mechanisms. Immune tolerance is modulated by gut microbiota function and structure, and microbiome alterations (dysbiosis) have a pivotal role in the development of food allergy. Environmental factors, including a low-fiber/high-fat diet, cesarean delivery, antiseptic agents, lack of breastfeeding, and drugs can induce gut microbiome dysbiosis, and have been associated with food allergy. New experimental tools and technologies have provided information regarding the role of metabolites generated from dietary nutrients and selected probiotic strains that could act on immune tolerance mechanisms. The mechanisms are multiple and still not completely defined. Increasing evidence has provided useful information on optimal bacterial species/strains, dosage, and timing for intervention. The increased knowledge of the crucial role played by nutrients and gut microbiota-derived metabolites is opening the way to a post-biotic approach in the stimulation of immune tolerance through epigenetic regulation. This review focused on the potential role of gut microbiome as the target for innovative strategies against food allergy.

Breastfeeding initiation and duration and child health outcomes in the first baby study

Despite the known benefits of breastmilk, associations between breastfeeding and child overall health outcomes remain unclear. We aimed to understand associations between breastfeeding and health outcomes, including child weight, through age 3. Analysis included women (N = 3006) in the longitudinal, prospective First Baby Study from 2009 to 2014. For this analysis, breastfeeding initiation and duration were measured using self-reported data from the 1-, 6- and 12-month surveys; child illnesses were analyzed from the 6-, 12-, and 24-month interviews; height and weight at age 3 were used to determine overweight/obese (≥85th percentile) and obese (≥95th percentile). Adjusted logistic regressions were utilized to determine significance. Greater duration of breastfeeding was associated with fewer reported acute illnesses at 6 months (p < 0.001) and fewer diarrheal illness/constipation episodes at 6, 12, and 24 months (p = 0.05) in adjusted analyses. Fewer breastfed children, compared to non-breastfed children, were overweight/obese (23.5% vs. 37.8%; p = 0.032) or obese (9.1% vs. 21.6%; p = 0.012) at age 3. Breastfeeding duration was negatively associated with overweight/obese (never breastfed: 37.8%, 0-6 months: 26.9%, >6 months: 20.2%; p = 0.020) and obesity (never breastfed: 21.6%, 0-6 months: 11.0%, >6 months: 7.3%; p = 0.012). Overall, our findings support the hypothesis that duration of breastfeeding is associated with fewer reported acute illnesses at 6 months of age and diarrheal illness and/or constipation episodes at 6, 12, and 24 months. Additionally, results from our study suggest a protective effect of breastfeeding from childhood overweight/obesity, as children who received breastmilk for 6 months or longer had lower odds of overweight/obesity at age 3 years.

Dynamics of allergy development during the first 5 years of life

Allergic diseases have increased in developed countries during the past decades. A cohort of Slovak children was followed from birth to track allergic symptoms dynamics in early childhood. Information on allergic symptoms (atopic dermatitis = AD, rhino conjunctivitis = RC, wheezing = Wh, urticaria = Ur) and food allergies among children was based on clinical evaluation of children by allergists at three developmental stages (infant, toddler, preschool). Out of 320 cases of allergies, 64 infants, 145 toddlers, and 195 preschool children suffered from AD, RC, Wh, Ur, or their combinations (i.e., significant increase with age, p < 0.001). AD first appeared in infants, Wh and/or RC rose mainly in toddlers, and Ur among preschool children. AD in infants or toddlers disappeared in the subsequent developmental stage in approximately one third of all cases. Single AD persistence without remission or extension was not common and accounted only for 6.9% of AD infants' allergic manifestations. In addition to single-symptom allergic diseases, this study also identified several combinations of atopic symptoms.Conclusions: The proportion of multi-symptom allergies increased while single-symptom forms decreased. The observed temporal trends of allergic symptoms correspond to the atopic march. What is Known: • The observed temporal trends of allergic symptoms correspond to the atopic march. What is New: • Allergic diseases in children were first manifested as single forms, with atopic dermatitis (AD) commonly functioning as the "entry point" to allergies. • The overall proportion of single-symptom allergic disorders decreased over time while the proportion of multi-symptom allergies increased.

