Wheeze trajectories: Determinants and outcomes in the CHILD Cohort Study

Diagnosing Asthma in Children

Despite being the most common chronic lung disease in children, asthma continues to be frequently misdiagnosed in the pediatric population. The recommendations to establish a diagnosis of asthma in school-aged children have evolved over time, but there are still important discrepancies between published guidelines. Furthermore, preschool-aged children are often unable to perform objective testing, so the diagnosis of asthma remains a clinical one in the first several years of life, and there is still debate on the criteria and nomenclature to be used in this age group. In this review, we first discuss the definition and misdiagnosis of asthma in children. We then assess and compare published guidelines that outline how to establish the diagnosis of asthma in school-aged children. We also discuss the necessary steps to diagnose preschool-aged children with this disease. Last, we outline unanswered questions and opportunities for research in this field.

Understanding the childhood origins of asthma and chronic obstructive pulmonary disease: Insights from birth cohorts and studies across the life-span

Birth cohorts have identified modifiable risk factors for asthma and respiratory health in children and adults, demonstrating the important role and pathways through which early-life events influence not only child outcomes but also adult health, disease, and mortality. This focused literature update from 2021 to 2024 summarizes birth cohort studies across the life-span that contribute to our understanding of risk factors for and the childhood origins of asthma and chronic obstructive pulmonary disease that may inform prevention efforts. We conclude that there are critical periods of developmental plasticity and susceptibility during which early-life events and exposures likely have the greatest impact on the development of asthma and chronic obstructive lung disease phenotypes, and that there are important prenatal and early childhood exposures, which, if modified, might be candidates for improving respiratory health across the life-span. Birth cohorts have been and will continue to be critical to advancing our understanding of lung health and disease across the life-span, including asthma and chronic obstructive pulmonary disease. As child mortality declines and the human population ages, data from birth cohort studies are needed to inform strategies for optimizing healthy longevity, including the investment in understanding the lifelong consequences of adverse prenatal and early childhood exposures.

Effects of allergic diseases on social-emotional development in children at 12 months of age: A Prospective Cohort Study

OBJECTIVES

The link between allergic diseases and deficits in children's neurodevelopment has been suggested, but it remains unclear regarding the allergy-related effects on social-emotional development in early life. Our study aimed to explore the association between allergic diseases and social-emotional development during infancy using a prospective study.

METHODS

937 infants at 6 months were recruited from two community hospitals in Shanghai, of which 805 infants followed up at 12 months. The outcome was social-emotional concern, defined by Ages & Stages Questionnaire: Social-Emotional and personal social domain from Ages & Stages Questionnaire with established cutoffs. Allergic diseases were assessed using modified International Study of Asthma and Allergies in Childhood core questionnaire. Allergy patterns were classified based on time of onset and persistence as "Never", "Transient" (allergy at age of 0-6 months only or 7-12 months only), "Persistent" (allergy at age of 0-6 and 7-12 months).

RESULTS

8.45 % of 12-month infants exhibited social-emotional concerns. Infants had increased risk of social-emotional concerns at 12 months who suffered allergic diseases during 0-12 months (adjusted odd ratio [aOR], 2.22; 95 % confidence interval [CI], 1.33-3.70), 7-12 months (aOR[95%CI]: 2.07 [1.21, 3.57]) and 0-6 months (aOR[95%CI]: 1.90 [1.12, 3.21]). Additionally, infants with persistent allergy had a 161 % higher risk of social-emotional concern (aOR[95%CI]: 2.61 [1.29, 5.28], P = 0.008) compared to infants without allergy (P for trend = 0.001).

CONCLUSION

Allergic infants were more likely to experience social-emotional concerns, particularly for those with persistent allergy. To optimize social-emotional development, we highlight regular monitoring of mental health and effective management of allergy during infancy.

The role of wheezing subtypes in the development of early childhood asthma

BACKGROUND

Early childhood wheezing is associated with asthma risk at later ages, emphasizing the need for understanding wheezing patterns and their implications for asthma development.

METHODS

Children in the F2-generation (n = 603) of the Isle of Wight Birth Cohort (IOWBC) were followed-up at 3, 6, 12, 24, 36, and 72 months. Prevalence of wheeze and wheeze type (general, infectious, and non-infectious) were recorded. Group-based trajectory models covering ages 3 to 36 months were used to identify early childhood wheezing trajectories for each type of wheeze. These trajectories were examined for their association with asthma status and lung function at 6 years and later.

RESULTS

Distinct trajectories for general ("Persistent", "Transient", "Progressive", and "Infrequent/Never"), infectious ("Persistent", "Transient", and "Infrequent/Never"), and non-infectious ("Progressive", "Early Occurrence", and "Infrequent/Never") wheezing were identified. Compared to the "Infrequent/Never" trajectories, four trajectories were associated with an increased risk of asthma, namely "Progressive" non-infectious, "Early Occurrence" non-infectious, "Persistent" infectious, and "Persistent" general wheeze trajectories.

CONCLUSIONS

The identification of wheeze trajectories across different etiologies as significant risk factors for asthma may aid in understanding the complex, multifactorial nature of asthma onset. The findings suggest that early identification of specific wheeze patterns, not just occurrence of wheezing, can inform clinical interventions and potentially mitigate the risk of developing asthma.

Machine learning-derived asthma and allergy trajectories in children: a systematic review and meta-analysis

INTRODUCTION

Numerous studies have characterised trajectories of asthma and allergy in children using machine learning, but with different techniques and mixed findings. The present work aimed to summarise the evidence and critically appraise the methodology.

