Exhaled Volatile Organic Compounds for Asthma Control Classification in Children with Moderate to Severe Asthma: Results from the SysPharmPediA Study.

RATIONALE: Early identification of children with poorly controlled asthma is imperative for optimizing treatment strategies. The analysis of exhaled volatile organic compounds (VOCs) is an emerging approach to identify prognostic and diagnostic biomarkers in pediatric asthma. OBJECTIVES: To assess the accuracy of gas chromatography-mass spectrometry based exhaled metabolite analysis to differentiate between controlled and uncontrolled pediatric asthma. METHODS: This study encompassed a discovery (SysPharmPediA) and validation phase (U-BIOPRED, PANDA). Firstly, exhaled VOCs that discriminated asthma control levels were identified. Subsequently, outcomes were validated in two independent cohorts. Patients were classified as controlled or uncontrolled, based on asthma control test scores and number of severe attacks in the past year. Additionally, potential of VOCs in predicting two or more future severe asthma attacks in SysPharmPediA was evaluated. MEASUREMENTS AND MAIN RESULTS: Complete data were available for 196 children (SysPharmPediA=100, U-BIOPRED=49, PANDA=47). In SysPharmPediA, after randomly splitting the population into training (n=51) and test sets (n=49), three compounds (acetophenone, ethylbenzene, and styrene) distinguished between uncontrolled and controlled asthmatics. The area under the receiver operating characteristic curve (AUROCC) for training and test sets were respectively: 0.83 (95% CI: 0.65-1.00) and 0.77 (95% CI: 0.58-0.96). Combinations of these VOCs resulted in AUROCCs of 0.74 ±0.06 (UBIOPRED) and 0.68 ±0.05 (PANDA). Attacks prediction tests, resulted in AUROCCs of 0.71 (95% CI 0.51-0.91) and 0.71 (95% CI 0.52-0.90) for training and test sets. CONCLUSIONS: Exhaled metabolites analysis might enable asthma control classification in children. This should stimulate further development of exhaled metabolites-based point-of-care tests in asthma.

Key risk factors of asthma-like symptoms are mediated through infection burden in early childhood.

BACKGROUND: Risk factors of asthma-like symptoms in childhood may act through an increased infection burden because infections often trigger these symptoms. OBJECTIVE: We sought to investigate whether the effect of established risk factors of asthma-like episodes in early childhood is mediated through burden and subtypes of common infections. METHODS: The study included 662 children from the Copenhagen Prospective Studies on Asthma in Childhood 2010 mother-child cohort, in which infections were registered prospectively in daily diaries from age 0 to 3 years. The association between established risk factors of asthma-like episodes and infection burden was analyzed by quasi-Poisson regressions, and mediation analyses were performed for significant risk factors. RESULTS: In the first 3 years of life, the children experienced a median of 16 (interquartile range, 12-23) infectious episodes. We found that the infection burden significantly (PACME < .05) mediated the association of maternal asthma (36.6% mediated), antibiotics during pregnancy (47.3%), siblings at birth (57.7%), an asthma exacerbation polygenic risk score (30.6%), and a bacterial airway immune score (80.2%) with number of asthma-like episodes, whereas the higher number of episodes from male sex, low birth weight, low gestational age, and maternal antibiotic use after birth was not mediated through an increased infection burden. Subtypes of infections driving the mediation were primarily colds, pneumonia, gastroenteritis, and fever, but not acute otitis media or acute tonsillitis. CONCLUSIONS: Several risk factors of asthma-like symptoms in early childhood act through an increased infection burden in the first 3 years of life. Prevention of infectious episodes may therefore be beneficial to reduce the burden of asthma-like symptoms in early childhood.

Urinary eicosanoid levels in early life and risk of atopic disease in childhood.

