Prenatal exposure to acid-suppressive drugs and the risk of allergic diseases in the offspring: a cohort study

Drug-induced fetal and offspring disorders, beyond birth defects

Studies on drug utilization in western countries disclosed that about nine over ten women use at least one or more drugs during pregnancy. Determining whether a drug is safe or not in pregnant women is a challenge of all times. As a developing organism, the fetus is particularly vulnerable to effects of drugs used by the mother. Historically, research has predominantly focused on birth defects, which represent the most studied adverse pregnancy outcomes. However, drugs can also alter the ongoing process of pregnancy and impede the general growth of the fetus. Finally, adverse drug reactions can theoretically damage all developing systems, organs or tissues, such as the central nervous system or the immune system. This extensive review focuses on different aspects of drug-induced damages affecting the fetus or the newborn/infant, beyond birth defects, which are not addressed here.

Treatable traits in asthma during pregnancy: a call for a shift towards a precision-based management approach

Asthma is the most common chronic medical condition in pregnancy. Asthma exacerbations in pregnancy are unpredictable, and are associated with adverse maternal and fetal perinatal outcomes such as preterm birth and low birthweight. Goals of asthma management in pregnancy are to establish effective asthma control and prevent exacerbations. Optimising the management of asthma in pregnancy is an important goal of practice and future research.Treatable traits is a precision medicine paradigm proposed for the management of airways diseases, which holistically addresses the complexity and heterogeneity of airways disease. It is an individualised treatment approach that aims to improve outcomes. This makes treatable traits well suited for pregnant women with asthma, who have a high prevalence of obesity, mental health conditions, poor symptom perception and suboptimal asthma management skills including low treatment adherence. These traits are measurable and treatable. In this review, we explore current knowledge on the burden of asthma, maternal and perinatal consequences of asthma during pregnancy, the treatable traits paradigm, the prevalence of treatable traits in pregnant women with asthma, and consider how the treatable traits paradigm can be integrated into the management of asthma in pregnancy.

Low agreement between Swedish national registers and parental questionnaires on allergic rhinitis

BACKGROUND

Allergic rhinitis (AR) has been well documented using questionnaire-based studies. Here, we examine the agreement between parental-reported data during childhood with the emphasis on 12-year-olds and data from two national Swedish registers to determine whether register data on AR can supplement or replace questionnaire data.

METHODS

Data were collected from a prospective, longitudinal cohort study of children born in western Sweden in 2003. Parental questionnaires were filled out at 6 months and one, four, eight, and 12 years of age. A total of 3634 children were linked to the Swedish Prescribed Drug Register (SPDR) and the National Patient Register (NPR) using personal identity numbers. The agreement between the register and questionnaire data was estimated using Cohen's kappa with 95% confidence intervals.

RESULTS

According to the SPDR, 9.9% (n = 360/3634) of the children were dispensed specific AR medication at 11-13 years of age compared with the 12 years questionnaire where 23% reported AR medication use during the last 12 months. The overall agreement between questionnaire and SPDR data on AR medication was slight (kappa 0.05). At 11-12 years, 1.8% (n = 65/3634) of the children received an outpatient AR diagnosis in the NPR, while 10% reported doctor-diagnosed AR in the questionnaire. The overall agreement between questionnaire and NPR data on AR diagnosis was slight (kappa 0.16).

CONCLUSIONS

There was poor agreement between questionnaire and register data regarding AR and dispensed medication. Explanations could include over-the-counter drugs and diagnosis in primary care, which are not included in the registers.

Acid-suppressive medication and incidence of chronic childhood immune-mediated diseases: A scoping review

BACKGROUND

Use of acid-suppressive medications (ASMs), for example, proton pump inhibitors (PPIs) and histamine-2 receptor antagonists (H2RAs), has been rising along with the incidence of pediatric immune-mediated diseases (IMDs). We conducted a scoping review to characterize the literature about prenatal or pediatric exposure to ASMs in relation to incident pediatric IMDs.