METHODS

10 databases were searched. Screening, data extraction and quality assessment were performed in pairs. Trajectory characteristics were tabulated and visualised. Associated risk factor and outcome estimates were pooled using a random-effects meta-analysis.

RESULTS

89 studies were included. Early-onset (infancy) persistent, mid-onset (∼2-5 years) persistent, early-onset early-resolving (within ∼2 years) and early-onset mid-resolving (by ∼3-6 years) wheezing and eczema, respectively, were the most commonly identified disease trajectories. Intermediate/transient trajectories were rare. Male sex was associated with a higher risk of most wheezing trajectories and possibly with early-resolving eczema, while being slightly protective against mid-onset persistent eczema. Parental disease/genetic markers were associated with persistent trajectories of wheezing and eczema, respectively. Prenatal (and less so postnatal) tobacco smoke exposure was associated with most wheezing trajectories, as were lower respiratory tract infections in infancy (particularly with the early-onset resolving patterns). Most studies (69%) were of low methodological quality (particularly in modelling approaches and reporting). Few studies investigated allergic multimorbidity, allergic rhinitis and food allergy.

CONCLUSIONS

Childhood asthma/wheezing and eczema can be characterised by a few relatively consistent trajectories, with some actionable risk factors such as pre-/postnatal smoke exposure. Improved computational methodology is warranted to better assess generalisability and elucidate the validity of intermediate/transient trajectories. Likewise, allergic multimorbidity and trajectories of allergic rhinitis and food allergy need to be further elucidated.

Artificial intelligence in pediatric allergy research

Atopic dermatitis, food allergy, allergic rhinitis, and asthma are among the most common diseases in childhood. They are heterogeneous diseases, can co-exist in their development, and manifest complex associations with other disorders and environmental and hereditary factors. Elucidating these intricacies by identifying clinically distinguishable groups and actionable risk factors will allow for better understanding of the diseases, which will enhance clinical management and benefit society and affected individuals and families. Artificial intelligence (AI) is a promising tool in this context, enabling discovery of meaningful patterns in complex data. Numerous studies within pediatric allergy have and continue to use AI, primarily to characterize disease endotypes/phenotypes and to develop models to predict future disease outcomes. However, most implementations have used relatively simplistic data from one source, such as questionnaires. In addition, methodological approaches and reporting are lacking. This review provides a practical hands-on guide for conducting AI-based studies in pediatric allergy, including (1) an introduction to essential AI concepts and techniques, (2) a blueprint for structuring analysis pipelines (from selection of variables to interpretation of results), and (3) an overview of common pitfalls and remedies. Furthermore, the state-of-the art in the implementation of AI in pediatric allergy research, as well as implications and future perspectives are discussed.

CONCLUSION

AI-based solutions will undoubtedly transform pediatric allergy research, as showcased by promising findings and innovative technical solutions, but to fully harness the potential, methodologically robust implementation of more advanced techniques on richer data will be needed.

WHAT IS KNOWN

• Pediatric allergies are heterogeneous and common, inflicting substantial morbidity and societal costs. • The field of artificial intelligence is undergoing rapid development, with increasing implementation in various fields of medicine and research.

WHAT IS NEW

• Promising applications of AI in pediatric allergy have been reported, but implementation largely lags behind other fields, particularly in regard to use of advanced algorithms and non-tabular data. Furthermore, lacking reporting on computational approaches hampers evidence synthesis and critical appraisal. • Multi-center collaborations with multi-omics and rich unstructured data as well as utilization of deep learning algorithms are lacking and will likely provide the most impactful discoveries.

Three-year outcome of a very young severe uncontrolled preschool wheezers cohort, a real-life study

Preschool wheeze is a public health issue. Disease control can be difficult to obtain in this population, in which no biologic therapy is indicated. We studied the evolution of severe preschool wheezers in real-life and identified the factors leading to no-control. We conducted a retrospective study at our tertiary asthma center. Each child under 3 years of age with severe, uncontrolled preschool wheeze was admitted to a pediatric day hospital for further investigations. We collected the results of clinical, biological and radiological exams, and follow-up data at 1 (Y+1), 2 (Y+2) and 3 years (Y+3). We included 135 patients; 63 (47 %) were still being followed at Y+3; 53 % were discontinued due to disease control. The median age at inclusion was 12 months. 29 % of patients followed up still had severe uncontrolled wheezing at Y+3. Eosinophils greater than 0.23G/L (p = 0.03) and a first case of bronchiolitis before the age of 2 months (p = 0.01) were factors in uncontrolled wheezing at Y1. Tobacco exposure was a factor associated with uncontrolled wheezing at Y+2 (p < 0.001). A first case of bronchiolitis before the age of 2 months (p = 0.007), male sex (p < 0.001) and a familial history of atopy (p = 0.05) were factors in uncontrolled disease at Y+3. We report a real-life study, with a very young population and very severe wheezing. Our therapeutic approach is original, enabling us to study the evolution of "therapeutic pressure" in the early years of this frequent disease, the pathophysiology of which is still poorly understood.

Maternal exposure to smoking and wheezing phenotypes in children: a cohort study of the Japan Environment and Children's Study

BACKGROUND

Previous studies have shown that prenatal maternal smoking and maternal secondhand smoke exposure during pregnancy were associated with an increased risk of wheezing and asthma development. However, few studies have examined the influence of different sources of tobacco exposure in different perinatal timeframes (preconception, prenatal, and postnatal) on wheezing phenotypes in children. Using national survey data from Japan, we investigated the effects of exposure to tobacco smoke during pregnancy on wheezing phenotypes in children before the age of 3 years.

