Clinical phenotypes in asthma during childhood

Understanding the heterogeneity of childhood allergic sensitization and its relationship with asthma

PURPOSE OF REVIEW

To review the current state of knowledge on the relationship between allergic sensitization and asthma; to lay out a roadmap for the development of IgE biomarkers that differentiate, in individual sensitized patients, whether their sensitization is important for current or future asthma symptoms, or has little or no relevance to the disease.

RECENT FINDINGS

The evidence on the relationship between sensitization and asthma suggests that some subtypes of allergic sensitization are not associated with asthma symptoms, whilst others are pathologic. Interaction patterns between IgE antibodies to individual allergenic molecules on component-resolved diagnostics (CRD) multiplex arrays might be hallmarks by which different sensitization subtypes relevant to asthma can be distinguished. These different subtypes of sensitization are associated amongst sensitized individuals at all ages, with different clinical presentations (no disease, asthma as a single disease, and allergic multimorbidity); amongst sensitized preschool children with and without lower airway symptoms, with different risk of subsequent asthma development; and amongst sensitized patients with asthma, with differing levels of asthma severity.

SUMMARY

The use of machine learning-based methodologies on complex CRD data can help us to design better diagnostic tools to help practising physicians differentiate between benign and clinically important sensitization.

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.

Drug-induced fetal and offspring disorders, beyond birth defects

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

COBRAPed cohort: Do sensitization patterns differentiate children with severe asthma from those with a milder disease?

BACKGROUND

It is unclear whether sensitization patterns differentiate children with severe recurrent wheeze (SRW)/severe asthma (SA) from those with non-severe recurrent wheeze (NSRW)/non-severe asthma (NSA). Our objective was to determine whether sensitization patterns can discriminate between children from the French COBRAPed cohort with NSRW/NSA and those with SRW/SA.

METHODS

IgE to 112 components (c-sIgE) (ImmunoCAP® ISAC) were analyzed in 125 preschools (3-6 years) and 170 school-age children (7-12 years). Supervised analyses and clustering methods were applied to identify patterns of sensitization among children with positive c-sIgE.

RESULTS

We observed c-sIgE sensitization in 51% of preschool and 75% of school-age children. Sensitization to house dust mite (HDM) components was more frequent among NSRW than SRW (53% vs. 24%, p < .01). Sensitization to non-specific lipid transfer protein (nsLTP) components was more frequent among SA than NSA (16% vs. 4%, p < .01) and associated with an FEV1/FVC < -1.64 z-score. Among sensitized children, seven clusters with varying patterns were identified. The two broader clusters identified in each age group were characterized by "few sensitizations, mainly to HDM." One cluster (n = 4) with "multiple sensitizations, mainly to grass pollen, HDM, PR-10, and nsLTP" was associated with SA in school-age children.

CONCLUSIONS

Although children with wheeze/asthma display frequent occurrences and high levels of sensitization, sensitization patterns did not provide strong signals to discriminate children with severe disease from those with milder disease. These results suggest that the severity of wheeze/asthma may depend on both IgE- and non-IgE-mediated mechanisms.

Characteristics of Allergic, Eosinophilic, and Overlapping Asthma Phenotypes Among Pediatric Patients with Current Asthma: A Cross-Sectional Study from Saudi Arabia

Purpose

Asthma is one of the most common chronic diseases affecting 10%-30% of children in Saudi Arabia. Although data exist on adult asthma phenotyping and endotyping in Saudi Arabia, little is known about asthma phenotypes in Saudi children.

Patients and Methods

This cross-sectional study enrolled pediatric patients diagnosed with bronchial asthma and followed in the pediatric pulmonology clinic of the Abha Maternity and Children Hospital between August 2021 and May 2023.

Results

A total of 321 children (aged 5-14 years) were analyzed. The population was classified into allergic [169 (52.6%)], eosinophilic [144 (44.9%)], and overlapping allergic and eosinophilic asthma [97 (30.2%)] phenotypes. Regarding asthma severity, 35.5%, 50.2%, and 14.3% were classified as mild, moderate, and severe, respectively. Of the 321 patients in the study, 124 (38.6%) had at least one asthma exacerbation that required hospitalization. The number of reported missed school days in the previous year was 1571 days [190 (59.2%) patients reported at least one missed school day]. The factors associated with the likelihood of uncontrolled asthma for all study participants included: emergency room (ER) visit last year (OR = 3.7, 95% CI:0.6-15.9]), overlapping eosinophilic and allergic (OR = 3.2, 95% CI = 1.8-5.9), and allergic phenotype (OR = 2.7, 95% CI = 1.3-5.4). The level of asthma control differed significantly among the three asthma phenotypes (p = 0.037).

Conclusion

Allergic asthma is the most prevalent asthma phenotype in this study, followed by the eosinophilic phenotype. The research has also shown that several factors predict uncontrolled asthma, including a family history of asthma, previous admission to the PICU, and previous hospitalization ever. There is, therefore, a definite need for multicenter cohort studies to better understand the phenotypes and endotypes of childhood asthma, as it could offer therapeutic and prognostic relevance.

Understanding progression from pre-school wheezing to school-age asthma: Can modern data approaches help?

Preschool wheezing and childhood asthma create a heavy disease burden which is only exacerbated by the complexity of the conditions. Preschool wheezing exhibits both "curricular" and "aetiological" heterogeneity: that is, heterogeneity across patients both in the time-course of its development and in its underpinning pathological mechanisms. Since these are not fully understood, but clinical presentations across patients may nonetheless be similar, current diagnostic labels are imprecise-not mapping cleanly onto underlying disease mechanisms-and prognoses uncertain. These uncertainties also make a identifying new targets for therapeutic intervention difficult. In the past few decades, carefully designed birth cohort studies have collected "big data" on a large scale, incorporating not only a wealth of longitudinal clinical data, but also detailed information from modalities as varied as imaging, multiomics, and blood biomarkers. The profusion of big data has seen the proliferation of what we term "modern data approaches" (MDAs)-grouping together machine learning, artificial intelligence, and data science-to make sense and make use of this data. In this review, we survey applications of MDAs (with an emphasis on machine learning) in childhood wheeze and asthma, highlighting the extent of their successes in providing tools for prognosis, unpicking the curricular heterogeneity of these conditions, clarifying the limitations of current diagnostic criteria, and indicating directions of research for uncovering the etiology of the diseases underlying these conditions. Specifically, we focus on the trajectories of childhood wheeze phenotypes. Further, we provide an explainer of the nature and potential use of MDAs and emphasize the scope of what we can hope to achieve with them.

What's childhood asthma in French Guiana? A cohort study based on children referred for allergology consultations at the Cayenne hospital center

Background

Asthma is a multifactorial chronic disease, whose most frequent etiology is allergy, especially to Blomia tropicalis. In French Guiana, the childhood prevalence of Blomia T sensitization is unkwown. The aim of this study was to determine the proportion of sensitization to Blomia T and other mites in asthmatic children, and to describe the characteristics of childhood asthma in French Guiana.

