What's new in atopic eczema? An analysis of systematic reviews published in 2012 and 2013. Part 2. Treatment and prevention

The effect of early skin-to-skin contact after cesarean section on breastfeeding duration and development of atopic-allergic diseases

INTRODUCTION

Breastfeeding to strengthen the immune system suggests allergy prevention as a possible option. The connection between breastfeeding and the development of atopic-allergic diseases is being discussed. The primary aim of this work was to investigate an association of the first early skin-to-skin contact following cesarean section with the development of atopic diseases within the 1st year of life.

METHODS

The present study was conducted as a bicentric prospective cohort study in central Germany with a 15-month recruitment period. Data collection was by telephone interviews with a follow-up of 12 months. The statistical evaluation procedure was based on a hierarchical test of the association of early skin-to-skin contact between mother and child with the two main outcome measures. The primary outcome is the duration of breastfeeding. The second outcome is the onset of atopic-allergic disease within the 1st year of life.

RESULTS

Mothers breastfed longer if they had skin-to-skin contact within the first 30 minutes postpartum [χ²(df=5) = 19.020, p=0.002], if they breastfed their newborns early immediately after birth (p<0.001), and if the first skin-to-skin contact lasted more than one hour [χ²(df=4) = 19.617, p<0.001]. Regarding atopic-allergic diseases, no significant effects of skin-to-skin contact were found in relation to disease development. Regarding breastfeeding, no significant effects of atopic-allergic diseases could be detected either.

CONCLUSIONS

The results of this study reflect the benefits of skin-to-skin contact in the context of breastfeeding and atopic disease. The current scientific knowledge regarding skin contact and the development of atopic-allergic diseases should be extended and deepened.

Novel and emerging prebiotics: Advances and opportunities

Consumers are conscientiously changing their eating preferences toward healthier options, such as functional foods enriched with pre- and probiotics. Prebiotics are attractive bioactive compounds with multidimensional beneficial action on both human and animal health, namely on the gastrointestinal tract, cardiometabolism, bones or mental health. Conventionally, prebiotics are non-digestible carbohydrates which generally present favorable organoleptic properties, temperature and acidic stability, and are considered interesting food ingredients. However, according to the current definition of prebiotics, application categories other than food are accepted, as well as non-carbohydrate substrates and bioactivity at extra-intestinal sites. Regulatory issues are considered a major concern for prebiotics since a clear understanding and application of these compounds among the consumers, regulators, scientists, suppliers or manufacturers, health-care providers and standards or recommendation-setting organizations are of utmost importance. Prebiotics can be divided in several categories according to their development and regulatory status. Inulin, galactooligosaccharides, fructooligosaccharides and lactulose are generally classified as well established prebiotics. Xylooligosaccharides, isomaltooligosaccharides, chitooligosaccharides and lactosucrose are classified as "emerging" prebiotics, while raffinose, neoagaro-oligosaccharides and epilactose are "under development." Other substances, such as human milk oligosaccharides, polyphenols, polyunsaturated fatty acids, proteins, protein hydrolysates and peptides are considered "new candidates." This chapter will encompass actual information about the non-established prebiotics, mainly their physicochemical properties, market, legislation, biological activity and possible applications. Generally, there is a lack of clear demonstrations about the effective health benefits associated with all the non-established prebiotics. Overcoming this limitation will undoubtedly increase the demand for these compounds and their market size will follow the consumer's trend.

Exclusive Breastfeeding Duration and its Effect on the Health of the Children in Iran, a Meta Analysis

PROBLEM

Given the importance of exclusive breastfeeding (EB) duration on growth and to maintain health in children, we decided to systematically review the existing research on EB duration and its effect on the health of 2- to 5-year-old children in Iran.

ELIGIBILITY CRITERIA

A systematic literature search was conducted in the Database of Abstracts of Reviews of Effects (DARE), Google Scholar, PubMed, Psyc INFO, Thomson Reuters, Cochrane, and Medical Library (MedLib) to detect appropriate studies (1994 to 2016). Outcomes of mean, mean difference, and proportions were pooled.

SAMPLE

In this meta-analysis, 38 studies met the eligibility criteria.

RESULTS

The pooled mean of EB was calculated as 4.1 months (CI 95%: 3.2, 4.99). The meta prevalence of EB up to 4 months and 5 to 6 months was estimated 65.0% (CI 95%: 54.0, 77.0) and 54% (CI 95%: 46.0, 62.0) respectively. Based on studies conducted over the years from 1994 to 2016, an increasing trend of EB was found in infants up to 4 months (p ≤ 0.0001). Among children with anemia and respiratory diseases EB until 5 to 6 months was more common than in healthy children (CI 95%; 1.1, 2.11, and 1.01, 1.47 respectively).

