Effect of prolonged and exclusive breast feeding on risk of allergy and asthma: cluster randomised trial

Human Milk Feeding in Inherited Metabolic Disorders: A Systematic Review of Growth, Metabolic Control, and Neurodevelopment Outcomes

Human milk (HM) is the optimal source of nutrition for infants. Yet the suitability of HM macronutrient composition, paired with the challenge of regulating HM intake, may deserve some consideration for infants with inherited metabolic disorders (IMDs) requiring restrictive and controlled dietary management. Except for classic galactosemia, HM feeding is expected to be feasible, allowing infants to maintain metabolic stability, while growing and developing optimally. However, information about HM feeding in nonphenylketonuria (PKU) literature is scarce. In this systematic review, 52 studies were included, representing 861 infants (86% PKU) receiving HM after IMD diagnosis (mean duration 4-10 months depending on the IMD). For non-PKU IMDs (e.g., other amino acidopathies, urea cycle disorders, organic acidemias, fatty acid oxidation disorders), outcomes of HM feeding were available for few infants, except for medium-chain acyl-CoA dehydrogenase (MCAD) deficiency (n = 48). In PKU, HM feeding combined with phenylalanine-free formula, led to adequate metabolic control (25 studies), growth (15 studies), and neurodevelopment (10 studies). For other IMDs, more evidence is required, but the limited data suggest that HM feeding is possible, with attentive monitoring and disease-specific formula supplementation where applicable. In MCAD deficiency, ensuring adequate HM intake is essential, as symptoms were more frequently reported in exclusively breastfed infants. No IMD-specific articles were found on the relationship between HM feeding and many other outcomes of interest (e.g., immune status or comorbidity risk later in life). With the exception of galactosemia, HM feeding is expected to benefit infants with IMD. More data should be published for IMDs other than PKU.

Breastfeeding, genetic susceptibility, and the risk of asthma and allergic diseases in children and adolescents: a retrospective national population-based cohort study

BACKGROUND

Asthma and allergic diseases (such as allergic rhinitis) are multifactorial chronic respiratory diseases, and have many common pathogenic mechanisms. This study aimed to assess the joint effects of breastfeeding and genetic susceptibility on asthma, allergic disease in children and adolescents and sought to examine whether the effect of breastfeeding was consistent under distinct levels of genetic risk.

METHODS

A total of 351,931 UK Biobank participants were analyzed. Firstly, Cox proportional hazards model was used to evaluate the relation between breastfeeding and asthma, allergic disease and their comorbidity. Next, we incorporated the polygenic risk score as an additional covariate into the model. Then, we explored the role of breastfeeding at each stage of asthma and allergic disease through a multi-state model. Meanwhile, several sensitivity analyses were conducted to evaluate the robustness of our results. Finally, we calculated the attributable protection and population attributable protection of breastfeeding.

RESULTS

Breastfeeding was related to a reduced risk of occurring asthma (adjusted hazard ratio [HR] = 0.89, 95% confidence interval [CI] 0.86 ~ 0.93), allergic disease (HR = 0.89, 95%CI 0.87 ~ 0.91) and comorbidity (HR = 0.89, 95%CI 0.83 ~ 0.94). The effect of breastfeeding was almost unchanged after considering PRS and did not substantially differ across distinct genetic risk levels. Breastfeeding showed a stronger risk-decreased impact on individuals who developed from allergic rhinitis to comorbidity (HR = 0.83, 95%CI 0.73 ~ 0.93). Further, the influence of breastfeeding was robust against covariates considered and the confounding influence of adolescent smoking. Finally, due to breastfeeding, 12.0%, 13.0% or 13.0% of the exposed population would not suffer from asthma, allergic diseases and the comorbidity, while 7.1%, 7.6% or 7.6% of the general population would not suffer from these diseases.

CONCLUSIONS

This study provided supportive evidence for the risk-reduced effect of breastfeeding on asthma, allergic diseases, and the comorbidity in children and adolescents, and further revealed that such an influence was consistent across distinct genetic risk levels.

How to Prevent Atopic Dermatitis (Eczema) in 2024: Theory and Evidence

Atopic dermatitis (AD) or eczema is a chronic inflammatory skin disease characterized by dry, itchy, and inflamed skin. We review emerging concepts and clinical evidence addressing the pathogenesis and prevention of AD. We examine several interventions ranging from skin barrier enhancement strategies to probiotics, prebiotics, and synbiotics; and conversely, from antimicrobial exposure to vitamin D and omega fatty acid supplementation; breastfeeding and hydrolyzed formula; and house dust mite avoidance and immunotherapy. We appraise the available evidence base within the context of the Grades of Recommendation, Assessment, Development, and Evaluation approach. We also contextualize our findings in relation to concepts relating AD and individual-patient allergic life trajectories versus a linear concept of the atopic march and provide insights into future knowledge gaps and clinical trial design considerations that must be addressed in forthcoming research. Finally, we provide implementation considerations to detect population-level differences in AD risk. Major international efforts are required to provide definitive evidence regarding what works and what does not for preventing AD.

Atopic diseases-Diagnostics, mechanisms, and exposures

Epidemiological data suggest that atopic diseases begin in early life and that most cases present clinically during early childhood. The diseases are highly prevalent and increase as communities adopt western lifestyles. Disentangling the pathophysiological mechanisms leading to disease debut is necessary to identify beneficial/harmful exposures so that successful prevention and treatment can be generated. The objective of this review is to explore the definition of atopy and mechanisms of atopic diseases, and to investigate the importance of environmental factors in early life, prior to disease development. First, the distribution of sIgE levels in children is investigated, as this is one of the main criteria for the definition of atopy. Thereafter, it is explored how studies of parental atopic status, sensitization patterns, and early debut and severity of atopic dermatitis have substantiated the theory of an early-life window of opportunity for intervention that precedes the development of atopic diseases in childhood. Then, it is examined whether early-life exposures such as breastfeeding, dogs, cats, and house dust mites in the home perinatally constitute important influencers in this crucial time of life. Finally, it is discussed how these findings could be validated in randomized controlled trials, which might prepare the ground for improved diagnostics and prevention strategies to mitigate the current atopic pandemic.

Effects of Exclusive Breastfeeding Promotion Interventions on Child Outcomes: A Systematic Review and Meta-Analysis

INTRODUCTION

Interventions promoting exclusive breastfeeding (EBF) may benefit infant health outcomes, but evidence is inconsistent. The objective of this review was to assess the effect of interventions promoting EBF on health outcomes in infants and children under 7 years of age.

METHODS

A literature search was conducted using EMBASE, MEDLINE, CINAHL, Cochrane Central, Cochrane Database of Systematic Reviews, and WHO International Clinical Trials Registry Platform from inception to April 2022. Inclusion criteria were randomized or cluster-randomized controlled trials aiming to increase EBF that reported effects on offspring growth, morbidity, and/or mortality up to age 7 years. The primary outcome was infant/child growth. Secondary outcomes were infant morbidity and mortality and EBF rates. Data were pooled using a random-effects model.

RESULTS

Thirty-two studies (40 papers) were identified. No effect on infant/child growth was observed. EBF promotion interventions significantly improved EBF rates up to 6 months (n = 25; OR 3.15; 95% CI: 2.36, 4.19) and significantly reduced the odds of respiratory illness at 0-3 months by 59% (n = 2; OR 0.41; 95% CI: 0.20, 0.84) but not at later time-points. A borderline significant effect was observed for diarrhea (n = 12; OR 0.84; 95% CI: 0.70, 1.00). Effects on hospitalizations or mortality were not significant.

DISCUSSION/CONCLUSION

EBF promotion interventions improve EBF rates and might yield modest reductions in infant morbidity without affecting infant/child growth. Future studies should investigate the cost-effectiveness of these interventions and examine potential benefits on other health outcomes.