The effect of breastfeeding on the risk of asthma in high-risk children: a case-control study in Shanghai, China

BACKGROUND

Increasing evidence shows that antibiotic use in pregnancy may increase the risk of childhood asthma but epidemiologic studies are still limited and findings are inconsistent. Meanwhile, exclusive and prolonged breastfeeding may prevent children from allergic diseases. We aimed to assess the association between prenatal antibiotic use and the risk of childhood asthma, and explore whether breastfeeding modifies the risk.

METHODS

We conducted a case-control study in Shanghai, China, from June 2015 to January 2016. A total of 634 asthma cases and 864 controls aged 3-12 years were included. Multiple logistic regressions were used to estimate crude and adjusted odds ratios (aOR).

RESULTS

The prevalence of antibiotic use in pregnancy in the cases and controls was 7.1 and 3.5%, respectively. A significant association between prenatal antibiotic use and childhood asthma was observed (aOR: 1.7, 95% CI: 1.0-2.9), particularly in boys (aOR: 2.2, 95% CI: 1.1-4.4) and children with family history of allergic disorders (aOR: 3.1, 95% CI: 1.2-8.4). However, this association existed only in children who were not breastfed exclusively in the first six months of life (aOR 2.6, 95% CI 1.3-5.1) but not in children who were exclusively breastfed (aOR 0.9, 95% CI 0.4-2.1). Likewise, exclusive breastfeeding also decreased the association between antibiotic use in pregnancy and asthma in boys and in children with family histories of allergic diseases.

CONCLUSIONS

Antibiotic use in pregnancy was a risk factor for childhood asthma. However, this risk may be attenuated by exclusive breastfeeding in the first six months of life, especially among high-risk children.

Influences of Cesarean Delivery on Breastfeeding Practices and Duration: A Prospective Cohort Study

BACKGROUND

Mothers are encouraged to exclusively breastfeed for the first 6 months. However, cesarean delivery rates have increased worldwide, which may affect breastfeeding. Research aim: This study aimed to determine the potential effects of cesarean delivery on breastfeeding practices and breastfeeding duration.

METHODS

This was a 6-month cohort study extracted from a 24-month prospective cohort study of mother-infant pairs in three communities in Hunan, China. Data about participants' characteristics, delivery methods, breastfeeding initiation, use of formula in the hospital, exclusive breastfeeding, and any breastfeeding were collected at 1, 3, and 6 months following each infant's birth. The chi-square test, logistic regression model, and Cox proportional hazard regression model were used to examine the relationship between breastfeeding practices and cesarean delivery.

RESULTS

The number of women who had a cesarean delivery was 387 (40.6%), and 567 (59.4%) women had a vaginal delivery. The exclusive breastfeeding rates at 1, 3, and 6 months were 80.2%, 67.4%, and 21.5%, respectively. Women who had a cesarean delivery showed a lower rate of exclusive breastfeeding and any breastfeeding than those who had a vaginal delivery ( p < .05). In addition, cesarean delivery was related with using formula in the hospital and delayed breastfeeding initiation. Cesarean delivery also shortened the breastfeeding duration (hazard ratio = 1.40, 95% confidence interval [1.06, 1.84]).

CONCLUSION

Healthcare professionals should provide more breastfeeding skills to women who have a cesarean delivery and warn mothers about the dangers of elective cesarean section for breastfeeding practices.

