Increased risk of eczema but reduced risk of early wheezy disorder from exclusive breast-feeding in high-risk infants

Exploring the roles of prostanoids, leukotriens, and dietary fatty acids in cutaneous inflammatory diseases: Insights from pharmacological and genetic approaches

Prostanoids and leukotrienes (LTs) are representative of ω6 fatty acid-derived metabolites that exert their actions through specific receptors on the cell surface. These lipid mediators, being unstable in vivo, act locally at their production sites; thus, their physiological functions remain unclear. However, recent pharmacological and genetic approaches using experimental murine models have provided significant insights into the roles of these lipid mediators in various pathophysiological conditions, including cutaneous inflammatory diseases. These lipid mediators act not only through signaling by themselves but also by potentiating the signaling of other chemical mediators, such as cytokines and chemokines. For instance, prostaglandin E2 -EP4 and LTB4 -BLT1 signaling on cutaneous dendritic cells substantially facilitate their chemokine-induced migration ability into the skin and play critical roles in the priming and/or activation of antigen-specific effector T cells in the skin. In addition to these ω6 fatty acid-derived metabolites, various ω3 fatty acid-derived metabolites regulate skin immune cell functions, and some exert potent anti-inflammatory functions. Lipid mediators act as modulators of cutaneous immune responses, and manipulating the signaling from lipid mediators has the potential as a novel therapeutic approach for human skin diseases.

Analysis of Multimorbidity of Moderate to Severe Allergic Rhinitis in Children: A Real-World Study

INTRODUCTION

Allergic rhinitis (AR) in children is associated with various comorbidities, posing challenges for treatment and management. There have been few investigations of these multimorbidities in Chinese children with AR. Here, we investigated the prevalence of multimorbidities in children with moderate to severe AR and analyzed the influencing factors using real-world data.

METHODS

In total, 600 children who visited the outpatient clinic of our hospital and were diagnosed with moderate-severe AR were prospectively enrolled. All children underwent allergen detection and electronic nasopharyngoscopy. Parents or guardians completed a questionnaire that included age, sex, mode of delivery, feeding pattern, and familial history of allergy. The multimorbidities investigated included atopic dermatitis (AD), asthma, allergic conjunctivitis (AC), chronic rhinosinusitis (CRS), adenoid hypertrophy (AH), tonsil hypertrophy (TH), recurrent epistaxis, and recurrent respiratory tract infections (RRTIs).

RESULTS

The AR multimorbidities reported in children were as follows: recurrent epistaxis (46.5%), AC (46.3%), AD (40.7%), asthma (22.5%), RRIs (21.3%), CRS (20.5%), AH (19.7%), and TH (12.5%). In univariate logistic regression analysis, age (<6 years), birth mode, familial history of allergy, and single dust mite allergy were associated with AR multimorbidity (p < 0.05). Multivariate logistic regression revealed that a familial history of allergy was an independent risk factor for AC (odds ratio [OR] = 1.539, 95% confidence interval [CI]: 1.104-2.145) and AH (OR = 1.506, 95% CI: 1.000-2.267) (p < 0.05). Age (<6 years) was independently associated with the risk of AD (OR = 1.405, 95% CI: 1.003-1.969) and RRTIs (OR = 1.869, 95% CI: 1.250-2.793) (p < 0.05), cesarean section with AR and CRS risk (OR = 1.678, 95% CI: 1.100-2.561), and single dust mite allergy with asthma (OR = 1.590, 95% CI: 1.040-2.432) and CRS (OR = 1.600, 95% CI: 1.018-2.515) risk (p < 0.05). Further, non-dust mite allergy was independently associated with AR and CRS (OR = 2.056, 95% CI: 1.084-3.899).

CONCLUSION

AR was found to be accompanied by different comorbidities, including both allergic and non-allergic comorbidities, complicating disease treatment. These findings demonstrated that age (<6 years), familial history of allergy, types of allergens, and cesarean section were risk factors for different multimorbidities associated with AR.

The developing airway and gut microbiota in early life is influenced by age of older siblings

BACKGROUND

Growing up with siblings has been linked to numerous health outcomes and is also an important determinant for the developing microbiota. Nonetheless, research into the role of having siblings on the developing microbiota has mainly been incidental.

RESULTS

Here, we investigate the specific effects of having siblings on the developing airway and gut microbiota using a total of 4497 hypopharyngeal and fecal samples taken from 686 children in the COPSAC₂₀₁₀ cohort, starting at 1 week of age and continuing until 6 years of age. Sibship was evaluated longitudinally and used for stratification. Microbiota composition was assessed using 16S rRNA gene amplicon sequencing of the variable V4 region. We found siblings in the home to be one of the most important determinants of the developing microbiota in both the airway and gut, with significant differences in alpha diversity, beta diversity, and relative abundances of the most abundant taxa, with the specific associations being particularly apparent during the first year of life. The age gap to the closest older sibling was more important than the number of older siblings. The signature of having siblings in the gut microbiota at 1 year was associated with protection against asthma at 6 years of age, while no associations were found for allergy.

CONCLUSIONS

Having siblings is one of the most important factors influencing a child's developing microbiota, and the specific effects may explain previously established associations between siblings and asthma and infectious diseases. As such, siblings should be considered in all studies involving the developing microbiota, with emphasis on the age gap to the closest older sibling rather than the number of siblings. Video abstract.

Analysing the protection from respiratory tract infections and allergic diseases early in life by human milk components: the PRIMA birth cohort

Background

Many studies support the protective effect of breastfeeding on respiratory tract infections. Although infant formulas have been developed to provide adequate nutritional solutions, many components in human milk contributing to the protection of newborns and aiding immune development still need to be identified. In this paper we present the methodology of the “Protecting against Respiratory tract lnfections through human Milk Analysis” (PRIMA) cohort, which is an observational, prospective and multi-centre birth cohort aiming to identify novel functions of components in human milk that are protective against respiratory tract infections and allergic diseases early in life.

Methods

For the PRIMA human milk cohort we aim to recruit 1000 mother–child pairs in the first month postpartum. At one week, one, three, and six months after birth, fresh human milk samples will be collected and processed. In order to identify protective components, the level of pathogen specific antibodies, T cell composition, Human milk oligosaccharides, as well as extracellular vesicles (EVs) will be analysed, in the milk samples in relation to clinical data which are collected using two-weekly parental questionnaires. The primary outcome of this study is the number of parent-reported medically attended respiratory infections. Secondary outcomes that will be measured are physician diagnosed (respiratory) infections and allergies during the first year of life.

Discussion

The PRIMA human milk cohort will be a large prospective healthy birth cohort in which we will use an integrated, multidisciplinary approach to identify the longitudinal effect human milk components that play a role in preventing (respiratory) infections and allergies during the first year of life. Ultimately, we believe that this study will provide novel insights into immunomodulatory components in human milk. This may allow for optimizing formula feeding for all non-breastfed infants.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-022-07107-w.

Lower caprylate and acetate levels in the breast milk is associated with atopic dermatitis in infancy

BACKGROUND

Atopic dermatitis (AD) occurs in exclusively breastfed infants. As fatty acids have some immunomodulatory effect, we aimed to investigate the influence of fatty acid compositions in breast milk (BM) on the development of AD in exclusively breastfed infants.