Breastfeeding and ApoB in late adolescence: a Hong Kong birth cohort study

Breastfeeding is widely promoted. Experimental evidence concerning long-term benefits is limited. Observational studies are open to bias from confounding by socio-economic position. We assessed the association of breastfeeding with late adolescent lipid sub-fractions, particularly apolipoprotein B (ApoB) and non-high-density lipoprotein cholesterol (non-HDL-c), overall and by sex. We took advantage of a setting where breastfeeding has little association with higher socio-economic position and where several results from randomized controlled trials of breastfeeding promotion have been replicated. We used the population-representative "Children of 1997" birth cohort comprising 88% of births in Hong Kong in April and May 1997. Associations of breastfeeding in the first 3 months of life (never, mixed, exclusive) with lipid sub-fractions were obtained using linear regression adjusted for potential confounders including parental socio-economic position, maternal place of birth, type of delivery, gestational age, and birth weight. Differences by sex were assessed. Multiple imputation and inverse probability weighting were used to recover the original sample. Of the 3462 participants included, mean age was 17.6 years and 48.8% were girls. Mean ApoB was 0.74 g/L (standard deviation 0.15). Exclusive versus never breastfeeding was associated with lower ApoB (-0.027 g/L, 95% confidence interval (CI)-0.046 to-0.007, p = 0.007) and lower non-HDL-c (-0.143 mmol/L, 95% CI-0.237 to-0.048) with similar estimates by sex.

CONCLUSION

Breastfeeding may provide some population-level lifelong protection against cardiovascular disease. This study supports policies promoting breastfeeding as a modifiable exposure that contributes to a healthy start in life as an investment for lifelong cardiovascular disease prevention.

WHAT IS KNOWN

• Apolipoprotein B (ApoB) is a recognized risk factor for cardiovascular disease, but whether breastfeeding affects ApoB in later life overall and by sex is unknown.

WHAT IS NEW

• Exclusive breastfeeding in the first 3 months of life was associated with lower ApoB in late adolescence, with similar estimates for both sexes. • The inverse association of breastfeeding with ApoB suggests that breastfeeding could reduce cardiovascular disease and overall mortality over the lifespan.

Evidence for human milk as a biological system and recommendations for study design-a report from "Breastmilk Ecology: Genesis of Infant Nutrition (BEGIN)" Working Group 4

Human milk contains all of the essential nutrients required by the infant within a complex matrix that enhances the bioavailability of many of those nutrients. In addition, human milk is a source of bioactive components, living cells and microbes that facilitate the transition to life outside the womb. Our ability to fully appreciate the importance of this matrix relies on the recognition of short- and long-term health benefits and, as highlighted in previous sections of this supplement, its ecology (i.e., interactions among the lactating parent and breastfed infant as well as within the context of the human milk matrix itself). Designing and interpreting studies to address this complexity depends on the availability of new tools and technologies that account for such complexity. Past efforts have often compared human milk to infant formula, which has provided some insight into the bioactivity of human milk, as a whole, or of individual milk components supplemented with formula. However, this experimental approach cannot capture the contributions of the individual components to the human milk ecology, the interaction between these components within the human milk matrix, or the significance of the matrix itself to enhance human milk bioactivity on outcomes of interest. This paper presents approaches to explore human milk as a biological system and the functional implications of that system and its components. Specifically, we discuss study design and data collection considerations and how emerging analytical technologies, bioinformatics, and systems biology approaches could be applied to advance our understanding of this critical aspect of human biology.

25 Years of translational research in the Copenhagen Prospective Studies on Asthma in Childhood (COPSAC)

The Copenhagen Prospective Studies on Asthma in Childhood (COPSAC) mother-child cohorts have provided a foundation of 25 years of research on the origins, prevention, and natural history of childhood asthma and related disorders. COPSAC's approach is characterized by clinical translational research with longitudinal deep phenotyping and exposure assessments from pregnancy, in combination with multi-omic data layers and embedded randomized controlled trials. One trial showed that fish oil supplementation during pregnancy prevented childhood asthma and identified pregnant women with the highest benefits from supplementation, thereby creating the potential for personalized prevention. COPSAC revealed that airway colonization with pathogenic bacteria in early life is associated with an increased risk of asthma. Further, airway bacteria were shown to be a trigger of acute asthma-like symptoms, with benefit from antibiotic treatment. COPSAC identified an immature gut microbiome in early life as a risk factor for asthma and allergy and further demonstrated that asthma can be predicted by infant lung function. At a molecular level, COPSAC has identified novel susceptibility genes, early immune deviations, and metabolomic alterations associated with childhood asthma. Thus, the COPSAC research program has enhanced our understanding of the processes causing childhood asthma and has suggested means of personalized prevention and treatment.

Comparison of the effects of different infant formulas on the growth and development and intestinal flora of infants

The purpose of this study was to compare the effects of different infant formulas on the growth and development, sleep, allergy symptoms, and intestinal flora of infants. A total of 428 infants participated in the study. Breastfeeding (BF) was used as the control, and the remaining subjects were randomly assigned to the full goat milk protein formula group (FGM), partial goat milk protein formula group (PGM), and cow milk formula group (M). During the 6-month feeding experiment, data on the growth, sleep, allergy symptoms, and intestinal flora of infants were collected using questionnaires, anthropometric measurements, and biochemical examinations. In general, the basic information of the participants was consistent among the groups. There were no differences in infant weight, length, or head circumference among the groups (p > .05). The sleep time of infants in the formula-fed groups was longer than that of the breastfeeding group at baseline (p < .05), but there were no differences at mid-term or outcome (p > .05). The incidence of allergic symptoms continued to decrease, and the total scores of allergic symptoms did not differ among the groups (p > .05). The relative abundance of intestinal Bifidobacteriaceae in the PGM group was lower than that in the other groups (p < .05). There was no difference in the β-diversity of intestinal flora between formula-fed and breastfed infants (p > .05). There were strong correlations in the composition of the main intestinal flora at the family level between the formula and breastfeeding groups. This study showed that within 6 months of feeding, there were no significant differences in the growth and development, allergic symptoms, or intestinal flora of the infants among the groups.

Potential of Lactoferrin in the Treatment of Lung Diseases

Lactoferrin (LF) is a multifunctional iron-binding glycoprotein that exhibits a variety of properties, such as immunomodulatory, anti-inflammatory, antimicrobial, and anticancer, that can be used to treat numerous diseases. Lung diseases continue to be the leading cause of death and disability worldwide. Many of the therapies currently used to treat these diseases have limited efficacy or are associated with side effects. Therefore, there is a constant pursuit for new drugs and therapies, and LF is frequently considered a therapeutic agent and/or adjunct to drug-based therapies for the treatment of lung diseases. This article focuses on a review of the existing and most up-to-date literature on the contribution of the beneficial effects of LF on the treatment of lung diseases, including asthma, viral infections, cystic fibrosis, or lung cancer, among others. Although in vitro and in vivo studies indicate significant potency of LF in the treatment of the listed diseases, only in the case of respiratory tract infections do human studies seem to confirm them by demonstrating the effectiveness of LF in reducing episodes of illness and shortening the recovery period. For lung cancer, COVID-19 and sepsis, the reports are conflicting, and for other diseases, there is a paucity of human studies conclusively confirming the beneficial effects of LF.

Early-life risk factors for development of asthma from 8 to 28 years of age: a prospective cohort study

Background

The objective was to estimate the incidence rate of asthma from age 8 to 28 years and evaluate early-life risk factors for asthma onset at different ages.

Methods

In 1996, within the Obstructive Lung Disease in Northern Sweden (OLIN) studies, a cohort of 3430 schoolchildren (97% of invited) was recruited at age 8 years to a prospective study about asthma. The cohort was followed annually from age 8 to 19 years and at 28 years by questionnaire surveys (67% of the original cohort participated). Asthma was categorised as never-asthma, onset age ≤8 years, onset age 9-13 years, onset age 14-19 years or onset age >19 years.

Results

Of the 3430 individuals in the cohort, 690 (20.1%) reported asthma in any survey. The average incidence rate was 10.0/1000 per year at ≤8 years, 11.9/1000 per year at 9-13 years, 13.3/1000 per year at 14-19 years and 6.1/1000 per year at >19 years. The incidence was higher among boys until age 10 years, but from age 15 years, it became higher among girls. Family history of asthma, allergic sensitisation and breastfeeding <3 months were associated with asthma onset throughout the study. Low birthweight, maternal smoking during pregnancy, severe respiratory infection, rhinoconjunctivitis and eczema were associated with asthma onset ≤8 and 9-13 years.

Conclusions

The incidence of asthma was high during childhood and the teenage period, and decreased substantially during young adulthood. Early-life factors were associated with asthma onset throughout childhood but had also a lasting effect on asthma incidence until adulthood.