Methods

A retrospective cohort study focused on children from 0 to 18 years of age, followed for asthma at the Department of Pediatrics of the Cayenne Hospital Center in French Guiana. All asthmatic children followed by the same paediatric allergist were systematically skin-tested with Bt total extract, and Bt-specific IgE tests were additionally performed to confirm specific sensitization. All follow-up variables were collected from medical records. The outcome was sensitization to Blomia tropicalis and other allergens, and the explanatory variables were those of asthma follow-up. Patients were categorized into Blomia tropicalis sensitization yes/no. Logistic regression analysis was used to assess the relationship between follow-up variables and the outcome.

Results

302 patients were followed: 177 cases of allergic rhinitis, 135 allergic conjunctivitis, 105 atopic dermatitis, 153 food allergy, and 14 cases of drug allergy. Poly-allergy (respiratory, food, skin, and medicinal) was present in 239 children. There were 158 children followed for asthma, of whom 103 (65%) were sensitized to Blomia tropicalis. The median age of the asthmatic children sensitized to Blomia tropicalis was 7 years, and 3 years for those who were not sensitized (p < 0.001). Among the girls (n = 58), 67% were sensitized to Blomia; 97 (92%) asthmatic children co-sensitized to Blomia tropicalis, Dermatophagoides pteronyssinus, and Dermatophagoides farinae. Multivariate analysis showed that the childhood asthma in French Guiana is characterized by a median age of 7 years (p < 0.001), a high prevalence of Blomia tropicalis (p < 0.001), co-sensitization to other mites (p < 0.001), and a high prevalence of co-sensitization to cockroaches (p = 0.006). The area under the ROC curve was close to 0.9, confirming the quality of our model.

Conclusion

In French Guiana, asthma is characterized by a high prevalence of Blomia tropicalis sensitization.

Blood eosinophils during bronchiolitis: Associations with atopy, asthma and lung function in young adults

AIM

To study if blood eosinophils during bronchiolitis were associated with atopy, asthma and lung function in young adults and if these associations differed between respiratory syncytial virus (RSV) bronchiolitis and non-RSV bronchiolitis.

METHODS

This historical cohort enrolled 225 subjects. Blood eosinophils were measured during bronchiolitis in infancy, and the subjects were invited to a follow-up at 17-20 years of age including questionnaires for asthma and examinations of lung function and atopy.

RESULTS

The level of eosinophils was positively associated with subsequent atopy in the unadjusted analysis, but not in the adjusted analysis, and not with asthma. There was a negative association between the level of eosinophils and forced vital capacity (FVC) (-0.11; -0.19, -0.02) and forced expiratory volume in first second (FEV₁ ) (-0.12; -0.21, -0.03) (regression coefficient; 95% confidence interval). The non-RSV group had higher levels of eosinophils during bronchiolitis, but there was no interaction between the level of eosinophils and RSV status for any outcome.

CONCLUSIONS

The level of eosinophils during bronchiolitis was negatively associated with lung function in young adult age, but we found no associations with atopy or asthma. These associations were not different after RSV bronchiolitis compared to non-RSV bronchiolitis.

MicroRNA-146a-5p and microRNA-210-3p Correlate with T Regulatory Cells Frequency and Predict Asthma Severity in Egyptian Pediatric Population

Background

Severe bronchial asthma (BA) affects 5-10% of children, which imposes socioeconomic burden. Therefore, it is crucial to identify biomarkers for risk stratification in children with BA. T regulatory cells (Tregs) play a balancing role in allergic response regulation. We aimed to investigate the relationship between Treg, miR-210-3p, and miR-146a-5p in relation to asthma phenotypes in search of novel biomarkers of disease severity.

Methods

This study included 50 children with BA classified into Group 1 (n = 25) children with mild to moderate asthma and Group 2 (n = 25) children with severe asthma. In addition to 26 control subjects. Flow cytometry was used to detect Tregs. Plasma miR-210-3p and miR-146a levels were determined using quantitative real-time PCR. Patients' FEV1 (Forced Expiratory Volume in the first second) was measured.

Results

miR-210-3p level correlated negatively with Treg frequency (r = -0.828, P < 0.001) and FEV1 (r = -0.621, P < 0.001). The level of miR-146a-5p positively correlated positively with Treg% (r = 0.303, P = 0.032). ROC curve analysis revealed that miR-210-3p was the most sensitive biomarker of severity, with the area under curve (AUC) = 0.923, 96% sensitivity, and 60% specificity. According to multivariate analysis, miR-210-3p is an independent risk factor for BA severity [OR =3.119, P = 0.030], while miR-146a-5p is a protective factor [OR =0.811, P = 0.049].

Conclusion

Treg frequency is linked to FEV1, miR-146a-5p and miR-210-3p in childhood BA. Upregulation of miR-210-3p is a sensitive biomarker and an independent risk factor for BA severity in Egyptian children.

Transcriptomic analysis identified SLC40A1 as a key iron metabolism-related gene in airway macrophages in childhood allergic asthma

Introduction: Asthma is the most common chronic condition in children, with allergic asthma being the most common phenotype, accounting for approximately 80% of cases. Growing evidence suggests that disruption of iron homeostasis and iron regulatory molecules may be associated with childhood allergic asthma. However, the underlying molecular mechanism remains unclear. Methods: Three childhood asthma gene expression datasets were analyzed to detect aberrant expression profiles of iron metabolism-related genes in the airways of children with allergic asthma. Common iron metabolism-related differentially expressed genes (DEGs) across the three datasets were identified and were subjected to functional enrichment analysis. Possible correlations between key iron metabolism-related DEGs and type 2 airway inflammatory genes were investigated. Single-cell transcriptome analysis further identified major airway cell subpopulations driving key gene expression. Key iron metabolism-related gene SLC40A1 was validated in bronchoalveolar lavage (BAL) cells from childhood asthmatics with control individuals by quantitative reverse transcription-polymerase chain reaction (qRT-PCR) and immunofluorescence. The intracellular iron content in BAL cells was assessed by Perls iron staining and the iron levels in BAL supernatant was measured by iron assay to assess airway iron metabolism status in childhood asthmatics. Results: Five common iron metabolism-related DEGs were identified, which were functionally related to iron homeostasis. Among these genes, downregulated SLC40A1 was strongly correlated with type 2 airway inflammatory markers and the gene signature of SLC40A1 could potentially be used to determine type 2-high and type 2-low subsets in childhood allergic asthmatics. Further single-cell transcriptomic analysis identified airway macrophages driving SLC40A1 expression. Immunofluorescence staining revealed colocalization of FPN (encoded by SLC40A1) and macrophage marker CD68. Down-regulation of SLC40A1 (FPN) was validated by qRT-PCR and immunofluorescence analysis. Results further indicated reduced iron levels in the BAL fluid, but increased iron accumulation in BAL cells in childhood allergic asthma patients. Furthermore, decreased expression of SLC40A1 was closely correlated with reduced iron levels in the airways of children with allergic asthma. Discussion: Overall, these findings reveal the potential role of the iron metabolism-related gene SLC40A1 in the pathogenesis of childhood allergic asthma.

