Breast-feeding duration and infant atopic manifestations, by maternal allergic status, in the first 2 years of life (KOALA study)

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.

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.

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.

How does parental history of atopic disease predict the risk of atopic dermatitis in a child? A systematic review and meta-analysis

BACKGROUND

Parental history of atopic disease is a well-established risk factor for the development of atopic dermatitis (AD), but several aspects of this association remain unclear.

OBJECTIVE

We sought to determine the association of parental history of atopic disease with AD in offspring.

METHODS

We searched PubMed and EMBASE through June 2018 for relevant records and adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Pooled odds ratios (ORs) with 95% CI were calculated using random-effects models.

RESULTS

A total of 163 records covering 149 unique studies were included. Of these, 119 studies were included in the meta-analysis. Individuals with parental history of atopic disease had increased odds of AD (OR, 1.81; 95% CI, 1.65-1.99). Parental asthma (OR, 1.56; 95% CI, 1.18-2.05) and allergic rhinitis (OR, 1.68; 95% CI, 1.34-2.11) had a smaller effect than AD (OR, 3.30; 95% CI, 2.46-4.42). The effect of maternal and paternal history was comparable for all atopic diseases. An increase in odds was observed when comparing the effect of having 1 (OR, 1.30; 95% CI, 1.15-1.47) or 2 atopic parents (OR, 2.08; 95% CI, 1.83-2.36), as well as having a parent with 1 (OR, 1.49; 95% CI, 1.28-1.74) or more atopic diseases (OR, 2.32; 95% CI, 1.92-2.81).

CONCLUSIONS

This study provides evidence-based risk estimates that may guide physicians who counsel parents with a history of atopic disease about their children's risk of AD. This information is of particular importance for future efforts toward establishing prophylactic interventions for AD on a general population level.

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.

Early-Life Intestine Microbiota and Lung Health in Children

The gastrointestinal microbiota plays a critical role in nutritional, metabolic, and immune functions in infants and young children and has implications for future lung health status. Understanding the role of intestinal dysbiosis in chronic lung disease progression will provide opportunities to design early interventions to improve the course of the disease. Gut microbiota is established within the first 1 to 3 years of life and remains relatively stable throughout the life span. In this review, we report the recent development in research in gut-lung axis, with focus on the effects of targeting microbiota of infants and children at risk of or with progressive lung diseases. The basic concept is to exploit this approach in critical window to achieve the best results in the control of future health.

Early-Life Host-Microbiome Interphase: The Key Frontier for Immune Development

Human existence can be viewed as an "animal in a microbial world." A healthy interaction of the human host with the microbes in and around us heavily relies on a well-functioning immune system. As development of both the microbiota and the host immune system undergo rapid changes in early life, it is not surprising that even minor alterations during this co-development can have profound consequences. Scrutiny of existing data regarding pre-, peri-, as well as early postnatal modulators of newborn microbiota indeed suggest strong associations with several immune-mediated diseases with onset far beyond the newborn period. We here summarize these data and extract overarching themes. This same effort in turn sets the stage to guide effective countermeasures, such as probiotic administration. The objective of our review is to highlight the interaction of host immune ontogeny with the developing microbiome in early life as a critical window of susceptibility for lifelong disease, as well as to identify the enormous potential to protect and promote lifelong health by specifically targeting this window of opportunity.

Mother Nature in Eczema: Maternal Factors Influencing Atopic Dermatitis

Atopic dermatitis (AD) is a highly prevalent chronic inflammatory skin disease. Current knowledge about the etiology of AD suggests that it is multifactorial and involves the interaction of several factors, including environmental triggers, genetics, immunologic factors, and skin barrier dysfunction. The prenatal environment has a significant influence on fetal development, including the maturation of skin barrier function. This review summarizes maternal factors that have been reported to influence the development of AD in offspring, including maternal genetics, nutrition, breastfeeding, environment, and behaviors.

Factors associated to recurrent wheezing in infants under one year of age in the province of Salamanca, Spain: Is intervention possible? A predictive model

OBJECTIVES

Wheezing is a very common problem in infants in the first months of life. The objective of this study is to identify risk factors that may be acted upon in order to modify the evolution of recurrent wheezing in the first months of life, and to develop a model based on certain factors associated to recurrent wheezing in nursing infants capable of predicting the probability of developing recurrent wheezing in the first year of life.