Atopic dermatitis across the life course

Atopic dermatitis, the most common chronic inflammatory skin disease, can occur at any age, and patterns of disease activity vary over time. Both prevalence and incidence are highest in infancy and early childhood, followed by a second peak in older adulthood. Birth cohort studies from European countries following children through adolescence have identified subgroups of patients with early-onset persistent disease, early-onset resolving disease, and later-onset disease. Parental history of atopy and genetic factors are among the most consistent predictors of more persistent disease. Studies have begun to examine whether molecular markers differ by age group, although longitudinal data are lacking. Breastfeeding, probiotics and skin-directed therapies such as emollients have been investigated as potential preventive measures, but randomized trials have not found consistent long-term benefit. Future research should focus on patterns of disease activity beyond early adulthood and the role of treatments on long-term disease activity.

Support for healthy breastfeeding mothers with healthy term babies

BACKGROUND

There is extensive evidence of important health risks for infants and mothers related to not breastfeeding. In 2003, the World Health Organization recommended that infants be breastfed exclusively until six months of age, with breastfeeding continuing as an important part of the infant's diet until at least two years of age. However, current breastfeeding rates in many countries do not reflect this recommendation.

OBJECTIVES

1. To describe types of breastfeeding support for healthy breastfeeding mothers with healthy term babies. 2. To examine the effectiveness of different types of breastfeeding support interventions in terms of whether they offered only breastfeeding support or breastfeeding support in combination with a wider maternal and child health intervention ('breastfeeding plus' support).  3. To examine the effectiveness of the following intervention characteristics on breastfeeding support:      a. type of support (e.g. face-to-face, telephone, digital technologies, group or individual support, proactive or reactive);      b. intensity of support (i.e. number of postnatal contacts);      c. person delivering the intervention (e.g. healthcare professional, lay person);     d. to examine whether the impact of support varied between high- and low-and middle-income countries.

SEARCH METHODS

We searched Cochrane Pregnancy and Childbirth's Trials Register (which includes results of searches of CENTRAL, MEDLINE, Embase, CINAHL, ClinicalTrials.gov, WHO International Clinical Trials Registry Platform (ICTRP)) (11 May 2021) and reference lists of retrieved studies.

SELECTION CRITERIA

Randomised or quasi-randomised controlled trials comparing extra support for healthy breastfeeding mothers of healthy term babies with usual maternity care. Support could be provided face-to-face, over the phone or via digital technologies. All studies had to meet the trustworthiness criteria.  DATA COLLECTION AND ANALYSIS: We used standard Cochrane Pregnancy and Childbirth methods. Two review authors independently selected trials, extracted data, and assessed risk of bias and study trustworthiness.  The certainty of the evidence was assessed using the GRADE approach.

MAIN RESULTS

This updated review includes 116 trials of which 103 contribute data to the analyses. In total more than 98,816 mother-infant pairs were included.  Moderate-certainty evidence indicated that 'breastfeeding only' support probably reduced the number of women stopping breastfeeding for all primary outcomes: stopping any breastfeeding at six months (Risk Ratio (RR) 0.93, 95% Confidence Interval (CI) 0.89 to 0.97); stopping exclusive breastfeeding at six months (RR 0.90, 95% CI 0.88 to 0.93); stopping any breastfeeding at 4-6 weeks (RR 0.88, 95% CI 0.79 to 0.97); and stopping exclusive breastfeeding at 4-6 (RR 0.83 95% CI 0.76 to 0.90). Similar findings were reported for the secondary breastfeeding outcomes except for any breastfeeding at two months and 12 months when the evidence was uncertain if 'breastfeeding only' support helped reduce the number of women stopping breastfeeding.  The evidence for 'breastfeeding plus' was less consistent. For primary outcomes there was some evidence that 'breastfeeding plus' support probably reduced the number of women stopping any breastfeeding (RR 0.94, 95% CI 0.91 to 0.97, moderate-certainty evidence) or exclusive breastfeeding at six months (RR 0.79, 95% CI 0.70 to 0.90).  'Breastfeeding plus' interventions may have a beneficial effect on reducing the number of women stopping exclusive breastfeeding at 4-6 weeks, but the evidence is very uncertain (RR 0.73, 95% CI 0.57 to 0.95). The evidence suggests that 'breastfeeding plus' support probably results in little to no difference in the number of women stopping any breastfeeding at 4-6 weeks (RR 0.94, 95% CI 0.82 to 1.08, moderate-certainty evidence). For the secondary outcomes, it was uncertain if 'breastfeeding plus' support helped reduce the number of women stopping any or exclusive breastfeeding at any time points.  There were no consistent findings emerging from the narrative synthesis of the non-breastfeeding outcomes (maternal satisfaction with care, maternal satisfaction with feeding method, infant morbidity, and maternal mental health), except for a possible reduction of diarrhoea in intervention infants.  We considered the overall risk of bias of trials included in the review was mixed. Blinding of participants and personnel is not feasible in such interventions and as studies utilised self-report breastfeeding data, there is also a risk of bias in outcome assessment.   We conducted meta-regression to explore substantial heterogeneity for the primary outcomes using the following categories: person providing care; mode of delivery; intensity of support; and income status of country.  It is possible that moderate levels (defined as 4-8 visits) of 'breastfeeding only' support may be associated with a more beneficial effect on exclusive breastfeeding at 4-6 weeks and six months. 'Breastfeeding only' support may also be more effective in reducing women in low- and middle-income countries (LMICs) stopping exclusive breastfeeding at six months compared to women in high-income countries (HICs). However, no other differential effects were found and thus heterogeneity remains largely unexplained. The meta-regression suggested that there were no differential effects regarding person providing support or mode of delivery, however, power was limited.  AUTHORS' CONCLUSIONS: When 'breastfeeding only' support is offered to women, the duration and in particular, the exclusivity of breastfeeding is likely to be increased. Support may also be more effective in reducing the number of women stopping breastfeeding at three to four months compared to later time points.  For 'breastfeeding plus' interventions the evidence is less certain. Support may be offered either by professional or lay/peer supporters, or a combination of both. Support can also be offered face-to-face, via telephone or digital technologies, or a combination and may be more effective when delivered on a schedule of four to eight visits. Further work is needed to identify components of the effective interventions and to deliver interventions on a larger scale.

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.

Dietary Factors Associated with Asthma Development: A Narrative Review and Summary of Current Guidelines and Recommendations

Asthma is a complex disease, caused by a combination of genetic and environmental factors. The prevalence of asthma is increasing too rapidly to be attributable to genetic factors alone. Thus, environmental factors are becoming increasingly recognized as the cause of asthma. Modifying these environmental factors may be a simple approach for asthma prevention. To date, dietary intervention is an interesting modifiable factor because it can be implemented at the population level. The modification of systemic inflammation, oxidation, and microbial composition might be a mechanistic basis for prevention. This review summarizes the mechanistic basis and evidence from clinical studies on the association between dietary factors and asthma development. We also summarize the recommendations from many organizations and regional guidelines to assist the practicing physician to improve patient care.

The association between duration of breastfeeding and childhood asthma outcomes

BACKGROUND

Postnatal exposures, including breastfeeding, may influence asthma development.

OBJECTIVE

To investigate the association between breastfeeding duration and child asthma.

METHODS

We studied 2021 mother-child dyads in the ECHO PATHWAYS consortium of prospective pregnancy cohorts (GAPPS, CANDLE, TIDES). Women reported the duration of any and exclusive breastfeeding and child asthma outcomes during follow-up at child age 4 to 6 years. Outcomes included current wheeze (previous 12 months), ever asthma, current asthma (having ≥2 of current wheeze, ever asthma, medication use in past 12-24 months), and strict current asthma (ever asthma with either or both current wheeze and medication use in past 12-24 months). We used multivariable logistic regression to assess associations (odds ratios and 95% confidence intervals) between breastfeeding and asthma outcomes adjusting for potential confounders. We assessed effect modification by mode of delivery, infant sex, and maternal asthma.