BACKGROUND: Eicosanoids are lipid mediators including thromboxanes (TXs), prostaglandins (PGs), and leukotrienes with a pathophysiological role in established atopic disease. However, their role in the inception of disease is unclear. This study aimed to investigate the association between urinary eicosanoids in early life and development of atopic disease. METHODS: This study quantified the levels of 21 eicosanoids in urine from children from the COPSAC2010 (Copenhagen Prospective Studies on Asthma in Childhood 2010) (age 1 year, n = 450) and VDAART (Vitamin D Antenatal Asthma Reduction Trial) (age 3 years, n = 575) mother-child cohorts and analyzed the associations with development of wheeze/asthma, atopic dermatitis, and biomarkers of type-2 inflammation, applying false discovery rate of 5% (FDR5%) multiple testing correction. RESULTS: In both cohorts, analyses adjusted for environmental determinants showed that higher TXA2 eicosanoids in early life were associated with increased risk of developing atopic dermatitis (P < FDR5%) and type-2 inflammation (P < .05). In VDAART, lower PGE2 and PGI2 eicosanoids and higher isoprostanes were also associated with increased risk of atopic dermatitis (P < FDR5%). For wheeze/asthma, analyses in COPSAC2010 showed that lower isoprostanes and PGF2 eicosanoids and higher PGD2 eicosanoids at age 1 year associated with an increased risk at age 1-10 years (P < .05), whereas analyses in VDAART showed that lower PGE2 and higher TXA2 eicosanoids at age 3 years associated with an increased risk at 6 years (P < FDR5%). CONCLUSIONS: This study suggests that early life perturbations in the eicosanoid metabolism are present before the onset of atopic disease in childhood, which provides pathophysiological insight in the inception of atopic diseases.

Genetic and T2 biomarkers linked to the efficacy of HDM sublingual immunotherapy in asthma.

BACKGROUND: Hypersensitivity to house dust mite (HDM) allergens is a common cause of allergic asthma symptoms and can be effectively treated with allergy immunotherapy (AIT). OBJECTIVE: To investigate whether genetic and type 2 (T2) inflammatory biomarkers correlate with disease severity in subjects with allergic asthma, and whether this can be modified by AIT. METHODS: MITRA (NCT01433523) was a phase III, randomised, double-blind, placebo-controlled trial of HDM sublingual immunotherapy (SLIT)-tablets in adults with HDM allergic asthma. Post hoc analyses of the study population (N=742) evaluated associations between T2 inflammatory (blood eosinophils, eosinophil cationic protein (ECP), total IgE and tryptase) and genetic (single-nucleotide polymorphisms, SNP) biomarkers (n=582) for the primary study endpoint (time to first moderate/severe asthma exacerbation). SNP associations were verified in HDM-positive subgroup from an independent 3-year Severe Asthma Research Programme (SARP3) subject cohort. RESULTS: An increased asthma exacerbation risk in subjects homozygous for SNP rs7216389 (chromosomal locus 17q12-21) was reduced (p=0.037) by treatment with HDM SLIT (HR=0.37 (95% CI 0.22 to 0.64), p<0.001). The associations between exacerbation risk and 17q12-21 SNPs were replicated in the SARP3 HDM-positive subgroup. High levels of T2 biomarkers were associated with increased risk of asthma exacerbations in the placebo group. HDM SLIT-tablet treatment reduced this risk (blood eosinophils: HR=0.50 (95% CI 0.30 to 0.85); ECP: HR=0.45 (95% CI 0.29 to 0.87); tryptase: HR=0.45 (95% CI 0.25 to 0.80)). The treatment effect was higher (p=0.006) for subjects with a higher number of elevated T2 biomarkers. CONCLUSIONS: HDM SLIT-tablet AIT is efficacious in HDM-sensitised asthma subjects with a genetic asthma predisposition and/or an underlying T2 endotype. TRIAL REGISTRATION NUMBER: NCT01433523.

Bacterial colonisation of the airway in neonates and risk of asthma and allergy until age 18†years.