METHODS

The sample was drawn from a cross-sectional, multicentre, descriptive epidemiological study based on the general population. A total of 1164 children were studied, corresponding to a questionnaire response rate of 71%. The questionnaire of the Estudio Internacional de Sibilancias en Lactantes (EISL) was used. Multiple logistic regression analysis was used to estimate the probability of developing recurrent wheezing and to quantify the contribution of each individual variable in the presence of the rest.

RESULTS

Infants presenting eczema and attending nursery school, with a mother who has asthma, smoked during the third trimester of pregnancy, and did not consume a Mediterranean diet during pregnancy were found to have a probability of 79.7% of developing recurrent wheezing in the first year of life. In contrast, infants with none of these factors were seen to have a probability of only 4.1% of developing recurrent wheezing in the first year of life. These results in turn varied according to modifications in the risk or protective factors.

CONCLUSIONS

The mathematical model estimated the probability of developing recurrent wheezing in infants under one year of age in the province of Salamanca (Spain), according to the risk or protective factors associated to recurrent wheezing to which the infants are or have been exposed.

Changes in the Immune Components of Preterm Human Milk and Associations With Maternal and Infant Characteristics

OBJECTIVE

To describe difference in cytokines, chemokines, and growth factors (CCGFs) and secretory immunoglobulin A (sIgA) in the breast milk of mothers who gave birth preterm and maternal or infant characteristics related to these immune components.

DESIGN

A prospective, repeated-measures, one-group design.

SETTING

Data were collected at an 82-bed NICU in West Central Florida.

PARTICIPANTS

Seventy-six very-low-birth-weight infants weighing less than 1,500 g and their mothers.

METHODS

Daily aliquots of breast milk from mothers of preterm infants were collected from the daily infants' feedings and pooled at the end of each week, and CCGFs and sIgA were measured weekly with MagPix multiplexing (Luminex, Austin, TX) and enzyme-linked immunosorbent assay.

RESULTS

The CCGFs showed high individual variability, but the levels of most CCGFs and sIgA fell over time. Immune variables were generally greater in milk from mothers of infants smaller than 1,000 g. The breast milk of mothers of male preterm infants had significantly greater sIgA than the breast milk of mothers of female preterm infants. We found relationships between age, body mass index, parity, sIgA, and some of the CCGFs in the breast milk of women who gave birth preterm.

CONCLUSION

Immune molecules declined in concentration over time in the breast milk of mothers who give birth preterm during the NICU stay, and maternal and infant factors appeared to play some role in the levels of these immune molecules. Further exploration of this relationship is warranted.

A single mouse monoclonal antibody, E58 modulates multiple IgE epitopes on group 1 cedar pollen allergens

We recently described a dominant role for conformational epitopes on the group 1 allergen of the mountain cedar (Juniperus ashei, Cupressaceae), Jun a 1, in pollen hypersensitivity in South Central U.S.A. Since these epitopes are surface exposed and are likely to be flexible, they may be susceptible to molecular or physical perturbations. This may make Jun a 1 a potential target for new forms of therapy for cedar pollinosis. Here, we describe a mouse monoclonal antibody, termed E58, which binds to the group 1 allergens of the cedar pollens from three highly populated regions of the world (central U.S.A., France and Japan). Upon binding to these allergens, E58 strongly reduces the binding of patient's IgE antibodies to these dominant allergens. This characteristic of E58, and potentially other similar antibodies, suggests an opportunity to develop preventative or therapeutic agents that may inhibit cedar pollen sensitization or prevent their allergic reactions.

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 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.

Dietary nucleotide and nucleoside exposure in infancy and atopic dermatitis, recurrent wheeze, and allergic sensitization

We hypothesized that early life exposure to nucleotides and nucleosides lowers the risk of recurrent wheeze, atopic dermatitis, and allergic sensitization among n = 429 children. Concentrations in breast milk were established by high-performance liquid chromatography; concentrations in formula milks were obtained from manufacturers. Questionnaires and home visits were used to assess outcomes. Adjusted odds ratios in the highest tertile compared with those in the lowest tertile of exposure ranged from 1.11 to 1.99 in predominantly formula-fed children, and from 0.40 to 0.53 in predominantly breast-fed children, but were not significant. Thus, we found no evidence for association between nucleotide and nucleoside exposure and the development of atopic outcomes in children up to 2 years.