METHODS

Electronic searches were conducted to identify studies from 2001 to 2023 on (a) prenatal or pediatric exposure to PPIs and/or H2RAs and (b) the risk of developing chronic IMDs during childhood. Eligible studies after title/abstract and full-text screening underwent data abstraction.

RESULTS

Of 26 eligible studies, 11 focused on prenatal ASM exposure and 16 on pediatric exposure. Asthma was the most commonly investigated outcome (16 studies), followed by other allergic diseases (8), eosinophilic esophagitis (3), inflammatory bowel disease (2), and other autoimmune diseases (2). Positive associations between ASM exposure and pediatric IMD outcomes emerged in all but two recent studies, which reported null or negative associations with allergic diseases. The strength of associations was similar across exposure times (prenatal/pediatric), medications (PPIs/H2RAs), and outcomes. Dose-response relationships were often present (7/11 studies). Reported effects by trimester and age of exposure varied. Commonly reported limitations were residual confounding, exposure misclassification, and outcome misclassification.

CONCLUSION

In summary, prenatal or pediatric exposure to PPIs and/or H2RAs has frequently, but not exclusively, been associated with the development of asthma, other allergic diseases, and chronic gastrointestinal IMDs. However, concerns remain about confounding and other sources of bias. Prescribers and families should be aware of these possible risks of ASMs.

Nature with Nurture: the Role of Intrinsic Genetic and Extrinsic Environmental Factors on Eosinophilic Esophagitis

PURPOSE OF REVIEW

As the rising prevalence and incidence of eosinophilic esophagitis (EoE) has quickly outpaced the rate of esophageal biopsies, particularly in Westernized countries, several studies have suggested a link between intrinsic genetic and extrinsic environmental risk factors and the development, presentation, and diagnosis of EoE. This review aims to critically assess existing studies describing the role of the environment on the development, symptomatic presentation, and diagnosis of this recently recognized chronic immune-mediated disease.

RECENT FINDINGS

We present and critically evaluate the working hypotheses and supportive studies thus far on environmental factors on EoE, describe sources of potential bias in diagnosis due to socioeconomic factors and thus undermining studies of EoE etiology, and highlight opportunities for future research. As genetics alone do not explain the rapid rise of EoE, we must look to environmental, or extrinsic, factors both in the early-life period which shape the development of the gut microbiome, as well as later life contributing to diagnosis of this new disease. Future etiologic studies linking risk factors to EoE development in individual patients are needed.

Exposure to Proton Pump Inhibitors and the Risk of Incident Asthma in Patients with Coronary Artery Diseases: A Population-Based Cohort Study

We aimed to determine the association between proton pump inhibitor (PPI) use and incident asthma in patients with coronary artery disease (CAD). This nationwide cohort study collected claims data from the Taiwanese Bureau of National Health Insurance from 2004 to 2013. The primary outcome, i.e., the risk of incident asthma, was assessed by estimating hazard ratios (HRs) and 95% confidence intervals (CIs). The adjusted HR of asthma development was estimated using the Cox regression model. Sensitivity and subgroup analyses were also conducted. A total of 8894 PPI users and 12,684 H2-receptor antagonist (H2RA) users were included in patients with CAD. Compared with H2RA use, an increased risk of incident asthma was found between PPI use and the risk of incident asthma in patients with CAD after adjusting for sex, age, urbanization, and low income (HR: 1.41; 95% CI: 1.04–1.89). The sensitivity analysis results were consistent with the main analysis results. However, the subgroup analysis revealed no association of incident asthma in patients with diabetes mellitus, hyperlipidemia, stroke, allergic rhinitis, pneumonia, cancer, or depression in the PPI group compared with those in the H2RA group. In conclusion, PPI use increased the risk of asthma development in patients with CAD.