METHODS

Pregnant women who lived in the 15 regional centers in the Japan Environment and Children's Study were recruited. We obtained information on prenatal and postnatal exposure to active and secondhand smoke (SHS) and wheeze development up to 3 years of age. Multiple logistic regression analysis was performed to determine the association between tobacco smoke exposure and wheezing phenotypes in children.

RESULTS

We analyzed 73,057 singleton births and identified four longitudinal wheezing phenotypes: never wheezing; early transient wheezing (wheezing by age 1 year but not thereafter); late-onset wheezing (wheezing by age 2-3 years but not beforehand); and persistent wheezing. Maternal smoking during pregnancy was significantly associated with early transient and persistent wheezing in children compared with no maternal smoking [early transient wheezing: 1-10 cigarettes per day, adjusted odds ratio (aOR) 1.43, 95% confidence interval (CI) 1.23-1.66; ≥ 11 cigarettes per day, aOR 1.67, 95% CI 1.27-2.20; persistent wheezing: 1-10 cigarettes per day, aOR 1.64, 95% CI 1.37-1.97; ≥ 11 cigarettes per day, aOR 2.32, 95% CI 1.70-3.19]. Smoking cessation even before pregnancy was also significantly associated with increased risk of early transient wheezing, late-onset wheezing, and persistent wheezing in children. Moreover, maternal exposure to SHS during pregnancy was significantly associated with increased risk of early transient and persistent wheezing compared with no such exposure.

CONCLUSIONS

Maternal smoking before and throughout pregnancy was associated with wheeze development in children up to 3 years of age. It appears that smoking is detrimental compared to never smoking, regardless of whether individuals quit smoking before or after becoming aware of the pregnancy.

Symptom trajectories in infancy for the prediction of subsequent wheeze and asthma in the BILD and PASTURE cohorts: a dynamic network analysis

BACKGROUND

Host and environment early-life risk factors are associated with progression of wheezing symptoms over time; however, their individual contribution is relatively small. We hypothesised that the dynamic interactions of these factors with an infant's developing respiratory system are the dominant factor for subsequent wheeze and asthma.

METHODS

In this dynamic network analysis we used data from term healthy infants from the Basel-Bern Infant Lung Development (BILD) cohort (435 neonates aged 0-4 weeks recruited in Switzerland between Jan 1, 1999, and Dec 31, 2012) and replicated the findings in the Protection Against Allergy Study in Rural Environments (PASTURE) cohort (498 infants aged 0-12 months recruited in Germany, Switzerland, Austria, France, and Finland between Jan 1, 2002, and Oct 31, 2006). BILD exclusion criteria for the current study were prematurity (<37 weeks), major birth defects, perinatal disease of the neonate, and incomplete follow-up period. PASTURE exclusion criteria were women younger than 18 years, a multiple pregnancy, the sibling of a child was already included in the study, the family intended to move away from the area where the study was conducted, and the family had no telephone connection. Outcome groups were subsequent wheeze, asthma, and healthy. The first outcome was defined as ever wheezed between the age of 2 years and 6 years. Week-by-week correlations of the determining factors with cumulative symptom scores (CSS) were calculated from weeks 2 to 52 (BILD) and weeks 8 to 52 (PASTURE). The complex dynamic interaction between the determining factors and the CSS was assessed via dynamic host-environment correlation network, quantified by a simple descriptor: trajectory function G(t). Wheeze outcomes at age 2-6 years were compared in 335 infants from BILD and 437 infants from PASTURE, and asthma outcomes were analysed at age 6 years in a merged cohort of 783 infants.

FINDINGS

CSS was significantly different for wheeze and asthma outcomes and became increasingly important during infancy in direct comparison with all determining factors. Weekly symptoms were tracked for groups of infants, showing a non-linear increase with time. Using logistic regression classification, G(t) distinguished between the healthy group and wheeze or asthma groups (area under the curve>0·97, p<0·0001; sensitivity analysis confirmed significant CSS association with wheeze [BILD p=0·0002 and PASTURE p=0·068]) and G(t) was also able to distinguish between the farming and non-farming exposure groups (p<0·0001).

INTERPRETATION

Similarly to other risk factors, CSS had weak sensitivity and specificity to identify risks at the individual level. At group level however, the dynamic host-environment correlation network properties (G(t)) showed excellent discriminative ability for identifying groups of infants with subsequent wheeze and asthma. Results from this study are consistent with the 2018 Lancet Commission on asthma, which emphasised the importance of dynamic interactions between risk factors during development and not the risk factors per se.

FUNDING

The Swiss National Science Foundation, the Kühne Foundation, the EFRAIM study EU research grant, the FORALLVENT study EU research grant, and the Leibniz Prize.

Human milk oligosaccharides are associated with maternal genetics and respiratory health of human milk-fed children

Breastfeeding provides many health benefits, but its impact on respiratory health remains unclear. This study addresses the complex and dynamic nature of the mother-milk-infant triad by investigating maternal genomic factors regulating human milk oligosaccharides (HMOs), and their associations with respiratory health among human milk-fed infants. Nineteen HMOs are quantified from 980 mothers of the CHILD Cohort Study. Genome-wide association studies identify HMO-associated loci on chromosome 19p13.3 and 19q13.33 (lowest P = 2.4e-118), spanning several fucosyltransferase (FUT) genes. We identify novel associations on chromosome 3q27.3 for 6'-sialyllactose (P = 2.2e-9) in the sialyltransferase (ST6GAL1) gene. These, plus additional associations on chromosomes 7q21.32, 7q31.32 and 13q33.3, are replicated in the independent INSPIRE Cohort. Moreover, gene-environment interaction analyses suggest that fucosylated HMOs may modulate overall risk of recurrent wheeze among preschoolers with variable genetic risk scores (P < 0.01). Thus, we report novel genetic factors associated with HMOs, some of which may protect the respiratory health of children.