Potential Role of the Lung Microbiome in Shaping Asthma Phenotypes

The introduction of 16s ribosomal RNA sequencing as a nonculture technique has led to the discovery of the presence of microbiota in the lower airways of healthy individuals. These bacterial communities may originate from the mouth and nasopharynx or from the environment by inhalation. The microbial composition of the lower airways may be modulated by dietary factors, antibiotic therapy, and microbial infections, particularly in early life. In addition, circulatory products from gut microbiota may influence the lung microbiota to maintain mucosal immunity. Recent studies have revealed that, in asthma, the lower airway microbiota show reduced diversity and community composition that is linked to severity and inflammatory phenotype. There is also a greater prevalence of proteobacteria, including Haemophilus, in symptomatic asthma. Microbial dysbiosis may contribute to both the inception and progression of asthma in infants and children, and to corticosteroid resistance in asthma. A better understanding of the regulation of the lung and gut microbiota in asthma may pave the way for targeting microbiota to prevent and treat asthma.

Contribution of early nutrition on the development of malnutrition and allergic diseases in the first year of life: a study protocol for the Mother and Infant Cohort Study (MICOS)

BACKGROUND

Nutrition and environmental factors are essential for the education of the neonatal immune system. Epidemiological evidence has shown that malnutrition and allergic diseases that occur during early childhood share similar protective and risk factors. This paper describes the protocol of the Mother and Infant Cohort Study (MICOS), which aims to determine the contribution of early nutrition to the development of malnutrition and allergic diseases in infants' first year of life.

METHODS

MICOS is a prospective cohort study conducted at selected government health clinics in two states, namely Selangor and Wilayah Persekutuan Kuala Lumpur, Malaysia. Women in their third trimester of pregnancy are recruited into the study and their infants will be followed-up at 3, 6, and 12 months of age. Information on prenatal factors including socio-demographic characteristics, obstetric history, pre-pregnancy body mass index, gestational weight gain, smoking, family history of allergic diseases, maternal dietary intake and sunlight exposure during pregnancy are obtained through face-to-face interviews. Postnatal factors including dietary intake, sun exposure, and anthropometric measurements of the mothers, as well as feeding practices, dietary intake, anthropometric measurements, and development of allergic diseases of the infants are assessed at each follow-up. Blood samples are collected from the mothers in the third trimester to determine 25-hydroxyvitamin D levels as well as from the infants at age 12 months to determine atopic sensitisation.

DISCUSSION

The concept of developmental origins of health and disease (DOHaD) which emphasises on the role of early life environments in shaping future health and disease susceptibility in adulthood has gained a huge interest in recent years. The DOHaD paradigm has influenced many fields of research including malnutrition and allergic diseases. While findings from the developed countries remain controversial, such studies are scarce in developing countries including Malaysia. The present study will determine the cause and effect relationship between early nutrition and the development of malnutrition and allergic diseases in infants' first year of life.

Hair nicotine at 15 months old, tobacco exposure and wheeze or asthma from 15 months to 6 years old

OBJECTIVE

To investigate the relationship between hair nicotine levels at 15 months of age and prior parent-reported smoking exposure, and the risk of wheezing and current asthma from 15 months to 6 years of age.

STUDY DESIGN

We measured hair nicotine levels at 15 months of age in 376 of 535 infants enrolled in a prospective birth cohort in Christchurch, New Zealand. We obtained detailed information from parents about smoking exposure during pregnancy and in the home at 3 and 15 months of age. Data for demographics, wheezing, and asthma were obtained from yearly questionnaires up to age 6 years. We assessed hair nicotine levels in relation to reported smoke exposure in pregnancy and up to age 15 months, and the association between high levels of hair nicotine and annual reports of current wheeze and current asthma using multiple logistic regression.

RESULTS

Hair nicotine increased with numbers of smokers and daily cigarettes smoked at home, and was also strongly associated with smoking in pregnancy. High level of hair nicotine was associated with increased risk of wheeze (Odds ratio 2.30, P = 0.001) and, though not significant, of current asthma (Odds ratio 2.02, P = 0.056) at 15 months of age, after controlling for socio-economic status, ethnicity, body mass index, respiratory infections in the first 3 months of life, and duration of exclusive breastfeeding. At older ages the associations were non-significant.