Review of recent evidence on the management of heartburn in pregnant and breastfeeding women

Gastroesophageal reflux disease (GERD) is one the most common medical complaints in pregnant women. Some women continue to experience GERD symptoms after delivery. Effective management of GERD symptoms is important to improve productivity and quality of life. Management of heartburn in pregnant and breastfeeding women involves lifestyle modifications, dietary modifications, non-pharmaceutical remedies and pharmaceutical drugs. For most patients, lifestyle/dietary modifications are helpful in reducing GERD symptoms. For patients who require a more intense intervention, various types of pharmaceutical drugs are available. However, the suitability of each treatment for use during pregnancy and lactation must be taken into consideration. This article explores the reported efficacy and safety of these treatment options in pregnant and breastfeeding women. Recommended treatment algorithm in pregnant and breastfeeding women have been developed.

Association between acid-suppressive drug use and atopic dermatitis in patients with upper gastrointestinal diseases: A population-based retrospective cohort study

WHAT IS KNOWN AND OBJECTIVE

Proton-pump inhibitors (PPIs) and histamine-2-receptor antagonists (H2RAs) are two of the most widely used acid-suppressive drugs (ASDs). Some studies have reported that prenatal ASD exposure may increase the risk of asthma and other allergic diseases. This study investigated the effects of ASDs on the risk of atopic dermatitis in patients with upper gastrointestinal diseases.

METHODS

This population-based retrospective cohort study used data of 289,850 patients with at least two diagnoses of upper gastrointestinal diseases (UGIDs) between 1 January 2001 and 31 December 2005, from Taiwan's National Health Insurance Research Database. The AD risks among ASD users and nonusers were compared. Differences in sociodemographic characteristics and potential covariates were examined. AD hazard ratios were estimated, and groups were compared using Cox proportional hazards regression analysis after adjustment for age, sex and other covariates.

RESULTS AND DISCUSSION

In total, 109,980 patients were included. The adjusted hazard ratio (HR) of AD risk in ASD users relative to that in nonusers was 1.52 (95% confidence interval [CI]: 1.40-1.64, p < 0.001). For a dose-effect sub-analysis, patients were divided into four groups based on their defined daily dose. ASDs dose-dependently affected the AD risk (p for trend <0.01). Furthermore, the adjusted HR of the AD risk among ASD nonusers was 2.30 (95% CI: 2.06-2.57) relative to that in the comparison group (ASD nonusers without UGIDs). Among patients with UGIDs, ASD users had a higher AD risk than ASD nonusers. A subgroup analysis revealed only H2RA use was associated with an increased AD risk (adjusted HR 1.70, 95% CI: 1.53-1.89, p < 0.001).

WHAT IS NEW AND CONCLUSIONS

These results indicate that the use of H2RAs was associated with an increased risk of AD among patients with UGIDs, and the increase in risk appeared to be dose-dependent. ASDs should be used only in situations where clear clinical benefits can be obtained.

Can we identify allergic rhinitis from administrative data: A validation study

BACKGROUND

Important insights on, for example, prevalence, disease progression, and treatment of allergic rhinitis can be obtained from large-scale database studies if researchers are able to identify allergic individuals. We aimed to assess the validity of 13 different algorithms based on Danish nationwide prescription and/or hospital data to identify adults with allergic rhinitis.

METHODS

Our primary gold standard of allergic rhinitis was a positive serum specific IgE (≥0.35) and self-reported nasal symptoms retrieved from two general health examination studies conducted in Danish adults (18-69 years) during 2006 to 2008 (n = 3416) and 2012 to 2015 (n = 7237). The secondary gold standard of allergic rhinitis was self-reported physician diagnosis. We calculated sensitivity, specificity, positive predictive value (PPV), negative predictive value, and corresponding 95% confidence intervals (95% CI) for each register-based algorithm in the two time periods.