A novel syndrome of silent rhinovirus-associated bronchoalveolitis in children with recurrent wheeze

BACKGROUND

Rhinovirus (RV) infections trigger wheeze episodes in children. Thus, understanding of the lung inflammatory response to RV in children with wheeze is important.

OBJECTIVES

This study sought to examine the associations of RV on bronchoalveolar lavage (BAL) granulocyte patterns and biomarkers of inflammation with age in children with treatment-refractory, recurrent wheeze (n = 616).

METHODS

Children underwent BAL to examine viral nucleic acid sequences, bacterial cultures, granulocyte counts, and phlebotomy for both general and type-2 inflammatory markers.

RESULTS

Despite the absence of cold symptoms, RV was the most common pathogen detected (30%), and when present, was accompanied by BAL granulocytosis in 75% of children. Compared to children with no BAL pathogens (n = 341), those with RV alone (n = 127) had greater (P < .05) isolated neutrophilia (43% vs 16%), mixed eosinophils and neutrophils (26% vs 11%), and less pauci-granulocytic (27% vs 61%) BAL. Children with RV alone furthermore had biomarkers of active infection with higher total blood neutrophils and serum C-reactive protein, but no differences in blood eosinophils or total IgE. With advancing age, the log odds of BAL RV alone were lower, 0.82 (5th-95th percentile CI: 0.76-0.88; P < .001), but higher, 1.58 (5th-95th percentile CI: 1.01-2.51; P = .04), with high-dose daily corticosteroid treatment.

CONCLUSIONS

Children with severe recurrent wheeze often (22%) have a silent syndrome of lung RV infection with granulocytic bronchoalveolitis and elevated systemic markers of inflammation. The syndrome is less prevalent by school age and is not informed by markers of type-2 inflammation. The investigators speculate that dysregulated mucosal innate antiviral immunity is a responsible mechanism.

Early prediction of pediatric asthma in the Canadian Healthy Infant Longitudinal Development (CHILD) birth cohort using machine learning

BACKGROUND

Early identification of children at risk of asthma can have significant clinical implications for effective intervention and treatment. This study aims to disentangle the relative timing and importance of early markers of asthma.

METHODS

Using the CHILD Cohort Study, 132 variables measured in 1754 multi-ethnic children were included in the analysis for asthma prediction. Data up to 4 years of age was used in multiple machine learning models to predict physician-diagnosed asthma at age 5 years. Both predictive performance and variable importance was assessed in these models.

RESULTS

Early-life data (≤1 year) has limited predictive ability for physician-diagnosed asthma at age 5 years (area under the precision-recall curve (AUPRC) < 0.35). The earliest reliable prediction of asthma is achieved at age 3 years, (area under the receiver-operator curve (AUROC) > 0.90) and (AUPRC > 0.80). Maternal asthma, antibiotic exposure, and lower respiratory tract infections remained highly predictive throughout childhood. Wheezing status and atopy are the most important predictors of early childhood asthma from among the factors included in this study.

CONCLUSIONS

Childhood asthma is predictable from non-biological measurements from the age of 3 years, primarily using parental asthma and patient history of wheezing, atopy, antibiotic exposure, and lower respiratory tract infections.

IMPACT

Machine learning models can predict physician-diagnosed asthma in early childhood (AUROC > 0.90 and AUPRC > 0.80) using ≥3 years of non-biological and non-genetic information, whereas prediction with the same patient information available before 1 year of age is challenging. Wheezing, atopy, antibiotic exposure, lower respiratory tract infections, and the child's mother having asthma were the strongest early markers of 5-year asthma diagnosis, suggesting an opportunity for earlier diagnosis and intervention and focused assessment of patients at risk for asthma, with an evolving risk stratification over time.

Persistent DNA Methylation Changes across the First Year of Life and Prenatal NO2 Exposure in a Canadian Prospective Birth Study

BACKGROUND

Evidence suggests that prenatal air pollution exposure alters DNA methylation (DNAm), which could go on to affect long-term health. It remains unclear whether DNAm alterations present at birth persist through early life. Identifying persistent DNAm changes would provide greater insight into the molecular mechanisms contributing to the association of prenatal air pollution exposure with atopic diseases.

OBJECTIVES

This study investigated DNAm differences associated with prenatal nitrogen dioxide (NO 2 ) exposure (a surrogate measure of traffic-related air pollution) at birth and 1 y of age and examined their role in atopic disease. We focused on regions showing persistent DNAm differences from birth to 1 y of age and regions uniquely associated with postnatal NO 2 exposure.

METHODS

Microarrays measured DNAm at birth and at 1 y of age for an atopy-enriched subset of Canadian Health Infant Longitudinal Development (CHILD) study participants. Individual and regional DNAm differences associated with prenatal NO 2 (n = 128 ) were identified, and their persistence at age 1 y were investigated using linear mixed effects models (n = 124 ). Postnatal-specific DNAm differences (n = 125 ) were isolated, and their association with NO 2 in the first year of life was examined. Causal mediation investigated whether DNAm differences mediated associations between NO 2 and age 1 y atopy or wheeze. Analyses were repeated using biological sex-stratified data.