METHODS

We enrolled two- to four-month-old exclusively breastfed infants. The objective SCORing Atopic Dermatitis (objSCORAD) was evaluated. The lipid layer of BM was analyzed by gas chromatography for fatty acid levels. Medical charts were reviewed.

RESULTS

Forty-seven AD infants and 47 healthy controls were enrolled. The objSCORAD was 20.5 ± 1.7 (shown as mean ± SEM) in the AD group. The age, sex, parental atopy history, and nutrient intake of mothers were not significantly different between two groups. The palmitate and monounsaturated fatty acid (MUFA) levels in BM positively correlated with objSCORAD, while caprylate, acetate, and short-chain fatty acid (SCFA) levels negatively correlated with objSCORAD (p = .031, .019, .039, .013, .022, respectively). However, the butyrate levels in BM were not significantly different. The caprylate and acetate levels in BM were significantly associated with the presence of infantile AD (p = .021 and .015, respectively) after adjusting for age, sex, parental allergy history, MUFA, palmitate, and SCFA levels in BM. ObjSCORAD in infancy was significantly associated with persistent AD (p = .026) after adjusting for age, sex, parental atopy history, caprylate, palmitate, MUFA, acetate, and SCFA levels in BM.

CONCLUSION

Caprylate and acetate levels in BM for exclusively breastfed infants were negatively associated with objSCORAD. Lower caprylate and acetate in BM might be the risk factors for infantile AD, while butyrate in BM was not associated with infantile AD.

Atopic Dermatitis: Conventional and Integrative Medicine

Although Western medicine and ideas about atopic dermatitis (AD) have become popular in many Asian countries, local beliefs about the disease and its treatment often prevail. The multi- racial background of these countries as well as the influence of the diverse religions (such as Taoism and Ramadan) in these regions often lead to diverse belief systems about the causes of AD (such as the Chi concept, also known as the balance of yin and yang) and the types of treatment (e.g. herbal remedies, topical versus concoctions, and decoctions). In addition, many of the cultural practices are preserved among the Southeast Asian minorities residing in the United Kingdom and North America. Eastern treatments typically take a holistic approach to AD and emphasize the psychosomatic component of the disorder. This overview provides a summary of the difference between conventional, complementary, alternative, and integrative medicine in terms of epidemiology, aetiology, therapy, and prognosis in children with AD. There are a number of similarities in genetic and environmental factors in epidemiology and aetiology; however, differences exist in terms of the concept of management. Complementary and alternative medicine, traditional Chinese medicine, and integrative medicine usage are not only prevalent among the Asian population but are also becoming more popular and accepted in Western societies.

Breastfeeding and Allergic Diseases: What's New?

Asthma and other allergic disorders, such as atopic dermatitis and food allergies, are common chronic health problems in childhood. The rapid rise in the prevalence of these conditions registered over the last few decades has stressed the need to identify the modifiable risk factors associated with the development of these diseases. Breast milk, recognized as the gold standard for healthy growth and development of the newborn, is one of the major factors associated with a lower incidence of allergic and infectious diseases in childhood and young adulthood. Although the underlying mechanisms for these effects are not well understood, breastfeeding leads to immune system maturation. In this narrative review, we summarize existing evidence on breastfeeding and human milk composition in relation to allergic disease prevention or development.

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

BACKGROUND

To our knowledge, disease burden of atopic dermatitis (AD) as number of days with symptoms and medical treatment has never been studied as measure of severity.

OBJECTIVES

To investigate risk factors for AD burden in the first 3 years of life.

METHODS

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.

RESULTS

The children with AD had a median (interquartile range) of 136 symptom days (61-294 days) and 72 steroid days (27-145 days) during the first 3 years 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.

LIMITATIONS

Participants with a personal interest in atopic diseases could be more likely to participate.

CONCLUSION

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.

Genetic predisposition and environmental factors associated with the development of atopic dermatitis in infancy: a prospective birth cohort study

The influence of environmental factors on atopic dermatitis (AD) has been investigated in many cross-sectional studies. It remains however unclear if they could influence AD development early in life. This prospective birth cohort study aimed to monitor aspects of family lifestyle and child's nutrition within a Caucasian population and to assess its association with AD development over the first 2 years of life. Genetic predisposition was evaluated based on family history and profilaggrin genotyping. Of 149 included children, 36 developed AD. Infants with a family history of atopy developed AD 2.6 times more frequently (30 of 97) than infants without atopic predisposition (6 of 52). Genotyping was carried out on 50% of the children included. Profilaggrin mutations (R501X, 2282del4, R2447X, and S3247X) were infrequent in our population. Lower incidence of AD was observed in infants exposed to a damp housing environment, lower household income, and smoking mothers with a higher but not with a lower education level.Conclusion: Family history of atopy was a significant risk factor for AD regardless of the most common, currently defined, FLG mutations. Humidity at home and passive smoking seem associated with AD development in infancy. What is Known: • Atopic dermatitis (AD) is associated with mutations in various genes of the immune system and the epidermal barrier complex in particular filaggrin (FLG) mutation. • Inherited factors alone cannot explain the rising AD; environmental factors are therefore likely to play a decisive role in this rise but the exact role that these factors may play in increasing AD risk in infancy remains unclear. Moreover, the relationship between environmental factors and AD has been the focus of mostly cross-sectional studies and not prospective studies. What is New: • This prospective birth cohort study demonstrates that family history of atopy is a significant risk factor for AD regardless of the most common, currently defined, FLG mutations. • A lower incidence of AD was observed in infants exposed to a moist housing environment, lower household income, and smoking of mothers with a higher but not with a lower education level.

Maternal ω3 docosapentaenoic acid inhibits infant allergic dermatitis through TRAIL-expressing plasmacytoid dendritic cells in mice

Background

Maternal dietary exposures are considered to influence the development of infant allergies through changes in the composition of breast milk. Cohort studies have shown that ω3 polyunsaturated fatty acids (PUFAs) in breast milk may have a beneficial effect on the preventing of allergies in infants; however, the underlying mechanisms remain to be investigated. We investigated how the maternal intake of dietary ω3 PUFAs affects fatty acid profiles in the breast milk and their pups and reduced the incidence of allergic diseases in the pups.

Methods

Contact hypersensitivity (CHS) induced by 2,4‐dinitrofluorobenzene (DNFB) and fluorescein isothiocyanate was applied to the skin in pups reared by mother maintained with diets mainly containing ω3 or ω6 PUFAs. Skin inflammation, immune cell populations, and expression levels of immunomodulatory molecules in pups and/or human cell line were investigated by using flow cytometric, immunohistologic, and quantitative RT‐PCR analyses. ω3 PUFA metabolites in breast milk and infant's serum were evaluated by lipidomics analysis using LC‐MS/MS.

Results

We show that maternal intake of linseed oil, containing abundant ω3 α‐linolenic acid, resulted in the increased levels of ω3 docosapentaenoic acid (DPA) and its 14‐lipoxygenation products in the breast milk of mouse dams; these metabolites increased the expression of TNF‐related apoptosis‐inducing ligand (TRAIL) on plasmacytoid dendritic cells (pDCs) in their pups and thus inhibited infant CHS. Indeed, the administration of DPA‐derived 14‐lipoxygenation products to mouse pups ameliorated their DNFB CHS.

Conclusion

These findings suggest that an inhibitory mechanism in infant skin allergy is induced through maternal metabolism of dietary ω3 PUFAs in mice.