RESULTS

Sensitivity (≤0.40) was low for all algorithms irrespective of definition of allergic rhinitis (gold standard) or time period. The highest PPVs were obtained for algorithms requiring both antihistamines and intranasal corticosteroids; yielding a PPV of 0.69 (0.62-0.75) and a corresponding sensitivity of 0.10 (0.09-0.12) for the primary gold standard of allergic rhinitis in 2012 to 2015.

CONCLUSION

Algorithms based on both antihistamines and intranasal corticosteroids yielded the highest PPVs. However, the PPVs were still moderate and came at the expense of low sensitivity when applying the strict primary gold standard (sIgE and nasal symptom).

Proton Pump Inhibitors in Children: the Good, the Bad, and the Ugly

PURPOSE OF REVIEW

The evidence supporting or contesting the prescription of proton pump inhibitors (PPIs) for children and updates on side effects are reviewed.

RECENT FINDINGS

PPIs remain an important therapeutic option for esophagitis and gastritis. However, recent studies demonstrate no benefit when prescribing PPIs for chronic cough, infantile reflux, asthma, or functional gastrointestinal disorders. Recent studies suggest adverse effects on microbiome diversity and immune function, resulting in increased rates of gastrointestinal infections, bone fractures, and atopic disorders. PPIs influence a variety of cell types within the in the innate and adaptive immune systems. PPI prescriptions in children may be indicated for select conditions; however, multiple side effects and immune effects have been described. While most of these side effects are rare and mild, some studies suggest enduring adverse effects. Future studies to elucidate the mechanism behind some of these immune and infectious complications will be beneficial.

The Role of Two Human Milk Oligosaccharides, 2'-Fucosyllactose and Lacto-N-Neotetraose, in Infant Nutrition

Human breast milk contains numerous biomolecules. Human milk oligosaccharides (HMOs) are the third most abundant component of breast milk, after lactose and lipids. Amongst the synthetized HMOs, 2'-fucosyllactose (2'-FL) and lacto-N-neotetraose (LNnT) are widely studied and are considered safe for infant nutrition. Several studies have reported the health benefits of HMOs, which include modulation of the intestinal microbiota, anti-adhesive effect against pathogens, modulation of the intestinal epithelial cell response, and development of the immune system. The amount and diversity of HMOs are determined by the genetic background of the mothers (HMO secretors or non-secretors). The non-secretor mothers secrete lower HMOs than secretor mothers. The breastfed infants of secretor mothers gain more health benefit than those of non-secretor mothers. In conclusion, supplementation of infant formula with 2'-FL and LNnT is a promising innovation for infant nutrition.

Pharmacoepidemiology in pregnancy

Taking a medication is usually a challenge for a pregnant woman as the beneficial drug effect on the mother has to be considered regarding its potential adverse effects, not only for her but also for her unborn child. As medication use is common in pregnant women, by chance or necessity, it gives the opportunity to evaluate the consequences of prenatal drug exposure in real life through pharmacoepidemiological studies. This paper provides an overview of data sources, study designs and data analysis methods that can be used for pregnancy medication safety studies. In the future, the implementation of responsive international networks may be the keystones of drug evaluation in pregnancy.

Acid suppressant medications and the risk of allergic diseases

INTRODUCTION

Acid suppressant medications (ASMs), such as proton pump inhibitors and histamine-2 receptor antagonists, are used often and throughout the lifespan. These medications have been linked to the development of a variety of allergic diseases. Areas covered: This review discusses prior studies investigating the association between acid ASM exposure and the development of allergic diseases. We performed a thorough literature search to identify potentially relevant studies for inclusion. In summary, exposure to these medications prenatally, in childhood and in adulthood, may increase the risk of allergic diseases. The current evidence is limited by primarily observational study design and potential bias and confounding. The mechanism of action is not yet known, but there are several proposed theories. Expert commentary: There is a growing body of evidence to support that exposure to acid ASMs increases the risk of developing allergic diseases. Further research is needed to not only clarify this relationship but to define the potential mechanism of action. If further research confirms these observations, we believe that could warrant changes in the patterns of prescribing and use of acid ASMs.