RESULTS

Among women, 33%, 13%, 9%, and 45% reported 0 to less than 2, 2 to 4, 5 to 6, and more than 6 months of any breastfeeding, respectively. The duration of any breastfeeding had a protective linear trend with ever asthma but no other outcomes. There was a duration-dependent protective association of exclusive breastfeeding and child asthma outcomes (eg, current asthma adjusted odds ratio [95% confidence interval], 0.64 [0.41-1.02], 0.61 [0.38-0.98], and 0.52 (0.31-0.87) for 2to 4 months, 5 to 6 months, and more than 6 months, respectively, compared with <2 months). For exclusive breastfeeding, protective associations were stronger in dyads with children born by vaginal vs cesarean delivery although interactions did not reach statistical significance (Pinteractions 0.12-0.40).

CONCLUSION

Longer duration of exclusive breastfeeding had a protective association with child asthma.

Human milk-sharing practices and infant-feeding behaviours: A comparison of donors and recipients

Human milk sharing (HMS) is growing in popularity as an infant-feeding strategy in the United States. HMS families are a hidden population because HMS is a nonnormative and stigmatized behaviour. Thus, gaining access to HMS participants is challenging, and research on this topic remains limited. In particular, little is known about the broader infant-feeding behaviours of HMS parents. This study aimed to describe and compare the infant-feeding behaviours and HMS practices among a network of HMS donors and recipients. A detailed online survey was distributed to HMS parents in the Washington, DC region. Bivariate analyses were used to summarize the data by donor/recipient status when possible. Group differences were tested using analysis of variance for continuous variables and χ² tests for categorical variables. Donors and recipients did not differ in their sociodemographic characteristics. Recipients were significantly more likely than donors to have experienced complications of labour and delivery, traumatic birth, postpartum depression or a negative breastfeeding experience. Donors and recipients did not differ significantly in their duration of lactation or HM-feeding. Interestingly, 30% of recipients ever produced excess milk and 21% of donors ever had difficulty producing enough milk for their child. Compared with donors, recipients faced numerous maternal health challenges, but were still able to achieve a long duration of HM-feeding. HMS recipients represent a vulnerable group who may benefit from additional psychosocial and lactation support to improve their health and breastfeeding outcomes. Additional research is needed to investigate the associations between HMS participation, infant-feeding behaviours and lactation outcomes.

Early infant feeding and allergic respiratory diseases in Ibb city, Yemen

Background

Allergic respiratory diseases (ARD) are a highly prevalent health problem affecting infants and children in Yemen. Early infant feeding predisposition to the development of ARD has been a controversial question. The aim of this study is to investigate the association between early feeding before 6 months of age and the development of ARD among children attending Childhood and Maternity Public Hospital (CMPH), Ibb, Yemen Republic.

Subjects and methods

The study population included 151 child patients attending the pediatric clinic at CMPH. Upon clinical and laboratory examinations, 72 out of 151 patients had ARD, while the other 79 had diseases other than ARD; all of them were used in risk assessment. Fifteen blood samples from healthy volunteers were used in laboratory investigations as a control. Complete blood count and IgE level were investigated for all participants. Children's parents were requested to give an informed consent and fill questionnaire about demography and history details.

Results

Early infant feeding was a significant risk factor for the development of ARD with an odds ratio (OR) of 6.8 and 95% confidence interval (CI) 3.0 to 15.3. Artificial milk particularly was risk factor with an OR of 6.1 and 95% confidence interval 2.7 to 13.5. Artificial milk exhibited more wheezing and asthma attack than others (OR 4.3, 95% CI 1.9 to 9.4 and OR 7.6, 95% CI 3.5 to 16.3, respectively). The risk of wheezing and asthma attack also increase with early feeding generally (OR 3.0, 95% CI 1.3 to 7.2 and OR 4.8, 95% CI 2.2 to 8.1, respectively). The patients had a higher sensitization markers than the control, such as eosinophil count and total serum IgE. The highest levels of IgE ever reported existed among early fed patients with artificial milk.

Conclusions

Early infant feeding, particularly with artificial milk, is a risk factor predisposing infants to the development of allergic respiratory disease presented with more clinical features of wheezing and asthma attack.

Allergic Diseases: A Comprehensive Review on Risk Factors, Immunological Mechanisms, Link with COVID-19, Potential Treatments, and Role of Allergen Bioinformatics

The prevalence of allergic diseases is regarded as one of the key challenges in health worldwide. Although the precise mechanisms underlying this rapid increase in prevalence are unknown, emerging evidence suggests that genetic and environmental factors play a significant role. The immune system, microbiota, viruses, and bacteria have all been linked to the onset of allergy disorders in recent years. Avoiding allergen exposure is the best treatment option; however, steroids, antihistamines, and other symptom-relieving drugs are also used. Allergen bioinformatics encompasses both computational tools/methods and allergen-related data resources for managing, archiving, and analyzing allergological data. This study highlights allergy-promoting mechanisms, algorithms, and concepts in allergen bioinformatics, as well as major areas for future research in the field of allergology.

Prevalence and risk factors associated with allergic rhinitis in Mexican school children: Global Asthma Network Phase I

Background

The International Study of Asthma and Allergies in Childhood (ISAAC) showed a wide variability in prevalence and severity of allergic rhinitis (AR) and rhinoconjunctivitis (ARC), in addition to other atopic diseases (Asher et al, 2006).¹ The Global Asthma Network (GAN) has continued to study these conditions.

Objective

To estimate the prevalence of AR and ARC in children and adolescents in Mexico and to assess their association with different risk factors.

Methods

GAN Phase I is a cross-sectional, multicentre survey carried out in 15 centres corresponding to 14 Mexican cities throughout 2016–2019 using the validated Spanish language version of the GAN Phase I questionnaires. The questionnaires were completed by 35 780 parents of 6–7 year old primary school pupils (children) and by 41 399 adolescents, 13–14 years old.

Results

The current and cumulative prevalence of AR was higher in the adolescents (26.2–37.5%, respectively) in comparison to the children (17.9–24.9%, respectively), especially in female participants. This tendency was also observed in the current prevalence of ARC, where 15.1% of female adolescents reported nasal symptoms accompanied with itchy-watery eyes in the past year. The most important risk factors for AR and ARC were the presence of wheezing in the past 12 months, wheezing in the first year of life, the previous diagnosis of asthma and eczema symptoms. Furthermore, allergic symptoms had a negative tendency concerning altitude.

Conclusion

This is the largest AR epidemiological study ever conducted in Mexico. It shows an increase in AR prevalence, as well as significant associations with modifiable risk factors, which could help to establish recommendations to reduce the burden of this condition.

Flood Control: How Milk-Derived Extracellular Vesicles Can Help to Improve the Intestinal Barrier Function and Break the Gut-Joint Axis in Rheumatoid Arthritis

Many studies provided compelling evidence that extracellular vesicles (EVs) are involved in the regulation of the immune response, acting as both enhancers and dampeners of the immune system, depending on the source and type of vesicle. Research, including ours, has shown anti-inflammatory effects of milk-derived EVs, using human breast milk as well as bovine colostrum and store-bought pasteurized cow milk, in in vitro systems as well as therapeutically in animal models. Although it is not completely elucidated which proteins and miRNAs within the milk-derived EVs contribute to these immunosuppressive capacities, one proposed mechanism of action of the EVs is via the modulation of the crosstalk between the (intestinal) microbiome and their host health. There is increasing awareness that the gut plays an important role in many inflammatory diseases. Enhanced intestinal leakiness, dysbiosis of the gut microbiome, and bowel inflammation are not only associated with intestinal diseases like colitis and Crohn's disease, but also characteristic for systemic inflammatory diseases such as lupus, multiple sclerosis, and rheumatoid arthritis (RA). Strategies to target the gut, and especially its microbiome, are under investigation and hold a promise as a therapeutic intervention for these diseases. The use of milk-derived EVs, either as stand-alone drug or as a drug carrier, is often suggested in recent years. Several research groups have studied the tolerance and safety of using milk-derived EVs in animal models. Due to its composition, milk-derived EVs are highly biocompatible and have limited immunogenicity even cross species. Furthermore, it has been demonstrated that milk-derived EVs, when taken up in the gastro-intestinal tract, stay intact after absorption, indicating excellent stability. These characteristics make milk-derived EVs very suitable as drug carriers, but also by themselves, these EVs already have a substantial immunoregulatory function, and even without loading, these vesicles can act as therapeutics. In this review, we will address the immunomodulating capacity of milk-derived EVs and discuss their potential as therapy for RA patients.