CONCLUSION

In children aged 15 months hair nicotine level was related to smoking exposure, and was associated with increased risk of wheeze and asthma.

Relationship between breastfeeding and asthma prevalence in young children exposed to adverse childhood experiences

OBJECTIVE

To investigate if duration of supplemental breastfeeding is associated with a lower asthma risk and whether adverse childhood experiences (ACEs) early in life influence this relationship in children ages 3 to 5 years.

METHODS

Data were from the 2011-2012 National Survey of Children's Health, a nationally representative cross-sectional survey. Modified Poisson regression models were used to estimate incident risk ratios (IRR) for lifetime and current asthma in young children aged 3 to 5 years (n = 15,642). We tested for effect measure modification using stratified analyses.

RESULTS

Exclusive breastfeeding for at least 6 months or supplemental breastfeeding for children ≥12 months significantly reduced the risk of lifetime asthma prevalence compared to never breastfed children (IRR 0.64; 95% CI: 0.46-0.88, p = 0.007; and IRR 0.68; 95% CI: 0.47-0.99, p = 0.044, respectively), adjusted for covariates. In stratified analyses, breastfeeding reduced the risk of lifetime asthma for children who experienced 1 ACE but not for children who experienced 2 or more ACEs.

CONCLUSION

Exclusive breastfeeding for at least 6 months, with and without supplementation, appears to prevent asthma or delay its onset. The protective effect of breastfeeding was attenuated among children who experienced more than 2 ACEs. The known harmful effects that ACEs have on children's health may outweigh the benefits of breastfeeding in reducing the risk of a child developing asthma. Understanding how specific time periods in a child's life may be most affected by exposure to early life adversities, along with the protective effect of breastfeeding against asthma, are important areas of further study.

Breastfeeding and the risk of childhood asthma: A two-stage instrumental variable analysis to address endogeneity

BACKGROUND

Several explanations for the inconsistent results on the effects of breastfeeding on childhood asthma have been suggested. The purpose of this study was to investigate one unexplored explanation, which is the presence of a potential endogenous relationship between breastfeeding and childhood asthma. Endogeneity exists when an explanatory variable is correlated with the error term for reasons such as selection bias, reverse causality, and unmeasured confounders. Unadjusted endogeneity will bias the effect of breastfeeding on childhood asthma.

METHODS

To investigate potential endogeneity, a cross-sectional study of breastfeeding practices and incidence of childhood asthma in 87 pediatric patients in Georgia, the USA, was conducted using generalized linear modeling and a two-stage instrumental variable analysis. First, the relationship between breastfeeding and childhood asthma was analyzed without considering endogeneity. Second, tests for presence of endogeneity were performed and having detected endogeneity between breastfeeding and childhood asthma, a two-stage instrumental variable analysis was performed. The first stage of this analysis estimated the duration of breastfeeding and the second-stage estimated the risk of childhood asthma.

RESULTS

When endogeneity was not taken into account, duration of breastfeeding was found to significantly increase the risk of childhood asthma (relative risk ratio [RR]=2.020, 95% confidence interval [CI]: [1.143-3.570]). After adjusting for endogeneity, duration of breastfeeding significantly reduced the risk of childhood asthma (RR=0.003, 95% CI: [0.000-0.240]).

CONCLUSION

The findings suggest that researchers should consider evaluating how the presence of endogeneity could affect the relationship between duration of breastfeeding and the risk of childhood asthma.

Duration and exclusiveness of breastfeeding and school-age lung function and asthma

BACKGROUND

Breastfeeding reduces the risk of asthma in early childhood, but it is not clear whether its effect on respiratory morbidity is still present in later childhood.