Effect of breastfeeding duration on lung function, respiratory symptoms and allergic diseases in school-age children

BACKGROUND

A positive effect of breastfeeding on lung function has been demonstrated in cohorts of children with asthma or risk for asthma. We assessed the impact of breastfeeding on lung function and symptoms at the age of 6 years in an unselected, healthy birth cohort.

METHODS

We prospectively studied healthy term infants from the Bern-Basel Infant Lung Development (BILD) cohort from birth up to 6 years. Any breastfeeding was assessed by weekly phone calls during the first year of life. Risk factors (eg, smoking exposure, parental history of allergic conditions, and education) were obtained using standardized questionnaires. The primary outcomes were lung function parameters measured at 6 years of age by spirometry forced expiratory volume in 1 second, body plethysmography (functional residual capacity [FRCpleth ], the total lung capacity [TLCpleth ], and the effective respiratory airway resistance [Reff ]) and fractional exhaled nitric oxide (FeNO). Secondary outcomes included ever wheeze (between birth and 6 years), wheeze in the past 12 months, asthma, presence of allergic conditions, atopic dermatitis, rhinitis, and positive skin prick test at the age of 6 years.

RESULTS

In 377 children the mean breastfeeding duration was 36 weeks (SD 14.4). We found no association of breastfeeding duration with obstructive or restrictive lung function and FeNO. After adjustment for confounders, we found no associations of breastfeeding duration with respiratory symptoms or the presence of allergic conditions.

CONCLUSION

This study found no evidence of an association between breastfeeding and comprehensive lung function in unselected healthy children with long-term breastfeeding. Our findings do not support the hypothesis that the duration of breastfeeding has a direct impact on lung function in a healthy population with low asthmatic risk.

The Role of Prebiotics and Probiotics in Prevention of Allergic Diseases in Infants

Allergic diseases have been linked to genetic and/or environmental factors, such as antibiotic use, westernized high fat and low fiber diet, which lead to early intestinal dysbiosis, and account for the rise in allergy prevalence, especially in western countries. Allergic diseases have shown reduced microbial diversity, including fewer lactobacilli and bifidobacteria, within the neonatal microbiota, before the onset of atopic diseases. Raised interest in microbiota manipulating strategies to restore the microbial balance for atopic disease prevention, through prebiotics, probiotics, or synbiotics supplementation, has been reported. We reviewed and discussed the role of prebiotics and/or probiotics supplementation for allergy prevention in infants. We searched PubMed and the Cochrane Database using keywords relating to "allergy" OR "allergic disorders," "prevention" AND "prebiotics" OR "probiotics" OR "synbiotics." We limited our evaluation to papers of English language including children aged 0-2 years old. Different products or strains used, different period of intervention, duration of supplementation, has hampered the draw of definitive conclusions on the clinical impact of probiotics and/or prebiotics for prevention of allergic diseases in infants, except for atopic dermatitis in infants at high-risk. This preventive effect on eczema in high-risk infants is supported by clear evidence for probiotics but only moderate evidence for prebiotic supplementation. However, the optimal prebiotic or strain of probiotic, dose, duration, and timing of intervention remains uncertain. Particularly, a combined pre- and post-natal intervention appeared of stronger benefit, although the definition of the optimal intervention starting time during gestation, the timing, and duration in the post-natal period, as well as the best target population, are still an unmet need.

Genetic, Clinical, and Environmental Factors Associated With Persistent Atopic Dermatitis in Childhood

Importance

Knowledge about factors associated with persistence of atopic dermatitis (AD) during childhood is sparse.

Objective

To explore heritable, environmental, and clinical factors associated with persistent AD based on 13 years' follow-up of an at-risk birth cohort.

Design, Setting, and Participants

In the Copenhagen Prospective Study on Asthma in Childhood 2000 (COPSAC2000) clinical birth cohort study, 411 children born to mothers with asthma were followed up until the age of 13 years at a clinical research unit in Copenhagen, Denmark, from August 1998 to June 2015. Atopic dermatitis was diagnosed prospectively during close clinical follow-up according to the criteria of Hanifin and Rajka. Data were gathered on parental history, social circumstances, and environmental factors through parent interviews. The cohort was followed up with biannual visits to the clinic until the age of 7 years and were seen again at age 13 years. Data were analyzed from August 2015 to January 2018.

Main Outcomes and Measures

Atopic dermatitis was diagnosed using Hanifin and Rajka major and minor criteria, and severity was determined by Scoring Atopic Dermatitis (SCORAD) index, with possible scores from 0 to 83, with higher scores indicating more severe AD.

Results

Of the 411 children in the cohort, 203 (49.4%) were male and 186 (45.3%) were diagnosed with AD before the age of 13 years; 40 of 166 children (24.1%) had persistent AD at the age of 13 years, and 126 (76.0%) experienced remission. Factors associated with persistent AD to age 13 years included heritability, environmental exposures, asthma and allergic sensitization, clinical presentation at the time of diagnosis, the composition of Hanifin and Rajka diagnostic minor criteria, and AD severity according to SCORAD. A higher AD genetic risk score was associated with an increased the risk for persistent AD (multivariable odds ratio [OR], 1.8; 95% CI, 1.1-2.9; P = .02), together with paternal asthma (multivariable OR, 3.7; 95% CI, 1.2-11.5; P = .02); paternal AD (multivariable OR, 6.2; 95% CI, 1.17-23.2; P = .007), and higher social circumstances (multivariable OR, 1.6; 95% CI, 1.0-2.5; P = .05). Particular clinical presentations at time of diagnosis were also associated with specific minor criteria of Hanifin and Rajka (Dennie-Morgan and anterior neck folds, white dermographism, intolerance to wool, itching when sweating, tendency to skin infection, food intolerance, and food allergy) (OR, 2.6; 95% CI, 1.1-6.2; P = .03) as well as increased severity at diagnosis (OR, 1.1; 95% CI, 1.0-1.1; P = .007).

Conclusions and Relevance

In a birth cohort of children at risk for asthma who received close clinical follow-up to age 13 years, known genetic AD risk variants, paternal asthma and AD, high social circumstances, diagnostic minor criteria, and disease severity at onset were associated with persistent AD at age 13 years. These findings may be applied in clinical practice to evaluate the likely disease course for individual patients.

Lower respiratory tract infections appear to be the most important risk factor for current asthma in subarctic schoolchildren

AIM

The aim of this study was to identify possible risk factors for current asthma revealed by two studies in Northern Norway in 1985 and 2008 and to evaluate these factors contributing to the increased prevalence of asthma over these 23 years.

METHODS

As part of the 'Asthma and allergy study among schoolchildren in Nordland county' we performed a case-control study (70.0% attendance) comparing 153 children with current asthma (cases) to their non-asthmatic controls. The results from this 2008 study were compared to a similar case-control study (93.2% attendance) performed in 1985 based on 62 current asthmatics.

RESULTS

In 1985, the most important risk factors for current asthma were repeated lower respiratory tract infections (LRTIs) with adjusted odds ratio (aOR) 52.11, together with urticaria ever and atopic disease in the family. In 2008, the most important risk factors were food allergy with aOR 7.06, LRTIs during the first three years of life with aOR 5.80 and hospitalisation caused by LRTIs.

CONCLUSION

In both studies, LRTI was the most important risk factor for current asthma. Whether or not LRTIs have contributed to the increased asthma prevalence in this population over 23 years remains unresolved.