Review criteria

The search terms "extracellular vesicles", "exosomes", "microvesicles", "rheumatoid arthritis", "gut-joint axis", "milk", and "experimental arthritis" were used. English-language full text papers (published between 1980 and 2021) were identified from PubMed and Google Scholar databases. The reference list for each paper was further searched to identify additional relevant articles.

Infant Feeding Practices During the First Postnatal Year and Risk of Asthma and Allergic Disease During the First 6 Years of Life

Background: Breastfeeding may protect against childhood asthma and allergic diseases. Studies have not focused on the mode of feeding human milk and followed children to school age although feeding human milk from a bottle rather than the breast may alter the risk of disease. Materials and Methods: At 12 months' postpartum, women in the Moms2Moms study (Columbus, OH) completed a survey assessing sociodemographic and infant feeding behaviors. At 6 years' postpartum, they completed a survey and pediatric medical records were abstracted to assess asthma and allergic disease diagnoses. Logistic regression models were used to estimate associations between infant feeding behaviors and asthma or allergic disease. Results: Of 285 children, 16% had asthma and 44% ever had ≥1 allergy diagnosis. Longer durations of each infant feeding behavior were not clearly associated with increased odds of asthma or allergic disease by age 6. Results suggested that longer durations of breast milk feeding (regardless of the mode of feeding) may be related to a lower risk of food allergy (e.g., odds ratio [OR]1-month, adjusted = 0.96, 95% confidence interval [CI] = 0.87-1.05; OR12-month, adjusted = 0.57, 95% CI = 0.19-1.74), but that the mode of feeding (regardless of the substance fed) may be more meaningful for environmental allergies (e.g., exclusive direct breast milk feeding OR12-month, adjusted = 0.32, 95% CI = 0.06-1.81). However, effect estimates were imprecise and CIs included the null. Conclusions: Although no clear associations between mode of breast milk feeding (breast versus expressed) and asthma and allergy outcomes were observed, future research with larger samples should further evaluate these associations.

Perinatal and Early-Life Nutrition, Epigenetics, and Allergy

Epidemiological studies have shown a dramatic increase in the incidence and the prevalence of allergic diseases over the last several decades. Environmental triggers including risk factors (e.g., pollution), the loss of rural living conditions (e.g., farming conditions), and nutritional status (e.g., maternal, breastfeeding) are considered major contributors to this increase. The influences of these environmental factors are thought to be mediated by epigenetic mechanisms which are heritable, reversible, and biologically relevant biochemical modifications of the chromatin carrying the genetic information without changing the nucleotide sequence of the genome. An important feature characterizing epigenetically-mediated processes is the existence of a time frame where the induced effects are the strongest and therefore most crucial. This period between conception, pregnancy, and the first years of life (e.g., first 1000 days) is considered the optimal time for environmental factors, such as nutrition, to exert their beneficial epigenetic effects. In the current review, we discussed the impact of the exposure to bacteria, viruses, parasites, fungal components, microbiome metabolites, and specific nutritional components (e.g., polyunsaturated fatty acids (PUFA), vitamins, plant- and animal-derived microRNAs, breast milk) on the epigenetic patterns related to allergic manifestations. We gave insight into the epigenetic signature of bioactive milk components and the effects of specific nutrition on neonatal T cell development. Several lines of evidence suggest that atypical metabolic reprogramming induced by extrinsic factors such as allergens, viruses, pollutants, diet, or microbiome might drive cellular metabolic dysfunctions and defective immune responses in allergic disease. Therefore, we described the current knowledge on the relationship between immunometabolism and allergy mediated by epigenetic mechanisms. The knowledge as presented will give insight into epigenetic changes and the potential of maternal and post-natal nutrition on the development of allergic disease.

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

Background

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

Methods

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

Results

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

Conclusions

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

Trial registration

The trial is registered in Current Controlled Trials as ISRCTN28090297.

Supplementary Information

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

Effect of Avoiding Cow's Milk Formula at Birth on Prevention of Asthma or Recurrent Wheeze Among Young Children: Extended Follow-up From the ABC Randomized Clinical Trial

Importance

Children with food allergies may develop asthma or recurrent wheeze.

Objective

To evaluate whether asthma or recurrent wheeze among children were changed by avoiding supplementing breastfeeding (BF) with cow's milk formula (CMF) in the first 3 days of life.

Design, Setting, and Participants

This randomized, unmasked, clinical trial was conducted at 1 university hospital in Japan beginning October 2013 with follow-up examinations occurring until January 2020. A total of 312 newborns at risk for atopy were randomized and assigned to either BF with or without amino acid-based elemental formula (EF) or BF with CMF, with follow-up examinations for participants showing signs of atopy conducted at 24 months. Follow-up examinations ran through January 2020.

Interventions

Immediately after birth, newborns were randomly assigned (1:1 ratio) to either breastfeeding with or without amino acid-based elemental formula for at least the first 3 days of life (no CMF group) or breastfeeding supplemented with CMF (≥5 mL/d) from the first day of life to 5 months of age (CMF group).

Main Outcomes and Measures

Asthma or recurrent wheeze diagnosed by the pediatric allergy specialists of this trial; subgroups were stratified by serum levels of 25-hydroxyvitamin D and IgE.

Results

Of 312 infants (156 [50.0%] randomized to the no CMF group), 302 (96.8%) were followed up at their second birthday: 77 of 151 (51.0%) in the no CMF group and 81 of 151 (53.6%) in the CMF group underwent extended follow-up because of having atopic conditions. Asthma or recurrent wheeze developed in 15 (9.9%) of the children in the no CMF group, significantly less than the children in the CMF group (27 [17.9%]; risk difference, -0.079; 95% CI, -0.157 to -0.002). In participants with vitamin D levels above the median at 5 months of age, asthma or recurrent wheeze developled in 5 (6.4%) children in the no CMF group, significantly less than in the children in the CMF group (17 [24.6%]; risk difference, -0.182; 95% CI, -0.298 to -0.067; P for interaction = .04). In the highest quartile group of total IgE at age 24 months, asthma or recurrent wheeze developed in 2 children (5.3%) in the no CMF group, significantly less than the children in the CMF group (14 [43.8%]; risk difference, -0.385; 95% CI, -0.571 to -0.199; P for interaction = .004).

Conclusions and Relevance

The findings of this study suggest that avoiding CMF supplementation in the first 3 days of life has the potential to reduce the risk of asthma or recurrent wheeze in young children, especially among those with high vitamin D or high IgE levels.

Trial Registration

umin.ac.jp/ctr Identifier: UMIN000011577.

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.

Halting the March: Primary Prevention of Atopic Dermatitis and Food Allergies

Atopic dermatitis (AD) is one of the most common inflammatory skin conditions, affecting 15% to 30% of children and 2% to 10% of adults. Population-based studies suggest that having AD is associated with subsequent development of other atopic diseases, in what is known as the "atopic march." We will provide an overview of studies that investigate primary prevention strategies for the first 2 diseases in the march, namely, AD and food allergies (FA). These strategies include emollients, breastfeeding, microbial exposures, probiotics, vitamin D and UV light, water hardness, and immunotherapy. Some studies, including randomized controlled trials on emollients and microbial supplementation, have found encouraging results; however, the evidence remains limited and contradictory. With regard to breastfeeding, microbial and lifestyle exposures, vitamin D and UV light, water hardness, and immunotherapy, the lack of randomized controlled trials makes it difficult to draw definitive conclusions. Current American Academy of Pediatrics guidelines support the idea that breastfeeding for 3 to 4 months can decrease AD incidence in children less than 2 years old. Recommendations regarding a direct relationship between breastfeeding on FA, however, cannot be made because of insufficient data. Regarding microbial supplementation, most guidelines do not recommend probiotics or prebiotics for the purpose of preventing allergic diseases because of limited evidence. Before definitive conclusions can be made regarding these interventions, more well-designed, longitudinal, and randomized controlled trials, particularly in at-risk populations, are required.

The association of infant feeding patterns with food allergy symptoms and food allergy in early childhood

Background

The role of infant feeding for food allergy in children is unclear and studies have not addressed simultaneous exposures to different foods. The goal of this study was to analyze existing data on feeding practices that represent realistic exposure and assess the risk of food allergy symptoms and food allergy in children.