Skin Barrier Function and Infant Tidal Flow-Volume Loops-A Population-Based Observational Study

Background: The relationship between the skin barrier- and lung function in infancy is largely unexplored. We aimed to explore if reduced skin barrier function by high transepidermal water loss (TEWL), or manifestations of eczema or Filaggrin (FLG) mutations, were associated with lower lung function in three-month-old infants. Methods: From the population-based PreventADALL cohort, 899 infants with lung function measurements and information on either TEWL, eczema at three months of age and/or FLG mutations were included. Lower lung function by tidal flow-volume loops was defined as a ratio of time to peak tidal expiratory flow to expiratory time (tPTEF/tE) <0.25 and a tPTEF <0.17 s (<25th percentile). A high TEWL >8.83 g/m2/h (>75th percentile) denoted reduced skin barrier function, and DNA was genotyped for FLG mutations (R501X, 2282del4 and R2447X). Results: Neither a high TEWL, nor eczema or FLG mutations, were associated with a lower tPTEF/tE. While a high TEWL was associated with a lower tPTEF; adjusted OR (95% CI) 1.61 (1.08, 2.42), the presence of eczema or FLG mutations were not. Conclusions: Overall, a high TEWL, eczema or FLG mutations were not associated with lower lung function in healthy three-month-old infants. However, an inverse association between high TEWL and tPTEF was observed, indicating a possible link between the skin barrier- and lung function in early infancy.

Pyroptosis and respiratory diseases: A review of current knowledge

Pyroptosis is a relatively newly discovered programmed cell death accompanied by an inflammatory response. In the classical view, pyroptosis is mediated by caspases-1,-4,-5,-11 and executed by GSDMD, however, recently it was demonstrated that caspase-3 and-8 also participate in the process of pyroptosis, by cleaving GSDMD/E and GSDMD respectively. Different from autophagy and apoptosis, many pores are formed on the cell membrane during pyroptosis, which makes the cell membrane lose its integrity, eventually leading to the release of cytokines interleukin(IL)-1β and IL-18. When the body is infected with pathogens or exposed to some stimulations, pyroptosis could play an immune defense role. It is found that pyroptosis exists widely in infectious and inflammatory respiratory diseases such as acute lung injury, bronchial dysplasia, chronic obstructive pulmonary disease, and asthma. Excessive pyroptosis may accompany airway inflammation, tissue injury, and airway damage, and induce an inflammatory reaction, leading to more serious damage and poor prognosis of respiratory diseases. This review summarizes the relationship between pyroptosis and related respiratory diseases.

The association between duration of breastfeeding and childhood asthma outcomes

BACKGROUND

Postnatal exposures, including breastfeeding, may influence asthma development.

OBJECTIVE

To investigate the association between breastfeeding duration and child asthma.

METHODS

We studied 2021 mother-child dyads in the ECHO PATHWAYS consortium of prospective pregnancy cohorts (GAPPS, CANDLE, TIDES). Women reported the duration of any and exclusive breastfeeding and child asthma outcomes during follow-up at child age 4 to 6 years. Outcomes included current wheeze (previous 12 months), ever asthma, current asthma (having ≥2 of current wheeze, ever asthma, medication use in past 12-24 months), and strict current asthma (ever asthma with either or both current wheeze and medication use in past 12-24 months). We used multivariable logistic regression to assess associations (odds ratios and 95% confidence intervals) between breastfeeding and asthma outcomes adjusting for potential confounders. We assessed effect modification by mode of delivery, infant sex, and maternal asthma.

RESULTS

Among women, 33%, 13%, 9%, and 45% reported 0 to less than 2, 2 to 4, 5 to 6, and more than 6 months of any breastfeeding, respectively. The duration of any breastfeeding had a protective linear trend with ever asthma but no other outcomes. There was a duration-dependent protective association of exclusive breastfeeding and child asthma outcomes (eg, current asthma adjusted odds ratio [95% confidence interval], 0.64 [0.41-1.02], 0.61 [0.38-0.98], and 0.52 (0.31-0.87) for 2to 4 months, 5 to 6 months, and more than 6 months, respectively, compared with <2 months). For exclusive breastfeeding, protective associations were stronger in dyads with children born by vaginal vs cesarean delivery although interactions did not reach statistical significance (Pinteractions 0.12-0.40).

CONCLUSION

Longer duration of exclusive breastfeeding had a protective association with child asthma.

Metabolomics of bronchoalveolar lavage in children with persistent wheezing

Background

Recent studies have demonstrated the important role of metabolomics in the pathogenesis of asthma. However, the role of lung metabolomics in childhood persistent wheezing (PW) or wheezing recurrence remains poorly understood.

Methods

In this prospective observational study, we performed a liquid chromatography/mass spectrometry-based metabolomic survey on bronchoalveolar lavage samples collected from 30 children with PW and 30 age-matched infants (control group). A 2-year follow-up study on these PW children was conducted.

Results

Children with PW showed a distinct characterization of respiratory metabolome compared with control group. Children with PW had higher abundances of choline, oleamide, nepetalactam, butyrylcarnitine, l-palmitoylcarnitine, palmitoylethanolamide, and various phosphatidylcholines. The glycerophospholipid metabolism pathway was the most relevant pathway involving in PW pathophysiologic process. Additionally, different gender, prematurity, and systemic corticoids use demonstrated a greater impact in airway metabolite compositions. Furthermore, for PW children with recurrence during the follow-up period, children who were born prematurely had an increased abundance of butyrylcarnitine relative to those who were carried to term.

Conclusions

This study suggests that the alterations of lung metabolites could be associated with the development of wheezing, and this early alteration could also be correlated with wheezing recurrence later in life.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12931-022-02087-6.

Consumption of differently processed milk products and the risk of asthma in children

BACKGROUND

Consumption of unprocessed cow's milk has been associated with a lower risk of childhood asthma and/or atopy. Not much is known about differently processed milk products. We aimed to study the association between the consumption of differently processed milk products and asthma risk in a Finnish birth cohort.

METHODS

We included 3053 children from the Finnish Type 1 Diabetes Prediction and Prevention (DIPP) Nutrition Study. Asthma and its subtypes were assessed at the age of 5 years, and food consumption by food records, at the age of 3 and 6 months and 1, 2, 3, 4, and 5 years. We used conventional and processing (heat treatment and homogenization)-based classifications for milk products. The data were analyzed using a joint model for longitudinal and time-to-event data.

RESULTS

At the age of 5 years, 184 (6.0%) children had asthma, of whom 101 (54.9%) were atopic, 75 (40.8%) were nonatopic, and eight (4.3%) could not be categorized. Consumption of infant formulas [adjusted hazard ratio (95% confidence intervals) 1.15 (1.07, 1.23), p < .001] and strongly heat-treated milk products [1.06 (1.01, 1.10), p = .01] was associated with the risk of all asthma. Consumption of all cow's milk products [1.09 (1.03, 1.15), p = .003], nonfermented milk products [1.08 (1.02, 1.14), p = .008], infant formulas [1.23 (1.13, 1.34), p < .001], and strongly heat-treated milk products [1.08 (1.02, 1.15), p = .006] was associated with nonatopic asthma risk. All these associations remained statistically significant after multiple testing correction.