RESULTS

At birth (n = 128 ), 18 regions of DNAm were associated with NO 2 , with several annotated to HOX genes. Some of these regions were specifically identified in males (n = 73 ), but not females (n = 55 ). The effect of prenatal NO 2 across CpGs within altered regions persisted at 1 y of age. No significant mediation effects were identified. Sex-stratified analyses identified postnatal-specific DNAm alterations.

DISCUSSION

Regional cord blood DNAm differences associated with prenatal NO 2 persisted through at least the first year of life in CHILD participants. Some differences may represent sex-specific alterations, but replication in larger cohorts is needed. The early postnatal period remained a sensitive window to DNAm perturbations. https://doi.org/10.1289/EHP13034.

Infant lung function and early skin barrier impairment in the development of asthma at age 3 years

BACKGROUND

Largely unexplored, we investigated if lower lung function, impaired skin barrier function by transepidermal water loss (TEWL), eczema, and filaggrin (FLG) mutations in infancy were associated with asthma in early childhood.

METHODS

From the factorially designed randomized controlled intervention study PreventADALL, we evaluated 1337/2394 children from all randomization groups with information on asthma at age 3 years, and at age 3 months either lung function, TEWL, eczema, and/or FLG mutations. Lower lung function was defined as the time to peak tidal expiratory flow to expiratory time (tPTEF /tE ) <0.25, and skin barrier impairment as a high TEWL >9.50 g/m2 /h. Eczema was clinically observed, and DNA genotyped for FLG mutations. Asthma was defined as asthma-like symptoms (≥3 episodes of bronchial obstruction) between age 2-3 years as well as a history of doctor-diagnosed asthma and/or asthma medication use. Associations were analyzed in logistic regression models, presented with adjusted ORs (aOR) and 95% confidence intervals (CI).

RESULTS

Lower lung function and skin barrier impairment were associated with asthma in general; aOR (95% CI) 5.4 (2.1, 13.7) and 1.6 (1.1, 2.5), while eczema and FLG mutations were associated with asthma in children with atopic dermatitis or allergic sensitization only. Stratifying for sex, the risk of asthma was only increased in boys with lower lung function; aOR (95% CI) 7.7 (2.5, 23.6), and in girls with FLG mutations; aOR (95% CI) 3.5 (1.5, 8.2).

CONCLUSION

Lower lung function and impaired skin barrier function in infancy may increase the risk of asthma at age 3 years.

Periconceptional maternal diet quality and offspring wheeze trajectories: Japan Environment and Children's Study

BACKGROUND

The role of prenatal diet on childhood wheezing and subsequent risk of asthma is inconclusive, which may be partly due to the heterogeneity in wheezing phenotypes. We aimed to identify wheeze trajectories in early childhood and to examine their associations with periconceptional maternal diet quality.

METHODS

Data from 70,530 mother-child pairs of liveborn singletons from the Japan Environment and Children's Study were analysed. Wheezing was reported by caregivers using a modified International Study of Asthma and Allergies in Childhood questionnaire yearly from 1 to 4 years of age, from which trajectories were derived using group-based trajectory modelling. Maternal diet in the year preceding the first trimester of pregnancy was assessed using a validated food frequency questionnaire; overall diet quality was determined using the balanced diet score based on the Japanese Food Guide Spinning Top. Bayesian inference of multinomial logistic regression models was performed to examine the association between maternal diet quality and wheeze trajectory in early childhood.

RESULTS

We identified four wheeze trajectories: 'never/infrequent' (69.1%; reference group), 'early-childhood onset' (6.2%), 'transient early' (16.5%) and 'persistent' (8.2%). After adjustment for confounders, a higher quartile of maternal balanced diet score was associated with a lower risk of belonging to the 'transient early' and 'persistent' wheeze trajectories compared with the 'never/infrequent' wheeze trajectory by 10% of both. Maternal balanced diet score was not associated with belonging to the 'early-childhood onset' wheeze trajectory.

CONCLUSION

Improving maternal diet quality prior to conception may reduce certain wheeze phenotypes in early childhood.

Future of biologics in pediatric asthma: Optimizing response, early introduction, and equitable access to treatment

OBJECTIVE

To evaluate the current evidence, its limitations, and future research directions for the use of biologics in pediatric asthma, with a particular focus on the potential use of biologics to prevent pediatric asthma and equity issues in access to biologic treatment and research participation.

DATA SOURCES

PubMed articles about the use of biologics in pediatric asthma were searched up to May 2023.

STUDY SELECTIONS

Recent (2019-2023) original research articles and reviews were prioritized.

RESULTS

Although there are now 5 U.S. Food and Drug Administration-approved biologics for use in pediatric asthma, there are important knowledge gaps that ongoing research seeks to address, which include (1) the long-term efficacy and safety of using biologics in children, (2) the comparative efficacy of different biologics, (3) multi-omics-based classification of asthma endotypes and phenotypes in children to find potential new therapeutic targets and enable identification and validation of new biomarkers that may predict and help monitor response to treatment, and (4) whether starting biologics in early childhood can modify the natural history of asthma and potentially prevent asthma development.

SUMMARY

To promote equitable access to biologics and optimize asthma outcomes, future research should recruit patients across the full spectrum of socioeconomic and racial/ethnic backgrounds. Large-scale national and international collaborations between asthma researchers and clinicians are also necessary to fully understand the role of biologics in pediatric asthma.

Is sibship composition a risk factor for childhood asthma? Systematic review and meta-analysis

BACKGROUND

Following the "hygiene hypothesis", the role of sibship composition in asthma and wheezing has been extensively studied, but the findings are inconsistent. For the first time, this systematic review and meta-analysis synthesized evidences from studies investigating the association of sibship size and birth order with risk of asthma and wheezing.