Risk and protective factors for the development of childhood asthma

Childhood asthma prevalence worldwide has been increasing markedly over several decades. Various theories have been proposed to account for this alarming trend. The disease has a broad spectrum of potential determinants ranging from genetics to lifestyle and environmental factors. Epidemiological observations have demonstrated that several important lifestyle and environmental factors including obesity, urban living, dietary patterns such as food low in antioxidants and fast food, non-breastfeeding, gut flora imbalance, cigarette smoking, air pollution, and viral infection are associated with asthma exacerbations in children. However, only environmental tobacco smoke has been associated with the development of asthma. Despite epidemiological studies indicating that many other factors are probably associated with the development of asthma, the relationships are not considered causal due to the inadequate evidence and inconsistent results from recent studies. This may highlight that sufficient data and exact mechanisms of causality are still in need of further study.

Microbiome diversity and asthma and allergy risk

The prevalence of asthma and allergy has been constantly increasing in Westernized countries in the last decades. Asthma and allergies are complex diseases with a local tissue inflammation that are determined by genetic and environmental factors. Because the commensal microflora is crucial to maintain inflammatory homeostasis and to induce immune regulation, the microbiome may play an important role for the development of allergic conditions. New techniques such as next-generation sequencing methods give the opportunity to explore the microbial community structure of the human body comprehensively. In this review, we will discuss the available literature concerning the human microbiota and asthma and allergy development and occurrence. The focus is on studies of the local microbiome of the place of inflammation, the gastrointestinal microbiome, and the influence of intrinsic factors relating to the host and extrinsic factors relating to the external environment on the microbiome.

Breastfeeding and childhood asthma: systematic review and meta-analysis

Asthma and wheezing disorders are common chronic health problems in childhood. Breastfeeding provides health benefits, but it is not known whether or how breastfeeding decreases the risk of developing asthma. We performed a systematic review and meta-analysis of studies published between 1983 and 2012 on breastfeeding and asthma in children from the general population. We searched the PubMed and Embase databases for cohort, cross-sectional, and case-control studies. We grouped the outcomes into asthma ever, recent asthma, or recent wheezing illness (recent asthma or recent wheeze). Using random-effects meta-analyses, we estimated pooled odds ratios of the association of breastfeeding with the risk for each of these outcomes. We performed meta-regression and stratified meta-analyses. We included 117 of 1,464 titles identified by our search. The pooled odds ratios were 0.78 (95% confidence interval: 0.74, 0.84) for 75 studies analyzing "asthma ever," 0.76 (95% confidence interval: 0.67, 0.86) for 46 studies analyzing "recent asthma," and 0.81 (95% confidence interval: 0.76, 0.87) for 94 studies analyzing recent wheezing illness. After stratification by age, the strong protective association found at ages 0-2 years diminished over time. We found no evidence for differences by study design or study quality or between studies in Western and non-Western countries. A positive association of breastfeeding with reduced asthma/wheezing is supported by the combined evidence of existing studies.

Breastfeeding and risk of atopic dermatitis up to the age 42 months: a birth cohort study in Japan

PURPOSE

The purpose of this study was to investigate the association between breastfeeding and atopic dermatitis (AD) up to the age 42 months.

METHODS

Data from a nationally representative population-based birth cohort study in Japan were used (N = 38,757). Feeding pattern and breastfeeding duration were investigated via questionnaires when infants were aged 6 months. Physician-diagnosed AD during the previous 1 year was ascertained via questionnaires when the children were aged 18, 30, and 42 months. The associations between feeding patterns or breastfeeding duration and physician-diagnosed AD from the age 6 to 42 months, categorized by AD status (no history of AD, episodic AD, and persistent AD), were analyzed using ordered logistic regression adjusted for covariates.

RESULTS

Breastfeeding was positively associated with AD, with dose-response association (P for trend < .001). Exclusively breastfed infants were 1.26 times more likely to have AD (95% confidence interval, 1.12-1.41) than infants fed formula alone. Furthermore, children with a longer breastfeeding duration were also significantly more likely to have AD (P for trend < .001).

CONCLUSIONS

Breastfeeding is associated with an increased risk of AD up to the age 42 months. Further study is needed to elucidate the mechanism underlying the association between breastfeeding and AD.