Methods

The Infant Feeding Practices Study II conducted by the CDC and US-FDA enrolled pregnant women and collected infant feeding information using nine repeated surveys. Participants were re-contacted after 6 years. Food allergy data were collected at 4, 9, 12, and 72 months. In total, 1387 participants had complete infant feeding pattern data for 6 months and information on food allergy symptoms and doctors’ diagnosed food allergy. Feeding patterns constituted six groups: 3-months of feeding at breast followed by mixed feeding, 3-months of breast milk and bottled milk followed by mixed feeding, 1-month of feeding at breast followed by mixed feeding, 6-months of mixed feeding i.e., concurrent feeding of breast milk, bottled milk and formula, 2–3 months of formula followed by formula and solid food, and formula and solid food since the first month. To estimate risks of food allergy, we used linear mixed models, controlling for potential confounders.

Results

Of the 328 children with food allergy symptoms in infancy and at 6 years, 52 had persistent symptoms from infancy. Children exposed to mixed feeding had a higher risk of food allergy symptoms (Risk Ratio [RR] 1.54; 95% Confidence Interval [CI] 1.04, 2.29) compared to 3-months of feeding at breast adjusted for confounding. No statistically significant risk of infant feeding patterns was found for doctors’ diagnosed food allergy. Paternal allergy posed a higher risk for food allergy symptoms (RR 1.36; 95% CI 1.01, 1.83). Prenatal maternal smoking increased the risk for doctors’ diagnosed food allergy (RR 2.97; 95% CI 1.53, 5.79).

Conclusions

Analysis of this prospective birth cohort suggest that introduction of multiple feeding source may lead to food allergy symptoms. Future efforts are needed to determine acceptable approaches to improve the ascertainment of food allergy in children and the role of infant feeding.

FADS1 and FADS2 Polymorphisms Modulate Fatty Acid Metabolism and Dietary Impact on Health

Variants in the FADS gene cluster modify the activity of polyunsaturated fatty acid (PUFA) desaturation and the lipid composition in human blood and tissue. FADS variants have been associated with plasma lipid concentrations, risk of cardiovascular diseases, overweight, eczema, pregnancy outcomes, and cognitive function. Studies on variations in the FADS genecluster provided some of the first examples for marked gene-diet interactions in modulating complex phenotypes, such as eczema, asthma, and cognition. Genotype distribution differs markedly among ethnicities, apparently reflecting an evolutionary advantage of genotypes enabling active long-chain PUFA synthesis when the introduction of agriculture provided diets rich in linoleic acid but with little arachidonic and eicosapentaenoic acids. Discovering differential effects of PUFA supply that depend on variation of FADS genotypes could open new opportunities for developing precision nutrition strategies based either on an individual's genotype or on genotype distributions in specific populations.

Immunomodulatory effects of breast milk on food allergy

OBJECTIVE

To summarize the literature on immunomodulatory effects of breast milk on sensitization and possible mechanisms of action.

DATA SOURCES

Animal and human studies in PubMed that assessed breastfeeding or breast milk composition in food allergy.

STUDY SELECTIONS

All recent studies and some older key publications focusing on this topic.

RESULTS

Human milk composition is highly variable among mothers, which can affect the developing infant immune system. Human milk also affects the infant gut microbiome, which is associated with food allergy. High levels of human milk immune factors (IgA, cytokines, oligosaccharides) are associated with reduced risk of food allergy in the infant; it remains uncertain whether these are directly protective or biomarkers of transferred protection. Animal studies highlight potential mechanisms of protection provided by antigens, transforming growth factor β, and immunocomplexes, yet their relevance is poorly understood in humans. The role of food antigens in human milk in initial sensitization or tolerance induction is unclear.

CONCLUSION

The protection against allergy development provided by human milk may be attributable to the effect on the infant gut microbiome or direct effects on immune system. Studies evaluating the effect of breastfeeding and human milk composition on food allergy are needed.

Associations of atopic dermatitis and asthma with child behaviour: Results from the PROBIT cohort

BACKGROUND

Conflicting findings from studies evaluating associations of allergic disease with child behaviour require longitudinal studies to resolve.

OBJECTIVE

To estimate the magnitude of associations of atopic dermatitis (AD) in infancy, and symptoms of asthma and AD at 6.5 years, with child behaviour at 6.5 years.

METHODS

Secondary cohort analysis of the Promotion of Breastfeeding Intervention Trial (PROBIT). PROBIT enrolled 17 046 infants at birth and followed them up at 6.5 years (n = 13 889). Study paediatricians collected data on infantile AD at repeated follow-up examinations during the first year of life. At 6.5 years, paediatricians performed skin prick tests and parents reported asthma and AD symptoms during the prior year. In addition, parents and teachers completed the Strength and Difficulties Questionnaire, which includes scales on hyperactivity/inattention, emotional problems, conduct problems, peer problems and prosocial behaviours.

RESULTS

Physician-diagnosed AD in the first year of life was not associated with increased risk for behavioural problems at 6.5 years. Emotional problems at 6.5 years were more common among children with AD symptoms (OR: 2.24, 95% CI: 1.62-3.12) and asthma symptoms (OR: 1.45; 95% CI: 1.07-1.96) during the past year at 6.5 years and ORs for children with symptoms of more severe AD and asthma were also higher. AD in the past year was also associated with probable hyperactivity/inattention disorder at 6.5 years (OR: 2.05; 95% CI: 1.09-3.84). Other subscales of the SDQ were not related to asthma or AD symptoms during the past year.

CONCLUSIONS AND CLINICAL RELEVANCE

Children with AD symptoms were at higher risk for concomitant hyperactivity/inattention and emotional disorder, and children with asthma symptoms were at higher risk of having concomitant emotional problems. However, AD during infancy did not predict childhood behaviours.

The Effects of Early Nutritional Interventions on the Development of Atopic Disease in Infants and Children: The Role of Maternal Dietary Restriction, Breastfeeding, Hydrolyzed Formulas, and Timing of Introduction of Allergenic Complementary Foods

This clinical report updates and replaces a 2008 clinical report from the American Academy of Pediatrics, which addressed the roles of maternal and early infant diet on the prevention of atopic disease, including atopic dermatitis, asthma, and food allergy. As with the previous report, the available data still limit the ability to draw firm conclusions about various aspects of atopy prevention through early dietary interventions. Current evidence does not support a role for maternal dietary restrictions during pregnancy or lactation. Although there is evidence that exclusive breastfeeding for 3 to 4 months decreases the incidence of eczema in the first 2 years of life, there are no short- or long-term advantages for exclusive breastfeeding beyond 3 to 4 months for prevention of atopic disease. The evidence now suggests that any duration of breastfeeding ≥3 to 4 months is protective against wheezing in the first 2 years of life, and some evidence suggests that longer duration of any breastfeeding protects against asthma even after 5 years of age. No conclusions can be made about the role of breastfeeding in either preventing or delaying the onset of specific food allergies. There is a lack of evidence that partially or extensively hydrolyzed formula prevents atopic disease. There is no evidence that delaying the introduction of allergenic foods, including peanuts, eggs, and fish, beyond 4 to 6 months prevents atopic disease. There is now evidence that early introduction of peanuts may prevent peanut allergy.

Birth Mode, Breastfeeding, Pet Exposure, and Antibiotic Use: Associations With the Gut Microbiome and Sensitization in Children

PURPOSE OF REVIEW

The infant gut microbiota has become a focus of multiple epidemiologic and cohort studies. This microbiome is derived from the mother (via the vaginal canal, maternal skin contact, breastfeeding, and possibly in utero microbial transfer) and is likely influenced by multiple external factors. It is now believed by some experts that colonization and formation of the newborn and alterations of gut microbiota in children are dependent on earlier alterations of the microbiota of mothers during or perhaps even before pregnancy. This review will focus on specific factors (pet keeping, breastfeeding, antibiotic use, and mode of delivery) that influence the infant gut microbiome and atopy.

RECENT FINDINGS

This is a review of recent literature describing how pet keeping, breastfeeding, antibiotic use, and mode of delivery influences and changes the infant gut microbiome and atopy. General trends in gut microbiota differences have emerged in different birth cohorts when each external factor is analyzed, but consistency between studies is difficult to replicate. The aforementioned factors do not seem to confer an overwhelming risk for development of atopy alone. This review provides a comprehensive review of early life environmental factors and their influence on the infant gut microbiome and atopy.

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.