OBJECTIVE

To examine the associations of any breastfeeding, breastfeeding duration, and breastfeeding exclusiveness with lung function and asthma in school-aged children and whether associations were influenced by respiratory tract infections and maternal or child's atopic status.

METHODS

This study of 4,464 children was embedded in a population-based prospective cohort study. Information on breastfeeding was obtained by multiple questionnaires from birth until 1 year of age. At 10 years of age, lung function was measured by spirometry, and information on asthma was obtained by questionnaire. Adjusted linear and logistic regression models were used to examine the associations.

RESULTS

Shorter duration of breastfeeding was associated with a lower forced expiratory volume in 1 second (FEV₁) only (z score change, -0.01; 95% confidence interval [CI], -0.02 to -0.00) per month shorter breastfeeding, but not asthma. When categorized, breastfeeding for 2 to 4 months was associated with a lower forced vital capacity (FVC) (z score change, -0.11; 95% CI, -0.20 to -0.03) compared with breastfeeding for 6 months or longer. Nonexclusive breastfeeding for 4 months was associated with a lower FVC (z score change, -0.08; 95% CI, -0.16 to -0.01) compared with exclusive breastfeeding for 4 months. Results did not materially change after additional adjustment for lower respiratory tract infections and were not modified by maternal history of asthma or atopy, child's eczema, or inhalant allergic sensitization.

CONCLUSION

Shorter duration and nonexclusivity of breastfeeding were associated with a lower FEV₁ and FVC but not asthma at school-age.

The microbiome in allergic disease: Current understanding and future opportunities-2017 PRACTALL document of the American Academy of Allergy, Asthma & Immunology and the European Academy of Allergy and Clinical Immunology

PRACTALL is a joint initiative of the American Academy of Allergy, Asthma & Immunology and the European Academy of Allergy and Clinical Immunology to provide shared evidence-based recommendations on cutting-edge topics in the field of allergy and immunology. PRACTALL 2017 is focused on what has been established regarding the role of the microbiome in patients with asthma, atopic dermatitis, and food allergy. This is complemented by outlining important knowledge gaps regarding its role in allergic disease and delineating strategies necessary to fill these gaps. In addition, a review of progress in approaches used to manipulate the microbiome will be addressed, identifying what has and has not worked to serve as a baseline for future directions to intervene in allergic disease development, progression, or both.

Breastfeeding and Asthmatic Symptoms in The Offspring of Latinas: The Role of Maternal Nativity

Previous research has generally found exclusive breastfeeding to protect against asthma in young children. However, maternal nativity in a Latina population has not been assessed as a potential confounder or effect modifier. Using cross-sectional data restricted to Latina mothers (n = 704) from a birth cohort in Los Angeles interviewed in 2003 and 2006, we estimated risk ratios (RR) for exclusive breastfeeding and asthmatic symptoms in the offspring. 56 children (8%) had asthmatic symptoms at age 3.5 years. We found a 49% reduction in risk of asthmatic symptoms with >3 months of exclusive breastfeeding (aRR 0.51, 95% CI 0.28, 0.90). Foreign-born Latinas were more likely to initiate and continue breastfeeding for at least 3 months compared with US-born Latinas. Three or more months of exclusive breastfeeding reduced the risk of asthmatic symptoms in the offspring of Latinas, and maternal nativity did not confound or modify this association.

The microbiome and development of allergic disease

PURPOSE OF REVIEW

First, to review how the global rise in prevalence of asthma prompted studies of the relationships between microbial exposure in early infancy, the rate and pattern of development of immune function, and the development of allergic sensitization and of wheezing in childhood. And, second, to review how those studies laid the groundwork for a possible strategy for primary prevention of asthma through manipulation of the microbiome of the gastrointestinal and/or respiratory tracts.