The Effect of Digestion and Digestibility on Allergenicity of Food

Food allergy prevalence numbers are still on the rise. Apart from environmental influences, dietary habits, food availability and life-style factors, medication could also play a role. For immune tolerance of food, several contributing factors ensure that dietary compounds are immunologically ignored and serve only as source for energy and nutrient supply. Functional digestion along the gastrointestinal tract is essential for the molecular breakdown and a prerequisite for appropriate uptake in the intestine. Digestion and digestibility of carbohydrates and proteins thus critically affect the risk of food allergy development. In this review, we highlight the influence of amylases, gastric acid- and trypsin-inhibitors, as well as of food processing in the context of food allergenicity.

Systematic review of atopic dermatitis disease definition in studies using routinely collected health data

BACKGROUND

Routinely collected electronic health data obtained for administrative and clinical purposes are increasingly used to study atopic dermatitis (AD). Methods for identifying AD patients in routinely collected electronic health data differ, and it is unknown how this might affect study results.

OBJECTIVES

To evaluate how patients with AD have been identified in studies using routinely collected electronic health data, to determine whether these methods were validated and to estimate how the method for identifying patients with AD affected variability in prevalence estimates.

METHODS

We systematically searched PubMed, Embase and Web of Science for studies using routinely collected electronic health data that reported on AD as a primary outcome. Studies of localized AD and other types of dermatitis were excluded. The protocol for this review was registered in PROSPERO (CRD42016037968).

RESULTS

In total, 59 studies met eligibility criteria. Medical diagnosis codes for inclusion and exclusion, number of occasions of a code, type of provider associated with a code and prescription data were used to identify patients with AD. Only two studies described validation of their methods and no study reported on disease severity. Prevalence estimates ranged from 0·18% to 38·33% (median 4·91%) and up to threefold variation in prevalence was introduced by differences in the method for identifying patients with AD.

CONCLUSIONS

This systematic review highlights the need for clear reporting of methods for identifying patients with AD in routinely collected electronic health data to allow for meaningful interpretation and comparison of results.

Acid-Suppressive Drug Use During Pregnancy and the Risk of Childhood Asthma: A Meta-analysis

CONTEXT

The association between acid-suppressive drug exposure during pregnancy and childhood asthma has not been well established.

OBJECTIVE

To conduct a systematic review and meta-analysis on this association to provide further justification for the current studies.

DATA SOURCES

We searched PubMed, Medline, Embase, the Cochrane Database of Systematic Reviews, EBSCO Information Services, Web of Science, and Google Scholar from inception until June 2017.

STUDY SELECTION

Observational studies in which researchers assessed acid-suppressive drug use during pregnancy and the risk of childhood asthma were included.

DATA EXTRACTION

Of 556 screened articles, 8 population-based studies were included in the final analyses.

RESULTS

When all the studies were pooled, acid-suppressive drug use in pregnancy was associated with an increased risk of asthma in childhood (relative risk [RR] = 1.45; 95% confidence interval [CI] 1.35-1.56; I² = 0%; P < .00001). The overall risk of asthma in childhood increased among proton pump inhibitor users (RR = 1.34; 95% CI 1.18-1.52; I² = 46%; P < .00001) and histamine-2 receptor antagonist users (RR = 1.57; 95% CI 1.46-1.69; I² = 0%; P < .00001).

LIMITATIONS

None of the researchers in the studies in this meta-analysis adjusted for the full panel of known confounders in these associations.

CONCLUSIONS

The evidence suggests that prenatal, maternal, acid-suppressive drug use is associated with an increased risk of childhood asthma. This information may help clinicians and parents to use caution when deciding whether to take acid-suppressing drugs during pregnancy because of the risk of asthma in offspring.