CONCLUSIONS

High consumption of infant formula and other strongly heat-treated milk products may be associated with the development of asthma.

Gram-negative microbiota is related to acute exacerbation in children with asthma

BACKGROUND

The upper-airway microbiota may be associated with the pathogenesis of asthma and useful for predicting acute exacerbation. However, the relationship between the lower-airway microbiota and acute exacerbation in children with asthma is not well understood. We evaluated the characteristics of the airway microbiome using induced sputum from children with asthma exacerbation and compared the microbiota-related differences of inflammatory cytokines with those in children with asthma.

METHODS

We analysed the microbiome using induced sputum during acute exacerbation of asthma in children. We identified microbial candidates that were prominent in children with asthma exacerbation and compared them with those in children with stable asthma using various analytical methods. The microbial candidates were analysed to determine their association with inflammatory cytokines. We also developed a predictive functional profile using PICRUSt.

RESULTS

A total of 95 children with allergic sensitisation including 22 with asthma exacerbation, 67 with stable asthma, and 6 controls were evaluated. We selected 26 microbial candidates whose abundances were significantly increased, decreased, or correlated during acute exacerbation in children with asthma. Among the microbial candidates, Campylobacter, Capnocytophaga, Haemophilus, and Porphyromonas were associated with inflammatory cytokines including macrophage inflammatory protein (MIP)-1β, programmed death-ligand 1, and granzyme B. Both Campylobacter and MIP-1β levels were correlated with sputum eosinophils. Increased lipopolysaccharide biosynthesis and decreased glycan degradation were observed in children with asthma exacerbation.

CONCLUSION

Gram-negative microbes in the lower airway were related to acute exacerbation in children with asthma. These microbes and associated cytokines may play a role in exacerbating asthma in children.

Rhinovirus Infection and Familial Atopy Predict Persistent Asthma and Sensitisation 7 Years after a First Episode of Acute Bronchiolitis in Infancy

Background: We set out to assess the risk factors for asthma outcome in a cohort of infants who experienced their first episode of acute bronchiolitis. Methods: A cohort of 222 infants who were included during a first episode of acute bronchiolitis was prospectively followed. Herein, we present the results of their assessments (symptom history, skin prick tests, specific IgE assay, respiratory function tests) at age seven. Results: Of the 68/222 (30.6%) children assessed at age seven, 15 (22.05%) presented with asthma and were mainly males (p = 0.033), 14 (20%) had respiratory allergies, 17 (25%) presented atopic dermatitis and none had a food allergy. Family history of atopy was associated with asthma and sensitisation to aeroallergens at age seven (p = 0.003, p = 0.007). Rhinovirus (hRV) infection and rhinovirus/respiratory syncytial virus (RSV) co-infection were significantly associated with asthma at age seven (p = 0.035, p = 0.04), but not with the initial severity of bronchiolitis. Eosinophil counts at ages three and seven were significantly higher in the asthmatics (p = 0.01, p = 0.046). Conclusion: Any infant, especially male, presenting a first episode of acute bronchiolitis due to hRV with a family history of atopy should be closely monitored via follow-up due to a higher risk for asthma at school age.

Association between house dust mites sensitization and level of asthma control and severity in children attending Mansoura University Children’s Hospital

Background

House dust mites (HDM) are considered as a major source of indoor aeroallergen all over the world that precipitate allergic reactions including rhinoconjunctivitis, food allergy, atopic dermatitis, and allergic asthma. In this study, we aimed to assess the clinical and laboratory profile of some Egyptian asthmatic children who are sensitized to house dust mites and determine the association of HDM sensitization and severity of asthma according to recent GINA guidelines.

Results

The most frequent clinical phenotype among the HDM-positive group was a cough (96.7%), while the clinical phenotypic wheeze was frequent in HDM negative group (96.7%). There is a statistically significant difference between studied cases classified according to sensitivity to HDM regarding level of asthma control (50.0% were uncontrolled among cases sensitive to HDM and 56.7% of cases non-sensitive to HDM were controlled (p = 0.001*). Severity according to treatment results was significantly higher among cases sensitive to HDM (26.7% of cases sensitive to HDM versus 3.3% of cases non-sensitive to HDM), p = 0.017.

Conclusions

HDM sensitization is associated mainly with cough asthma phenotype and allergic rhinitis in our studied cases. HDM sensitization increases asthma severity and decreases the ability to control asthma symptoms.

Trial registration

ClinicalTrial.gov, NCT04958616.

Determining the Best Tool Comparable with Global Initiative for Asthma Criteria for Assessing Pediatric Asthma Control

Background: Guidelines such as Global Initiative for Asthma (GINA) recommend disease control as the mainstay of asthma management. Objective: To investigate which measure of asthma control best correlates with the GINA criteria for determining asthma control in children. Methods: Child asthma-patients at a tertiary hospital were enrolled in the study after evaluation of response to treatment. Asthma control test (ACT)/pediatric asthma control test (PACT), Pediatric Asthma Quality of Life Questionnaire (PAQLQ), fractional exhaled nitric oxide (FeNO), and lung function parameters were evaluated. Patients were examined by asthma specialists and control status was evaluated based on GINA. Results: The median age (interquartile range) of patients was 10.7 (8.4-12.9) years, 57.9% of patients were boys. Of 228 children, 84.2%, 9.6%, and 6.1% displayed "well-controlled", "partially controlled", and "uncontrolled" asthma, respectively, according to GINA. The patients with "partially controlled" and "uncontrolled" asthma were grouped as "not well-controlled." The cutoff levels were 22, 21, and 5.9 for PACT, ACT, and PAQLQ, respectively, for determining "well-controlled" asthma (P < 0.001). With these cutoff values, ACT exhibited higher comparability with GINA than PACT and PAQLQ (κ = 0.473, 0.221, and 0.150, respectively, P < 0.001). PAQLQ had higher agreement with GINA criteria in children ≥12 years old (κ = 0.326, P < 0.001 and κ = 0.151, P = 0.014, respectively). Correctly classified patients with PACT, ACT, and PALQLQ based on GINA with these cutoff levels were 93 (64.1%), 63 (75.9%), and 139 (62.9%), respectively. FeNO and lung function parameters were unsuccessful at revealing control status according to GINA. Conclusion: ACT is better than PACT for comparability with GINA. Better correlation of PAQLQ and ACT and better comparability of PAQLQ and GINA were evident in older children.