BACKGROUND: We previously showed an association between neonatal bacterial airway colonisation and increased risk of persistent wheeze/asthma until age 5 years. Here, we study the association with persistent wheeze/asthma and allergy-related traits until age 18 years. METHODS: We investigated the association between airway colonisation with Streptococcus pneumoniae, Moraxella catarrhalis and/or Haemophilus influenzae in 1-month-old neonates from the COPSAC2000 mother-child cohort and the development of persistent wheeze/asthma and allergy-related traits longitudinally until age 18 years using generalised estimating equations. Replication was sought in the similarly designed COPSAC2010 cohort of 700 children. RESULTS: Neonatal airway colonisation was present in 66 (21%) out of 319 children and was associated with a 4-fold increased risk of persistent wheeze/asthma (adjusted OR 4.01 (95% CI 1.76-9.12); p<0.001) until age 7 years, but not from age 7 to 18 years. Replication in the COPSAC2010 cohort showed similar results using 16S data. Colonisation was associated with an increased number of exacerbations (adjusted incidence rate ratio 3.20 (95% CI 1.38-7.44); p<0.01) until age 7 years, but not from age 7 to 18 years. Colonisation was associated with increased levels of blood eosinophils (adjusted geometric mean ratio 1.24 (95% CI 1.06-1.44); p<0.01) and tumour necrosis factor (TNF)-α (adjusted geometric mean ratio 1.09 (95% CI 1.02-1.16); p=0.01) until age 12 years. There were no associations with lung function, bronchial reactivity, fractional exhaled nitric oxide, allergic sensitisation, total IgE or atopic dermatitis up to age 18 years. CONCLUSIONS: Neonatal airway colonisation was associated with early-onset persistent wheeze/asthma, exacerbations, elevated blood eosinophils and elevated TNF-α in blood, most prominent in early childhood, thereafter diminishing and no longer evident by age 18 years.

European Respiratory Society Statement on preschool wheezing disorders: updated definitions, knowledge gaps, and proposed future research directions.

Since the publication of the European Respiratory Society (ERS) Task Force reports on the management of preschool wheezing in 2008 and 2014, a large body of evidence has accumulated suggesting the clinical phenotypes that were proposed, episodic (viral) wheezing and multiple-trigger wheezing, do not relate to underlying airway pathology and may not help determine response to treatment. Specifically, using clinical phenotypes alone may no longer be appropriate, and new approaches that can be used to inform clinical care are needed for future research. This ERS Task Force reviewed the literature published after 2008 related to preschool wheezing and has suggested the criteria used to define wheezing disorders in preschool children should include age of diagnosis (0 to <6 years), confirmation of wheezing on at least one occasion, and more than one episode of wheezing ever.Furthermore, diagnosis and management may be improved by identifying treatable traits, including inflammatory biomarkers (blood eosinophils, aeroallergen sensitisation) associated with type-2 immunity and differential response to inhaled corticosteroids, lung function parameters, and airway infection. However, more comprehensive use of biomarkers/treatable traits in predicting the response to treatment requires prospective validation. There is evidence that specific genetic traits may help guide management, but these must be adequately tested. In addition, the Task Force identified an absence of caregiver-reported outcomes, caregiver/self-management options, and features that should prompt specialist referral for this age group. Priorities for future research include a focus on identifying i) mechanisms driving preschool wheezing, ii) biomarkers of treatable traits and efficacy of interventions in those without allergic sensitisation/eosinophilia, iii) the need to include both objective outcomes and caregiver-reported outcomes in clinical trials, iv) the need for a suitable action plan for children with preschool wheezing and v) a definition of severe/difficult-to-treat preschool wheezing.

Genetic predisposition to high BMI increases risk of early life respiratory infections and episodes of severe wheeze and asthma.

BACKGROUND: High BMI is an established risk factor for asthma, but the underlying mechanisms remain unclear.Objective: To increase understanding of the BMI-asthma relationship by studying the association between genetic predisposition to higher body mass index (BMI) and asthma, infections, and other asthma-traits during childhood. METHODS: Data was obtained from the two ongoing COPSAC mother-child cohorts. Polygenic risk score (PRS) for adult BMI were calculated for each child. Replication was done in the large-scale iPSYCH cohort using data on hospitalization for asthma and infections. RESULTS: In the COPSAC cohorts (n=974), the adult BMI PRS was significantly associated with lower respiratory tract infections (LRTI) (IRR 1.20 95% CI 1.08-1.33, FDR=0.005) age 0-3 years and episodes of severe wheeze (IRR 1.30, 1.06-1.60, FDR=0.04) age 0-6 years. LRTI partly mediated the association between the adult BMI PRS and severe wheeze (proportion mediated: 0.59, 0.28-2.24, pACME 2E-16). In contrast, these associations were not mediated through the child's current BMI and the PRS was not associated with an asthma diagnosis or reduced lung function up to age 18. The associations were replicated in iPSYCH (n=114 283), where the adult BMI PRS significantly increased the risk of hospitalizations for LRTI and wheeze or asthma during childhood to age 18 years. CONCLUSION: Children with genetic predisposition to higher BMI had increased risk of LRTI and severe wheeze, independent of the child's current BMI. These results shed further light on the complex relationship between BMI and asthma.