RECENT FINDINGS

Atopy and asthma are complex diseases thought to result from a 'gene-by-environment' interaction; the rapidity of their rise in prevalence points to a change in environment as most likely causal. Epidemiologic studies noting associations between events in infancy and later development of atopic diseases have suggested that their rise in prevalence is related to a deficiency in microbial exposure in early life. The findings from birth cohort studies of humans and from interventional studies of mice converge in suggesting that a deficiency in microbial colonization of the respiratory or gastrointestinal tract by certain commensal microbes results in skewed development of systemic and/or local immune function that increases susceptibility to allergic sensitization and to viral lower respiratory infection. Recent studies are now honing in on identifying the microbes, or collection of microbes, whose collective functions are necessary for induction of immune tolerance, and thus of reduced susceptibility.

SUMMARY

Atopy and asthma appear to have their roots in an insufficiency of early-life exposure to the diverse environmental microbiota necessary to ensure colonization of the gastrointestinal and/or respiratory tracts with the commensal microbes necessary for induction of balanced, toleragenic immune function. Identification of the commensal bacteria necessary, now ever closer at hand, will lay the groundwork for the development of strategies for primary prevention of atopic disease, especially of childhood asthma.

Future treatment for asthma

The landscape of asthma has considerably changed after 40 years of inhaled corticosteroid development and nearly 20 years since the first monoclonal antibodies (mAbs) were approved. New members of pharmacological families and more effective drug-delivery devices have been designed but the proportion of uncontrolled patients, unfortunately, remains stable. The most promising treatments now rely on targeted therapies that encourage the improvement of the characterisation of our patients. These clinical (phenotype) or new biological (endotype) tools lead to palpable personalised medicine. This review examines not only the future of mAbs and other new ways of treating asthma but also describes futuristic views based on the paradigm shifts that are ready to occur.

Breastfeeding and timing of first dietary introduction in relation to childhood asthma, allergies, and airway diseases: A cross-sectional study

OBJECTIVES

We investigated associations of breastfeeding (BF) durations and patterns and of timing of other dietary introductions with prevalence of asthma, wheeze, hay fever, rhinitis, pneumonia, and eczema among preschool children.

METHODS

During April 2011-April 2012, we conducted a cross-sectional study in 72 kindergartens from five districts of Shanghai, China and obtained 13,335 questionnaires of children 4-6-years-old. We used multiple logistic regression models to evaluate the target associations.

RESULTS

Compared to children who were never BF, children who were exclusively breastfed 3-6 months had the lowest risk of asthma (adjusted odds ratio and 95% confidence interval: 0.81, 0.72-0.91) and wheeze (0.93, 0.87-0.99); and exclusive BF >6 months was significantly associated with a reduced risk of hay fever (0.93, 0.89-0.97), rhinitis (0.97, 0.94-0.99), pneumonia (0.97, 0.94-0.99), and eczema (0.96, 0.93-0.99). No significant associations were found between time when fruits or vegetables were introduced and the studied diseases. Associations were independent of the child's sex and parent's ownership of the current residence. Longer duration BF was only significantly protective when there was no family history of atopy.

CONCLUSIONS

This study suggests that heredity, but not sex and socioeconomic status, may negatively impact the effect of BF on childhood airway and allergic diseases. Our findings support China's national recommendation that mothers provide exclusive BF for the first four months, and continue partial BF for more than 6 months.

Factors associated with the time to the first wheezing episode in infants: a cross-sectional study from the International Study of Wheezing in Infants (EISL)