METHODS

Fifteen databases were searched to identify eligible studies. Study selection and data extraction were performed independently by pairs of reviewers. Meta-analysis with robust variance estimation (RVE) was used to produce pooled risk ratio (RR) effect estimates from comparable numerical data.

RESULTS

From 17,466 identified records, 158 reports of 134 studies (> 3 million subjects) were included. Any wheezing in the last ≤ 1.5 years occurred more frequently in infants with ≥ 1 sibling [pooled RR 1.10, 95% confidence interval (CI) 1.02-1.19] and ≥ 1 older sibling (pooled RR 1.16, 95% CI 1.04-1.29). The pooled effect sizes for asthma were overall statistically nonsignificant, although having ≥ 1 older sibling was marginally protective for subjects aged ≥ 6 years (pooled RR 0.93, 95% CI 0.88-0.99). The effect estimates weakened in studies published after 2000 compared with earlier studies.

CONCLUSIONS

Being second-born or later and having at least one sibling is associated with a slightly increased risk of temporary wheezing in infancy. In contrast, being second-born or later is associated with marginal protection against asthma. These associations appear to have weakened since the turn of the millennium, possibly due to lifestyle changes and socioeconomic development. Video Abstract.

Limited clinical role of blood eosinophil levels in early life atopic disease: A mother-child cohort study

BACKGROUND

Blood eosinophil count is a well-established biomarker of atopic diseases in older children and adults. However, its predictive role for atopic diseases in preschool children is not well established.

OBJECTIVE

To investigate the association between blood eosinophil count in children and development of atopic diseases up to age 6 years.

METHODS

We investigated blood eosinophil count at age 18 months and 6 years in relation to recurrent wheeze/asthma, atopic dermatitis, allergic rhinitis, and allergic sensitization during the first 6 years of life in the two Copenhagen Prospective Studies on Asthma in Childhood cohorts (n = 1111). Blood eosinophil count was investigated in association with remission of existing atopic disease, current atopic disease, and later development of atopic disease.

RESULTS

Blood eosinophil count at 18 months was not associated with current wheezing/asthma or atopic dermatitis, while blood eosinophil count at age 6 years was associated with increased occurrence of current wheezing/asthma (OR = 1.1; 1.04-1.16, p = .0005), atopic dermatitis (OR = 1.06; 1.01-1.1, p = .02), and allergic rhinitis (OR = 1.11; 1.05-1.18, p = .0002). Blood eosinophil count at 18 months did not predict persistence or development of recurrent wheeze/asthma or atopic dermatitis at age 6 years.

CONCLUSION

Blood eosinophil count at 18 months was not associated with current wheezing/asthma or atopic dermatitis and did not predict persistence or development of disease. This implies a limited clinical role of blood eosinophil levels in early-life atopic disease and questions the clinical value of blood eosinophil counts measured in toddlers as a predictive biomarker for subsequent atopic disease in early childhood.

Early-immune development in asthma: A review of the literature

This review presents a comprehensive examination of the various factors contributing to the immunopathogenesis of asthma from the prenatal to preschool period. We focus on the contributions of genetic and environmental components as well as the role of the nasal and gut microbiome on immune development. Predisposing genetic factors, including inherited genes associated with increased susceptibility to asthma, are discussed alongside environmental factors such as respiratory viruses and pollutant exposure, which can trigger or exacerbate asthma symptoms. Furthermore, the intricate interplay between the nasal and gut microbiome and the immune system is explored, emphasizing their influence on allergic immune development and response to environmental stimuli. This body of literature underscores the necessity of a comprehensive approach to comprehend and manage asthma, as it emphasizes the interactions of multiple factors in immune development and disease progression.

Frequency of exacerbation and degree of required asthma medication can characterize childhood longitudinal asthma trajectories

BACKGROUND

To the best of our knowledge, there have been no investigations of longitudinal asthma trajectories based on asthma exacerbation frequency and medications required for asthma control in children.

OBJECTIVE

To investigate longitudinal asthma trajectories based on the exacerbation frequency throughout childhood and asthma medication ranks.

METHODS

A total of 531 children aged 7 to 10 years were enrolled from the Korean childhood Asthma Study. Required asthma medications for control of asthma from 6 to 12 years of age and asthma exacerbation frequency from birth to 12 years of age were obtained from the Korean National Health Insurance System database. Longitudinal asthma trajectories were identified on the basis of asthma exacerbation frequency and asthma medication ranks.

RESULTS

Four asthma clusters were identified: lesser exacerbation with low-step treatment (8.1%), lesser exacerbations with middle-step treatment (30.7%), highly frequent exacerbations in early childhood with small-airway dysfunction (5.7%), and frequent exacerbations with high-step treatment (55.6%). The frequent exacerbations with high-step treatment cluster were characterized by a high prevalence of male sex, increased blood eosinophil (counts) with fractional exhaled nitric oxide, and high prevalence of comorbidities. The highly frequent exacerbation in early childhood with small-airway dysfunction cluster was characterized by recurrent wheeze in preschool age, with high prevalence of acute bronchiolitis in infancy and a greater number of family members with small-airway dysfunction at school age.

CONCLUSION

The present study identified 4 longitudinal asthma trajectories on the basis of the frequency of asthma exacerbation and asthma medication ranks. These results would help clarify the heterogeneities and pathophysiologies of childhood asthma.

