Uncontrolled asthma from childhood to young adulthood associates with airflow obstruction

IntroductionLung function development from childhood to young adulthood is important for lung health later in life. We investigated the association between asthma control and lung function from 8 to 24 years of age.MethodsA total of 668 participants from the population-based BAMSE cohort study, with persistent or incidental asthma and between 8 and 24 years of age, were included. Asthma was defined as controlled or uncontrolled at each examination based on the Global Initiative for Asthma (GINA) criteria. Dynamic spirometry was performed at 8, 16 and 24 years of age. Associations between uncontrolled asthma and pre-bronchodilation forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC) and FEV1/FVC ratio were evaluated with a generalised estimating equation model, as overall associations and at each examination. Unadjusted and adjusted (for sex, current asthma, allergic sensitisation, body mass index, smoking, smoke exposure, inhaled corticosteroid use) analyses were done; and were thereafter stratified by sex, elevated blood eosinophils (≥0.3×109 cells·µL−1), elevated FENO (≥25 ppb), allergic sensitisation and ever/never smoking.ResultsUncontrolled asthma was associated with a lower overall FEV1/FVC z-score from 8 to 24 years of age (adjusted regression coefficient −0.11; 95% CI (−0.20 to −0.02; p=0.016). After stratification, this association was primarily seen among females (adjusted regression coefficient −0.170; 95% CI (−0.298 to −0.044; p=0.009) and participants with elevated FENO (regression coefficient −0.207; 95% CI −0.342 to −0.073; p=0.002), in contrast to males and participants with normal FENO.ConclusionUncontrolled asthma is associated with airflow obstruction from childhood to young adulthood. This highlights the importance of active management of asthma during growth.

The evidence for interventions in early childhood allergy prevention – towards a living systematic review: protocol

Background: Research in early childhood allergy prevention (ECAP) is flourishing and new intervention strategies have proven to be promising. Due to the dynamic nature of ECAP, gaps between what is known and how guidelines inform practice are likely. A living systematic review (LSR) can narrow this gap by incorporating new evidence as it becomes available. No efficacy comparisons across various ECAP interventions for similar outcomes have been carried out. Networks of randomised clinical trials can be evaluated in the context of a network meta-analysis (NMA). We aim to establish a LSR on the efficacy and safety of any intervention investigated in randomised controlled trials (RCT) to prevent the occurrence of allergic sensitisation (AS), symptoms or diagnoses of allergic diseases in infancy and early childhood (0-3 years). Methods: A baseline SR will synthesise the evidence from existing SRs of RCTs as well as RCTs not yet considered in these. After completion of the baseline SR we propose to conduct a LSR. Using this methodology, we aim to undertake constant evidence surveillance, three-monthly search updates, and review updates every three months, should new evidence emerge. Conclusions: The ECAP evidence landscape has undergone dramatic transformations and this process is likely to continue. As a response to this, a LSR offers the potential to allow more timely synthesis of new evidence as it emerges. Long gaps between updates of SRs makes it harder for guidelines and recommendations to be up to date. Users of information, such as parents, may be confused if they encounter new evidence that is not part of a trusted guideline. A LSR approach allows us to continuously search the literature and update the evidence-base of existing ECAP interventions resulting in a decreased timespan from evidence accrual to informing clinical practice.

The Role of the Environment and Exposome in Atopic Dermatitis

Purpose of review Atopic dermatitis (AD) is a chronic inflammatory skin disorder affecting up to 20% of children and up to 5% of adults worldwide, contributing to significant disease-related morbidity in this patient cohort. Its aetiopathogenesis is underpinned by multiple factors, including genetic susceptibility, skin barrier defects, a skewed cutaneous immune response and microbiome perturbation in both the skin and the gut. In this review, we aim to examine the biological effects of key environmental exposures (the sum of which is termed the “exposome”) at the population, community and individual levels in order to describe their effect on AD pathogenesis. Recent findings It is now understood that as well as considering the type of environmental exposure with regard to its effect on AD pathogenesis, the dosage and timing of the exposure are both critical domains that may lead to either exacerbation or amelioration of disease. In this review, we consider the effects of population-wide exposures such as climate change, migration and urbanization; community-specific exposures such as air pollution, water hardness and allergic sensitisation; and individual factors such as diet, microbiome alteration, psychosocial stress and the impact of topical and systemic therapy. Summary This review summarises the interaction of the above environmental factors with the other domains of AD pathogenesis, namely, the inherent genetic defects, the skin barrier, the immune system and the cutaneous and gut microbiota. We specifically emphasise the timing and dosage of exposures and its effect on the cellular and molecular pathways implicated in AD.

Childhood CCL18, CXCL10 and CXCL11 levels differentially relate to and predict allergy development

Background: Chemokines are important mediators in immune cell recruitment, contributing to allergy development. However, extensive studies of chemokines in the circulation in relation to the presence and development of allergic diseases remain scarce. Our aim was to investigate associations of circulating allergy-related chemokines with development of asthma and sensitisation cross-sectionally and longitudinally in a population-based cohort. Methods: The chemokines CCL17, CCL22, CXCL10, CXCL11 and CCL18 were measured in plasma samples from children in the Manchester Asthma and Allergy Study. Samples were available from cord blood at birth (n=376), age 1 (n=195) and 8 years (n=334). Cross-sectional and longitudinal association analyses were performed in relation to asthma and allergic sensitisation, as well as allergic phenotype clusters previously derived using machine learning in the same study population. Results: In children with asthma and/or allergic sensitisation, CCL18 levels were consistently elevated at ages 1 and/or 8 years. In a longitudinal model including information on asthma from 4 time-points (ages 5, 8, 11 and 16 years), we observed a significant association between increasing CCL18 levels at age 1 and a higher risk of asthma from early school age to adolescence (OR=2.9, 95% CI 1.1-7.6, p=0.028). We observed similar associations in longitudinal models for allergic sensitisation. Asthma later in life was preceded by increased CXCL10 levels after birth, and decreased CXCL11 levels at birth. Conclusion: Elevated CCL18 levels throughout childhood precede the development of asthma and allergic sensitisation. The Th1-associated chemokines CXCL10 and CXCL11 also associated with development of both outcomes, with differential temporal effects.

