Longitudinal study of childhood wheezy bronchitis and asthma: outcome at age 42

Spanish Consensus on Remission in Asthma (REMAS)

The concept of "remission" in asthma has been around for a long time and it has been a controversial topic. Despite the attempts of some studies to characterize this entity, the discussion continues. In the case of asthma there is still no clear definition, either in terms of its meaning or the parameters that should be included or whether it should be divided into clinical or complete remission. To help defining these controversial concepts, SEPAR has advocated the multidisciplinary working group REMAS (REMission in ASthma). Following the Delphi methodology and with the involvement of more than 120 specialists in asthma management, this group has arrived at a consensus on the definitions of remission in asthma and establishing the criteria and characteristics that will be of use in future studies evaluating the efficacy or effectiveness of treatments.

Effectiveness of allergen immunotherapy with house dust mite extract for pediatric bronchial asthma

Aim: We compared the effectiveness of rush subcutaneous immunotherapy (SCIT) and sublingual immunotherapy (SLIT) using standardized house dust mite (HDM) extract for pediatric bronchial asthma (BA). Methods: We followed the pediatric BA treatment score during 3 years of treatment. We assessed the median time to no longer requiring long-term control pharmacotherapy (LTCP) for BA (LTCP-free). We compared the outcomes after adjustment for confounding factors and propensity score matching. Results: Patients in the HDM SCIT group achieved the LTCP-free status significantly earlier than those in the HDM SLIT group after adjustment for confounding factors and propensity score matching. Conclusion: Patients treated for pediatric BA with rush HDM SCIT had earlier onset of therapeutic effects than those with HDM SLIT.

Based on what parameters is safe to discontinuate inhaled corticosteroids in children with asthma?

OBJECTIVE

Remission of childhood asthma has not been widely studied. Patients in clinical remission continue to have some degree of bronchial hyperresponsiveness (BHR). The aim of this study was to investigate whether clinical parameters and lung function test are good parameters for discontinuation of inhaled corticosteroids (ICS) in asthmatic children, including patients with persistent BHR, as measured by the methacholine challenge test (MCT).

METHODS

One year after discontinuation of inhaled corticosteroids (ICS), MCT was performed in a group of 40 asthmatic children to confirm or exclude BHR. In all patients, ICS treatment was discontinued based on the same parameters: symptoms, spirometry, daily PEF, and negative bronchodilator test. After achieving complete asthma control for at least 6 to 12 months, ICS treatment was stepped down and discontinued. Clinical course and spirometry were followed up after ICS discontinuation.

RESULTS

Positive MCT was found in 50% of the patients. There was no statistically significant difference between the positive and negative MCT groups in age at initiation and discontinuation of ICS therapy, duration of ICS therapy, duration of stepping down period, FEV1, and PEF at the time of withdrawal of ICS and one year later. ICS treatment had to be restarted in two patients from the positive MCT group, due to recurrence of asthma symptoms.

CONCLUSION

Clinical parameters, normal spirometry, daily PEF values, and a negative bronchodilator test are good parameters for discontinuing ICS treatment in asthmatic children, even in patients with persistent BHR. Children should continue to be monitored, as symptoms may recur.

Relationship between early life asthma and chronic airway disease in adult life - in search for disease trajectories over the life span- the RELATE study based on the Kongsberg cohort

BACKGROUND

Chronic airway disease in adults may have its origin in early life. The purpose of this study is to investigate the long-term prognosis of severe childhood asthma in search for an association between asthma in early life and obstructive lung disease in adulthood.

METHODS

This study is based on the Kongsberg cohort, which includes approximately 5000 children with severe asthma with a 4-month stay at the asthma care facility in Kongsberg, Norway during the years 1950 to 1979. An on average 60-year observational study based on a follow-up examination will be performed including questionnaires, blood samples, and tests of lung function and bronchial responsiveness. Blood samples will be stored in a biobank. In addition, we will conduct further analyses of the cohort based on nationwide register data, including socio-economic parameters and mortality.

DISCUSSION

Chronic airway disease is associated with substantial burden for both the individual patient and society. Our knowledge of early life origins of chronic airway disease later in life has been increasing in recent decades but is still limited. By exploring early life risk factors for chronic airway disease in adulthood, we may gain insights paving the way for future reduction in the burden of chronic airway diseases.