The Canadian Society for Immunology's 34th annual meeting 2022: symposia minireview

The Canadian Society for Immunology 2022 Annual Meeting (June 17-20, 2022) brought together immunologists from across the country to discuss current topics and cutting-edge research in immunology. Here we highlight the published work presented during three thematic symposia (1) Immune Development and Layered Immunity; (2) Primary Immune Deficiencies from Thymic Developmental Defects to Dysregulation and Inflammation; and (3) Opposing Inflammatory and Suppressive Regulation of Anti-Tumor Immunity.

Poorer Caregiver Mental and Social Health Is Associated With Worse Respiratory Outcomes in Preschool Children With Recurrent Wheezing

BACKGROUND

Mental and social health in caregivers of preschool children has been inadequately studied, but it may influence respiratory symptom recognition and management.

OBJECTIVE

To identify preschool caregivers at highest risk for poor mental and social health outcomes on the basis of patient-reported outcome measures.

METHODS

Female caregivers 18 to 50 years old (N = 129) with a preschool child aged 12 to 59 months with recurrent wheezing and at least 1 exacerbation in the previous year completed 8 validated patient-reported outcome measures of mental and social health. k-means cluster analysis was performed using the T score for each instrument. Caregiver/child dyads were followed for 6 months. Primary outcomes included caregiver quality of life and wheezing episodes in their preschool children.

RESULTS

Three clusters of caregivers were identified: low risk (n = 38), moderate risk (n = 56), and high risk (n = 35). The high-risk cluster had the lowest life satisfaction, meaning and purpose, and emotional support and the highest social isolation, depression, anger, perceived stress, and anxiety that persisted for more than 6 months. This cluster had the poorest quality of life and marked disparities in social determinants of health. Preschool children from caregivers in the high-risk cluster had more frequent respiratory symptoms and a higher occurrence of any wheezing episode, but a lower outpatient physician utilization for wheezing management.

CONCLUSIONS

Caregiver mental and social health is associated with respiratory outcomes in preschool children. Routine assessment of mental and social health in caregivers is warranted to promote health equity and improve wheezing outcomes in preschool children.

Blood Eosinophils for Prediction of Exacerbation in Preschool Children With Recurrent Wheezing

BACKGROUND

Although clinical features of type 2 inflammation have been associated with poorer longitudinal outcomes in preschool children with recurrent wheezing, it remains difficult to predict which children are at highest risk for poor outcomes during a routine clinical encounter.

OBJECTIVE

We tested the hypothesis that prespecified cut points of blood eosinophil counts would predict exacerbation and treatment response outcomes in preschool children with recurrent wheezing and that prediction could be improved with the addition of a second biomarker.

METHODS

Data from 3 clinical trials of 1,074 preschool children aged 12 to 71 months with recurrent wheezing were merged. The primary outcome was the occurrence of any exacerbation during follow-up. Secondary outcomes included the annualized rate of wheezing exacerbations and the occurrence of any exacerbation requiring hospitalization. Exploratory analyses focused on exacerbation outcomes, offline exhaled nitric oxide concentrations, and caregiver-reported asthma control scores after inhaled corticosteroid treatment initiation.

RESULTS

Each blood eosinophil cut point was associated with increased odds of exacerbation, higher exacerbation rates, and greater hospitalization occurrence in preschool children with recurrent wheezing. However, outcome detection was improved in children with more elevated blood eosinophil counts. Addition of a second biomarker of type 2 inflammation improved outcome detection and was further associated with an improved response to initiation of daily inhaled corticosteroids in exploratory analyses. However, the specificity of blood eosinophils was poor.

CONCLUSIONS

Although validation studies are warranted, blood eosinophil cut points may be useful for clinical assessment and future studies of exacerbation and treatment response in preschool children with recurrent wheezing.

Development and validation of a prediction model to predict school-age asthma in preschool children

OBJECTIVE

To develop and validate a clinical prediction model to identify school-age asthma in preschool asthmatic children.

STUDY DESIGN

In this retrospective prognosis cohort study, asthmatic children aged 3-5 years were enrolled with at least 2 years of follow-up, and their potential variables at baseline and the prognosis of school-age asthma were collected from medical records. A clinical prediction model was developed using Logistic regression. The performance of prediction model was assessed and quantified by discrimination of the area under the receiver operating characteristic curve (AUC) and calibration of Brier score. The model was validated by the temporal-validation method.

RESULTS

In the development dataset, 2748 preschool asthmatic children were included for model development, and 883 (32.13%) children were translated to school-age asthma. The independent prognostic variables with an increased risk for school-age asthma were used to develop the prediction model, including: age, parental asthma, early frequent wheezing, allergic rhinitis, eczema, allergic conjunctivitis, obesity, and aeroallergen of dust mite. While assessing model performance, the discrimination power of AUC was moderate [0.788 (0.770-0.805)] with sensitivity (81.5%) and specificity (60.9%), and the calibration of Brier score was 0.169, supporting the calibration ability. In the temporal-validation dataset of 583 preschool asthmatic children, our model showed satisfactory discrimination (AUC 0.818) and calibration (Brier score 0.150). The prediction model was presented by the web-based calculator (https://casthma.shinyapps.io/dynnomapp/) and a nomogram for clinical application.

CONCLUSION

In preschool asthmatic children, our prediction model could be used to predict the risk of school-age asthma.

Recent progress in the genetic and epigenetic underpinnings of atopy

In the past 2 years, there continue to be advances in our understanding of the genetic and epigenetic underpinnings of atopy pertaining to disease risk and disease severity. The joint role of genetics and the environment has been emphasized in multiple studies. Combining genetics with family history, biomarkers, and comorbidities is further refining our ability to predict the development of individual atopic diseases as well as the advancement of the atopic march. Polygenic risk scores will be an important next step for the field moving toward clinical translation of the genetic findings thus far. A systems biology approach, as illustrated by studies of the microbiome and epigenome, will be necessary to fully understand disease development and to develop increasingly targeted therapeutics.