Consumption of human milk glycoconjugates by infant-associated bifidobacteria: mechanisms and implications

Human milk is a rich source of nutrients and energy, shaped by mammalian evolution to provide all the nutritive requirements of the newborn. In addition, several molecules in breast milk act as bioactive agents, playing an important role in infant protection and guiding a proper development. While major breast milk nutrients such as lactose, lipids and proteins are readily digested and consumed by the infant, other molecules, such as human milk oligosaccharides and glycosylated proteins and lipids, can escape intestinal digestion and transit through the gastrointestinal tract. In this environment, these molecules guide the composition of the developing infant intestinal microbiota by preventing the colonization of enteric pathogens and providing carbon and nitrogen sources for other colonic commensals. Only a few bacteria, in particular Bifidobacterium species, can gain access to the energetic content of milk as it is displayed in the colon, probably contributing to their predominance in the intestinal microbiota in the first year of life. Bifidobacteria deploy exquisite molecular mechanisms to utilize human milk oligosaccharides, and recent evidence indicates that their activities also target other human milk glycoconjugates. Here, we review advances in our understanding of how these microbes have been shaped by breast milk components and the strategies associated with their consumption of milk glycoconjugates.

Latitude modifies the effect size of factors related to recurrent wheeze in the first year of life

BACKGROUND

Although the association between latitude and asthma prevalence has been studied to a certain extent, its influence on the magnitude of the association of risk/protective factors with recurrent wheeze in infants has never been reported.

METHODS

The adjusted odd ratios (aOR) of various risk/protective factors for recurrent wheeze from 31,920 infants from 19 centres of the "Estudio Internacional de Sibilacias en Lactantes" (EISL) in very different parts of the world were used to build a meta-regression using the strength of the aOR of each factor as dependent variable and centre latitude as explanatory variable. The meta-regression was further adjusted for continent.

RESULTS

There was a positive significant correlation between latitude and the magnitude of the aOR between recurrent wheeze and having cold(s) during the first three months of life (p = 0.004); attending a nursery school (p = 0.011); and having additional siblings (p = 0.003). Furthermore, there was a negative correlation for having been breastfed for at least three months (p = 0.044). Heterogeneity (as measured by I2) of the magnitude of aORs between centres was quite high except for breast feeding: 73.1% for colds; 66.9% for nursery school; 52.6% for additional siblings; and 18.1% for breast feeding. Latitude explained a considerable amount of that heterogeneity: 63.8% for colds; 52.8% for nursery school; 86.6% for additional siblings; and 100% for breast feeding, probably as a consequence of its low heterogeneity.

CONCLUSION

The magnitude in which some risk/protective factors are associated to recurrent wheeze during the first year of life varies significantly with latitude.

Prevalence of allergen sensitization, most important allergens and factors associated with atopy in children

CONTEXT AND OBJECTIVE

Knowledge of the profile of allergen sensitization among children is important for planning preventive measures. The objective of this study was to assess the prevalence and profile of sensitization to inhaled allergens and food among children and adolescents in an outpatient population in the city of Palmas.

DESIGN AND SETTING

Cross-sectional study at outpatient clinics in Palmas, Tocantins, Brazil.

METHODS

Ninety-four patients aged 1-15 years who were attending two pediatric outpatient clinics were selected between September and November 2008. All of the subjects underwent clinical interviews and skin prick tests.

RESULTS

A positive skin prick test was observed in 76.6% of the participants (72.3% for inhalants and 28.9% for food allergens). The most frequent allergens were Dermatophagoides pteronyssinus (34%), cat epithelium (28.7%), dog epithelium (21.3%), Dermatophagoides farinae (19.1%), Blomia tropicalis (18.1%), cow's milk (9.6%) and grasses (9.6%). A positive skin prick test correlated with a history of atopic disease (odds ratio, OR = 5.833; P = 0.002), a family history of atopic disease (OR = 8.400; P < 0.001), maternal asthma (OR = 8.077; P = 0.048), pet exposure (OR = 3.600; P = 0.012) and cesarean delivery (OR = 3.367; P = 0.019).

CONCLUSION

Dermatophagoides pteronyssinus was the most frequent aeroallergen and cow's milk was the most prevalent food allergen. There was a positive correlation between a positive skin prick test and several factors, such as a family history of atopic disease, maternal asthma, pet exposure and cesarean delivery.