Developments in the field of allergy in 2014 through the eyes of Clinical and Experimental Allergy

The pathogenesis of asthma continues to be a major topic of interest to our authors with reviews and original papers on the role of viruses, mechanisms of inflammation, biomarkers, and phenotypes of asthma being major topics. A number of papers described new treatments for asthma focusing on blocking the Th2 response reflecting the fact that two decades of work in this area is finally bearing fruit. The pathogenesis of chronic rhinosinusitis is a growing area of interest, but there has been less on the genetics of airways disease than in previous years possibly reflecting the degree of rigour (and therefore a smaller body of work), with which these sorts of studies are now being undertaken. There continues to be a wide range of papers dealing with mechanisms of allergic disease ranging from clinical-based studies to basic research and the use of in vivo animal models especially mice. As before, mechanisms and new approaches to immunotherapy are common themes. Several were published in the allergens section investigating modification of allergens to increase their effectiveness and reduce the risk of adverse events. Risk factors for allergic disease was a common theme in the epidemiology section and food allergy a common theme in clinical allergy with papers on the development of protocols to induce tolerance and attempts to find biomarkers to distinguish sensitization from allergic disease. This was another exciting year for the editors, and we hope the readers of the journal.

Exposure to acid-suppressing drugs during pregnancy and the risk of asthma in childhood: an observational cohort study

BACKGROUND

Some research has suggested a potential link between prenatal exposure to proton pump inhibitors (PPIs) or H2 -receptor antagonists (H2 RAs) and the development of childhood asthma.

AIM

To quantify the relative risk of asthma in children who experienced pre-natal exposure to PPIs and/or H2 RAs, adjusting for potential confounders.

METHODS

In this observational cohort study (NCT01787435), women aged 18-45 years with completed pregnancies between January 1996 and December 2010 were identified from The Health Improvement Network in the United Kingdom, and were linked to infants. Hazard ratios (HRs) were estimated using Cox proportional hazard models.

RESULTS

Our analysis identified 2371 prenatally exposed and 7745 unexposed infants. The incidence of asthma (per 1000 person-years) was 19.52 in the unexposed cohort, 23.88 in the PPI cohort and 32.16 in the H2 RA cohort. After adjusting for maternal healthcare utilisation during the year before pregnancy, the HR for asthma in infants whose mothers received prescriptions at any time during pregnancy was 1.12 (95% confidence interval: 0.88-1.44) for PPIs and 1.43 (1.20-1.70) for H2 RAs, when compared with unexposed infants. With further adjustment for maternal comorbidities and other medications, the HR for asthma was 1.03 (0.76-1.40) for PPIs and 1.32 (1.05-1.64) for H2 RAs.

CONCLUSIONS

Our analysis showed no association between prenatal exposure to PPIs and asthma in childhood after adjusting for confounders. The association found for H2 RAs may be explained largely by underlying environmental or genetic factors, as suggested by reductions in hazard ratio estimates following adjustment for maternal comorbidities.

Identification of Dutch children diagnosed with atopic diseases using prescription data: a validation study

Purpose

The aim of this study is to validate medication proxies for the identification of children diagnosed with atopic disorders that can be applied in various types of epidemiological research.

Methods

Records of 7439 children, aged between 0 and 10 years, in the period 2001 until 2010, were retrieved from the Registration Network Groningen database, a general practitioners database in the north-eastern part of the Netherlands. The sensitivity and positive predictive value (PPV) of 22 medication proxies for the identification of children diagnosed with atopic disorders (asthma, atopic dermatitis, and allergic rhinitis) were computed using the registered diagnoses as gold standards. In addition, different capture periods (1 year, half year, and length of study period) for the detection of prescriptions were tested for all the medication proxies.

