Phenotypes of wheezing and asthma in preschool children

Environmental exposures associated with early childhood recurrent wheezing in the mother and child in the environment birth cohort: a time-to-event study

BACKGROUND

Antenatal factors and environmental exposures contribute to recurrent wheezing in early childhood.

AIM

To identify antenatal and environmental factors associated with recurrent wheezing in children from birth to 48 months in the mother and child in the environment cohort, using time-to-event analysis.

METHOD

Maternal interviews were administered during pregnancy and postnatally and children were followed up from birth to 48 months (May 2013-October 2019). Hybrid land-use regression and dispersion modelling described residential antenatal exposure to nitrogen dioxide (NO2) and particulate matter of 2.5 µm diameter (PM2.5). Wheezing status was assessed by a clinician. The Kaplan-Meier hazard function and Cox-proportional hazard models provided estimates of risk, adjusting for exposure to environmental tobacco smoke (ETS), maternal smoking, biomass fuel use and indoor environmental factors.

RESULTS

Among 520 mother-child pairs, 85 (16%) children, had a single wheeze episode and 57 (11%) had recurrent wheeze. Time to recurrent wheeze (42.9 months) and single wheeze (37.8 months) among children exposed to biomass cooking fuels was significantly shorter compared with children with mothers using electricity (45.9 and 38.9 months, respectively (p=0.03)). Children with mothers exposed to antenatal ETS were 3.8 times more likely to have had recurrent wheeze compared with those not exposed (adjusted HR 3.8, 95% CI 1.3 to 10.7). Mean birth month NO2 was significantly higher among the recurrent wheeze category compared with those without wheeze. NO2 and PM2.5 were associated with a 2%-4% adjusted increased wheezing risk.

CONCLUSION

Control of exposure to ETS and biomass fuels in the antenatal period is likely to delay the onset of recurrent wheeze in children from birth to 48 months.

A Review of the Latest Guidelines for Diagnosing and Managing Asthma in Children in the United States and Canada

Globally, asthma remains the most widespread chronic respiratory condition in children, with a larger proportion of children being affected by the condition. Regardless of the higher prevalence rates, the outcomes of pediatric asthma have remained inadequate, even as there are numerous preventable deaths (approximately 300 children in the United States and 250 children in Canada, annually). The characteristic symptoms of pediatric asthma include wheezing, cough, and shortness of breath that are characteristically triggered by several potential stimuli. However, several diagnostic challenges exist and have resulted in either overdiagnosis or underdiagnosis, making pediatric asthma diagnosis and management problematic. Effective management of asthma in children entails a holistic approach that encompasses non-pharmacological and pharmacological management, alongside self-management and educational aspects. Working with pediatric asthma patients and their families/caregivers is vital to promoting and realizing better asthma diagnosis and management outcomes. Educational guidelines regarding the best ways for effective treatment, avoidance of triggers, modifiable risk factors, and the actions that should be taken during chronic asthma attacks through individualized action plans are vital. Thus, the objective of this systematic review is to provide an overview of the latest guidelines on pediatric asthma diagnosis and management. In this regard, this review presents several similarities in existing pediatric asthma diagnosis and management guidelines in the United States and Canada. For instance, most guidelines and studies reviewed have proposed the use of objective tests for confirmation of asthma diagnosis, particularly in symptomatic individuals. The peak flow variability measurement, bronchodilator reversibility testing, and spirometry have also been proposed by the guidelines and studies, even as the recommendations regarding the timing and hierarchy of the objective test substantially vary between the guidelines and studies. We hope that the present review will be helpful to physicians and healthcare service providers working within pediatric health contexts.

Clinical features and later prognosis of replicable early-life wheeze clusters from two birth cohorts 12 years apart

BACKGROUND

Clustering techniques can define the heterogeneity of asthma and wheezing. Defining early-life wheezing clusters and associated asthma risk could potentially inform patient management strategies. Clustering models that yield replicable cluster groups will have greater validity and clinical utility. This study sought to identify early-life wheezing clusters that are translatable into clinical practice and assess their stability over time in two whole-population birth cohorts established a decade apart from the same geographical location.

METHODS

Nonparametric K-means cluster analysis was performed separately on two birth cohorts from the Isle of Wight, UK; the Isle of Wight Birth Cohort (IOWBC) and Food Allergy and Intolerance Research Cohort (FAIR), using clinically defining variables in wheezing subjects in the first 3-4 years. Associations of resulting clusters with potential early-life risk factors and 10-year asthma outcomes were further assessed.