Immunologically Active Components in Human Milk and Development of Atopic Disease, With Emphasis on Food Allergy, in the Pediatric Population

Breast-feeding is currently recommended to prevent the development of allergic diseases; however, data are conflicting and mechanisms are unclear. The immunomodulatory composition of human milk is poorly characterized and varies between mothers. We and others have shown that high levels of human milk IgA and certain cytokines and human milk oligosaccharides are associated with protection against food allergy in the infant, but it is unclear whether they are responsible for or simply biomarkers of the vertical transfer of protection. Because human milk has pre- and probiotic properties, the anti-allergy protection afforded by human milk may be due to its control on the developing gut microbiome. In mice, murine milk IgA supports gut homeostasis and shapes the microbiota, which in turn diversifies the intestinal IgA repertoire that reciprocally promotes the diversity of gut microbiome; these mechanisms are poorly understood in humans. In addition, several human milk bioactives are immunostimulatory, which may in part provide protection against allergic diseases. The regulation of immunologically active components in human milk is incompletely understood, although accumulating evidence suggests that IgA and cytokines in human milk reflect maternal exposures. This review summarizes the current literature on human milk components that have been associated with protection against food allergy and related allergic disorders in early childhood and discusses the work relating to regulation of these levels in human milk and possible mechanisms of action.

Epidemiology and Risk Factors of Infection in Early Childhood

BACKGROUND

There is a large, unexplained variation in the frequency of childhood infections. We described incidence and risk factors of infections in early childhood.

METHODS

Simple infections were captured during the first 3 years of life in the Copenhagen Prospective Studies on Asthma in Childhood 2000 birth cohort. Environmental exposures were analyzed by quasi-Poisson regression and sparse principal component analysis.

RESULTS

The 334 children experienced a median of 14 (range 2-43) infectious episodes at ages 0 to 3 years. The overall rate of infections was associated with the number of children in the day care (adjusted incidence rate ratio [aIRR] 1.09 [1.2-1.16]) and the m² per child in the day care (aIRR 0.96 [0.92-0.99]). Upper respiratory infections were also associated with the number of children in the day care (aIRR 1.11 [1.03-1.20]) and the m² per child in the day care (aIRR 0.95 [0.91-0.99]), whereas lower respiratory infections were associated with caesarean section (aIRR 1.49 [1.12-1.99]), maternal smoking (aIRR 1.66 [1.18-2.33]), older siblings (aIRR 1.54 [1.19-2.01]), and the age at entry to day care (aIRR 0.77 [0.65-0.91]). The sparse principal component analysis revealed a risk factor profile driven by tobacco exposure, social circumstances, and domestic pets, but could only be used to explain 8.4% of the infection burden.

CONCLUSIONS

Children experienced around 14 infections during the first 3 years of life, but incidences varied greatly. Environmental exposures only explained a small fraction of the variation, suggesting host factors as major determinants of infectious burden.

Association of breast milk fatty acids with allergic disease outcomes-A systematic review

INTRODUCTION

Dietary polyunsaturated fatty acids (PUFAs) have immunoregulatory properties. Breast milk is rich in PUFA, and it has been hypothesized that these PUFAs may be important in the aetiology of allergic diseases. Despite a growing body of evidence, the associations between breast milk PUFA and allergic disease have not previously been systematically reviewed.

METHODS

The search was performed in PubMed and EMBASE databases using breastfeeding, fatty acid and allergic disease terms. Two authors were involved in selecting papers for review according to the inclusion criteria and extracting information on study characteristics and measures of association. Only studies that reported numeric associations between concentration of breast milk fatty acids and allergic disease outcomes were included.

RESULTS

A total of 18 papers met the inclusion criteria, reporting results from 15 study populations. The majority were cohort studies (n=11), with data from only two case-control and two cross-sectional studies. Sample size varied between 30 and 352 participants, and follow-up time of the cohorts varied between 3 months and 14 years. Nine studies reported on eczema, seven reported on sensitization, and only five reported on asthma/wheeze. There was heterogeneity among studies in terms of presenting the association between PUFA and allergy; therefore, estimates could not be pooled. Only a few studies observed associations between n-3 and n-6 PUFAs and allergic disease, and the magnitude of this effect varied greatly.

CONCLUSIONS

There is insufficient evidence to suggest that colostrum or breast milk polyunsaturated fatty acids influence the risk of childhood allergic diseases.

New approach shows no association between maternal milk fatty acid composition and childhood wheeze or asthma

BACKGROUND

Previous observational studies have implied breastmilk fatty acid composition may play a role in the development of atopic eczema or atopic sensitization in breastfed infants and toddlers. However, studies investigating associations with wheeze and asthma in later childhood are scarce and did not account for inherent correlation of compositional data. Our aim was to explore the association of maternal milk fatty acid composition with childhood wheezing phenotypes and asthma up to age 13 years using a new statistical approach.

METHODS

Breastmilk was collected 6 weeks and 6 months postdelivery in the Ulm Birth Cohort Study (n=720 and n=454, respectively). Concentrations of 28 fatty acids were measured by high-resolution capillary gas-liquid chromatography. To control for constant-sum constraint, concentration data were transformed using the centered log ratio method. Compositional biplots and correlation matrices were used to group centered log ratio transformed fatty acids. Adjusted risk ratios with parent-reported wheezing phenotypes and doctor-diagnosed asthma were computed using a modified Poisson regression.

RESULTS

We observed no straightforward evidence of associations between overall breastmilk fatty acid composition and specific wheeze phenotypes or doctor-diagnosed asthma.

CONCLUSION

Using appropriate statistical methodology, we report null associations. These findings may partly be attributable to several cohort-specific factors associated with breastfeeding and breastmilk collection. Further studies could improve on ours by analyzing samples of breastmilk and formula and by including all children for whom these are exclusively or together the major source of fatty acids in the first months of life.

Human Milk and Allergic Diseases: An Unsolved Puzzle

There is conflicting evidence on the protective role of breastfeeding in relation to the development of allergic sensitisation and allergic disease. Studies vary in methodology and definition of outcomes, which lead to considerable heterogeneity. Human milk composition varies both within and between individuals, which may partially explain conflicting data. It is known that human milk composition is very complex and contains variable levels of immune active molecules, oligosaccharides, metabolites, vitamins and other nutrients and microbial content. Existing evidence suggests that modulation of human breast milk composition has potential for preventing allergic diseases in early life. In this review, we discuss associations between breastfeeding/human milk composition and allergy development.

Does Breast-feeding Relate to Development of Atopic Dermatitis in Young Korean Children?: Based on the Fourth and Fifth Korea National Health and Nutrition Examination Survey 2007-2012

Purpose

There have been conflicting reports concerning the relationship between breast-feeding and the development of atopic dermatitis (AD) in early childhood. The objective of this study was to investigate the associations between breast-feeding and the risk of AD in early childhood in Korea.

Methods

We combined the fourth and fifth Korea National Health and Nutrition Examination Survey data collected from 2007 to 2012 and analyzed 2,015 children at 1 to 3 years old. Regression analysis was used to determine the association of the following variables: AD, feeding types, duration of breast-feeding, and others.

Results

The annual prevalence of exclusive breast-feeding and AD decreased. Parents with allergic diseases preferred breast-feeding and extended duration of feeding compared with those without. In multiple logistic regression analyses, exclusive breast-feeding in feeding type I (P=0.070; adjusted odds ratio [OR]=1.990), exclusive breast-feeding in feeding type II (P=0.095; adjusted OR=1.495) and breast-feeding duration (P=0.430; adjusted OR=1.013) were not significantly related to AD.