Sphingolipid classes and the interrelationship with pediatric asthma and asthma risk factors.

BACKGROUND: While dysregulated sphingolipid metabolism has been associated with risk of childhood asthma, the specific sphingolipid classes and/or mechanisms driving this relationship remain unclear. We aimed to understand the multifaceted role between sphingolipids and other established asthma risk factors that complicate this relationship. METHODS: We performed targeted LC-MS/MS-based quantification of 77 sphingolipids in plasma from 997 children aged 6 years from two independent cohorts (VDAART and COPSAC2010 ). We examined associations of circulatory sphingolipids with childhood asthma, lung function, and three asthma risk factors: functional SNPs in ORMDL3, low vitamin D levels, and reduced gut microbial maturity. Given racial differences between these cohorts, association analyses were performed separately and then meta-analyzed together. RESULTS: We observed elevations in circulatory sphingolipids with asthma phenotypes and risk factors; however, there were differential associations of sphingolipid classes with clinical outcomes and/or risk factors. While elevations from metabolites involved in ceramide recycling and catabolic pathways were associated with asthma and worse lung function [meta p-value range: 1.863E-04 to 2.24E-3], increased ceramide levels were associated with asthma risk factors [meta p-value range: 7.75E-5 to .013], but not asthma. Further investigation identified that some ceramides acted as mediators while some interacted with risk factors in the associations with asthma outcomes. CONCLUSION: This study demonstrates the differential role that sphingolipid subclasses may play in asthma and its risk factors. While overall elevations in sphingolipids appeared to be deleterious overall; elevations in ceramides were uniquely associated with increases in asthma risk factors only; while elevations in asthma phenotypes were associated with recycling sphingolipids. Modification of asthma risk factors may play an important role in regulating sphingolipid homeostasis via ceramides to affect asthma. Further function work may validate the observed associations.

Maternal inflammation during pregnancy is associated with risk of ADHD in children at age 10.

INTRODUCTION: Maternal inflammation during pregnancy may affect early neurodevelopment in offspring as suggested by preclinical and register data. However, clinical evidence for risk of aberrant neurodevelopment later in childhood is scarce. In the population-based COPSAC2010 mother-child cohort, we investigated associations between maternal inflammation levels during pregnancy and the risk of a diagnosis of ADHD as well as the load of ADHD symptoms in the children at age 10. METHODS: The COPSAC2010 cohort consists of 700 mother-child pairs followed prospectively since pregnancy week 24.Maternal high-sensitivity C-Reactive Protein (hs-CRP) level at week 24 of gestation was investigated in relation to child neurodevelopment by age 10 using logistic and linear regression models with extensive confounder adjustment, including socioeconomic status and maternal polygenic risk of ADHD. The children completed a comprehensive examination of neurodevelopment including categorical (i.e., diagnostic) and dimensional (i.e., symptom load) psychopathology using the Kiddie Schedule for Affective Disorders and Schizophrenia Present and Lifetime Version (K-SADS-PL) and parental rated ADHD-Rating Scale (ADHD-RS). RESULTS: A total of 604 (86 %) of the 700 children in the COPSAC2010 cohort participated in the COPSYCH visit at age 10. Sixty-five (10.8 %) fulfilled a research diagnosis of ADHD (16 girls and 49 boys). Higher maternal hs-CRP level in pregnancy at week 24 (median 5.4 mg/L) was significantly associated with increased risk for a diagnosis of ADHD, adjusted OR 1.40, 95 %CI (1.16-1.70), p = 0.001. Additionally, higher maternal hs-CRP was associated with increased ADHD symptom load in the entire cohort, reflected by ADHD-RS raw scores. DISCUSSION: These clinical data demonstrated a robust association of prenatal maternal inflammation assessed by hs-CRP with a diagnosis of ADHD by age 10. Moreover, maternal inflammation was associated with ADHD symptom load in the complete cohort. Identifying inflammation as an important marker will provide a potential target for future increased awareness and prevention during pregnancy thereby ultimately improving neurodevelopmental outcomes in children.

Preventive effects of prenatal administration of OM-85/BV on asthma and respiratory infection risk in the offspring: A review of animal models.