Breastfeeding and allergy: the evidence

Whether breastfeeding protects against the development of allergic disease has been a frequent subject of study and debate for 75 years. This paper summarizes the published evidence concerning the risks of atopic dermatitis, asthma, allergic rhinitis, positive allergen skin tests, and food allergy associated with infant feeding. The summary is based largely on systematic reviews and meta-analyses carried out by other authors. In addition, I also incorporate the evidence from our long-term follow-up of Belarusian children participating in a cluster-randomized trial of a breastfeeding promotion intervention.

Systematic review and meta-analysis investigating breast feeding and childhood wheezing illness

There is conflicting evidence concerning the relationship between breast feeding and wheezing illness. The objective of this study was to investigate whether there is any association between breast feeding and wheezing in children aged over 5 years and to discover possible sources of heterogeneity. An electronic search of MEDLINE and EMBASE databases was conducted from January 2000 to June 2010. In addition, reference lists from relevant publications were searched. Birth cohort, cross-sectional and case-control studies were included if they measured any breast feeding or exclusive breast feeding for 3 or 4 months. Wheezing illness, including asthma, was identified based on symptoms, reported diagnosis or objective criteria. Thirty-one publications were identified for meta-analysis. There was no association found between any or exclusive breast feeding and wheezing illness, although there was a high level of heterogeneity between the studies. Subgroup analysis revealed that any breast feeding slightly lowers the odds of wheeze (pooled odds ratio 0.92 [0.86, 0.98]) but slightly increases the odds of asthma defined by specific criteria (pooled odds ratio 1.10 [1.00, 1.22]). This meta-analysis does not provide evidence that breast feeding is protective against wheezing illness in children aged 5 years and over. The difference in the effects of breast feeding according to the nature of the wheezing illness highlights the importance of the heterogeneity of illness phenotypes.

Prevalence of and risk factors for wheezing in the first year of life

OBJECTIVE

To determine the prevalence of and the risk factors for wheezing in infants under one year of age and residing in the city of Porto Alegre, Brazil.

METHODS

This was a cross-sectional study and is part of a multicenter, multinational project. The parents or legal guardians of the infants were interviewed at primary health care clinics or during home visits. We used a standardized questionnaire, validated for use in Brazil. Potential risk factors were assessed by means of a Poisson regression model with robust variance estimation, using the Wald test to determine the significance of each variable in the model.

RESULTS

The sample comprised 1,013 infants. The majority of those were male (53%), and the mean age was 13.5 ± 1.2 months. In 61% of the infants, there had been at least one episode of wheezing, which had recurred at least three times in one third of those infants. The mean age at the first episode of wheezing was 5.16 months (median, 5 months). Over 40% of the infants with wheezing visited emergency rooms due to wheezing, and 17% of those were hospitalized at least once in the first year of life because of this symptom. In the multivariate analysis, the risk factors for wheezing were as follows: male gender; history of pneumonia; maternal smoking during pregnancy; day care center attendance; low maternal level of education; early weaning; multiple episodes of cold; first viral infection prior to 3 months of age; existence of siblings; and history of asthma in the nuclear family.

CONCLUSIONS

The prevalence of wheezing is high among infants in the city of Porto Alegre. We identified various risk factors for wheezing in infants.

Infant feeding practices and physician diagnosed atopic dermatitis: a prospective cohort study in Taiwan

It is common to recommend breastfeeding and a delayed introduction of solids to prevent atopic dermatitis (AD). However, the scientific evidence for this is inconclusive. The aim of this study was to explore the effect of breastfeeding and solids on AD, when taking account of reverse causality. This on-going birth cohort study was designed to sample 24,200 representative post-partum women and their babies from the Taiwan National Birth Registration database. Using two home interviews at 6 and 18 months after birth, with structured questionnaires about diet and physician's diagnosis of AD by parental reports, a total of 20,172 pairs (83.4%) were reviewed completely. Considering reverse causality, we excluded 2399 children with AD in the first 6 months of life and 18,733 were finally recruited. All study participants provided informed consent as approved by the Ethics Review Board of the National Taiwan College of Public Health. After adjustment for potential confounders, the overall results showed that the increased duration of breastfeeding seemed to increase the risk of AD at 18 months in children. However, no significant effect was found for the delayed introduction of solids on the risk of AD. There is no evidence of a protective effect of prolonged breastfeeding and a delayed introduction of solids against AD among children at age 18 months, and may even be a risk factor of AD.