Conclusions

Breast-feeding was not found to be associated with an occurrence of AD in young children. Rather, parents with histories of allergic diseases tended to prefer breast-feeding and extend its duration. To clarify the role of breast-feeding in the development of AD, a nation-wide prospective study is needed.

Faecal eosinophil cationic protein and serum immunoglobulin E in relation to infant feeding practices

Background To date, the effects of exclusive breastfeeding duration and timing of solid food introduction on allergy prevention are unclear. The aim of this study was to determine the effect of variable feeding practices on intestinal inflammation in infants using faecal eosinophil cationic protein as a surrogate marker and to assess whether faecal eosinophil cationic protein is associated with serum immunoglobulin E. Methods Subjects ( n = 206) were enrolled from the Prediction of Allergies in Taiwanese CHildren (PATCH) birth cohort study. Stool samples were collected at 6 and 12 months for determining eosinophil cationic protein, and blood was collected for determining total and allergen-specific immunoglobulin E at 12 months. We compared these biomarkers between infants with variable exclusive breastfeeding duration and infants introduced to solid foods at various periods. The association between faecal eosinophil cationic protein, total serum immunoglobulin E and specific immunoglobulin E was also analysed. Results Faecal eosinophil cationic protein was significantly higher in exclusively breastfed infants compared with formula-fed infants and infants who were not exclusively breastfed at 6 months of age ( P < 0.05). At 12 months, infants who were introduced to solid foods at 5-6 months had the lowest faecal eosinophil cationic protein compared with those who were introduced at earlier and later periods. There was no significant association between faecal eosinophil cationic protein and serum immunoglobulin E. Conclusion We found that breastfeeding exclusively for >6 months did not reduce serum immunoglobulin E, but rather increased intestinal inflammation. Faecal eosinophil cationic protein was not associated with total serum immunoglobulin E and specific immunoglobulin E and might not be a useful indictor of immunoglobulin E sensitization in infancy.

Risk of Autoimmunity in EoE and Families: A Population-Based Cohort Study

OBJECTIVES

Recent genome-wide association studies have suggested possible genetic associations between eosinophilic esophagitis (EoE) and genes associated with autoimmunity. No studies to date have looked at potential genetic association of EoE with specific autoimmune diseases by evaluating such diagnoses within family members. Investigate the risk of specific autoimmune disease within EoE probands and their extended family members.

METHODS

The Utah Population Database offers a unique opportunity to link medical records from over 85% of Utah's population to genealogy records representing Utah. We searched for associations of specific autoimmune diseases in probands diagnosed with EoE and their extended family members (e.g., first cousins). Comparisons were made to age- and sex-matched controls and their respective families at a 5:1 ratio.

RESULTS

Excess risk for multiple autoimmune conditions was detected in subjects with a diagnosis of EoE. Celiac, Crohn's, ulcerative colitis (UC), rheumatoid arthritis, IgA deficiency, CVID, multiple sclerosis (MS), and Hashimoto's thyroiditis were found at increased risk in first-degree relatives of EoE subjects. UC, systemic sclerosis, and MS had nominally significant associations within second-degree family members of EoE subjects; and, in reverse analysis, probands and their families with the above three conditions were at an increased risk for EoE suggesting shared genetic factors with EoE.

CONCLUSIONS

Patients with EoE have an increased risk of multiple autoimmune diseases. Possible shared genetic etiologies were observed between EoE and UC, systemic sclerosis, and MS. Practitioners should be aware of these comorbid associations and query all EoE patients and family members for symptoms of these diseases.

High breast milk IL-1β level is associated with reduced risk of childhood eczema

BACKGROUND

We recently demonstrated a dual effect of breastfeeding with increased risk of eczema and decreased risk of wheezing in early childhood by increasing breastfeeding length. We hypothesize that immune mediators in breast milk could explain such association either through a direct effect or as a surrogate marker of maternal immune constitution.

OBJECTIVE

To investigate the possible association between cytokine and chemokine levels in breast milk and development of eczema and recurrent wheeze during early childhood.

METHODS

Levels of 19 pro-inflammatory and immunoregulatory cytokines and chemokines were measured in 223 breast milk samples from mothers in the Copenhagen Prospective Study on Asthma in Childhood2000 (COPSAC) high-risk birth cohort. Eczema and recurrent wheeze at the age of 0-3 years were prospectively diagnosed by COPSAC physicians adherent to predefined validated algorithms. Association analyses were performed by Cox regression adjusting for potential confounding factors and by multivariable principal component analysis.

RESULTS

Increased IL-1β in breast milk (≥ 0.7 pg/mL) was associated with more than a halved risk of eczema before age three (aHR = 0.41; 95% CI = 0.24-0.68; P < 0.001), which remained significant after false discovery rate adjustment (P = 0.008). The principal component analysis confirmed that a mediator pattern dominated by high levels of IL-1β, IL-17A, and CCL17 and low levels of CXCL1 and TSLP in breast milk protected against eczema (aHR = 0.82; 95% CI = 0.68-0.98; P = 0.03). No associations were observed for recurrent wheeze.

CONCLUSIONS AND CLINICAL RELEVANCE

Elevated breast milk IL-1β level was associated with decreased risk of early childhood eczema suggesting either a direct protective effect of IL-1β or IL-1b acting as a proxy for a healthy maternal immune system protecting high-risk offspring from eczema.

Exclusive or Partial Breastfeeding for 6 Months Is Associated With Reduced Milk Sensitization and Risk of Eczema in Early Childhood: The PATCH Birth Cohort Study

There is insufficient evidence to confirm the association between breastfeeding and allergic outcomes later in life. This study aimed to determine the relationships between different breastfeeding patterns and allergen sensitizations and risk of developing atopic diseases in early childhood. A total of 186 children from a birth cohort in the Prediction of Allergies in Taiwanese Children study for a 4-year follow-up period were enrolled. Total serum immunoglobulin E (IgE) levels and specific IgE antibodies against food and inhalant allergens were measured sequentially at 6 months as well as at 1, 1.5, 2, 3, and 4 years of age. A significantly lower prevalence of milk sensitization was found in children at ages 1 and 1.5 years who were exclusively or partially breastfed for ≥6 months. Breastfeeding ≥6 months was significantly associated with a reduced risk of developing eczema but not allergic rhinitis and asthma at ages 1 and 2 years. Compared with exclusive breastfeeding ≥6 months, partial breastfeeding <6 months was significantly associated with an increased risk of developing eczema at ages 1 and 2 years. As with exclusive breastfeeding, partial breastfeeding for at least 6 months appears to be associated with a reduced prevalence of milk sensitization as well as a reduced risk of developing eczema in early childhood.

Factors affecting breast milk composition and potential consequences for development of the allergic phenotype

There is conflicting evidence on the protective role of breastfeeding in relation to allergic sensitization and disease. The factors in breast milk which influence these processes are still unclear and under investigation. We know that colostrum and breast milk contain a variety of molecules which can influence immune responses in the gut-associated lymphoid tissue of a neonate. This review summarizes the evidence that variations in colostrum and breast milk composition can influence allergic outcomes in the infant, and the evidence that maternal and environmental factors can modify milk composition. Taken together, the data presented support the possibility that maternal dietary interventions may be an effective way to promote infant health through modification of breast milk composition.