Protocol for a cluster randomised controlled trial evaluating a parenting with home visitation programme to prevent physical and emotional abuse of children in Indonesia: the Families First Programme

INTRODUCTION

Every year, up to 1 billion children are victims of violence worldwide. Most child abuse takes place in the context of punishment. The Families First Programme, an adaptation of the Positive Discipline in Everyday Parenting Programme to the West Java context, is a parenting support programme anchored on children's rights that gives parents guidance on child development, parenting and positive discipline practices. This trial will evaluate the effectiveness of the Families First Programme compared with a waitlist control group.

METHODS AND ANALYSIS

This is a pragmatic, parallel-group, stratified, cluster-randomised controlled trial. Twenty rural and urban villages in the Cianjur District, Indonesia, involving 720 caregivers of children up to 7 years of age, will be randomised. Villages will receive either a parenting programme consisting of 10 group sessions and four home visits over 3 months and standard community health and social services or just the latter. After completion of the trial period, the programme will be offered to those in the delayed group. Outcome data will be collected before randomisation (baseline), immediately postintervention (3 months postrandomisation) and 6 months later (9 months postrandomisation). The primary outcome will be frequency of physical and emotional punishment as measured by a weighted sum from three self-report items. Primary outcome analysis will use Poisson regression with generalised estimating equations and assess the interaction between intervention and time over baseline and 3 and 9 months postrandomisation assessments. Concurrent process evaluation will be conducted to assess programme satisfaction and facilitators and barriers to the implementation of the programme generalisable to other settings.

ETHICS AND DISSEMINATION

Ethics approval was obtained from McGill University and Universitas Katolik Indonesia Atma Jaya. Results will be published in peer-reviewed journals and presented at scientific conferences and events for decision-makers, including in the participating communities.

TRIAL REGISTRATION NUMBER

NCT03374761.

Food Allergy and Asthma: Is There a Link?

Purpose of review

To describe and understand the links and interactions between food allergy and asthma.

Recent findings

Food allergy and asthma are characterized by an increasing prevalence. Moreover, food allergy and asthma often coexist. Both conditions are associated with each other in different ways. It has been shown that food allergy is a risk factor of developing asthma. Atopic dermatitis appears to be the common denominator in this interaction. Loss-of-function variants of the filaggrin mutation result in an impaired epidermal barrier function and have been shown to be a risk factor for the development of atopic dermatitis, allergies, and asthma. Early introduction of food allergens and optimal treatment of the skin barrier are preventive interventions for the development of food allergy and asthma. Asthma is also a risk factor for the development of severe or even fatal anaphylaxis in patients with food allergy. Isolated asthma is not a feature of a food allergic reaction; however, respiratory symptoms may be part of anaphylactic reactions. In addition, during an allergic reaction to food, non-specific bronchial hyperreactivity may increase. Cross-reactive allergens may be responsible for asthma-associated food allergy. This is particularly true for severe asthma upon ingestion of snail in patients allergic to house-dust mites. Finally, airborne allergens from occupational sources such as wheat, fish, and seafood may induce asthmatic reactions. This phenomenon is sometimes seen in non-occupational settings.

Summary

Food allergy and asthma are interconnected with each other beyond the presence of simple comorbidity. Food allergy precedes and predisposes to asthma, and mutual interactions range from respiratory symptoms and bronchial hyperreactivity during food-induced anaphylaxis to severe asthma due to cross-reactive food allergens and to occupational asthma upon exposure to airborne allergens. Moreover, coexisting asthma in food allergies may result in severe and sometimes fatal anaphylactic reactions.

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.

Breastfeeding and the Developmental Origins of Asthma: Current Evidence, Possible Mechanisms, and Future Research Priorities

Breastfeeding has many established health benefits, but its impact on asthma development is uncertain. Breastfeeding appears to have a positive and dose-dependent impact on respiratory health, particularly during early childhood and in high-risk populations; however, the strength and causality of these associations are unclear. It is challenging to compare results across studies due to methodological differences and biological variation. Resolving these inconsistencies will require well-designed, prospective studies that accurately capture asthma diagnoses and infant feeding exposures (including breastfeeding duration, exclusivity, and method of feeding), account for key confounders, evaluate dose effects, and consider effect modification and reverse causality. Mechanistic studies examining human milk bioactives and their impact on lung health and asthma development are beginning to emerge, and these will be important in establishing the causality and mechanistic basis of the observed associations between breastfeeding and asthma. In this review, we summarize current evidence on this topic, identify possible reasons for disagreement across studies, discuss potential mechanisms for a causal association, and provide recommendations for future research.

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

BACKGROUND

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

METHODS

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

DISCUSSION

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

Estimated exposures to perfluorinated compounds in infancy predict attenuated vaccine antibody concentrations at age 5-years

Perfluorinated alkylate substances (PFASs) are highly persistent and may cause immunotoxic effects. PFAS-associated attenuated antibody responses to childhood vaccines may be affected by PFAS exposures during infancy, where breastfeeding adds to PFAS exposures. Of 490 members of a Faroese birth cohort, 275 and 349 participated in clinical examinations and provided blood samples at ages 18 months and 5 years. PFAS concentrations were measured at birth and at the clinical examinations. Using information on duration of breastfeeding, serum-PFAS concentration profiles during infancy were estimated. As outcomes, serum concentrations of antibodies against tetanus and diphtheria vaccines were determined at age 5. Data from a previous cohort born eight years earlier were available for pooled analyses. Pre-natal exposure showed inverse associations with the antibody concentrations five years later, with decreases by up to about 20% for each two-fold higher exposure, while associations for serum concentrations at ages 18 months and 5 years were weaker. Modeling of serum-PFAS concentration showed levels for age 18 months that were similar to those measured. Concentrations estimated for ages 3 and 6 months showed the strongest inverse associations with antibody concentrations at age 5 years, particularly for tetanus. Joint analyses showed statistically significant decreases in tetanus antibody concentrations by 19-29% at age 5 for each doubling of the PFAS exposure in early infancy. These findings support the notion that the developing adaptive immune system is particularly vulnerable to immunotoxicity during infancy. This vulnerability appears to be the greatest during the first 6 months after birth, where PFAS exposures are affected by breast-feeding.

Prospective Cohort Study of Breastfeeding and the Risk of Childhood Asthma

OBJECTIVES

To study whether the duration of breastfeeding and time for introduction of complementary foods was associated with the risk of childhood asthma.

STUDY DESIGN

We used data from the Norwegian Mother and Child Study, a nationwide prospective cohort study that recruited pregnant women from across Norway between 1999 and 2008. Children with complete data of breastfeeding up to 18 months and current age >7 years were eligible (n = 41 020). Asthma as the primary outcome was defined based on ≥2 dispensed asthma medications at age 7 years registered in the Norwegian Prescription Database. We used log-binomial regression models to obtain crude relative risks (RRs) in the main analysis, and adjusted for selected confounders in multivariable analyses.

RESULTS

For duration of any breastfeeding, 5.9% of infants breastfed <6 months (adjusted RR [aRR] 1.05, 0.93-1.19) and 4.6% breastfed 6-11 months (aRR 0.96, 0.87-1.07) had dispensed asthma medications at age 7 years compared with 4.6% of infants breastfed ≥12 months (P_trend .62). Infants still breastfed at 6 months, but introduced to complementary foods <4 months and 4-6 months, had an aRR of 1.15 (0.98-1.36) and 1.09 (0.94-1.27) respectively, compared with infants fully breastfed for 6 months (P_trend .09). Ages at introduction of solids or formula separately were not significant predictors (P_trend .16 and .08, respectively).

CONCLUSIONS

We found no association between duration of breastfeeding or age of introduction to complementary foods and asthma at age 7 years.

Pathophysiology and Management of Mild to Moderate Pediatric Atopic Dermatitis

Atopic dermatitis (AD), or eczema, is a chronic inflammatory skin condition characterized by relapsing pruritic and dry, scaly lesions. AD affects 10% to 20% of children in the United States and significantly affects the quality of life of patients and their families. Primary care providers (PCPs) are often the first point of contact for the management of AD symptoms. As many as 70% of patients with mild to moderate disease can be managed by a PCP, underscoring the need for these providers to understand basic AD pathophysiology and current standards of care. This article will discuss the basic principles of AD diagnosis and management that PCPs need to optimize patient care, including AD pathogenesis, appropriate use of currently available topical therapies, basic skin care practices, and patient/caregiver counseling points. This article is sponsored by Spire Learning and supported by an educational grant from Pfizer Inc.