Asthma is the most common chronic disease in childhood affecting the daily lives of many patients despite current treatment regimens. Therefore, the need for new therapeutic approaches is evident, where a primary prevention strategy is the ultimate goal. Studies of children born to mothers in farming environments have shown a lower risk of respiratory infections and asthma development. Already at birth, these newborns have demonstrated accelerated maturation and upregulation of host defense immune functions suggesting a prenatal transplacental training of the innate immune system through maternal microbial exposure. This mechanism could possibly be utilized to help prevent both respiratory infections and asthma in young children. Human studies exploring the potential preventative effects of pregnancy bacterial lysate treatment on asthma and respiratory infections are lacking, however, this has been studied in experimental studies using mice through administrations of the bacterial lysate OM-85. This review will present the current literature on the immunomodulatory effects relevant for respiratory infections and asthma in the offspring of mice treated with OM-85 throughout pregnancy. Further, the review will discuss the cellular and molecular mechanisms behind these effects. In conclusion, we found promising results of an accelerated immune competence and improved resistance to airway challenges as a result of prenatal bacterial lysate treatment that may pave the way for implementing this in human trials to prevent asthma and respiratory infections.

A systematic review and meta-analysis on absolute eosinophil counts and the risk of asthma in preschool children with wheezing: An EAACI Task Force Report.

Preschool children with wheezing disorders pose diagnostic and therapeutic challenges and consume substantial healthcare resources. Peripheral eosinophil blood count (EBC) has been proposed as a potential indicator for future asthma development. This review by the European Academy of Allergy and Clinical Immunology (EAACI) Preschool Wheeze Task Force aimed to provide systematic evidence for the association between increased EBC and the risk of future asthma, as well as to identify potential cutoff values. In February 2023, a search of PubMed, EMBASE, and Cochrane Library databases was conducted to identify studies comparing EBCs in preschool children with wheezing who continued to wheeze later in life and those who did not. Included observational studies focused on children aged <6 years with a wheezing disorder, assessment of their EBCs, and subsequent asthma status. No language or publication date restrictions were applied. Among the initial 3394 studies screened, 10 were included in the final analysis, involving 1225 patients. The data from these studies demonstrated that high EBC in preschool children with wheezing is associated with future asthma development, with odds ratios of 1.90 (95% CI: 0.45-7.98, p = .38), 2.87 (95% CI: 1.38-5.95, p < .05), and 3.38 (95% CI: 1.72-6.64, p < .05) for cutoff values in the <300, 300-449, and ≥450 cells/µL ranges, respectively. Defining a specific cutoff point for an elevated EBC lacks consistency, but children with EBC >300 cells/µL are at increased risk of asthma. However, further research is needed due to the limitations of the included studies. Future investigations are necessary to fully elucidate the discussed association.

Oropharyngeal Microbiota Clusters in Children with Asthma or Wheeze Associate with Allergy, Blood Transcriptomic Immune Pathways, and Exacerbation Risk.

Rationale: Children with preschool wheezing or school-age asthma are reported to have airway microbial imbalances. Objectives: To identify clusters in children with asthma or wheezing using oropharyngeal microbiota profiles. Methods: Oropharyngeal swabs from the U-BIOPRED (Unbiased Biomarkers for the Prediction of Respiratory Disease Outcomes) pediatric asthma or wheezing cohort were characterized using 16S ribosomal RNA gene sequencing, and unsupervised hierarchical clustering was performed on the Bray-Curtis ß-diversity. Enrichment scores of the Molecular Signatures Database hallmark gene sets were computed from the blood transcriptome using gene set variation analysis. Children with severe asthma or severe wheezing were followed up for 12-18 months, with assessment of the frequency of exacerbations. Measurements and Main Results: Oropharyngeal samples from 241 children (age range, 1-17 years; 40% female) revealed four taxa-driven clusters dominated by Streptococcus, Veillonella, Rothia, and Haemophilus. The clusters showed significant differences in atopic dermatitis, grass pollen sensitization, FEV1% predicted after salbutamol, and annual asthma exacerbation frequency during follow-up. The Veillonella cluster was the most allergic and included the highest percentage of children with two or more exacerbations per year during follow-up. The oropharyngeal clusters were different in the enrichment scores of TGF-ß (transforming growth factor-ß) (highest in the Veillonella cluster) and Wnt/ß-catenin signaling (highest in the Haemophilus cluster) transcriptomic pathways in blood (all q values <0.05). Conclusions: Analysis of the oropharyngeal microbiota of children with asthma or wheezing identified four clusters with distinct clinical characteristics (phenotypes) that associate with risk for exacerbation and transcriptomic pathways involved in airway remodeling. This suggests that further exploration of the oropharyngeal microbiota may lead to novel pathophysiologic insights and potentially new treatment approaches.