Airway epithelial development and function: A key player in asthma pathogenesis?

Though asthma is a common and relatively easy to diagnose disease, attempts at primary or secondary prevention, and cure, have been disappointing. The widespread use of inhaled steroids has dramatically improved asthma control but has offered nothing in terms of altering long-term outcomes or reversing airway remodeling and impairment in lung function. The inability to cure asthma is unsurprising given our limited understanding of the factors that contribute to disease initiation and persistence. New data have focused on the airway epithelium as a potentially key factor orchestrating the different stages of asthma. In this review we summarize for the clinician the current evidence on the central role of the airway epithelium in asthma pathogenesis and the factors that may alter epithelial integrity and functionality.

Enigma variations: The multi-faceted problems of pre-school wheeze

Numerous publications on wheezing disorders in children younger than 6 years have appeared in the medical literature over the last decades with the aim of shedding light on the mechanistic pathways (endotypes) and treatment. Nevertheless, there is yet no consensus as to the appropriate way to manage preschool wheeze mainly because of the lack of a clear definition of "preschool asthma" and the paucity of scientific evidence concerning its underlying endotypes. A symptom-based approach is inadequate since the human airway can respond to external stimuli with a limited range of symptoms and signs, including cough and wheeze, and these manifestations represent the final expression of many clinical entities with potentially different pathophysiologies requiring different individualized treatments. Hence, new studies challenge the symptom-based approach and promote the importance of managing the wheezy child based on the "airway phenotype." This will enable the clinician to identify not only the child with a serious underlying pathology (e.g., a structural airway disorder or immunodeficiency) who is in need of prompt and specific treatment but also increase the specificity of treatment for the child with symptoms suggestive of an "asthma" syndrome. In the latter case, focus should be given to the identification of treatable traits. This review summarizes the current understanding in management of preschool wheezing and highlights the unmet need for further research.

Revisiting Mild Asthma: Current Knowledge and Future Needs

Asthma is a common chronic airways disease with significant impact on patients, caregivers, and the health-care system. Although most research and novel interventions mainly have focused on patients with uncontrolled severe asthma, most patients with asthma have mild disease. Epidemiologic studies suggest that many patients with mild asthma report frequent exacerbations of the disease and uncontrolled symptoms. However, despite its impact, mild asthma does not have either a uniformly agreed on definition for or a consensus on its clinical and pathophysiologic progression. More recently, the approach to treatment of patients with mild asthma has undergone significant changes primarily based on emerging evidence that airway inflammation in this population is important. This led to clinical research studies that explored the efficacy of as-needed inhaled corticosteroids along with the rescue medications that traditionally have been the mainstay of treatment. Despite some advancement in the field in recent years, many controversies and unmet needs remain. In this review, we examine the current understanding of the pathophysiologic features and management of mild asthma. In addition, we outline unmet needs for future research. We conclude that mild asthma contributes significantly to the morbidity and mortality of asthma and should be the focus of future research.

A review on the pathophysiology of asthma remission

Asthma is a chronic respiratory condition, which is highly prevalent worldwide. Although no cure is currently available, it is well recognized that some asthma patients can spontaneously enter remission of the disease later in life. Asthma remission is characterized by absence of symptoms and lack of asthma-medication use. Subjects in asthma remission can be divided into two groups: those in clinical remission and those in complete remission. In clinical asthma remission, subjects still have a degree of lung functional impairment or bronchial hyperresponsiveness, while in complete asthma remission, these features are no longer present. Over longer periods, the latter group is less likely to relapse. This remission group is of great scientific interest due to the higher potential to find biomarkers or biological pathways that elicit or are associated with asthma remission. Despite the fact that the definition of asthma remission varies between studies, some factors are reproducibly observed to be associated with remitted asthma. Among these are lower levels of inflammatory markers, which are lowest in complete remission. Additionally, in both groups some degree of airway remodeling is present. Still, the pathological disease state of asthma remission has been poorly investigated. Future research should focus on at least two aspects: further characterisation of the small airways and airway walls in order to determine histologically true remission, and more thorough biological pathway analyses to explore triggers that elicit this phenomenon. Ultimately, this will result in pharmacological targets that provide the potential to steer the course of asthma towards remission.