Pre and postnatal exposure to mercury and respiratory health in preschool children from the Spanish INMA Birth Cohort Study

Effects of mercury on maturing immune system have been reported, however the association with respiratory and allergy problems during infancy remains unclear. The aim of this study is to evaluate the association between pre and postnatal mercury exposure and respiratory and allergy problems among preschool children and to examine the role of potential modifying factors. Study subjects were children participant in Spanish Childhood and Environment Project (INMA, 2003-2008). We measured total mercury levels in cord blood (n = 1868) and hair at 4 years of age (n = 1347). Respiratory outcomes (wheezing, severe wheezing, chestiness, persistent cough, eczema and otitis) were obtained by questionnaires administered to parents. Associations were investigated by logistic regression adjusted for socio-demographic and lifestyle-related variables in each cohort and subsequent meta-analysis. We tested effect modification by factors related to individual susceptibility, diet and co-exposure with other pollutants. The geometric mean of cord blood and hair total mercury was 8.20 μg/L and 0.97 μg/g, respectively. No statistically significant association between pre or postnatal mercury exposure and respiratory and allergy outcomes was found. Notwithstanding, lower maternal intake of fruits and vegetables increased the risk of some respiratory outcomes due to the prenatal exposure to mercury (p_int < 0.05). Moreover, an inverse association between prenatal mercury exposure and some respiratory outcomes was observed among children with higher maternal exposure to organocholorine compounds or smoking (p_int < 0.05). Also, sex and postnatal smoking exposure modulated mercury postnatal effects on persistent cough (p_int < 0.05). In conclusion, no association between pre and postnatal mercury exposure and respiratory and allergy problems among the whole population at study was found. However, diet and other toxicants could modulate this relation, especially during prenatal period. More research on this topic is warranted due to the limited evidence.

Follow-up study of airway microbiota in children with persistent wheezing

Background

Increasing evidence revealed that airway microbial dysbiosis was associated with increased risk of asthma, or persistent wheezing (PW). However, the role of lung microbiota in PW or wheezing recurrence remains poorly understood.

Methods

In this prospective observational study, we performed a longitudinal 16S rRNA-based microbiome survey on bronchoalveolar lavage (BAL) samples collected from 35 infants with PW and 28 age-matched infants (control group). A 2-year follow-up study on these PW patients was conducted. The compositions of lower airway microbiota were analyzed at the phylum and genus levels.

Results

Our study showed a clear difference in lower airway microbiota between PW children and the control group. Children with PW had a higher abundance of Elizabethkingia and Rothia, and lower abundance of Fusobacterium compared with the control group. At the end of the 2-year follow-up, 20 children with PW (57.1%) experienced at least one episode of wheezing, and 15 (42.9%) did not suffer from wheezing episodes. Furthermore, PW children with recurrence also had increased abundances of Elizabethkingia and Rothia relative to those who had no recurrence. Additionally, wheezing history, different gender, and caesarean section demonstrated a greater impact in airway microbiota compositions.

Conclusion

This study suggests that the alterations of lower airway microbiota could be strongly associated with the development of wheezing, and early airway microbial changes could also be associated with wheezing recurrence later in life.

Vitamin D Supplementation: Oxidative Stress Modulation in a Mouse Model of Ovalbumin-Induced Acute Asthmatic Airway Inflammation

Asthma oxidative stress disturbances seem to enable supplementary proinflammatory pathways, thus contributing to disease development and severity. The current study analyzed the impact of two types of oral vitamin D (VD) supplementation regimens on the redox balance using a murine model of acute ovalbumin-induced (OVA-induced) asthmatic inflammation. The experimental prevention group received a long-term daily dose of 50 µg/kg (total dose of 1300 µg/kg), whereas the rescue group underwent a short-term daily dose of 100 µg/kg (total dose of 400 µg/kg). The following oxidative stress parameters were analyzed in serum, bronchoalveolar lavage fluid (BALF) and lung tissue homogenate (LTH): total oxidative status, total antioxidant response, oxidative stress index, malondialdehyde and total thiols. Results showed that VD significantly reduced oxidative forces and increased the antioxidant capacity in the serum and LTH of treated mice. There was no statistically significant difference between the two types of VD supplementation. VD also exhibited an anti-inflammatory effect in all treated mice, reducing nitric oxide formation in serum and the expression of nuclear factor kappa B p65 in the lung. In conclusion, VD supplementation seems to exhibit a protective role in oxidative stress processes related to OVA-induced acute airway inflammation.

Molecular analysis of phenotypic interactions of asthma

INTRODUCTION

Asthma is a heterogeneous disease characterized by multiples respiratory symptoms; this is a polygenic entity that involves a complex interaction of environmental factors and inherent to the individual. To understand the development of asthma, some phenotypes have been proposed.

OBJECTIVE

This work's purpose was to explore different molecules related to asthma development and to define each phenotype's specific characteristics.

MATERIAL AND METHODS

96 adult patients diagnosed with asthma before any treatment were enrolled in the protocol. Spirometric parameters, circulating leukocytes, serum IgE, body mass index, exhaled nitric oxide (FENO), and leukotrienes (LTB4) in urine were determined in each patient. The presence of asthma phenotypes proposed by the Global Initiative for Asthma (GINA) were explored: A) Allergic asthma, B) Non-allergic asthma, C) Late-onset asthma, D) Asthma with persistent airflow limitation, and E) Asthma with overweight and obesity.

RESULTS

In the cohort analyzed, we found four of phenotypes proposed by GINA; however, these phenotypes overlapped, due to this, 4 groups were integrated with allergic, non-allergic and obese patients, which were the main phenotypes. The main overlap was that of patients not-obese allergic, and was characterized by earlier onset, elevated levels of IgE, LTB4 and inflammasome related cytokines. Non-allergic patients had a significant association between interleukin (IL)-18 and IL-18 binding protein (BP) with narrow ratio between these cytokines. Finally, LTB4 had remarkable capacity to discriminate between allergic and not allergic patients.

CONCLUSIONS

Asthmatic phenotypes exist as interrelated characteristics and not as discrete entities. High levels of leukotrienes and IgE are hallmarks in the allergic phenotype of asthma.

Asthma phenotypes and endotypes in childhood

Asthma is a very heterogeneous disease and since early childhood many classifications have been proposed according to phenotype and endotype. The phenotype includes the clinical features of asthma such as age of onset, triggers, comorbidities, response to treatment and evolution over time. The endotype is more difficult to define, includes the underlying immunopathological mechanisms of the disease and requires reliable biomarkers. A deep knowledge of phenotype and endotype of the patient may guide a tailored therapeutic approach. In this review the main phenotypes and endotypes of asthma acknowledged in children will be discussed.

The Effect of Passive Exposure to Tobacco Smoke on the Immune Response in Children with Asthma

Introduction: There are a few publications about the impact of tobacco smoke on the children's immune system. Material and Methods: The study group consisted of 43 children with asthma. The control group consisted of 37 healthy children. The exposure to tobacco smoke was assessed by the presence of the cotinine in the urine (metabolit of nicotine). Results: The group of children with asthma exposed to tobacco smoke had significantly higher levels of the IL-1 and lower levels IL-4 than children not exposed to the passive smoking. The children from the control group exposed to tobacco smoke had a significantly higher concentration of IL-4 than unexposed children. In the whole analyzed population, there was a significant positive correlation between cotinine-IL1 and cotinine-CRP. Conclusion: In this study we found that the passive exposure to tobacco smoke has the immunomodulatory effects on the immune system.