Maternal antenatal peanut consumption and peanut and rye sensitization in the offspring at adolescence

BACKGROUND

There is considerable controversy whether maternal peanut ingestion during pregnancy might influence sensitization in later life. Objective To examine whether maternal peanut ingestion during pregnancy might increase sensitization in the offspring.

METHODS

A population-based longitudinal cohort study with 16 years follow-up was conducted (N=373). Subjects were recruited at birth as part of an infant health study. Maternal antenatal peanut consumption was documented at birth and peanut and rye sensitization were determined by measurement of serum-specific IgE at age 16.

RESULTS

Peanut sensitization was common (14%). In the entire cohort (n=310), there was no association between antenatal peanut ingestion and peanut sensitization (P=0.17). However, there was a strong association between antenatal peanut ingestion and decreased risk of rye sensitization and peanut sensitization in those (n=201) without a family history (FH) of asthma (Rye OR 0.30, 95% CI 0.14-0.63, P=0.001 and Peanut OR 0.18, 95% CI 0.04-0.78, P=0.02). There was an increased risk of rye sensitization in those (n=108) with a FH of asthma and antenatal peanut ingestion (Rye OR 2.69, 95% CI 1.11-6.51 P=0.03). It was considered that these sensitizations were likely to be related to the presence of IgE antibodies to cross-reacting carbohydrate epitopes common to rye and peanut allergens.

CONCLUSIONS AND CLINICAL RELEVANCE

Antenatal peanut ingestion may influence the development of IgE antibody to cross-reacting carbohydrate epitopes in later life. Genetic factors may modify this association.

International study of wheezing in infants: risk factors in affluent and non-affluent countries during the first year of life

Risk factors for wheezing during the first year of life (a major cause of respiratory morbidity worldwide) are poorly known in non-affluent countries. We studied and compared risk factors in infants living in affluent and non-affluent areas of the world. A population-based study was carried out in random samples of infants from centres in Latin America (LA) and Europe (EU). Parents answered validated questionnaires referring to the first year of their infant's life during routine health visits. Wheezing was stratified into occasional (1-2 episodes, OW) and recurrent (3 + episodes, RW). Among the 28687 infants included, the most important independent risk factors for OW and RW (both in LA and in EU) were having a cold during the first 3 months of life [OR for RW 3.12 (2.60-3.78) and 3.15 (2.51-3.97); population attributable fraction (PAF) 25.0% and 23.7%]; and attending nursery school [OR for RW 2.50 (2.04-3.08) and 3.09 (2.04-4.67); PAF 7.4% and 20.3%]. Other risk factors were as follows: male gender, smoking during pregnancy, family history of asthma/rhinitis, and infant eczema. Breast feeding for >3 months protected from RW [OR 0.8 (0.71-0.89) in LA and 0.77 (0.63-0.93) in EU]. University studies of mother protected only in LA [OR for OW 0.85 (0.76-0.95) and for RW 0.80 (0.70-0.90)]. Although most risk factors for wheezing are common in LA and EU; their public health impact may be quite different. Avoiding nursery schools and smoking in pregnancy, breastfeeding babies >3 months, and improving mother's education would have a substantial impact in lowering its prevalence worldwide.

Clinical aspects of pediatric food allergy and failed oral immune tolerance

Food allergy seems to represent a new spectrum of disease that has elicited significant community concern and extended waiting lists for allergists and gastroenterologists alike. The apparent rise in prevalence of IgE-mediated food allergy (and associated risk of anaphylaxis) has been postulated to result from effects of a "modern lifestyle" but as yet clear environmental risk factors have not yet emerged. Family history seems to contribute to risk suggesting that gene-environment interactions will be important for identifying a subpopulation with increased susceptibility to any identified lifestyle effects. Non-IgE-mediated food allergy (including food-induced enteropathies and colitides, eosinophilic esophagitis, and Crohn's disease) with potentially similar environmental triggers resulting in diverse immune dysregulatory mechanisms. The evidence underpinning the putative rise in food allergy is discussed and potential mechanisms of disease explored. Clinical aspects of various food allergic conditions including non-IgE-mediated food allergy are outlined.