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.

Environmental and genetic associations with aberrant early-life gut microbial maturation in childhood asthma.

BACKGROUND: Environmental, genetic, and microbial factors are independently associated with childhood asthma. OBJECTIVE: We sought to determine the roles of environmental exposures and 17q12-21 locus genotype in the maturation of the early-life microbiome in childhood asthma. METHODS: We analyzed fecal 16s rRNA sequencing at age 3 to 6 months and age 1 year to characterize microbial maturation of offspring of participants in the Vitamin D Antenatal Reduction Trial. We determined associations of microbial maturation and environmental exposures in the mediation of asthma risk at age 3 years. We examined 17q12-21 genotype and microbial maturation associations with asthma risk in Vitamin D Antenatal Reduction Trial and the replication cohort Copenhagen Prospective Studies on Childhood Asthma 2010. RESULTS: Accelerated fecal microbial maturation at age 3 to 6 months and delayed maturation at age 1 year were associated with asthma (P < .001). Fecal Bacteroides was reduced at age 3 to 6 months in association with subsequent asthma (P = .006) and among subjects with lower microbial maturation at age 1 year (q = 0.009). Sixty-one percent of the association between breast-feeding and asthma was mediated by microbial maturation at age 3 to 6 months. Microbial maturation and 17q12-21 genotypes exhibited independent, additive effects on childhood asthma risk. CONCLUSIONS: The intestinal microbiome and its maturation mediates associations between environmental exposures including breast-feeding and asthma. The intestinal microbiome and 17q12-21 genotype appear to exert additive and independent effects on childhood asthma risk.

Prenatal exposure to ambient air pollution is associated with early life immune perturbations.

BACKGROUND: Exposure to ambient air pollution has been linked to asthma, allergic rhinitis, and other inflammatory disorders, but little is known about the underlying mechanisms. OBJECTIVE: We studied the potential mechanisms leading from prenatal ambient air pollution exposure to asthma and allergy in childhood. METHODS: Long-term exposure to nitrogen dioxide (NO2) as well as to particulate matter with a diameter of ≤2.5 and ≤10 µm (PM2.5 and PM10) were modeled at the residence level from conception to 6 years of age in 700 Danish children followed clinically for development of asthma and allergy. Nasal mucosal immune mediators were assessed at age 4 weeks and 6 years, inflammatory markers in blood at 6 months, and nasal epithelial DNA methylation and gene expression at age 6 years. RESULTS: Higher prenatal air pollution exposure with NO2, PM2.5, and PM10 was associated with an altered nasal mucosal immune profile at 4 weeks, conferring an increased odds ratio [95% confidence interval] of 2.68 [1.58, 4.62] for allergic sensitization and 2.63 [1.18, 5.81] for allergic rhinitis at age 6 years, and with an altered immune profile in blood at age 6 months conferring increased risk of asthma at age 6 years (1.80 [1.18, 2.76]). Prenatal exposure to ambient air pollution was not robustly associated with immune mediator, epithelial DNA methylation, or gene expression changes in nasal cells at age 6 years. CONCLUSION: Prenatal exposure to ambient air pollution was associated with early life immune perturbations conferring risk of allergic rhinitis and asthma. These findings suggest potential mechanisms of prenatal exposure to ambient air pollution on the developing immune system.

Maternal vitamin D-related metabolome and offspring risk of asthma outcomes.