Male gender, asthmatic heredity, perinatal tobacco smoke exposure and respiratory infections have been associated with wheeze in the first years of life, among other risk factors. However, information about what factors modify the time to the first episode of wheeze in infants is lacking. The present study analyses which factors are associated with shorter time to the first episode of wheeze in infants. Parents of 11- to 24-month-old children were surveyed when attending their health-care centres for a control visit. They answered a questionnaire including the age in months when a first wheeze episode (if any) had occurred (outcome variable). The study was performed in 14 centres in Latin America (LA) and in 8 centres in Europe (EU) (at least 1,000 infants per centre). Factors known to be associated with wheezing in the cohort were included in a survival analysis (Cox proportional hazards model). Summary hazard ratios adjusted for all risk factors (aHR) were calculated using the meta-analysis approach with random effects. A total of 15,067 infants had experienced wheezing at least once, out of 35,049 surveyed. Male gender in LA (aHR 1.05, 95% confidence interval (CI) 1.00-1.10, P=0.047), parental asthma in LA and EU (aHR 1.05, 95% CI 1.00-1.11, P=0.037), infant eczema in EU (aHR 1.25, 95% CI 1.12-1.39, P<0.001) and having a cold during the first 3 months in LA and EU (aHR 1.97, 95% CI 1.90-2.04, P<0.001), in LA (aHR 1.98, 95% CI 1.90-2.06, P<0.001) and in EU (aHR 1.91, 95% CI 1.75-2.09, P<0.001) were associated with a shorter period of time to the first episode. Breast feeding for at least 3 months was associated with a longer period, only in LA (aHR 0.91, 95% CI 0.86-0.96, P<0.001). Cold symptoms during the first 3 months is the most consistent factor shortening the time to the first episode of wheezing; breast feeding for ⩾3 months delays it only in LA, whereas eczema shortens it only in EU. Avoiding a common cold in the first months of life could be a good strategy to delay the first wheeze episode; however, cohort studies will help to elucidate this association.

Gut Microbiome and the Development of Food Allergy and Allergic Disease

The impact of gut microbiome on human development, nutritional needs, and disease has become evident with advances in the ability to study these complex communities of microorganisms, and there is growing appreciation for the role of the microbiome in immune regulation. Several studies have examined associations between changes in the commensal microbiota and the development of asthma, allergic rhinitis, and asthma, but far less have evaluated the impact of the microbiome on the development of food allergy. This article reviews the human gastrointestinal microbiome, focusing on the theory and evidence for its role in the development of IgE-mediated food allergy and other allergic diseases.

Breastfeeding and asthma and allergies: a systematic review and meta-analysis

AIM

To systematically review the association between breastfeeding and childhood allergic disease.

METHODS

Predetermined inclusion/exclusion criteria identified 89 articles from PubMed, CINAHL and EMBASE databases. Meta-analyses performed for categories of breastfeeding and allergic outcomes. Meta-regression explored heterogeneity.

RESULTS

More vs. less breastfeeding (duration) was associated with reduced risk of asthma for children (5-18 years), particularly in medium-/low-income countries and with reduced risk of allergic rhinitis ≤5 years, but this estimate had high heterogeneity and low quality. Exclusive breastfeeding for 3-4 months was associated with reduced risk of eczema ≤2 years (estimate principally from cross-sectional studies of low methodological quality). No association found between breastfeeding and food allergy (estimate had high heterogeneity and low quality). Meta-regression found differences between study outcomes may be attributable to length of breastfeeding recall, study design, country income and date of study inception. Some of the protective effect of breastfeeding for asthma may be related to recall bias in studies of lesser methodological quality.

CONCLUSION

There is some evidence that breastfeeding is protective for asthma (5-18 years). There is weaker evidence for a protective effect for eczema ≤2 years and allergic rhinitis ≤5 years of age, with greater protection for asthma and eczema in low-income countries.

Breast-feeding and hospitalization for asthma in early childhood: a nationwide longitudinal survey in Japan

OBJECTIVE

Whether or not breast-feeding is protective against asthma among children is still controversial. Therefore, we examined the effects of breast-feeding on hospitalization for asthma in early childhood.

DESIGN

Secondary data analyses of a nationwide longitudinal survey of children in Japan ongoing since 2001, with results collected from 2001 to 2004. We used logistic regression models to evaluate the associations of breast-feeding with hospitalization for asthma in children between the ages of 6 and 42 months, adjusting for children's factors (sex, day-care attendance and presence of older siblings) and maternal factors (educational attainment and smoking habit). Setting All over Japan.