CONCLUSION

The duration of EB (4.1 months) was equal to the lower limit recommended by the World Health Organization (WHO). Overall, the duration of EB until 5 to 6 months is sufficient if the child's iron intake is well-monitored.

IMPLICATION

Monitoring of the implementation of recent guidelines or even modification of the duration period of the iron administration is potentially necessary.

Association between breastfeeding and eczema during childhood and adolescence: A cohort study

Background

Breastfeeding is said to protect children from eczema (atopic dermatitis), but the available evidence is conflicting and subject to the influences of parental atopy and reverse causation (when mothers extended duration of breastfeeding because their children had eczema).

Methods

In the prospective, population-based Leicester Respiratory Cohort study, we assessed duration of breastfeeding in children aged 1–4 years. Prevalence of eczema was determined by questionnaire surveys that were repeated until the children were 17 years old. We investigated the association between having been breastfed and current eczema using generalized estimating equations, adjusting for potential confounders, and tested for effect modification by parental atopy. We also assessed the association between having been breastfed and incident eczema at ages 2, 4, and 6 years using multivariable logistic regression.

Results

Among the 5,676 children in the study, 2,284 (40%) had never been breastfed, while 1,610 (28%), 705 (12%), and 1,077 (19%) had been breastfed for 0–3, 4–6, and >6 months, respectively. Prevalence of current eczema decreased from 36% in 1-year-olds to 18% in children aged 10–17 years. Breastfeeding was not associated with current eczema. Compared with children who had never been breastfed, the adjusted odds ratios for current eczema at any age were 1.02 (95% confidence interval 0.90–1.15) for children who had been breastfed for 0–3 months, 0.97 (0.82–1.13) for children breastfed for 4–6 months, and 0.98 (0.85–1.14) for children breastfed for >6 months. There was no strong evidence for an effect modification by parental atopy (p-value for interaction term was 0.061) and no association between having been breastfed and incident eczema later in childhood.

Conclusions

This population-based cohort study found no evidence for protection of breastfeeding against childhood eczema at any age, from infancy through adolescence.

Expert consensus document: The International Scientific Association for Probiotics and Prebiotics (ISAPP) consensus statement on the definition and scope of prebiotics

In December 2016, a panel of experts in microbiology, nutrition and clinical research was convened by the International Scientific Association for Probiotics and Prebiotics to review the definition and scope of prebiotics. Consistent with the original embodiment of prebiotics, but aware of the latest scientific and clinical developments, the panel updated the definition of a prebiotic: a substrate that is selectively utilized by host microorganisms conferring a health benefit. This definition expands the concept of prebiotics to possibly include non-carbohydrate substances, applications to body sites other than the gastrointestinal tract, and diverse categories other than food. The requirement for selective microbiota-mediated mechanisms was retained. Beneficial health effects must be documented for a substance to be considered a prebiotic. The consensus definition applies also to prebiotics for use by animals, in which microbiota-focused strategies to maintain health and prevent disease is as relevant as for humans. Ultimately, the goal of this Consensus Statement is to engender appropriate use of the term 'prebiotic' by relevant stakeholders so that consistency and clarity can be achieved in research reports, product marketing and regulatory oversight of the category. To this end, we have reviewed several aspects of prebiotic science including its development, health benefits and legislation.

Overview of systematic reviews in allergy epidemiology

BACKGROUND

There is a substantial body of evidence on the epidemiology of allergic conditions, which has advanced the understanding of these conditions. We aimed to systematically identify systematic reviews and meta-analyses on the epidemiology of allergic diseases to assess what has been studied comprehensively and what areas might benefit from further research.

METHODS

We searched PubMed and EMBASE up to 12/2014 for systematic reviews on epidemiological research on allergic diseases. We indexed diseases and topics covered and extracted data on the search characteristics of each systematic review.

RESULTS

The search resulted in 3991 entries after removing duplicates, plus 20 other items found via references and conference abstracts; 421 systematic reviews were relevant and included in this overview. The majority contained some evidence on asthma (72.9%). Allergic rhinitis, atopic eczema and food hypersensitivity were covered in 15.7%, 24.5% and 9.0%, respectively. Commonly studied risk factors for atopic eczema included dietary and microbial factors, while for asthma, pollution and genetic factors were often investigated in systematic reviews. There was some indication of differing search characteristics across topics.

CONCLUSION

We present a comprehensive overview with an indexed database of published systematic reviews in allergy epidemiology. We believe that this clarifies where most research interest has focussed and which areas could benefit from further research. We propose that this effort is updated every few years to include the most recently published evidence and to extend the search to an even broader list of hypersensitivity/allergic disorders.