BACKGROUND: Gestational vitamin D deficiency is implicated in development of respiratory diseases in offspring, but the mechanism underlying this relationship is unknown. OBJECTIVE: We sought to study the link between gestational vitamin D exposure and childhood asthma phenotypes using maternal blood metabolomics profiling. METHODS: Untargeted blood metabolic profiles were acquired using liquid chromatography-mass spectrometry at 1 week postpartum from 672 women in the Copenhagen Prospective Studies on Asthma in Childhood2010 (COPSAC2010) mother-child cohort and at pregnancy weeks 32 to 38 from 779 women in the Vitamin D Antenatal Asthma Reduction Trial (VDAART) mother-child cohort. In COPSAC2010, we employed multivariate models and pathway enrichment analysis to identify metabolites and pathways associated with gestational vitamin D blood levels and investigated their relationship with development of asthma phenotypes in early childhood. The findings were validated in VDAART and in cellular models. RESULTS: In COPSAC2010, higher vitamin D blood levels at 1 week postpartum were associated with distinct maternal metabolome perturbations with significant enrichment of the sphingomyelin pathway (P < .01). This vitamin D-related maternal metabolic profile at 1 week postpartum containing 46 metabolites was associated with decreased risk of recurrent wheeze (hazard ratio [HR] = 0.92 [95% CI 0.86-0.98], P = .01) and wheeze exacerbations (HR = 0.90 [95% CI 0.84-0.97], P = .01) at ages 0 to 3 years. The same metabolic profile was similarly associated with decreased risk of asthma/wheeze at ages 0 to 3 in VDAART (odds ratio = 0.92 [95% CI 0.85-0.99], P = .04). Human bronchial epithelial cells treated with high-dose vitamin D3 showed an increased cytoplasmic sphingolipid level (P < .01). CONCLUSIONS: This exploratory metabolomics study in 2 independent birth cohorts demonstrates that the beneficial effect of higher gestational vitamin D exposure on offspring respiratory health is characterized by specific maternal metabolic alterations during pregnancy, which involves the sphingomyelin pathway.

Association of Asthma Risk Alleles With Acute Respiratory Tract Infections and Wheezing Illnesses in Young Children.

BACKGROUND: Genome-wide association studies have identified several risk alleles for early childhood asthma, particularly in the 17q21 locus and in the cadherin-related family member 3 (CDHR3) gene. Contribution of these alleles to the risk of acute respiratory tract infections (ARI) in early childhood is unclear. METHODS: We analyzed data from the STEPS birth-cohort study of unselected children and the VINKU and VINKU2 studies on children with severe wheezing illness. Genome-wide genotyping was performed on 1011 children. We analyzed the association between 11 preselected asthma risk alleles and the risk of ARIs and wheezing illnesses of various viral etiologies. RESULTS: The asthma risk alleles in CDHR3, GSDMA, and GSDMB were associated with an increased rate of ARIs (for CDHR3, incidence rate ratio [IRR], 1.06; 95% confidence interval [CI], 1.01-1.12; P = .02), and risk allele in CDHR3 gene with rhinovirus infections (IRR, 1.10; 95% CI, 1.01-1.20, P = .03). Asthma risk alleles in GSDMA, GSDMB, IKZF3, ZPBP2, and ORMDL3 genes were associated with wheezing illnesses in early childhood, especially rhinovirus-positive wheezing illnesses. CONCLUSIONS: Asthma risk alleles were associated with an increased rate of ARIs and an increased risk of viral wheezing illnesses. Nonwheezing and wheezing ARIs and asthma may have shared genetic risk factors. Clinical Trials Registration. NCT00494624 and NCT00731575.

Supplementation With Fish Oil in Pregnancy Reduces Gastroenteritis in Early Childhood.

BACKGROUND: We hypothesized that insufficient intake of fish oil-derived omega-3 long-chain polyunsaturated fatty acids (n-3 LCPUFAs) during pregnancy is a contributing factor to gastroenteritis in early childhood. We examined the effect of n-3 LCPUFA supplementation on gastroenteritis symptoms in the offspring's first 3 years of life. METHODS: This was a double-blinded, randomized controlled trial whereby 736 mothers were administered n-3 LCPUFA or control from pregnancy week 24 until 1 week after birth. We measured the number of days with gastroenteritis, number of episodes with gastroenteritis, and the risk of having a gastroenteritis episode in the first 3 years of life. RESULTS: A median reduction of 2.5 days with gastroenteritis (P = .018) was shown, corresponding to a 14% reduction in the n-3 LCPUFA group compared with controls in the first 3 years of life (P = .037). A reduction in the number of gastroenteritis episodes (P = .027) and a reduced risk of having an episode (hazard ratio, 0.80 [95% confidence interval, .66-.97]; P = .023) were also shown. CONCLUSIONS: Fish oil supplementation from the 24th week of pregnancy led to a reduction in the number of days and episodes with gastroenteritis symptoms in the first 3 years of life. The findings suggest n-3 LCPUFA supplementation as a preventive measure against gastrointestinal infections in early childhood. CLINICAL TRIALS REGISTRATION: NCT00798226.