Heterogeneity of Childhood Asthma in Korea: Cluster Analysis of the Korean Childhood Asthma Study Cohort

PURPOSE

Asthma is a heterogeneous airway disease occurring in children, and it has various clinical phenotypes. A clear differentiation of the clinical phenotypes can provide better asthma management and prediction of asthma prognosis. Little is currently known about asthma phenotypes in Korean children. This study was designed to identify asthma phenotypes in school-aged Korean children.

METHODS

This study enrolled 674 children with physician-diagnosed asthma from the Korean childhood Asthma Study (KAS) cohort. The physicians verified the relevant histories of asthma and comorbid diseases, as well as airway lability and hyper-responsiveness from the results of pulmonary function tests and bronchial provocation tests. Questionnaires regarding the participants' baseline characteristics, their environment and self-rating of asthma control were collected at the time of enrollment. Laboratory tests were performed to assess allergy and airway inflammation. Children with asthma were classified by hierarchical cluster analysis.

RESULTS

Of the 674 patients enrolled from the KAS cohort, 447 were included in the cluster analysis. Cluster analysis of these 447 children revealed 4 asthma phenotypes: cluster 1 (n = 216, 48.3%) which was characterized by male-dominant atopic asthma; cluster 2 (n = 79, 17.7%) which was characterized by early-onset atopic asthma with atopic dermatitis; cluster 3 (n = 47, 10.5%) which was characterized by puberty-onset, female-dominant atopic asthma with the low lung function; and cluster 4 (n = 105, 23.5%) which was characterized by early-onset, non-atopic dominant asthma.

CONCLUSIONS

The asthma phenotypes among Korean children can be classified into 4 distinct clusters. Long-term follow-up with these phenotypes will be needed to define their prognosis and response to treatment.

Presence of Allergies and Their Impact on Sleep in Children Who Stutter

Purpose

Population-based research has identified insomnia or trouble sleeping, sleepiness during the day, and fatigue during the day as frequent coexisting conditions in children who stutter (CWS). Considering that allergies are well known to disturb sleep, the purpose of this study was to explore if there is an association between the presence of allergies and sleep issues among CWS, as well as if allergies are frequent in CWS.

Method

Data from the 2012 National Health Interview Survey were used. Children used in this sample were those whose caregivers answered definitively whether or not the child stuttered within the past 12 months. Additionally, caregivers identified the presence of allergies and/or asthma and the presence of insomnia or trouble sleeping in the sample child.

Results

The sample included 200 CWS and 9,951 children who do not stutter (CWNS). The odds of insomnia/trouble sleeping were greater in CWS who present with allergies and/or asthma, with the exception of food allergy, compared to CWS who do not present with with allergies and/or asthma. Additionally, the odds of insomnia/trouble sleeping were greater in CWS without any allergy, asthma, and coexisting disability ( OR = 7.48, p < .001) as compared to CWNS without any allergy, asthma, and coexisting disability. The presence of either any allergy or an asthma attack was higher among CWS (46.4%) compared to CWNS (29.5%), p < .001. Specifically, CWS were found to be at greater odds of presenting with any kind of respiratory allergy ( OR = 1.72, p = .034), food allergy ( OR = 2.32, p = .002), and skin allergy ( OR = 1.84, p = .009) than CWNS.

Conclusions

CWS were found to be at greater odds of allergies and asthma, conditions that also impair sleep. Interestingly, insomnia/trouble sleeping was prevalent among CWS, even when allergies, asthma, and coexisting disabilities were not present. The possible implications of these findings are discussed.

Effects of low exposure to traffic related air pollution on childhood asthma onset by age 10 years

Although NO₂, a major traffic related air pollutant, has been associated with onset of childhood asthma, young children may be more susceptible to traffic related air pollution exposure compared to other individuals. We linked data from National Longitudinal Survey of Children and Youths Cycle 1-5 (1994-2003) and the National Air Pollution Surveillance Program to determine the association between NO₂ exposure and either early or late onset childhood asthma phenotypes. Children diagnosed with asthma from age 0-3 were defined as having early onset asthma. Children diagnosed with asthma from age 4-9 were defined as having late onset asthma. Mean NO₂ exposure for each quartile was 6.31 ppb, 9.45 ppb, 11.83 ppb, and 17.9 ppb. Higher levels of NO₂ exposure were more strongly associated with early childhood asthma (Quartile 3 OR: 2.11, 95% CI: 1.29, 3.44, Quartile 4 OR: 2.16, 95% CI: 1.27, 3.68) compared to the lowest level of NO₂ exposure (Quartile 1). No such association was observed with risk of late childhood asthma onset. Asthma susceptibility to NO₂ exposure may vary with the childhood developmental stage, and young children may be susceptible to NO₂ exposure at levels well below national and international guidelines. Our study emphasizes the importance of considering the timing of childhood asthma onset in future studies and confirms the increased risk of early onset of childhood asthma associated even with relatively low NO₂ exposure levels.

Assessment of asthma severity according to treatment steps in Japanese pediatric patients: a descriptive cross-sectional study using an administrative claims database

OBJECTIVES

Japan has one of the highest asthma prevalence rates in Asia; however, there is a lack of epidemiological studies on asthma among children in Japan. This study aimed to describe the severity of asthma and the prescription patterns for its treatment among pediatric patients, by using a large-scale claims database.

METHODS

The analysis datasets were extracted from the JMDC database for the period of April 1, 2009 to March 30, 2015; included records were restricted to patients between 2 and 15 years of age. The Japanese Pediatric Guidelines for the treatment and management of asthma (JPGL) steps were used as a proxy for asthma treatment and severity. We also described the characteristics of asthma in children by stratifying the prevalence and incidence cohorts by index years.

RESULTS

In the prevalence cohort (56% male), from 2010 to 2014, approximately 80-90% of the children received step 1 or 2 treatment, with the remainder receiving step 3 or 4 treatment, as defined by the JPGL. The majority (approximately 90%) of patients visited clinics for asthma treatment, while a minority visited hospitals.

CONCLUSIONS

Our study showed the severity of asthma among Japanese pediatric patients, as well as their demographic characteristics, using a large-scale claims database. The majority of pediatric asthma patients received treatment for mild-to-moderate asthma, while less than 10% received treatment for severe asthma.

Precision medicine in atopic diseases

PURPOSE OF REVIEW

To analyze the status of precision medicine in atopic diseases.

RECENT FINDINGS

Atopic diseases are increasingly recognized as heterogeneous in nature and they can be quite different in severity, response to therapy, triggers, genetic back ground, ancestral risk and type of inflammation. This significant variability in the landscape of atopic diseases is not reflected in the common treatment guidelines that follow 'one fits all' approach for their management. Such an approach is largely based on minimal 'phenotype' elements, such as severity of disease and response to therapy and does not reflect the information accumulate in the last 20 years about particular pathogenic pathways (endotypes) leading to disease (phenotypes) based on biomolecular analysis of the single individuals. Accumulating data have defined asthma allergic rhinitis, food allergy based on their endotypes and clinically relevant phenotypes. In general, atopic diseases can be largely classified as high or low Th2 inflammatory status, which may explain the severity and response to therapy.