Mind the gaps: Clinical trial concepts to address unanswered questions in aeroallergen immunotherapy-An NIAID/AHRQ Workshop

The Agency for Healthcare Research and Quality and the National Institute of Allergy and Infectious Diseases organized a workshop to develop trial concepts that could improve the use and effectiveness of aeroallergen immunotherapy (AAIT). Expert groups were formed to accomplish the following tasks: (1) propose a study design to compare the effectiveness and safety of subcutaneous versus sublingual AAIT; (2) propose a study design to compare the effectiveness and safety of AAIT by using 1 or a few allergens versus all or most allergens to which a patient is sensitized; (3) propose a study design to determine whether AAIT can alter the progression of childhood allergic airways disease; and (4) propose a study design to determine the optimal dose and duration of AAIT to achieve maximal effectiveness with acceptable safety. Study designs were presented by the workgroups, extensively discussed at the workshop, and revised for this report. The proposed trials would be of long duration and require large highly characterized patient populations. Scientific caveats and feasibility matters are discussed. These concepts are intended to help the development of clinical trials that can address some of the major questions related to the practice of AAIT for the management and prevention of allergic airways disease.

Life Cycle of Childhood Asthma: Prenatal, Infancy and Preschool, Childhood, and Adolescence

Asthma is a heterogeneous developmental disorder influenced by complex interactions between genetic susceptibility and exposures. Wheezing in infancy and early childhood is highly prevalent, with a substantial minority of children progressing to established asthma by school age, most of whom are atopic. Adolescence is a time of remission of symptoms with persistent lung function deficits. The transition to asthma in adulthood is not well understood.

Lung function growth trajectories in non-asthmatic children aged 4-9 in relation to prenatal exposure to airborne particulate matter and polycyclic aromatic hydrocarbons - Krakow birth cohort study

BACKGROUND

Patterns of lung function development during childhood can be helpful in understanding the pathogenesis of respiratory diseases. A variety of environmental and lifestyle factors, present from the prenatal period to adulthood, may affect or modulate lung function growth. The aim of this study was to investigate, the associations between individual growth trajectories of children's lung function during childhood and prenatal exposure to airborne fine particulate matter (PM_2.5) and polycyclic aromatic hydrocarbons (PAH), which were hypothesized to adversely affect spirometry parameters.

MATERIAL AND METHODS

The study group comprised 294 non-asthmatic, full term children from the Krakow birth cohort, who underwent annual spirometry testing at the ages of 4-9 years. Individual personal air monitoring of PM_2.5 and PAH were performed over 48 h in the second trimester of pregnancy. Possible confounders or modifiers such as child's gender, height, atopic status and exposure to environmental tobacco smoke (ETS) were considered. Polynomial multilevel mixed models were used to assess the growth rates of children's lung functions.

RESULTS

Lung function trajectories differed significantly for boys and girls for FVC, FEV1 and FEF25-75. Girls had lower rates of increase than boys: - 20.5 (95%CI: - 32.4; - 8.6) ml/year (FVC); - 19.9 (95%CI: -30.7;-9.0) ml/year (FEV1); and - 32.5 (95%CI: - 56.9; - 8.2) ml/year (FEF25-75). Spirometry functions increased with age; however the growth rate decelerated over time. Significant lung function impairment (lower FVC and FEV1 levels) was observed from 4 to 9 years among subjects prenatally exposed to higher levels of PM_2.5 as well as PAH, but not in the case of FEF25-75. No significant differences were observed in the rates of increase over time in relation to prenatal PM_2.5 and PAH exposure.

CONCLUSION

Our results indicate that in non-asthmatic children high prenatal exposure to airborne PM_2.5 and PAH is associated with lower trajectories of FVC and FEV1, but not the rate of increase over time, suggesting that the initial effect is not diminishing in time.

Impact of childhood wheezing on lung function in adulthood: A meta-analysis

BACKGROUND

A growing body of evidence shows that childhood wheezing may lead to recurrent or persistent symptoms in adulthood, such that persistent wheezing associated with lung function deficits often have their roots in the first few years of life.

OBJECTIVES

We summarized information from several prospective cohort studies following children with or without wheezing into adulthood, to estimate the effect of childhood wheezing on adulthood lung function.

METHODS

Medical literatures were searched in the Medline, PubMed, ScienceDirect, Web of Science and Embase databases up to October 31, 2016. The adulthood lung function was selected as primary outcome, and chronic obstructive pulmonary disease (COPD) prevalence was selected as secondary outcome. The meta-analysis was performed with the Stata Version 14.0. A random-effects model was applied to estimate standardized mean difference (SMD) of lung function, and relative risk (RR) of COPD.