Asthma Management in Children

Asthma is a common, complex heterogeneous disease often beginning in early life and is characterized by reversible airflow obstruction. The phenotypic differences that exist in children with asthma may impact underlying comorbid conditions and pharmacologic treatment choices. Prenatal factors for increased risk of asthma could include maternal diet and the maternal microbiome. Evidence also suggests that postnatal microbial exposures and colonization contribute to the risk of allergic diseases and asthma. After confirming the diagnosis, asthma management in children centers on 3 broad areas: pharmacologic treatment, treatment of underlying comorbidities, and education of the patient and caregivers on the importance of adherence and device technique. Moreover, social determinants of health significantly impact on symptom burden and treatment response.

Risk Factors Affecting Development and Persistence of Preschool Wheezing: Consensus Document of the Emilia-Romagna Asthma (ERA) Study Group

Wheezing at preschool age (i.e., before the age of six) is common, occurring in about 30% of children before the age of three. In terms of health care burden, preschool children with wheeze show double the rate of access to the emergency department and five times the rate of hospital admissions compared with school-age asthmatics. The consensus document aims to analyse the underlying mechanisms involved in the pathogenesis of preschool wheezing and define the risk factors (i.e., allergy, atopy, infection, bronchiolitis, genetics, indoor and outdoor pollution, tobacco smoke exposure, obesity, prematurity) and the protective factors (i.e., probiotics, breastfeeding, vitamin D, influenza vaccination, non-specific immunomodulators) associated with the development of the disease in the young child. A multidisciplinary panel of experts from the Emilia-Romagna Region, Italy, addressed twelve key questions regarding managing preschool wheezing. Clinical questions have been formulated by the expert panel using the PICO format (Patients, Intervention, Comparison, Outcomes). Systematic reviews have been conducted on PubMed to answer these specific questions and formulate recommendations. The GRADE approach has been used for each selected paper to assess the quality of the evidence and the degree of recommendations. Based on a panel of experts and extensive updated literature, this consensus document provides insight into the pathogenesis, risk and protective factors associated with the development and persistence of preschool wheezing. Undoubtedly, more research is needed to improve our understanding of the disease and confirm the associations between certain factors and the risk of wheezing in early life. In addition, preventive strategies must be promoted to avoid children's exposure to risk factors that may permanently affect respiratory health.

Development of a Symptom-Based Tool for Screening of Children at High Risk of Preschool Asthma

IMPORTANCE

Despite advances in asthma therapeutics, the burden remains highest in preschool children; therefore, it is critical to identify primary care tools that distinguish preschool children at high risk for burdensome disease for further evaluation. Current asthma prediction tools, such as the modified Asthma Predictive Index (mAPI), require invasive tests, limiting their applicability in primary care and low-resource settings.

OBJECTIVE

To develop and evaluate the use of a symptom-based screening tool to detect children at high risk of asthma, persistent wheeze symptoms, and health care burden.

DESIGN, SETTING, AND PARTICIPANTS

The cohort for this diagnostic study included participants from the CHILD Study (n = 2511) from January 1, 2008, to December 31, 2012, the Raine Study from January 1, 1989, to December 31, 2012 (n = 2185), and the Canadian Asthma Primary Prevention Study (CAPPS) from January 1, 1989, to December 31, 1995 (n = 349), with active follow-up to date. Data analysis was performed from November 1, 2019, to May 31, 2022.

EXPOSURES

The CHILDhood Asthma Risk Tool (CHART) identified factors associated with asthma in patients at 3 years of age (timing and number of wheeze or cough episodes, use of asthma medications, and emergency department visits or hospitalizations for asthma or wheeze) to identify children with asthma or persistent symptoms at 5 years of age.

MAIN OUTCOMES AND MEASURES

Within the CHILD Study cohort, CHART was evaluated against specialist clinician diagnosis and the mAPI. External validation was performed in both a general population cohort (Raine Study [Australia]) and a high-risk cohort (CAPPS [Canada]). Predictive accuracy was measured by sensitivity, specificity, area under the receiver operating characteristic curve (AUROC), and positive and negative predicted values.

RESULTS

Among 2511 children (mean [SD] age at 3-year clinic visit, 3.08 [0.17] years; 1324 [52.7%] male; 1608 of 2476 [64.9%] White) with sufficient questionnaire data to apply CHART at 3 years of age, 2354 (93.7%) had available outcome data at 5 years of age. CHART applied in the CHILD Study at 3 years of age outperformed physician assessments and the mAPI in predicting persistent wheeze (AUROC, 0.94; 95% CI, 0.90-0.97), asthma diagnosis (AUROC, 0.73; 95% CI, 0.69-0.77), and health care use (emergency department visits or hospitalization for wheeze or asthma) (AUROC, 0.70; 95% CI, 0.61-0.78). CHART had a similar predictive performance for persistent wheeze in the Raine Study (N = 2185) in children at 5 years of age (AUROC, 0.82; 95% CI, 0.79-0.86) and CAPPS (N = 349) at 7 years of age (AUROC, 0.87; 95% CI, 0.80-0.94).

CONCLUSIONS AND RELEVANCE

In this diagnostic study, CHART was able to identify children at high risk of asthma at as early as 3 years of age. CHART could be easily incorporated as a routine screening tool in primary care to identify children who need monitoring, timely symptom control, and introduction of preventive therapies.