RESULTS

Five clusters were identified in both cohorts: (1) infantile-onset-transient-non-atopic-wheeze, (2) infantile-onset-persistent-non-atopic-wheeze, (3) infantile-onset-atopic-wheeze, (4) early-childhood-onset-non-atopic-wheeze, and (5) early-childhood-onset-atopic-wheeze. Two atopic wheezing clusters (3 and 5) were associated with greatest early-life wheeze frequency, highest wheeze persistence, and asthma prevalence at 10 years. Cluster 1 was commonest but had lowest early-life wheeze frequency and asthma prevalence at 10 years. Cluster 2, characterized by limited atopy but recurrent infantile respiratory infections and ongoing early-life wheezing, had high 10-year asthma prevalence only in IOWBC.

CONCLUSIONS

Early-life wheeze comprises several disease clusters (two more severe and three mild-moderate) with differing relationships to later childhood asthma, which can be replicated over time supporting their potential validity and clinical utility.

Network analyses of upper and lower airway transcriptomes identify shared mechanisms among children with recurrent wheezing and school-age asthma

Background

Predicting which preschool children with recurrent wheezing (RW) will develop school-age asthma (SA) is difficult, highlighting the critical need to clarify the pathogenesis of RW and the mechanistic relationship between RW and SA. Despite shared environmental exposures and genetic determinants, RW and SA are usually studied in isolation. Based on network analysis of nasal and tracheal transcriptomes, we aimed to identify convergent transcriptomic mechanisms in RW and SA.

Methods

RNA-sequencing data from nasal and tracheal brushing samples were acquired from the Gene Expression Omnibus. Combined with single-cell transcriptome data, cell deconvolution was used to infer the composition of 18 cellular components within the airway. Consensus weighted gene co-expression network analysis was performed to identify consensus modules closely related to both RW and SA. Shared pathways underlying consensus modules between RW and SA were explored by enrichment analysis. Hub genes between RW and SA were identified using machine learning strategies and validated using external datasets and quantitative reverse transcription-polymerase chain reaction (qRT-PCR). Finally, the potential value of hub genes in defining RW subsets was determined using nasal and tracheal transcriptome data.

Results

Co-expression network analysis revealed similarities in the transcriptional networks of RW and SA in the upper and lower airways. Cell deconvolution analysis revealed an increase in mast cell fraction but decrease in club cell fraction in both RW and SA airways compared to controls. Consensus network analysis identified two consensus modules highly associated with both RW and SA. Enrichment analysis of the two consensus modules indicated that fatty acid metabolism-related pathways were shared key signals between RW and SA. Furthermore, machine learning strategies identified five hub genes, i.e., CST1, CST2, CST4, POSTN, and NRTK2, with the up-regulated hub genes in RW and SA validated using three independent external datasets and qRT-PCR. The gene signatures of the five hub genes could potentially be used to determine type 2 (T2)-high and T2-low subsets in preschoolers with RW.

Conclusions

These findings improve our understanding of the molecular pathogenesis of RW and provide a rationale for future exploration of the mechanistic relationship between RW and SA.

The Use of Bacterial Lysate for the Prevention of Wheezing Episodes in Preschool Children: A Cost-Utility Analysis

BACKGROUND

Although increasing recent evidence has shown the efficacy of bacterial lysate therapy for the prevention of wheezing episodes and asthma exacerbations in pediatric patients, evidence of its cost-effectiveness in preschool patients is scarce.

OBJECTIVES

To evaluate the cost-utility of bacterial lysate therapy as an add-on to standard care of preschool children with recurrent wheezing.

METHODS

To achieve the objectives of the study, we used a Markov simulation model with 3 mutually exclusive nonabsorbent states (regular Markov chain). Effectiveness parameters were obtained from a recent systematic review of the literature with meta-analyses (5 randomized controlled trials, 433 children). Cost data were obtained from hospital bills and from the national manual of drug prices in Colombia. The study was carried out from the perspective of the national health care system in Colombia. The main outcome of the model was quality-adjusted life-years. To assess the robustness of the model's results, we performed deterministic and probabilistic sensitivity analysis.

RESULTS

Compared with standard care, bacterial lysate add-on therapy to standard care was associated with lower overall treatment costs (US $694.03 vs $830.71 average cost per patient) and the greatest gain in QALYs (0.9211 vs 0.9154 QALYs on average per patient), thus showing dominance.