SUMMARY

Precision medicine is aiming to use known endotype phenotype to guide specific individualized treatment. The work aimed in deep characterization of diseases to guide the disease management is crucial in light of the availability of ever more precise treatment able to target specific pathways.

Monoclonal Antibody Therapy in Childhood Asthma

PURPOSE OF REVIEW

There has been an explosion of monoclonal antibodies in the treatment of severe uncontrolled adult asthma. Studies have now been published in severe pediatric asthma. There are numerous questions that need to be answered in determining whether these modalities are appropriate and safe in children.

RECENT FINDINGS

This is a narrative review examining the latest pediatric literature on monoclonal antibodies, both approved and in the pipeline, for uncontrolled asthma. Presently, all of the biologics are positioned to treat patients with underlying type 2 high disease. Two monoclonal antibodies are approved for children 6 years of age and older, omalizumab and mepolizumab, with more likely approved in the near future. The effect of these agents in controlling severe pediatric asthma is promising. Data is limited to long-term efficacy and safety, and whether any agent has an effect on the natural history of asthma.

Sensitisation to aeroallergens in relation to asthma and other allergic diseases in Angolan children: a cross-sectional study

INTRODUCTION AND OBJECTIVES

In Africa, few studies of sensitisation profiles have been performed in children or adolescents and, in Angola, there are none. The objectives of the present study were to assess the sensitisation profile of Angolan schoolchildren and to determine the relationship between that pattern, sociodemographic factors, asthma and other allergic diseases.

MATERIALS AND METHODS

Cross-sectional, observational study in 5-14-year-old children, performed between September and November 2017, in the Province of Bengo, Angola. Five schools (15%) were randomly selected in the geographical area of the study: three from an urban area, and two from a rural area. Data were collected using the Portuguese versions of the ISAAC questionnaires for children and adolescents, regarding asthma, rhinitis and eczema. Skin prick tests (SPT) were performed with a battery of 12 aeroallergens. Stools were assessed for the presence of helminths. Descriptive statistics were used, as well as univariate calculation of odds ratios.

RESULTS

Sensitisation to aeroallergens was low (8%) and most sensitised children were asymptomatic. Most frequent sensitisations involved house dust mites, cockroach or fungi, and a high proportion of children (78.1%) were monosensitised. No relationship was detected between sensitisations and asthma, rhinitis or eczema. Place of residence, gender, age or helminthic infection did not affect the probability of having positive SPTs.

CONCLUSIONS

The most frequent sensitisations in children from Bengo Province in Angola involve house dust mites, followed by cockroach and fungi. No relationship was found between atopic sensitisation and asthma or other allergic diseases.

Developments in the field of allergy in 2017 through the eyes of Clinical and Experimental Allergy

In this article, we described the development in the field of allergy as described by Clinical and Experimental Allergy in 2017. Experimental models of allergic disease, basic mechanisms, clinical mechanisms, allergens, asthma and rhinitis and clinical allergy are all covered.

Associations between Neighborhood Walkability and Incident and Ongoing Asthma in Children

RATIONALE

Childhood asthma has shown variable associations with children's physical activity. Neighborhood walkability captures community features that promote walking and is protective against some chronic conditions, such as obesity and diabetes.

OBJECTIVES

We evaluated associations between home neighborhood walkability and incident and ongoing childhood asthma.

METHODS

In this population-based cohort study, we used prospectively collected administrative healthcare data for the Province of Ontario housed at the Institute for Clinical Evaluative Sciences. We followed an administrative data cohort of 326,383 Toronto children born between 1997 and 2003, inclusive, until ages 8-15 years. Home neighborhood walkability quintile was measured using a validated walkability index with four dimensions: population density, dwelling density, access to retail and services, and street connectivity. Incident asthma was defined by time of entry into the validated Ontario Asthma Surveillance Information System database, which requires two outpatient visits for asthma within two consecutive years or any hospitalization for asthma and follows children with asthma longitudinally starting at any age. Associations between walkability and incident asthma were examined using Cox proportional hazards models. Associations between ongoing asthma and walkability in each year of life were examined using generalized linear mixed models.

RESULTS

Twenty-one percent of children (n = 69,628) developed incident asthma and were followed longitudinally in the Ontario Asthma Surveillance Information System database. Low birth home neighborhood walkability was associated with an increased incidence of asthma (hazard ratio, 1.11; 95% confidence interval, 1.08-1.14). Among children with asthma, low walkability in a given year of a child`s life was associated with greater odds of ongoing asthma in the same year (odds ratio, 1.12; 95% confidence interval, 1.09-1.14).

CONCLUSIONS

Children living in neighborhoods with low walkability were at increased risk of incident and ongoing asthma. Neighborhood walkability improvement, such as by adding pedestrian paths to improve street connectivity, offers potential strategies to contribute to primary asthma prevention.

The etiologic origins for chronic obstructive pulmonary disease

COPD, characterized by long-term poorly irreversible airway limitation and persistent respiratory symptoms, has resulted in enormous challenges to human health worldwide, with increasing rates of prevalence, death, and disability. Although its origin was thought to be in the interactions of genetic with environmental factors, the effects of environmental factors on the disease during different life stages remain little known. Without clear mechanisms and radical cure for it, early screening and prevention of COPD seem to be important. In this review, we will discuss the etiologic origins for poor lung function and COPD caused by specific adverse effects during corresponding life stages, as well as try to find new insights and potential prevention strategies for this disease.

Exploring the Utility of Noninvasive Type 2 Inflammatory Markers for Prediction of Severe Asthma Exacerbations in Children and Adolescents

BACKGROUND

Noninvasive markers of type 2 inflammation are needed to identify children and adolescents who might benefit from personalized biologic therapy.

OBJECTIVE

We hypothesized that blood eosinophil counts would predict 1 or more acute visits for asthma and that prediction could be improved with the addition of a second, noninvasive type 2 inflammatory biomarker.

METHODS

Children and adolescents 5 to 21 years (N = 589) with an asthma exacerbation necessitating systemic corticosteroid treatment in the previous year completed a characterization visit and telephone calls at 6 and 12 months. The primary outcome was an acute visit for asthma with receipt of systemic corticosteroids. Acute visits were verified by medical record review. Exploratory outcomes included time to first acute visit and hospitalization.

RESULTS

Acute visits occurred in 106 (35.5%) children and 72 (24.8%) adolescents. Elevated blood eosinophils were associated with increased odds and shorter time to first acute visit, but optimal cut-points differed by age (≥150 vs ≥300 cells/μL for children vs adolescents, respectively). The addition of a second marker of type 2 inflammation did not improve prediction in children, but increased the odds and hazard of an acute visit up to 16.2% and 11.9%, respectively, in adolescents. Similar trends were noted for hospitalizations.

CONCLUSIONS

Blood eosinophils and other noninvasive markers of type 2 inflammation may be useful in the clinical assessment of children and adolescents with asthma. However, features of type 2 inflammation vary by age. Whether children and adolescents also respond differently to management of type 2 inflammation is unclear and warrants further evaluation.