Retrospective observational cohort study regarding the effect of breastfeeding on challenge-proven food allergy

BACKGROUND/OBJECTIVES

Human breast milk is generally regarded as the best nutrition for infants in their first months of life. Whether breastfeeding has a protective effect on food allergy is a point of debate and the subject of this study.

SUBJECTS/METHODS

This retrospective study was conducted in 649 children who underwent a double-blind placebo-controlled food challenge (DBPCFC) as part of routine care in a tertiary care clinic. Food allergy was defined as having at least one positive DBPCFC to any food. The association between both "any" breastfeeding (yes/no) and its duration in months with food allergy was studied by logistic regression analysis with correction for confounding variables.

RESULTS

The prevalence of food allergy was 58.9% (n = 382). Of all subjects, 75.8% (n = 492) was breastfed and 24.2% (n = 157) bottle-fed. There was no significant association between food allergy and breastfeeding versus bottle-feeding after correction for the confounding effect of increased breastfeeding by atopic parents and a history of asthma in the child (OR = 1.24, 95% CI = 0.85-1.79, p = 0.27). However, in breastfed children, every additional month of breastfeeding lowered the risk for food allergy by ~4% (OR = 0.96, 95% CI = 0.93-0.99, p = 0.02). No confounders were identified in this association.

CONCLUSION

These results show for the first time that in children investigated for possible food allergy, every additional month of breastfeeding is associated with a lower risk of developing clinical food allergy as diagnosed by DBPCFC. However, overall, there was no association between the prevalence of food allergy and breastfeeding versus bottle-feeding in this tertiary care population.

Effect of an Intervention to Promote Breastfeeding on Asthma, Lung Function, and Atopic Eczema at Age 16 Years: Follow-up of the PROBIT Randomized Trial

IMPORTANCE

Atopic diseases, including asthma and atopic eczema, are the most common chronic conditions of childhood.

OBJECTIVE

To investigate whether an intervention to promote prolonged and exclusive breastfeeding protects against asthma, atopic eczema, and low lung function in adolescence.

DESIGN, SETTING, AND PARTICIPANTS

Follow-up of the Promotion of Breastfeeding Intervention Trial (PROBIT), a cluster randomized trial in 30 Belarusian maternity hospitals and affiliated polyclinics; recruitment of 17 046 healthy term infants took place from June 15, 1996, to December 31, 1997. Data analysis was conducted from May 9, 2016, to April 21, 2017. The primary analytic approach was by modified intention-to-treat analysis.

INTERVENTIONS

Randomization to receive a breastfeeding promotion intervention vs usual care.

MAIN OUTCOMES AND MEASURES

Spirometry and flexural eczema on standardized skin examination by study pediatricians were the primary outcomes; secondary outcomes were self-reported asthma diagnosis ever, and wheezing and flexural eczema symptoms in the previous year.

RESULTS

A total of 13 557 (79.5%) participants were followed up from September 15, 2012 to July 15, 2015. The intervention (7064 [79.7%]) and control (6493 [79.4%]) groups were similar at follow-up (3590 [50.8%] and 3391 [52.2%] male; mean [SD] age, 16.2 [0.6] and 16.1 [0.5] years, respectively). In the intervention group, 0.3% (21 of 7064) had flexural eczema on skin examination and mean (SD) forced expiratory volume in the first second of expiration/forced vital capacity (FEV1/FVC) ratio z score was -0.10 (1.82), compared with 0.7% (43 of 6493) and 0.35 (1.34), respectively, in the control group. In modified intention-to-treat analysis, accounting for clustering by polyclinic, a 54% lower risk of flexural eczema on skin examination was observed in the intervention compared with the control group (odds ratio [OR], 0.46; 95% CI, 0.25 to 0.86). Self-reported flexural eczema symptoms in the past year (OR, 0.57; 95% CI, 0.27 to 1.18), asthma (OR, 0.76; 95% CI, 0.47 to 1.23), and wheezing in the past year (OR, 0.66; 95% CI, 0.37 to 1.18) were less frequently reported in the intervention compared with the control group, but 95% CIs were wide and included the null. There was no significant difference in the FEV1/FVC ratio z score (β -0.15; 95% CI, -0.76 to 0.45). All results were similar with additional adjustment for baseline characteristics, on instrumental variable analysis, and with multiple imputation among all 17 046 randomized participants.

CONCLUSIONS AND RELEVANCE

A breastfeeding promotion intervention reduced flexural dermatitis risk but had no detectable effect on lung function or questionnaire-derived measures of atopic eczema or asthma in adolescence in a setting where atopic eczema and allergies are rare.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT01561612.

Infant feeding pattern in the first six months of age in USA: a follow-up study

Background

Infant feeding may consist of direct breastfeeding (DBF), pumping and bottle feeding (P&F), formula feeding (FF), solid food feeding (SFF), and any combination. An accurate evaluation of infant feeding requires descriptions of different patterns, consistency, and transition over time.

Methods

In United States of America, the Infant Feeding Practice Study II collected information on the mode of feeding on nine occasions in 12 months. We focused on the first 6 months with six feeding occasions. To determine the longitudinal patterns of feeding the latent class transition analyses was applied and assessed the transition probabilities between these classes over time.

Results

Over 6 months, 1899 mothers provided feeding information. In month 1 the largest latent class is FF (32.9%) followed by DBF (23.8%). In month 2, a substantial proportion of the FF class included SFF; which increases over time. A not allocated class, due to missing information was identified in months 1-3, transitions to SFF starting in month 4 (8.9%). In month 1, two mixed patterns exist: DBF and P&F combined with FF (13.9%) and DBF combined with P&F (18.7%). The triple combination of DBF, P&F, and FF (13.9%) became FF in month 2 (transition probability: 24.8%), and DBF in combination with P&F (transition probability: 49.1%). The pattern of DBF combined with P&F is relatively stable until month 4, when at least 50% of these infants receive solid food. Only 23-26% of the infants receive direct breastfeeding (DBF) in months 1-4, in month 5-6 SFF is added. Mothers who used FF were less educated and employed fulltime. Mothers who smoke and not residing in the west of the United States were also more likely to practice formula feeding.

Conclusion

Infant feeding is complex. Breastfeeding is not predominant and we additionally considered the mixed patterns of feeding. To facilitate direct breastfeeding, a substantial increase in the duration of maternal leave is necessary in the United States.

Duration and exclusiveness of breastfeeding and risk of childhood atopic diseases

BACKGROUND

Breastfeeding may have immune modulatory effects that influence the development of childhood allergic sensitization and atopic diseases. We aimed to examine the associations of breastfeeding with childhood allergic sensitization, inhalant or food allergy and eczema, and whether any association was affected by disease-related modification of the exposure or modified by maternal history of allergy, eczema, or asthma.

METHODS

This study among 5828 children was performed in a population-based prospective cohort from fetal life onwards. We collected information on duration (<2 months, 2-4 months, 4-6 months, and ≥6 months) and exclusiveness (nonexclusive vs exclusive for 4 months) of breastfeeding in infancy by postal questionnaires. At age 10 years, inhalant allergic sensitization and food-allergic sensitization were measured by skin prick tests, and physician-diagnosed inhalant and food allergy by a postal questionnaire. Data on parental-reported eczema were available from birth until age 10 years.

RESULTS

We observed no association of breastfeeding with any allergic sensitization, physician-diagnosed allergy, or combination of these outcomes. Shorter breastfeeding duration was associated with an overall increased risk of eczema (P-value for trend <.05). Nonexclusively breastfed children had an overall increased risk of eczema (adjusted odds ratio [95% confidence interval]: 1.11 [1.01, 1.23]), compared with children exclusively breastfed for 4 months. Risk period-specific sensitivity analyses, additional adjustment for ointment use for eczema at age 2 months, and cross-lagged modeling showed no consistent results for disease-related modification of the exposure. Results were not modified by maternal history of allergy, eczema, or asthma (lowest P-value for interaction=.13).

CONCLUSION

Shorter duration or nonexclusiveness of breastfeeding is associated with a weak overall increased risk of eczema but not allergic sensitization or physician-diagnosed allergy at age 10 years.

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.