Atopic and non-atopic effects of fish oil supplementation during pregnancy.

BACKGROUND: We recently conducted a double-blinded randomised controlled trial showing that fish-oil supplementation during pregnancy reduced the risk of persistent wheeze or asthma in the child by 30%. Here, we explore the mechanisms of the intervention. METHODS: 736 pregnant women were given either placebo or n-3 long-chain polyunsaturated fatty acids (LCPUFAs) in the third trimester in a randomised controlled trial. Deep clinical follow-up of the 695 children in the trial was done at 12 visits until age 6 years, including assessment of genotype at the fatty acid desaturase (FADS) locus, plasma fatty acids, airway DNA methylation, gene expression, microbiome and metabolomics. RESULTS: Supplementation with n-3 LCPUFA reduced the overall risk of non-atopic asthma by 73% at age 6 (relative risk (RR) 0.27 (95% CI 0.06 to 0.85), p=0.042). In contrast, there was no overall effect on asthma with atopic traits (RR 1.42 (95% CI 0.63 to 3.38), p=0.40), but this was significantly modified by maternal FADS genotype and LCPUFA blood levels (interaction p<0.05), and supplementation did reduce the risk of atopic asthma in the subgroup of mothers with FADS risk variants and/or low blood levels of n-3 LCPUFA before the intervention (RR 0.31 (95% CI 0.11 to 0.75), p=0.016). Furthermore, n-3 LCPUFA significantly reduced the number of infections (croup, gastroenteritis, tonsillitis, otitis media and pneumonia) by 16% (incidence rate ratio 0.84 (95% CI 0.74 to 0.96), p=0.009). CONCLUSIONS: n-3 LCPUFA supplementation in pregnancy showed protective effects on non-atopic asthma and infections. Protective effects on atopic asthma depended on maternal FADS genotype and n-3 LCPUFA levels. This indicates that the fatty acid pathway is involved in multiple mechanisms affecting the risk of asthma subtypes and infections. TRIAL REGISTRATION NUMBER: NCT00798226.

Fungi and bacteria in the beds of rural and urban infants correlate with later risk of atopic diseases.

INTRODUCTION: Rural children have a lower risk of asthma and atopic diseases than urban children. However, whether indoor microbiota in non-farming rural homes provides protection is unclear. METHODS: Here, we examine if microbes in the beds of rural and urban infants are associated with later development of atopic diseases. We studied fungi and bacteria in the beds of 6-month-old infants (n = 514) in association with the risk of asthma, allergic rhinitis, eczema and aeroallergen sensitization at 6 years of age in the prospective COPSAC2010 cohort. RESULTS: Both fungal and bacterial diversity were lower in the beds of children, who later developed allergic rhinitis (-0.22 [-0.43,-0.01], padj = .04 and -.24 [-0.42,-0.05], padj = .01 respectively) and lower bacterial richness was discovered in beds of children later developing asthma (-41.34 [-76.95,-5.73], padj = .02) or allergic rhinitis (-45.65 [-81.19,-10.10], padj = .01). Interestingly, higher fungal diversity and richness were discovered in the beds of children developing eczema (0.23 [0.02,0.43], padj = .03 and 29.21 [1.59,56.83], padj = .04 respectively). We defined a limited set of fungal and bacterial genera that predicted rural/urban environment. Some rural-associated bacterial genera such as Romboutsia and Bacillus and fungal genera Spegazzinia and Physcia were also associated with reduced risk of diseases, including eczema. These fungal and bacterial fingerprints predicting the living environment were associated with asthma and allergic rhinitis, but not eczema, with rural compositions being protective. The bed dust bacteria mediated 27% of the protective association of a rural living environment for allergic rhinitis (p = .04). CONCLUSIONS: Bed dust microbes can be differentially associated with airway- and skin-related diseases. The differing bed dust microbiota between rural and urban infants may influence their later risk of asthma and allergic rhinitis.