[Asthma and pregnancy. Review of the current literature and management according to the GINA 2006-2007 guidelines]

INTRODUCTION

Many pregnant women are asthmatics and maternal asthma is a source of questions and complications concerning both the progress of the pregnancy itself and the impact on the foetus. In this situation good asthma control is essential as the disease can deteriorate with acute exacerbations, possibly precipitated by reduction or even withdrawal of treatment on account of fear of teratogenicity.

BACKGROUND

Even though asthma treatments are not totally harmless during pregnancy, their use has been validated by several studies and guidelines. To help clinicians, we undertake here a review of the complications induced by maternal asthma and its medications, and then suggest management guidelines according to the most recent publications.

CONCLUSIONS

The risks and benefits of asthma treatments should be explained in a real partnership between the patient and her general practitioner and specialists (obstetrician, chest physician or allergist). In order to reduce complications to both mother and child, perfect control of asthma is required and inhaled steroids remain the treatment of choice for partially or uncontrolled asthma in the pregnant woman.

Exclusive breastfeeding and incident atopic dermatitis in childhood: a systematic review and meta-analysis of prospective cohort studies

BACKGROUND

Breastfeeding is undisputedly preferable to formula feeding for infant nutrition because of its nutritional, immunological and psychological benefits. However, studies on the association between breastfeeding and development of atopic dermatitis (AD) have shown inconsistent results.

OBJECTIVES

To examine the association between exclusive breastfeeding for at least 3 months after birth and the development of AD in childhood.

METHODS

An electronic literature search of MEDLINE (January 1966-May 2008) and EMBASE (1980-May 2008) was conducted. Prospective cohort studies that met the predetermined criteria were independently assessed by three reviewers. The pooled effect estimate was calculated by random effects model. Heterogeneity across the studies was investigated by meta-regression analysis.

RESULTS

Twenty-one studies with 27 study populations were included for meta-analysis. The summary odds ratio (OR) for the effect of exclusive breastfeeding on the risk of AD was 0.89 (95% confidence interval, CI 0.76-1.04). Heterogeneity was found across the studies (chi(2) = 83.6, d.f. = 26; P < 0.001). Breastfeeding was associated with a decreased risk of AD (OR 0.70; 95% CI 0.50-0.99) when analysis was restricted to the studies comparing breastfeeding with conventional formula feeding. The pooled OR for study populations with atopic heredity was 0.78 (95% CI 0.58-1.05).

CONCLUSIONS

There is no strong evidence of a protective effect of exclusive breastfeeding for at least 3 months against AD, even among children with a positive family history.

Breastfeeding and allergies: time for a change in paradigm?

PURPOSE OF REVIEW

This review examines recent studies of the relationships between breastfeeding and the epidemiology of allergic diseases, especially atopic dermatitis in infants and asthma in early and later childhood.

RECENT FINDINGS

Results from observational birth cohort studies, case-control studies, and one cluster randomized intervention trial have generally failed to demonstrate a protective effect of breastfeeding on outcomes of atopic dermatitis, allergic sensitization, wheezing, or asthma. Difficulties in interpretation relate to the absence of nonbreastfed control or reference groups in some studies, meaning outcomes can only be compared between different durations of breastfeeding. Studies with a nonbreastfed control group suggest there is an increased risk for atopy and asthma associated with breastfeeding and that prolonged breastfeeding may eventually reduce this increased risk. The family history, sex of the child, and the presence of other risk factors for allergy and asthma also influence the outcome.

SUMMARY

Although breastfeeding is strongly recommended for its multiple benefits on child health, most recent studies do not confirm the 'conventional wisdom' that breastfeeding is protective against allergy and asthma. Early reduction in childhood wheezing may reflect protection from viral infections, but allergies and asthma at later ages may be increased.

Effect of breastfeeding duration on lung function at age 10 years: a prospective birth cohort study

INTRODUCTION

The protective effects of breastfeeding on early life respiratory infections are established, but there have been conflicting reports on protection from asthma in late childhood. The association of breastfeeding duration and lung function was assessed in 10-year-old children.