Gender- and age-specific risk factors for wheeze from birth through adolescence

BACKGROUND AND OBJECTIVE

Cross-sectional gender differences in wheeze are well documented, but few studies have examined the gender-specific risk factors for wheeze longitudinally. This study aims to identify gender- and age-specific risk factors for wheeze from birth through adolescence.

METHODS

The incidence of wheeze was ascertained every 6 months through age 14 years in a birth cohort consisting of 499 children with a parental history of atopy. Gender- and age-specific risk factors were identified through generalized estimating equations.

RESULTS

A total of 454 (91.0%) and 351 (70.3%) children were followed past age 7 and 13 years, respectively. Maternal asthma was a risk factor for wheeze in girls (OR = 2.05, 95% CI 1.44-2.91, P < 0.0001) and boys (OR = 1.79, 1.29-2.48, P = 0.0004) and had a similar effect on wheeze throughout the ages. Paternal asthma (OR = 1.83, 1.38-2.57, P = 0.0005) and infant bronchiolitis (OR = 2.15, 1.47-3.14, P < 0.0001) were risk factors for boys only, with similar effects throughout the ages.

CONCLUSION

Using a prospective cohort, we identified gender- and age-specific risk factors for wheeze. The identification of gender-specific early life risk factors may allow for timely interventions and a more personalized approach to the treatment of asthma.

Breast Milk and Solid Food Shaping Intestinal Immunity

After birth, the intestinal immune system enters a critical developmental stage, in which tolerogenic and pro-inflammatory cells emerge to contribute to the overall health of the host. The neonatal health is continuously challenged by microbial colonization and food intake, first in the form of breast milk or formula and later in the form of solid food. The microbiota and dietary compounds shape the newborn immune system, which acquires the ability to induce tolerance against innocuous antigens or induce pro-inflammatory immune responses against pathogens. Disruption of these homeostatic mechanisms might lead to undesired immune reactions, such as food allergies and inflammatory bowel disease. Hence, a proper education and maturation of the intestinal immune system is likely important to maintain life-long intestinal homeostasis. In this review, the most recent literature regarding the effects of dietary compounds in the development of the intestinal immune system are discussed.

Maternal fatty acid desaturase genotype correlates with infant immune responses at 6 months

Breast milk long-chain PUFA (LCPUFA) have been associated with changes in early life immune responses and may modulate T-cell function in infancy. We studied the effect of maternal fatty acid desaturase (FADS) genotype and breast milk LCPUFA levels on infants' blood T-cell profiles and ex vivo-produced cytokines after anti-CD3/CD28 stimulation of peripheral blood mononuclear cells in 6-month-old infants from the Copenhagen Prospective Study of Asthma in Childhood birth cohort. LCPUFA concentrations of breast milk were assessed at 4 weeks of age, and FADS SNP were determined in both mothers and infants (n 109). In general, breast milk arachidonic acid (AA) levels were inversely correlated with the production of IL-10 (r -0.25; P=0.004), IL-17 (r -0.24; P=0.005), IL-5 (r -0.21; P=0.014) and IL-13 (r -0.17; P=0.047), whereas EPA was positively correlated with the counts of blood regulatory T-cells and cytotoxic T-cells and decreased T-helper cell counts. The minor FADS alleles were associated with lower breast milk AA and EPA, and infants of mothers carrying the minor allele of FADS SNP rs174556 had higher production of IL-10 (r -0.23; P=0.018), IL-17 (r -0.25; P=0.009) and IL-5 (r -0.21; P=0.038) from ex vivo-activated immune cells. We observed no association between T-cell distribution and maternal or infant FADS gene variants. We conclude that increased maternal LCPUFA synthesis and breast milk AA are associated with decreased levels of IL-5, IL-13 (type-2 related), IL-17 (type-17 related) and IL-10 (regulatory immune responses), but not with interferon-γ and TNF-α, which could be due to an effect of the maternal FADS variants on the offspring immune response transferred via breast milk LCPUFA.

Maternal influences over offspring allergic responses

Asthma occurs as a result of complex interactions of environmental and genetic factors. Clinical studies and animal models of asthma indicate offspring of allergic mothers have increased risk of development of allergies. Environmental factors including stress-induced corticosterone and vitamin E isoforms during pregnancy regulate the risk for offspring development of allergy. In this review, we discuss mechanisms for the development of allergic disease early in life, environmental factors that may impact the development of risk for allergic disease early in life, and how the variation in global prevalence of asthma may be explained, at least in part, by some environmental components.

Breast-feeding does not protect against allergic sensitization in early childhood and allergy-associated disease at age 7 years

BACKGROUND

Extended breast-feeding is recommended for newborn children at risk of allergy-associated diseases, but the evidence of a protective effect on sensitization and these diseases remains elusive.

OBJECTIVE

The aim of this study was to investigate the effects of the duration of exclusive breast-feeding on the development of sensitization in preschool children.

METHODS

Information on breast-feeding was gathered by interviews involving 335 children aged 1, 6, and 12 months from the Copenhagen Prospective Study on Asthma in Childhood2000 birth cohort born to mothers with a history of asthma. Skin prick test responses and specific IgE levels against 12 common inhalant and 10 food allergens were assessed longitudinally at ages ½ year, 1½ years, 4 years, and 6 years. Eczema, wheeze/asthma, and allergic rhinitis were diagnosed at the Copenhagen Prospective Studies on Asthma in Childhood clinic at 7 years of age, strictly adhering to predefined algorithms. Associations between duration of exclusive breast-feeding and outcomes were analyzed by logistic regression.

RESULTS

We found no significant association between duration of exclusive breast-feeding and development of sensitization in the first 6 years of life (odds ratio [OR]: ½ year, 1.10 [95% CI, 0.90-1.36]; 1½ years, 1.15 [95% CI, 0.97-1.36]; 4 years, 1.08 [95% CI, 0.93-1.25]; and 6 years, 0.96 [95% CI, 0.84-1.10]) or with current eczema, wheeze/asthma, and allergic rhinitis at age 7 years (OR, 1.07 [95% CI, 0.92-1.24]; OR, 0.97 [95% CI, 0.82-1.14]; and OR, 1.02 [95% CI, 0.84-1.23], respectively). Adjusting for reverse causation by excluding children with eczema, wheeze, or a positive skin prick test response before ending exclusive breast-feeding did not alter the results.

CONCLUSION

Exclusive breast-feeding does not affect sensitization in early childhood or associated diseases at 7 years of age in at-risk children.

The role of the early-life environment in the development of allergic disease

A consensus has been reached that the development of allergic disorders is strongly influenced by early life exposures. An overview of several prenatal and early life factors that have been investigated for their associations with development of childhood allergy is presented. Delivery mode, the gut microbiome, vitamin D, folate, breastfeeding, pets, antibiotics, environmental tobacco smoke, and airborne traffic pollutants are discussed. Although many studies suggest an effect, overall, no risk factors clearly increase or reduce the risk of allergic outcomes.

Breast-feeding and health consequences in early childhood: is there an impact of time-dependent confounding?

BACKGROUND

Estimated effects of breast-feeding on childhood health vary between studies, possibly due to confounding by baseline maternal and child characteristics. Possible time-dependent confounding has received little consideration. Our aim was to evaluate the impact of such confounding.