Results

The highest PPV (0.84, 95 % CI 0.81–0.87) in combination with a sufficient sensitivity value (0.54, 95 % CI 0.50–0.57) for the identification of children diagnosed with asthma was yielded for the medication proxy, ≥2 prescriptions for anti-asthma medication within 1 year, including 1 inhaled steroid. PPV and sensitivity were even higher in the age group 6–10 years. The proxies designed for the identification of children diagnosed with atopic dermatitis and allergic rhinitis yielded only high PPVs (≥0.75) in combination with low sensitivity values (≤0.22). Altering the capture period for the detection of prescriptions to half a year or the length of the study period only affected sensitivity values.

Conclusion

Children diagnosed with asthma can be identified reliably with a range of medication proxies. The use of prescription data for the identification of children diagnosed with atopic dermatitis and allergic rhinitis is questionable.

Environmental and infectious factors in eosinophilic esophagitis

Identifying possible environmental or infectious etiologic factors for eosinophilic esophagitis (EoE) may offer insight into opportunities for disease prevention and treatment. We reviewed the current literature to assess environmental and infectious factors evaluated in EoE. Few studies have been conducted, however a consistent inverse association between EoE and H. pylori has been described. Several studies suggest a weak association between season and EoE diagnosis, but the evidence is inconclusive. EoE has also been associated with early life factors, including Cesarean delivery and antibiotic use. Larger studies are needed to evaluate these associations more thoroughly. Several papers have speculated the potential for anti-secretory agents to contribute to EoE. This has not been formerly evaluated. In summary, there is significant opportunity in the future to advance our understanding of possible environmental etiologic factors for EoE.

Prenatal exposure to H2 blockers and to proton pump inhibitors and asthma development in offspring

Fetal exposure to H2 blockers (H2 Bs) or proton pump inhibitors (PPIs) has been reported to be associated with asthma in children. We evaluated the risk of asthma in offspring following prenatal H2 Bs. We enrolled 91 428 children and their mothers who resided in southern Israel during 1998-2011. The computerized medications database was linked with records from the district hospital. Of the eligible children, 11 227 developed asthma, and overall 5.5% had been exposed to H2 Bs or PPIs prenatally. The risk of developing asthma was slightly higher in the group exposed to H2 Bs or PPIs (RR, 1.09; P = .023). At greater risk were children whose mothers purchased these medications more than 3 times (RR, 1.22; P = .038) or exposed to >20 defined daily doses or prenatally exposed to lansoprazole. The statistical association was significant and depended on magnitude of exposure and specific medication, but the absolute risk was low. The association between maternal consumption of H2 Bs or PPIs and asthma and childhood remained statistically significant 2 years after delivery, raising the possibility of confounding by the indication phenomenon. In view of the findings, a causal relationship could not be ascertained, and an unidentified etiological factor could be operative.

Healthy gut microbiota and long term health

This review summarises how the composition of the gastro-intestinal microbiota depends on pre- and postnatal factors, and birth itself. The impact of method of delivery, feeding during infancy and medications, such as antibiotics and anti-acid medication, on the composition of the gastro-intestinal microbiota has clearly been shown. However, the duration of the impact of these factors is not well established. The gastro-intestinal microbiome composition is associated with many auto-immune mediated diseases. Although causality has not been obviously demonstrated, there is a strong tendency in this direction. Nevertheless, results of the manipulation of the gastro-intestinal microbiome composition in these conditions are often disappointing. A better understanding on factors determining the longterm composition of the gastro-intestinal microbiome and its health consequences are a priority research topic. A better understanding of the association between the microbiome and the immune system may have a tremendous impact on general health.

Allergic airway diseases in childhood: an update

Complex multifactorial diseases such as allergic rhinitis and asthma are not only becoming an increasing burden to healthcare systems, but especially affect the life quality of children and families suffering from their allergic symptoms. Also physicians are challenged by the multifaceted diseases as their work involves not only the often difficult decisions on case-adapted diagnostics, treatment, and monitoring, but also possible preventive measures. This review gives an outline of the latest scientific developments related to the etiology, diagnosis, and management of allergic airway diseases in childhood, as well as prenatal and early life risk factors and strategies for prevention.