CONCLUSIONS

In Colombia, compared with standard care, bacterial lysate add-on therapy to standard care for treating preschool children with recurrent wheezing is a dominant strategy because it showed a greater gain in QALYs at lower total treatment costs.

Diagnosis and management of asthma in infants and preschoolers

Asthma is one of the most common chronic disease affecting children, and it often starts in infancy and preschool years. In previous birth cohorts, frequent wheezing in early life was associated with the development of asthma in later childhood and reduced lung function persisting into adulthood. Preschool wheezing is considered an umbrella term for distinctive diseases with different clinical features (phenotypes), each of which may be related to different underlying pathophysiologic mechanisms (endotypes). The classification of phenotypes of early wheezing is needed to identify children at high risk for developing asthma later who might benefit from early intervention. However, diagnosis of asthma in infants and preschoolers is particularly difficult because objective lung function tests cannot be performed and definitive biomarkers are lacking. Moreover, management of early asthma is challenging because of its different phenotypic presentations. Many prediction models and asthma guidelines have been developed to provide useful information for physicians to assess young children with recurrent wheezing and manage them appropriately. Many recent studies have investigated the application of personalized medicine for early asthma by identifying specific phenotypes and biomarkers. Further researches, including genetic and molecular studies, are needed to establish a clear definition of asthma and develop more targeted therapeutic approaches in this age group.

Identification of potential key genes for immune infiltration in childhood asthma by data mining and biological validation

Asthma is the most common chronic condition among children; however, the underlying molecular mechanism remains unclear. Dysregulated immune response and different infiltration states of immune cells are critical for asthma pathogenesis. Here, three childhood asthma gene expression datasets were used to detect key genes, immune cells, and pathways involved in childhood asthma. From these datasets, 33 common differentially expressed genes (DEGs) were identified, which showed enrichment in the T helper 1 (Th1) and T helper 2 (Th2) cell differentiation pathway and the T helper 17 (Th17) cell differentiation pathway. Using the weighted gene co-expression network analysis (WGCNA), CD3D and CD3G were identified as key genes closely correlated with childhood asthma. Upregulation of CD3D and CD3G was further validated in bronchoalveolar lavage cells from childhood asthmatics with control individuals by quantitative reverse transcription-polymerase chain reaction (qRT-PCR). The immune cell infiltration analysis indicated that CD3D and CD3G were negatively correlated with increased resting mast cells and eosinophils, and highly correlated with several cell markers of Th1, Th2, and Th17 cells. In addition, we found that CD3D and CD3G were closely related to the Th1 and Th2 cell differentiation pathway and the Th17 cell differentiation pathway. Our results reveal the important roles of two key genes and immune infiltration in the pathogenesis of childhood asthma. Thus, this study provides a new perspective for exploring potential molecular targets for childhood asthma treatment.

Management of asthma in childhood: study protocol of a systematic evidence update by the Paediatric Asthma in Real Life (PeARL) Think Tank

INTRODUCTION

Clinical recommendations for childhood asthma are often based on data extrapolated from studies conducted in adults, despite significant differences in mechanisms and response to treatments. The Paediatric Asthma in Real Life (PeARL) Think Tank aspires to develop recommendations based on the best available evidence from studies in children. An overview of systematic reviews (SRs) on paediatric asthma maintenance management and an SR of treatments for acute asthma attacks in children, requiring an emergency presentation with/without hospital admission will be conducted.

METHODS AND ANALYSIS

Standard methodology recommended by Cochrane will be followed. Maintenance pharmacotherapy of childhood asthma will be evaluated in an overview of SRs published after 2005 and including clinical trials or real-life studies. For evaluating pharmacotherapy of acute asthma attacks leading to an emergency presentation with/without hospital admission, we opted to conduct de novo synthesis in the absence of adequate up-to-date published SRs. For the SR of acute asthma pharmacotherapy, we will consider eligible SRs, clinical trials or real-life studies without time restrictions. Our evidence updates will be based on broad searches of Pubmed/Medline and the Cochrane Library. We will use A MeaSurement Tool to Assess systematic Reviews, V.2, Cochrane risk of bias 2 and REal Life EVidence AssessmeNt Tool to evaluate the methodological quality of SRs, controlled clinical trials and real-life studies, respectively.Next, we will further assess interventions for acute severe asthma attacks with positive clinical results in meta-analyses. We will include both controlled clinical trials and observational studies and will assess their quality using the previously mentioned tools. We will employ random effect models for conducting meta-analyses, and Grading of Recommendations Assessment, Development and Evaluation methodology to assess certainty in the body of evidence.