RESULTS

Six articles enrolling 1141 and 1005 children with and without wheezing, respectively. Meta-analysis showed that childhood wheezing decreased adulthood lung function as compared with no-wheezing subjects (SMD = -0.365, 95% confidence interval (CI): -0.569~-0.161, P = 0.000). Subgroup analyses indicated that childhood atopic wheezing reduced adulthood FEV1/FVC and FEV1%pred when compared with no-wheezing subjects. In addition, childhood atopic wheezing was significantly associated with COPD prevalence (RR = 5.307, 95% CI:1.033~27.271, P = 0.046).

CONCLUSIONS

Our meta-analysis suggests that childhood wheezing may induce ongoing declined lung function that extends into adult life, as well as an increased risk of COPD prevalence when accompanied with atopy.

Independent and combined effects of airway remodelling and allergy on airway responsiveness

Airway remodelling and allergic inflammation are key features of airway hyperresponsiveness (AHR) in asthma; however, their interrelationships are unclear. The present study investigated the separate and combined effects of increased airway smooth muscle (ASM) layer thickness and allergy on AHR. We integrated a protocol of ovalbumin (OVA)-induced allergy into a non-inflammatory mouse model of ASM remodelling induced by conditional and airway-specific expression of transforming growth factor-α (TGF-α) in early growth response-1 (Egr-1)-deficient transgenic mice, which produced thickening of the ASM layer following ingestion of doxycycline. Mice were sensitised to OVA and assigned to one of four treatment groups: Allergy - normal chow diet and OVA challenge; Remodelling - doxycycline in chow and saline challenge; Allergy and Remodelling - doxycycline in chow and OVA challenge; and Control - normal chow diet and saline challenge. Airway responsiveness to methacholine (MCh) and histology were assessed. Compared with the Control group, airway responsiveness to MCh was increased in the Allergy group, independent of changes in wall structure, whereas airway responsiveness in the Remodelling group was increased independent of exposure to aeroallergen. The combined effects of allergy and remodelling on airway responsiveness were greater than either of them alone. There was a positive relationship between the thickness of the ASM layer with airway responsiveness, which was shifted upward in the presence of allergy. These findings support allergy and airway remodelling as independent causes of variable and excessive airway narrowing.

Japanese guidelines for childhood asthma 2017

The Japanese Guideline for the Diagnosis and Treatment of Allergic Diseases 2017 (JAGL 2017) includes a minor revision of the Japanese Pediatric Guideline for the Treatment and Management of Asthma 2012 (JPGL 2012) by the Japanese Society of Pediatric Allergy and Clinical Immunology. The section on child asthma in JAGL 2017 provides information on how to diagnose asthma between infancy and adolescence (0-15 years of age). It makes recommendations for best practices in the management of childhood asthma, including management of acute exacerbations and non-pharmacological and pharmacological management. This guideline will be of interest to non-specialist physicians involved in the care of children with asthma. JAGL differs from the Global Initiative for Asthma Guideline in that JAGL emphasizes diagnosis and early intervention of children with asthma at <2 years or 2-5 years of age. The first choice of treatment depends on the severity and frequency of symptoms. Pharmacological management, including step-up or step-down of drugs used for long-term management based on the status of asthma control levels, is easy to understand; thus, this guideline is suitable for the routine medical care of children with asthma. JAGL also recommends using a control test in children, so that the physician aims for complete control by avoiding exacerbating factors and appropriately using anti-inflammatory drugs (for example, inhaled corticosteroids and leukotriene receptor antagonists).