Allergic diseases and asthma in pregnancy, a secondary publication

Every fifth pregnant woman is affected by allergies, especially rhinitis and asthma. Allergic symptoms existing before pregnancy may be either attenuated, or equally often promoted through pregnancy. Optimal allergy and asthma diagnosis and management during pregnancy is vital to ensure the welfare of mother and baby. For allergy diagnosis in pregnancy, preferentially anamnestic investigation as well as in vitro testing should be applied, whereas skin testing or provocation tests should be postponed until after birth. Pregnant women with confirmed allergy should avoid exposure to, or consumption of the offending allergen. Allergen immunotherapy should not be initiated during pregnancy. In patients on immunotherapy since before pregnancy, maintenance treatment may be continued, but the allergen dose should not be increased further. Applicable medications for asthma, rhinitis or skin symptoms in pregnancy are discussed and listed. In conclusion, i) allergies in pregnancy should preferentially be diagnosed in vitro; ii) AIT may be continued, but not started, and symptomatic medications must be carefully selected; iii) management of asthma and allergic diseases is important during pregnancy for welfare of mother and child.

Superantigens and adhesins of infant gut commensal Staphylococcus aureus strains and association with subsequent development of atopic eczema

BACKGROUND

According to the hygiene hypothesis, insufficient immune activation by microbes increases the risk of allergy development. Staphylococcus aureus, which is part of the skin and gut microbiota of infants in Western countries, produces a variety of T-cell-activating enterotoxins, called superantigens.

OBJECTIVES

To investigate whether early (0-2 months of age) gut colonization by S. aureus strains that carry specific superantigens and adhesins was related to subsequent development of atopic eczema in a Swedish birth cohort.

METHODS

Staphylococcus aureus was isolated from rectal swabs and cultured quantitatively from faecal samples, with individual strains being tested for carriage of genes for superantigens and adhesins. Atopic eczema was diagnosed at onset of symptoms and at 18 months of age.

RESULTS

Although the frequency of early gut colonization by S. aureus was not related to subsequent eczema development, the S. aureus strains that were found to colonize those infants who developed atopic eczema were less likely to carry the gene encoding the superantigen SElM (P = 0·008) and the gene for elastin-binding protein (P = 0·03), compared with strains that were isolated from infants who had not developed atopic eczema by 18 months of age.

CONCLUSIONS

Gut colonization by S. aureus strains carrying a certain combination of superantigen and adhesin genes was negatively associated with subsequent development of atopic eczema. Such strains may provide stimulation and promote maturation of the infant immune system.

Atopic eczema

Atopic eczema is an itchy inflammatory skin disease with a chronic relapsing-remitting course; it has increased in prevalence in recent decades and now affects up to 25% of school-aged children in the developed world and up to 10% of adults. Recent advances in understanding the aetiology of eczema have focused interest on skin barrier dysfunction as a common precursor and pathological feature. In addition, genetically determined skin barrier dysfunction (associated with mutations in the gene encoding filaggrin) is known to predispose to multiple systemic atopic diseases. First-line treatments for atopic eczema focus on maintaining and repairing the skin barrier (emollients) and reducing inflammation (topical steroids); allergen and irritant avoidance are also important to achieve disease control. Second and third-line treatments include topical calcineurin inhibitors, ultraviolet light and systemic immunosuppressant therapies of which only ciclosporin is licenced for the treatment of atopic eczema in adults. Novel biological therapies are in phase II-III clinical trials.

Probiotics for allergy prevention

Probiotics, given either as a supplement or in infant foods, have been evaluated in randomised controlled trials for allergy prevention. Here, the aim is to give an overview of the results from these primary prevention studies and to discuss current strategies. In most studies, single strains or a mixture of strains of lactic acid bacteria and bifidobacteria have been used--prenatally, postnatally or perinatally. Several meta-analyses have reported a moderate benefit of probiotics for eczema prevention, and the most consistent effect has been observed with a combined perinatal intervention in infants at high risk of allergic disease due to familial predisposition. In a recent meta-analysis, the use of multi-strain probiotics appeared to be most effective for eczema prevention. No preventive effect has been shown for other allergic manifestations. As long-term follow-up data on later onset allergic conditions (asthma and allergic rhinitis) are available only from a few of the initiated studies, reports from ongoing follow-up studies that are adequately powered to examine long-term outcomes are anticipated to provide more insight. Arguably, the differences in many aspects of study design and the use of different probiotic strains and combinations have made direct comparison difficult. To date, expert bodies do not generally recommend probiotics for allergy prevention, although the World Allergy Organization (WAO) in their recently developed guidelines suggests considering using probiotics in pregnant women, during breastfeeding and/or to the infant if at high risk of developing allergic disease (based on heredity). However, in concordance with other expert bodies, the WAO guideline panel stressed the low level of evidence and the need for adequately powered randomised controlled trials and a more standardised approach before clinical recommendations on specific strains, dosages and timing can be given.