ETHICS AND DISSEMINATION

Ethics approval is not required for SRs. Our findings will be published in peer reviewed journals and will inform clinical recommendations being developed by the PeARL Think Tank.

PROSPERO REGISTRATION NUMBERS

CRD42020132990, CRD42020171624.

[Predictors of hospitalization plus airway support among infants with recurrent wheezing in the emergency department]

OBJECTIVE

Most patients with recurrent wheezing are infants under 2 years of age. Clinical prediction models of the risk of receiving airway support during the hospital stay in this population have been poorly studied in tropical countries. This study aimed to evaluate the clinical predictors of hospitalization plus airway support among infants with recurrent wheezing evaluated in the emergency department in Colombia.

METHODS

A retrospective cohort study was performed. This study included all infants with two or more wheezing episodes who were younger than two years old in two tertiary centers in Rionegro, Colombia, between January 2019 and December 2019. The primary outcome measure was hospitalization plus any airway support. A multivariable logistic regression model was used to identify factors independently associated with hospitalization plus any airway support.

RESULTS

A total of 85 infants were hospitalized plus any airway support, of whom 34(40%) were treated with high flow nasal canula, 2(2%) received non-invasive ventilation, 6(7%) were mechanically ventilated, and 43 (51%) received conventional oxygen therapy. The multivariable logistic regression model showed that predictors of hospitalization plus airway support included prematurity (OR=1.79, 95%CI: 1.04-3.10), poor feeding (OR=2.22, 95%CI: 1.25-3.94), nasal flaring and/or grunting (OR=4.27, 95%CI: 2.41-7.56), and previous wheezing episodes requiring hospitalization (OR=3.36, 95%CI: 1.86-7.08). The model has a high specificity (99.6%) with acceptable discrimination and an area under the curve of 0.70(95%CI: 0.60-0.74).

CONCLUSIONS

The present study shows that prematurity, poor feeding, nasal flaring and/or grunting, and more than one previous episode of wheezing requiring hospitalization are independent predictors of hospitalization plus airway support in a population of infants with recurrent wheezing in the emergency department. More evidence must be collected to examine the results in other tropical countries.

[Predictors of hospitalization plus airway support among infants with recurrent wheezing in the emergency department]

OBJECTIVE

Most patients with recurrent wheezing are infants under 2 years of age. Clinical prediction models of the risk of receiving airway support during the hospital stay in this population have been poorly studied in tropical countries. This study aimed to evaluate the clinical predictors of hospitalization plus airway support among infants with recurrent wheezing evaluated in the emergency department in Colombia.

METHODS

A retrospective cohort study was performed. This study included all infants with two or more wheezing episodes who were younger than two years old in two tertiary centers in Rionegro, Colombia, between January 2019 and December 2019. The primary outcome measure was hospitalization plus any airway support. A multivariable logistic regression model was used to identify factors independently associated with hospitalization plus any airway support.

RESULTS

A total of 85 infants were hospitalized plus any airway support, of whom 34(40%) were treated with high flow nasal canula, 2(2%) received non-invasive ventilation, 6(7%) were mechanically ventilated, and 43 (51%) received conventional oxygen therapy. The multivariable logistic regression model showed that predictors of hospitalization plus airway support included prematurity (OR=1.79, 95%CI: 1.04-3.10), poor feeding (OR=2.22, 95%CI: 1.25-3.94), nasal flaring and/or grunting (OR=4.27, 95%CI: 2.41-7.56), and previous wheezing episodes requiring hospitalization (OR=3.36, 95%CI: 1.86-7.08). The model has a high specificity (99.6%) with acceptable discrimination and an area under the curve of 0.70(95%CI: 0.60-0.74).

CONCLUSIONS

The present study shows that prematurity, poor feeding, nasal flaring and/or grunting, and more than one previous episode of wheezing requiring hospitalization are independent predictors of hospitalization plus airway support in a population of infants with recurrent wheezing in the emergency department. More evidence must be collected to examine the results in other tropical countries.

Identification and seasonality of rhinovirus and respiratory syncytial virus in asthmatic children in tropical climate

INTRODUCTION

Asthma is a disease that has been associated with the presence of different genetic and socio-environmental factors.