Causes of variability in latent phenotypes of childhood wheeze

BACKGROUND

Latent class analysis (LCA) has been used extensively to identify (latent) phenotypes of childhood wheezing. However, the number and trajectory of discovered phenotypes differed substantially between studies.

OBJECTIVE

We sought to investigate sources of variability affecting the classification of phenotypes, identify key time points for data collection to understand wheeze heterogeneity, and ascertain the association of childhood wheeze phenotypes with asthma and lung function in adulthood.

METHODS

We used LCA to derive wheeze phenotypes among 3167 participants in the ALSPAC cohort who had complete information on current wheeze recorded at 14 time points from birth to age 16½ years. We examined the effects of sample size and data collection age and intervals on the results and identified time points. We examined the associations of derived phenotypes with asthma and lung function at age 23 to 24 years.

RESULTS

A relatively large sample size (>2000) underestimated the number of phenotypes under some conditions (eg, number of time points <11). Increasing the number of data points resulted in an increase in the optimal number of phenotypes, but an identical number of randomly selected follow-up points led to different solutions. A variable selection algorithm identified 8 informative time points (months 18, 42, 57, 81, 91, 140, 157, and 166). The proportion of asthmatic patients at age 23 to 24 years differed between phenotypes, whereas lung function was lower among persistent wheezers.

CONCLUSIONS

Sample size, frequency, and timing of data collection have a major influence on the number and type of wheeze phenotypes identified by using LCA in longitudinal data.

Maternal and neonatal 25-hydroxyvitamin D concentrations and school-age lung function, asthma and allergy. The Generation R Study

BACKGROUND

Vitamin D deficiency in early life might affect the developing lung and immune system, and subsequently influence the risk of asthma and allergy in later life.

OBJECTIVE

We examined the associations of 25-hydroxyvitamin D concentrations in mid-gestation and at birth with lung function, asthma, inhalant allergic sensitization and inhalant allergy at school-age.

METHODS

This study among 4951 children and their mothers was embedded in a population-based prospective cohort in Rotterdam, the Netherlands. Maternal venous blood samples in mid-gestation and umbilical cord blood samples at birth were used to determine 25-hydroxyvitamin D concentrations. At age 10 years, lung function was measured by spirometry, current asthma and physician-diagnosed inhalant allergy by questionnaire, and inhalant allergic sensitization by skin prick tests. We used multivariable regression models to examine associations.

RESULTS

Higher 25-hydroxyvitamin D concentrations in mid-gestation were associated with a higher forced vital capacity (FVC), but a lower forced expiratory volume in 1 second/FVC (FEV₁ /FVC) and a lower forced expiratory flow after exhaling 75% of FVC (FEF₇₅ ) (Z-score differences [95% CI] 0.02 [0.00, 0.03], -0.02 [-0.03, -0.01] and -0.01 [-0.03, -0.00], respectively, per 10 nmol/L 25-hydroxyvitamin D), but not with asthma. Furthermore, higher 25-hydroxyvitamin D concentrations in mid-gestation were associated with an increased risk of inhalant allergy (Odds Ratio [95% CI] 1.07 [1.02, 1.12]), but not with inhalant allergic sensitization. After additional adjustment for child's 25-hydroxyvitamin D concentrations at the age of 6 years, only the associations of 25-hydroxyvitamin D concentrations in mid-gestation with FEV₁ /FVC and FEF₇₅ remained. We did not find consistent associations of 25-hydroxyvitamin D concentrations at birth with respiratory or allergy outcomes.

CONCLUSION AND CLINICAL RELEVANCE

Our results suggest that maternal 25-hydroxyvitamin D concentrations in mid-gestation may influence lung development. The clinical implications of the observed associations remain unclear.

Asthma phenotypes and associated comorbidities in a large cohort of adolescents in Israel

Objectives: Asthma is a multifactorial, heterogeneous, complex and common chronic respiratory disease driven by diverse mechanisms. Although asthma presents various clinical forms with different levels of severity, it is unclear whether asthma severities are a consequence of disease management or varied etiologies. We sought to investigate this question.Methods: This article presents a cross-sectional study of 113,671 Israeli adolescents. Univariate and multivariable logistic regression models were performed to analyze the independent associations between mild asthma and moderate-to-severe asthma phenotypes and coexistent medical conditions within each gender separately. Hierarchical clustering of the odds ratios of the diverse statistically significant medical conditions associated with asthma severity-gender groups was also performed. We focused on the allergic and neurological-cognitive-mental disorders.Results: Among males, two associations were common to both asthma groups (atopic dermatitis and allergic rhinitis), five unique to mild asthma (urticaria/angioedema, Hymenoptera/bee allergies, allergic conjunctivitis, epilepsy and migraine) and two unique to moderate-to-severe asthma (learning disabilities and ADD/ADHD (Attention-deficit disorder/Attention-deficit/hyperactivity disorder)). Among females, two associations were common to both clinical asthma groups (allergic rhinitis and urticaria/angioedema), and five unique to moderate-to-severe asthma (atopic dermatitis, learning disabilities, ADD/ADHD, anxiety/mood disorders and migraine). Allergic rhinitis was the only condition to be associated with all four groups. Learning disabilities and ADD/ADHD were only associated with moderate-to-severe asthma (but not with mild asthma), in both males and females. Hierarchical clustering analysis uncovered two prominent clusters, separating mild from moderate-to-severe asthma.Conclusions: The differences between mild and moderate-to-severe asthma enhance asthma phenotype characterization, with respect to comorbidities, and indicate varied etiologies.

Exposure to Vitamin D Fortification Policy in Prenatal Life and the Risk of Childhood Asthma: Results From the D-Tect Study

Prenatal vitamin D insufficiency may be associated with an increased risk of developing childhood asthma. Results from epidemiological studies are conflicting and limited by short follow-up and small sample sizes. The objective of this study was to examine if children born to women exposed to the margarine fortification policy with a small dose of extra vitamin D during pregnancy had a reduced risk of developing asthma until age 9 years, compared to children born to unexposed women. The termination of a Danish mandatory vitamin D fortification policy constituted the basis for the study design. We compared the risk of inpatient asthma diagnoses in all Danish children born two years before (n = 106,347, exposed) and two years after (n = 115,900, unexposed) the termination of the policy. The children were followed in the register from 0–9 years of age. Data were analyzed using Cox proportional hazards regression. The Hazard Ratio for the first inpatient asthma admission among exposed versus unexposed children was 0.96 (95%CI: 0.90–1.04). When stratifying by sex and age, 0–3 years old boys exposed to vitamin D fortification showed a lower asthma risk compared to unexposed boys (HR 0.78, 95%CI: 0.67–0.92). Prenatal exposure to margarine fortification policy with extra vitamin D did not affect the overall risk of developing asthma among children aged 0–9 years but seemed to reduce the risk among 0–3 years old boys. Taking aside study design limitations, this could be explained by different sensitivity to vitamin D from different sex-related asthma phenotypes in children with early onset, and sex differences in lung development or immune responses.