METHODS

In the Isle of Wight birth cohort (n = 1456), breastfeeding practices and duration were prospectively assessed at birth and at subsequent follow-up visits (1 and 2 years). Breastfeeding duration was categorised as "not breastfed" (n = 196); "<2 months" (n = 243); "2 to <4 months" (n = 142) and ">or=4 months" (n = 374). Lung function was measured at age 10 years (n = 1033): forced vital capacity (FVC), forced expiratory volume in 1 s (FEV(1)), FEV(1)/FVC ratio and peak expiratory flow (PEF). Maternal history of asthma and allergy was assessed at birth. The effect of breastfeeding on lung function was analysed using general linear models, adjusting for birth weight, sex, current height and weight, family social status cluster and maternal education.

RESULTS

Compared with those who were not breastfed, FVC was increased by 54.0 (SE 21.1) ml (p = 0.001), FEV(1) by 39.5 (20.1) ml(p = 0.05) and PEF by 180.8 (66.1) ml/s (p = 0.006) in children who were breastfed for at least 4 months. In models for FEV(1) and PEF that adjusted for FVC, the effect of breastfeeding was retained only for PEF (p = 0.04).

CONCLUSIONS

Breastfeeding for at least 4 months enhances lung volume in children. The effect on airflow appears to be mediated by lung volume changes. Future studies need to elucidate the mechanisms that drive this phenomenon.

Age at first introduction of cow milk products and other food products in relation to infant atopic manifestations in the first 2 years of life: the KOALA Birth Cohort Study

OBJECTIVES

Scientific evidence is scarce about timing of solid-food introduction and its association with the development of atopy. We aimed to evaluate any associations between the introduction of cow milk products/other solid food products and infant atopic manifestations in the second year of life, taking into account reverse causation.

METHODS

Data from 2558 infants in an ongoing prospective birth cohort study in the Netherlands were analyzed. Data on the main determinants (introduction of cow milk products and other food products), outcomes (eczema; atopic dermatitis [United Kingdom Working Party criteria]; recurrent wheeze; any sensitization; sensitization against cow milk, hen egg, peanut, and at least 1 inhalant allergen), and confounders were collected by repeated questionnaires at 34 weeks of gestation and 3, 7, 12, and 24 months postpartum. Information on sensitization was gathered by venous blood collections performed during home visits at age 2. Analyses were performed by multiple logistic regression analyses.

RESULTS

More delay in introduction of cow milk products was associated with a higher risk for eczema. In addition, a delayed introduction of other food products was associated with an increased risk for atopy development at the age of 2 years. Exclusion of infants with early symptoms of eczema and recurrent wheeze (to avoid reverse causation) did not essentially change our results.

DISCUSSION

Delaying the introduction of cow milk or other food products may not be favorable in preventing the development of atopy.

Inflammatory breast diseases during lactation: health effects on the newborn-a literature review

Breastfeeding-associated inflammatory breast diseases appear especially during the first twelve weeks postpartum and are the most common reason for early cessation of breastfeeding. It also becomes increasingly evident that these inflammatory mammary diseases are triggered or perpetuated in a large part by psychosocial stress. Immunological processes taking place during this cascade in the mammary gland and consequences for the breastfeed newborn are mostly yet unknown. This review summarizes insights from studies on modulation of cytokine levels in breast milk during inflammatory processes like milk stasis and mastitis systematically. It also gives an overview on possible pathological effects, which these cytokine changes in the breast milk might have on the newborn.

Dietary approaches to the prevention of food allergy

PURPOSE OF REVIEW

The primary prevention of food allergy and atopy has become a public health priority in developed countries. Although some preventive dietary interventions have entered common practice, the level of evidence underpinning these strategies varies.

RECENT FINDINGS

Exclusive breast-feeding and delayed introduction of complementary foods from the age of 4-6 months are key strategies in primary food allergy and atopy prevention. Maternal elimination diets during pregnancy and lactation are currently not recommended. Partially and extensively hydrolyzed formulae may confer a small preventive effect in high-risk infants. Amino acid-based formula is, however, considered a treatment formula and not recommended for primary allergy prevention. The effect of prebiotic oligosaccharides and probiotic bacteria in prevention of food allergy remains unclear and requires further investigation. Maternal fish oil supplementation during pregnancy shows promise in reducing the risk of allergic sensitization in the infant, but prospective long-term data are required. Fish oil supplementation in young infants was not effective.

SUMMARY

Although there is evidence for the primary dietary prevention of eczema and possible respiratory allergies, data on food allergy prevention have, so far, remained less convincing. Further prospective research is needed to clarify the effectiveness of dietary interventions in primary food allergy prevention.