Contributions of asthma, rhinitis, and IgE to exhaled nitric oxide in adolescents

Fractional exhaled nitric oxide (FeNO) is an indicator of allergic airway inflammation. However, it is unknown how asthma, allergic rhinitis (AR) and allergic sensitisation relate to FeNO, particularly among adolescents and in overlapping conditions. We sought to determine the associations between asthma, AR, and aeroallergen IgE and FeNO in adolescents.We measured FeNO among 929 adolescents (11–16 years) in Project Viva, an unselected prebirth cohort in Massachusetts. We defined asthma as ever asthma physician diagnosis plus wheezing in the past year or taking asthma medications in the past month; AR as a physician diagnosis of hay fever or AR; and aeroallergen IgE as any IgE>0.35 IU·mL−1 among 592 participants who provided blood samples. We examined associations of asthma, AR, and IgE with percent difference in FeNO in linear regression models adjusted for sex, race/ethnicity, age and height; maternal education and smoking during pregnancy; and household/neighborhood demographics.Asthma (14%) was associated with 97% higher FeNO (95%CI 70, 128%), AR (21%) with 45% higher FeNO (95%CI 28, 65%), and aeroallergen IgE (58%) with 102% higher FeNO (95%CI 80, 126%) compared to those without each condition, respectively. In the absence of asthma or AR, aeroallergen IgE was associated with 75% higher FeNO (95%CI 52, 101), while asthma and AR were not associated with FeNO in the absence of IgE.The link between asthma and AR with FeNO is limited to those with IgE-mediated phenotypes. FeNO may be elevated in those with allergic sensitisation alone, even in the absence of asthma or AR.

The evidence for interventions in early childhood allergy prevention – towards a living systematic review: protocol

Background: Research in early childhood allergy prevention (ECAP) is flourishing and new intervention strategies have proven to be promising. Due to the dynamic nature of ECAP, gaps between what is known and how guidelines inform practice are likely. A living systematic review (LSR) can narrow this gap by incorporating new evidence as it becomes available. No efficacy comparisons across various ECAP interventions for similar outcomes have been carried out. Networks of randomised clinical trials can be evaluated in the context of a network meta-analysis (NMA). We aim to establish a LSR on the efficacy and safety of any intervention investigated in randomised controlled trials (RCT) to prevent the occurrence of allergic sensitisation (AS), symptoms or diagnoses of allergic diseases in infancy and early childhood (0-3 years). Methods: A baseline SR will synthesise the evidence from existing SRs of RCTs as well as RCTs not yet considered in these. After completion of the baseline SR we propose to conduct a LSR. Using this methodology, we aim to undertake constant evidence surveillance, three-monthly search updates, and review updates every three months, should new evidence emerge. Conclusions: The ECAP evidence landscape has undergone dramatic transformations and this process is likely to continue. As a response to this, a LSR offers the potential to allow more timely synthesis of new evidence as it emerges. Long gaps between updates of SRs makes it harder for guidelines and recommendations to be up to date. Users of information, such as parents, may be confused if they encounter new evidence that is not part of a trusted guideline. A LSR approach allows us to continuously search the literature and update the evidence-base of existing ECAP interventions resulting in a decreased timespan from evidence accrual to informing clinical practice.

Circulating Chemokine Levels and the Development of Allergic Phenotypes from Infancy to Adolescence: A Population-Based Birth Cohort Study

Background: Chemokines are important mediators in immune cell recruitment, contributing to allergy development. However, extensive studies of chemokines in the circulation in relation to the presence and development of allergic diseases remain scarce.Objective: To investigate associations of circulating allergy-related chemokines with development of asthma and sensitisation cross-sectionally and longitudinally in a population-based cohort. Methods: The chemokines CCL17, CCL22, CXCL10, CXCL11 and CCL18 were measured in plasma samples from children in a population-based birth cohort. Samples were available from cord blood at birth (n=376) and age 1 (n=195) and 8 years (n=334). Cross-sectional and longitudinal association analyses were performed in relation to asthma and allergic sensitisation, as well as allergic phenotype clusters previously derived using machine learning in the same study population.Results: In children with asthma and/or allergic sensitisation, CCL18 levels at ages 1 and/or 8 were consistently elevated. In a longitudinal model which included information on asthma from 4 time-points (ages 5, 8, 11 and 16 years), we observed a significant association between increasing levels of CCL18 at age 1 year and a higher risk of asthma from early school age to adolescence (OR=2.9, 95% CI 1.1-7.6, p=0.028). We observed similar associations in longitudinal models for allergic sensitisation. Asthma later in life was preceded by increased CXCL10 levels after birth, and decreased CXCL11 levels at birth. Conclusion: Elevated CCL18 levels throughout childhood foreshadow the development of asthma and allergic sensitisation. The Th1-associated chemokines CXCL10 and CXCL11 were also associated with development of both outcomes, with differential temporal effects.