METHODS

We estimated the relationship between cumulative exclusive breast-feeding up to 6 months and wheezing, rash and body mass index (BMI) at 12 months [in the Whistler cohort (n = 494) and PROBIT (n = 11,463)], and wheezing, rash, asthma, hay fever, eczema, allergy and BMI at age 6.5 years (PROBIT). We adjusted for time-dependent confounding by weight, length, rash, respiratory illness and day care attendance using marginal structural models (MSMs).

RESULTS

Weight and day care attendance appeared potential time-dependent confounders, since these predicted breast-feeding status and were influenced by previous breast-feeding. However, adjustment for time-dependent confounders did not markedly change the estimated associations. For example, in PROBIT the adjusted increase in BMI at 12 months per 1-month increase in exclusive breast-feeding was 0.04 (95% CI -0.09 to 0.01) using logistic regression and -0.06 (95% CI -0.11 to -0.01) using MSM. In Whistler, these estimates were each -0.05 (95% CI -0.10 to 0.00).

CONCLUSIONS

In two cohort studies, there was little evidence of time-dependent confounding by weight, length, rash, respiratory illness or day care attendance of the effects of breast-feeding on early childhood health.

S3-Guideline on allergy prevention: 2014 update: Guideline of the German Society for Allergology and Clinical Immunology (DGAKI) and the German Society for Pediatric and Adolescent Medicine (DGKJ)

The continued high prevalence of allergic diseases in Western industrialized nations combined with the limited options for causal therapy make evidence-based primary prevention necessary. The recommendations last published in the S3-guideline on allergy prevention in 2009 have been revised and a consensus reached on the basis of an up-to-date systematic literature search.

Evidence was sought for the period between May 2008 and May 2013 in the Cochrane and MEDLINE electronic databases, as well as in the reference lists of recent review articles. In addition, experts were surveyed for their opinions. The relevance of retrieved literature was checked by means of two filter processes: firstly according to title and abstract, and secondly based on the full text of the articles. Included studies were given an evidence grade, and a bias potential (low/high) was specified for study quality. A formal consensus on the revised recommendations was reached by representatives of the relevant specialist societies and (self-help) organizations (nominal group process).

Of 3,284 hits, 165 studies (one meta-analysis, 15 systematic reviews, 31 randomized controlled trials, 65 cohort studies, 12 case-control studies and 41 cross-sectional studies) were included and evaluated. Recommendations on the following remain largely unaltered: full breastfeeding for 4 months as a means of allergy prevention (hypoallergenic infant formula in the case of infants at risk); avoidance of overweight; fish consumption (during pregnancy/lactation and in the introduction of solid foods for infants); vaccination according to the recommendations of the German Standing Committee on Vaccination (Ständige Impfkommission, STIKO); avoidance of air pollutants and tobacco exposure and avoidance of indoor conditions conducive to the development of mold. The assertion that a reduction in house-dust mite allergen content as a primary preventive measure is not recommended also remains unchanged. The introduction of solid foods into infant diet should not be delayed. In the case of children at risk cats should not be acquired as domestic pets. Keeping dogs is not associated with an increased risk of allergy. The updated guideline includes a new recommendation to consider the increased risk of asthma following delivery by cesarean section. Additional statements have been formulated on pre- and probiotic agents, psychosocial factors, medications, and various nutritional components.

Revising the guideline by using an extensive evidence base has resulted not only in an endorsement of the existing recommendations, but also in modifications and in the addition of new recommendations. The updated guideline enables evidence-based and up-to-date recommendations to be made on allergy prevention.

Exclusive breastfeeding is associated with reduced cow's milk sensitization in early childhood

BACKGROUND

Although breastfed infants have consistently been reported as having fewer infections and respiratory morbidity during infancy, none have reached a definitive conclusion as to whether breastfeeding is an effective strategy to prevent allergic diseases. This study aims to investigate the relationship between exclusive breastfeeding and sequential changes of several biomarkers of allergy, such as absolute eosinophil count, total IgE level, and specific IgE level during the first 3 yrs of life.

METHODS

This is an unselected, population-based study that is part of a prospective birth cohort called the PATCH (Prediction of Allergy in Taiwanese Children). Blood analysis was performed at ages 6, 12, 18, 24, and 36 months. Clinical records of breastfeeding and detailed questionnaires regarding to allergic diseases were also obtained.

RESULTS

Analysis comparing exclusive breastfeeding ≥4 months with those <4 months and those partially breastfed showed a decreased risk of sensitization toward cow's milk protein up to the age of 2 yr (adjusted OR for cow's milk sensitization at 12 months was 0.2 [95% CI, 0.07-0.5]), at 18 months of age it was 0.2 [95% CI, 0.07-0.5], and at 24 months of age it was 0.2 [95% CI, 0.04-0.7]). In addition, although not significant, children of the exclusive breastfeeding group showed a trend of lower absolute eosinophil counts than their counterparts at all ages, and a lower total IgE level at the age of 3 yr.

CONCLUSIONS

Results of this study suggest that exclusive breastfeeding is associated with a reduced risk of cow's milk protein sensitization during early childhood.

Prevention of asthma: where are we in the 21st century?

Asthma is the most common chronic disease of childhood and, in the latter part of the 20th century, reached epidemic proportions. Asthma is generally believed to result from gene-environment interactions. There is consensus that a 'window of opportunity' exists during pregnancy and early in life when environmental factors may influence its development. We review multiple environmental, biologic and sociologic factors that may be important in the development of asthma. Meta-analyses of studies have demonstrated that multifaceted interventions are required in order to develop asthma prevention. Multifaceted allergen reduction studies have shown clinical benefits. Asthma represents a dysfunctional interaction with our genes and the environment to which they are exposed, especially in fetal and early infant life. The increasing prevalence of asthma also may be an indication of increased population risk for the development of other chronic non-communicable autoimmune diseases. This review will focus on the factors which may be important in the primary prevention of asthma. Better understanding of the complex gene-environment interactions involved in the development of asthma will provide insight into personalized interventions for asthma prevention.

What is new in the prevention of atopy and asthma?

PURPOSE OF REVIEW

Increasing understanding of mechanisms and influencing factors in the development of uncontrolled inflammatory responses in atopy and asthma should serve for the introduction of new preventive measures. This review tries to present the current state of the art and resumes that until now, no really effective concept can be offered to families at risk.

RECENT FINDINGS

In addition to modified feeding regimes (hydrolysed formula feeding in infancy), timing of the introduction of solids (avoidance of allergens versus early induction of tolerance), immune modulation using prebiotics or probiotics, a new target of potential intervention could be the human microbiome as a key player in the development of inflammatory diseases such as allergy and asthma. However, during the last 5 years, this concept could not yet be verified in interventional trials. There are new trials ongoing, studying the effect of microbial compounds in early infancy, vitamin D and polyunsaturated fatty acid supplementation during late pregnancy and the effect of azithromycin in children with recurrent wheeze. Results are to be expected within the next couple of years.

SUMMARY

New data on multifaceted intervention and the analysis of the human microbiome are to be expected. The recommendation for atopy and asthma prevention still focuses on avoidance of tobacco smoke exposure and food allergens during the first 4 months of life and feeding of hydrolysed formula if breast-feeding is not possible in high-risk infants, potentially early feeding of prebiotic sugars and/or certain strains of probiotic bacteria or bacterial compounds in certain subpopulations.