SUBJECTS

Term singleton children with information on feeding practices during infancy (n 43367).

RESULTS

After adjusting for maternal factors and children's factors, exclusive breast-feeding at 6-7 months of age was associated with decreased risk of hospitalization for asthma in children. The adjusted odds ratio was 0.77 (95% CI 0.56, 1.06). One-month longer duration of breast-feeding was associated with a 4% decreased risk of hospitalization for asthma (OR = 0.96; 95% CI 0.92, 0.99).

CONCLUSIONS

The protective effects of breast-feeding on hospitalization for asthma were observed in children between the ages of 6 and 42 months.

Is the Relationship Between Breastfeeding and Childhood Risk of Asthma and Obesity Mediated by Infant Antibiotic Treatment?

BACKGROUND

Studies of the protective effect of breastfeeding on asthma have not brought unequivocal results, and thus this issue remains controversial. Antibiotic use, known to increase asthma risk, may be involved in this relationship. The objective of this study was to assess the influence of breastfeeding duration on obesity and asthma risk in childhood and to test a mediating role of antibiotic use in infancy.

SUBJECTS AND METHODS

A cross-sectional anthropometric and questionnaire study was conducted on 1,277 schoolchildren 8 years of age. Data on weight status, asthma, breastfeeding duration, antibiotic administration in infancy, socioeconomic status, and lifestyle were analyzed. Multivariate standard and logistic regression and mediation analyses, controlling for confounders, were applied.

RESULTS

Total duration of breastfeeding was negatively related to the child's body mass index (p=0.038), fat percentage (p=0.030), and obesity risk (p=0.032). Dropping the variable of antibiotic use from the model made the breastfeeding duration a significant predictor of low asthma risk (p=0.027). Antibiotic treatment mediated the relationship between breastfeeding duration and asthma risk (Sobel's z=-2.61, p=0.009).

CONCLUSIONS

Our findings support protective effects of longer duration of breastfeeding against obesity and asthma. We propose a new mechanism for a relationship between breastfeeding and asthma: shorter breastfeeding compromises infant health and thereby leads to antibiotic treatment, which in turn increases the risk of asthma.

Breastfeeding duration and asthma in Puerto Rican children

RATIONALE

Little is known about breastfeeding and asthma in Puerto Ricans, the ethnic group most affected by this disease in the US. We examined the relation between the currently recommended duration of breastfeeding and asthma in school-aged Puerto Rican children.

METHODS

Case-control study of 1,127 Puerto Rican children aged 6-14 years living in Hartford, Connecticut (n = 449) and San Juan, Puerto Rico (n = 678). Parental recall of breastfeeding was categorized based on duration and according to current guidelines (i.e., none, 0-6 months, and >6 months). Asthma was defined as parental report of physician-diagnosed asthma and wheeze in the previous year. We used logistic regression for the multivariate analysis, which was conducted separately for each study site and for the combined cohort. All multivariate models were adjusted for age, gender, household income, atopy, maternal asthma, body mass index, early-life exposure to environmental tobacco smoke, and (for the combined cohort) study site.

RESULTS

After adjustment for covariates, children who were breastfed for up to 6 months had 30% lower odds of asthma (95% CI = 0.5-1.0, P = 0.04) than those who were not breastfed. In this analysis, breastfeeding for longer than 6 months was not significantly associated with asthma (OR = 1.5, 95% CI = 1.0-2.4, P = 0.06).

CONCLUSIONS

Our results suggest that breastfeeding for up to 6 months (as assessed by parental recall) is associated with decreased odds of asthma in Puerto Rican children, and that there is no additional beneficial effect of breastfeeding for over 6 months. These results support current recommendations on the duration of breastfeeding in an ethnic group at risk for asthma.