OBJECTIVE

To identify and evaluate the seasonality of respiratory syncytial virus (RSV) and human rhinovirus (RV) in asthmatic children and adolescents in tropical climate, as well as to assess the socioeconomic and environmental factors involved.

METHODS

The study was conducted in a referral hospital, where a total of 151 children were recruited with a respiratory infection. The International Study of Asthma and Allergies in Childhood (ISAAC) protocol and a questionnaire were applied, and a skin prick test was performed. The nasal swab was collected to detect RV and RSV through molecular assay. National Meteorological Institute (INMET) database was the source of climatic information.

RESULTS

The socio-environmental characterization of asthmatic children showed the family history of allergy, disturbed sleep at night, dry cough, allergic rhinitis, individuals sensitized to at least one mite. We identified RV in 75% of children with asthma and 66.7% of RSV in children with asthma. There was an association between the presence of RV and the dry season whereas the presence of the RSV was associated with the rainy season. Contributing to these results, a negative correlation was observed between the RSV and the wind speed and the maximum temperature (T. Max) and a positive correlation with precipitation.

CONCLUSIONS

The results suggest a high prevalence of RV and RSV in asthmatic children and the seasonality of these viruses were present in different climatic periods. This has significant implications for understanding short- and long-term clinical complications in asthmatic patients.

Maternal Prenatal Hair Cortisol Is Associated with Child Wheeze among Mothers and Infants with Tobacco Smoke Exposure and Who Face High Socioeconomic Adversity

The association of co-occurring prenatal stress and tobacco exposures on childhood wheezing and asthma are not well established. In this study, we compared maternal prenatal hair cortisol concentration (HCC) to the maternal report of infant wheezing (y/n) in the first year of life among mother-infant dyads exposed to tobacco smoke and socioeconomic adversity. Data were obtained from the Vitamin C to Decrease Effects of Smoking in Pregnancy on Infant Lung Function study. Maternal adversity was defined by the level of education, household income, and health insurance provider. Hair was collected at delivery, representing average circulating third-trimester cortisol levels. HCC was log transformed and dichotomized into high/low cortisol groups that were placed into a multivariate model predicting wheeze. Subjects (n = 132) were primarily White with ≤high school education and receiving government-provided health insurance. Forty-five percent of infants wheezed. Average HCC was 3.39 pg/mg hair. Women with HCC > 3.55 pg/mg were more than twice as likely to report having a child who wheezed (odds ratio 2.56, 95% confidence interval 1.22-5.40; p = 0.01), adjusting for insurance provider and maternal asthma. Among this sample of dyads with prenatal smoke exposure, elevated maternal HCC was associated with child wheeze that was not diminished after consideration of covariates.

Six-Year Follow-up of a Trial of Antenatal Vitamin D for Asthma Reduction

BACKGROUND

We previously reported the results of a trial of prenatal vitamin D supplementation to prevent asthma and recurrent wheeze in young children, which suggested that supplementation provided a protective effect at the age of 3 years. We followed the children through the age of 6 years to determine the course of asthma and recurrent wheeze.

METHODS

In this follow-up study, investigators and participants remained unaware of the treatment assignments through the children's sixth birthday. We aimed to determine whether, when maternal levels of 25-hydroxyvitamin D were taken into account, children born to mothers who had received 4400 IU of vitamin D₃ per day during pregnancy (vitamin D group) would have a lower incidence of asthma and recurrent wheeze at the age of 6 years than would those born to mothers who had received 400 IU of vitamin D₃ per day (control group). Time-to-event methods were used to compare the treatment groups with respect to time to the onset of asthma or recurrent wheeze. Multivariate methods were used to compare longitudinal measures of lung function between the treatment groups.

RESULTS

There was no effect of maternal vitamin D supplementation on asthma and recurrent wheeze in either an intention-to-treat analysis or an analysis with stratification according to the maternal 25-hydroxyvitamin D level during pregnancy. There was no effect of prenatal vitamin D supplementation on most of the prespecified secondary outcomes. We found no effects of prenatal supplementation on spirometric indexes. Although there was a very small effect on airway resistance as measured by impulse oscillometry, this finding was of uncertain significance.

CONCLUSIONS

Vitamin D supplementation during the prenatal period alone did not influence the 6-year incidence of asthma and recurrent wheeze among children who were at risk for asthma. (Funded by the National Heart, Lung, and Blood Institute; VDAART ClinicalTrials.gov number, NCT00920621.).