Breastfeeding, introduction of other foods and effects on health: a systematic literature review for the 5th Nordic Nutrition Recommendations

The present systematic literature review is part of the 5th revision of the Nordic Nutrition Recommendations. The overall aim was to review recent scientific data valid in a Nordic setting on the short- and long-term health effects of breastfeeding (duration of both any and exclusive breastfeeding) and introduction of foods other than breast milk. The initial literature search resulted in 2,011 abstracts; 416 identified as potentially relevant. Full paper review resulted in 60 quality assessed papers (6A, 48B, and 6C). A complementary search found some additional papers. The grade of evidence was classified as convincing, probable, limited-suggestive, and limited-no conclusion. The evidence was convincing of a protective dose/duration effect of breastfeeding against overweight and obesity in childhood and adolescence, overall infections, acute otitis media, and gastrointestinal and respiratory tract infections. The evidence was probable that exclusive breastfeeding for longer than 4 months is associated with slower weight gain during the second half of the first year which could be part of the reason behind the reduced risk of later overweight or obesity. There was also probable evidence that breastfeeding is a protective factor against inflammatory bowel disease, celiac disease, and diabetes (type 1 and 2), provides beneficial effects on IQ and developmental scores of children as well as a small reductive effect on blood pressure and blood cholesterol levels in adulthood. Other associations explored were limited-suggestive or inconclusive. In conclusion, convincing and probable evidence was found for benefits of breastfeeding on several outcomes. The recommendation in NNR2004 about exclusive breastfeeding for 6 months and continued partial breastfeeding thereafter can stand unchanged. The relatively low proportion of infants in the Nordic countries following this recommendation indicates that strategies that protect, support and promote breastfeeding should be enhanced, and should also recognize the benefits for long-term health.

Modes of infant feeding and the occurrence of coughing/wheezing in the first year of life

BACKGROUND

Controversies regarding infant feeding and childhood wheezing may result from insufficient differentiation among various feeding modes.

OBJECTIVES

We conducted prospective analyses of associations between the repeated ascertainment of feeding mode and wheezing in infancy.

METHODS

The Infant Feeding Practices Study II (2833 infants) provided data on coughing/wheezing episodes (CWEs) at 8 time points and feeding modes at 9 time points from months 1 to 12. Feeding modes were defined as direct breastfeeding, indirect breastfeeding (IBF, bottled breast milk), formula feeding (FF), and their combinations. In concurrent and delayed models using repeated measurements, the relative risks (RR) and their 95% confidence intervals (95% CI) of different feeding modes for CWEs were estimated. In the delayed models, only infants without symptoms were considered at risk for consequent CWE.

RESULTS

In a model with a 1-month delay, compared to direct breastfeeding, any other feeding mode showed a statistically significant risk for CWEs (IBF: RR = 1.69, 95% CI [1.05, 2.72]; FF: RR = 1.26, 95% CI [1.08, 1.47]; mixed breast feeding plus FF: RR = 1.25, 95% CI [1.01, 1.55]; and FF and direct breastfeeding: RR = 1.38, 95% CI [1.14, 1.68]). In a concurrent effect model, FF, the combination of FF and IBF, and mixed breastfeeding plus formula were risk factors (RR = 1.38, 95% CI [1.19, 1.59], RR = 1.83, 95% CI [1.27, 2.63], and RR=1.35, 95% CI [1.11, 1.65]; respectively).

CONCLUSIONS

Any mode of feeding that includes formula or bottled breast milk seems to be a moderate risk for cough or wheezing episodes in the first 12 months of life.

Non-pro-vitamin A and pro-vitamin A carotenoids in atopy development

Carotenoids are important derivatives of the human diet and occur in high concentrations in the human organism. Various carotenoids are also present in human breast milk and are transferred to breast-fed children. The alternative to breastfeeding is supplementation with an infant milk formula, but these formulas contain only a limited variety of carotenoids. Our question is: 'What is the function of various carotenoids in human nutrition with a special emphasis on child development and the development of atopy?' In this review, the mechanisms of action of the most important non-pro-vitamin A and pro-vitamin A carotenoids: α-carotene, β-carotene, β-cryptoxanthin, lutein, zeaxanthin, lycopene and retinoids are discussed. In summary, the combination of carotenoids, especially lycopene, seems to be of great importance, and exclusive usage of β-carotene in infant formula may yield in an increased atopy prevalence mediated in various target organs like the skin, lungs and immune competent cells. We conclude that the determination of novel bioactive metabolites of various carotenoids, at various stages in different organs during atopy development, might be the key to understanding the potential importance of carotenoids on atopy development.

Primary prevention of allergic disease through nutritional interventions

With the rising prevalence of atopic disease, primary prevention may play a role in reducing its burden, especially in high-risk infants. With this in mind, the Adverse Reactions to Foods Committee of the American Academy of Allergy, Asthma & Immunology was charged with the task of developing recommendations for primary care physicians and specialists about the primary prevention of allergic disease through nutritional interventions according to current available literature and expert opinion. Recommendations that are supported by data are as follows. Avoidance diets during pregnancy and lactation are not recommended at this time, but more research is necessary for peanut. Exclusive breast-feeding for at least 4 and up to 6 months is endorsed. For high-risk infants who cannot be exclusively breast-fed, hydrolyzed formula appears to offer advantages to prevent allergic disease and cow's milk allergy. Complementary foods can be introduced between 4 and 6 months of age. Because no formal recommendations have been previously provided about how and when to introduce the main allergenic foods (cow's milk, egg, soy, wheat, peanut, tree nuts, fish, shellfish), these are now provided, and reasons to consider allergy consultation for development of a personalized plan for food introduction are also presented.

Fatty acids in breast milk associated with asthma-like symptoms and atopy in infancy: a longitudinal study

OBJECTIVE

The relationship between fatty acids (FAs) in breast milk and the risk of childhood allergies is controversial. We prospectively investigated the relationship between FAs in colostrum and breast milk and asthma-like symptoms (AS) and atopy in infancy.

METHODS

Pregnant women were recruited in Columbia and Charleston, South Carolina. Colostrum and mature milk samples were collected. The concentrations of n-3 FAs (eicosapentaenoic acid, α-linolenic acid, docosapentaenoic acid, and docosahexaenoic acid) and n-6 FAs (linoleic acid, arachidonic acid, and eicosadienoic acid) were determined by gas chromatography. AS were ascertained at 6 and 12 months of age and atopy (skin prick test) at 12 months. FAs were dichotomized (high vs. median and low). Generalized estimating equations were used to determine the effect of FAs on repeated AS, compensating for intra-individual correlations and adjusting for confounders. Log-linear regression was used to analyze atopy.

RESULTS

FAs were analyzed in 24 colostrum and 78 breast milk samples. High levels of total n-6 (lipid based) FAs in breast milk were associated with an increased risk of AS in infants (risk ratio (RR) = 2.91; 95% confidence interval (CI): 1.37, 6.18), even after controlling for total n-3 FAs (RR = 2.07, 95% CI: 1.12, 3.85). High levels of total n-3 FAs controlling for n-6 FAs decreased the risk of atopy at the age of 12 months.

CONCLUSIONS

High levels of total n-6 polyunsaturated fatty acids (PUFAs) in breast milk are associated with an increased risk for AS, whereas high levels of total n-3 PUFAs decreased the risk of atopy. These data suggest that the effects of n-3 and n-6 PUFAs on allergic disorders should be further explored.