Clinical Tools to Assess Asthma Control in Children

Asthma affects an estimated 7 million children and causes significant health care and disease burden. The most recent iteration of the National Heart, Lung and Blood Institute asthma guidelines, the Expert Panel Report 3, emphasizes the assessment and monitoring of asthma control in the management of asthma. Asthma control refers to the degree to which the manifestations of asthma are minimized by therapeutic interventions and the goals of therapy are met. Although assessment of asthma severity is used to guide initiation of therapy, monitoring of asthma control helps determine whether therapy should be maintained or adjusted. The nuances of estimation of asthma control include understanding concepts of current impairment and future risk and incorporating their measurement into clinical practice. Impairment is assessed on the basis of frequency and intensity of symptoms, variations in lung function, and limitations of daily activities. "Risk" refers to the likelihood of exacerbations, progressive loss of lung function, or adverse effects from medications. Currently available ambulatory tools to measure asthma control range are subjective measures, such as patient-reported composite asthma control score instruments or objective measures of lung function, airway hyperreactivity, and biomarkers. Because asthma control exhibits short- and long-term variability, health care providers need to be vigilant regarding the fluctuations in the factors that can create discordance between subjective and objective assessment of asthma control. Familiarity with the properties, application, and relative value of these measures will enable health care providers to choose the optimal set of measures that will adhere to national standards of care and ensure delivery of high-quality care customized to their patients.

Selective targeting of CREB-binding protein/β-catenin inhibits growth of and extracellular matrix remodelling by airway smooth muscle

BACKGROUND AND PURPOSE

Asthma is a heterogeneous chronic inflammatory disease, characterized by the development of structural changes (airway remodelling). β-catenin, a transcriptional co-activator, is fundamentally involved in airway smooth muscle growth and may be a potential target in the treatment of airway smooth muscle remodelling.

EXPERIMENTAL APPROACH

We assessed the ability of small-molecule compounds that selectively target β-catenin breakdown or its interactions with transcriptional co-activators to inhibit airway smooth muscle remodelling in vitro and in vivo.

KEY RESULTS

ICG-001, a small-molecule compound that inhibits the β-catenin/CREB-binding protein (CBP) interaction, strongly and dose-dependently inhibited serum-induced smooth muscle growth and TGFβ1-induced production of extracellular matrix components in vitro. Inhibition of β-catenin/p300 interactions using IQ-1 or inhibition of tankyrase 1/2 using XAV-939 had considerably less effect. In a mouse model of allergic asthma, β-catenin expression in the smooth muscle layer was found to be unaltered in control versus ovalbumin-treated animals, a pattern that was found to be similar in smooth muscle within biopsies taken from asthmatic and non-asthmatic donors. However, β-catenin target gene expression was highly increased in response to ovalbumin; this effect was prevented by topical treatment with ICG-001. Interestingly, ICG-001 dose-dependently reduced airway smooth thickness after repeated ovalbumin challenge, but had no effect on the deposition of collagen around the airways, mucus secretion or eosinophil infiltration.

CONCLUSIONS AND IMPLICATIONS

Together, our findings highlight the importance of β-catenin/CBP signalling in the airways and suggest ICG-001 may be a new therapeutic approach to treat airway smooth muscle remodelling in asthma.

Strengths, Pitfalls, and Lessons from Longitudinal Childhood Asthma Cohorts of Children Followed Up into Adult Life

Asthma is a common problem worldwide and longitudinal studies of children followed up into adult life enable the assessment of clinical outcomes, examine the pattern of lung function outcomes, and importantly provide insight into aetiology and prognosis for patients with asthma. The aim of this review is to examine the major childhood asthma cohort studies which have continued into adult life, describing the strengths and weaknesses and the lessons that can be learnt regarding pathophysiology and potential future directions for research.

Growth, Nutritional Status, and Pulmonary Function in Children with Chronic Recurrent Bronchitis

Bronchitis is a common health problem in children. Frequent bronchitis in infancy increases the risk of developing chronic respiratory diseases. The aim of the study was to assess the level of growth and the nutritional status in children and youths with special regard to the level of body fatness assessed by measuring skin-fold thickness. Relationships between somatic development, pulmonary function and the course of the disease were also explored. The study was carried out using anthropometric and spirometric measurements and also information on the severity and course of the disease in 141 children with chronic or recurrent bronchitis. All of the subjects were patients of the Pulmonary Medicine and Allergology Center in Karpacz, Poland. The mean body height did not differ significantly between the children examined and their healthy peers. However, the infection-prone children had excessive body fatness and muscle mass deficiency. The increased level of subcutaneous adipose tissue occurred especially in children with short duration of the disease, i.e. a maximum of 1 year. The functional lung parameters were generally normal. The presence of atopic diseases such as allergic rhinitis or atopic dermatitis did not impair the course of the children's somatic development. Also, long-term disease or the presence of additional allergic diseases did not impair lung function in the examined children. Taking appropriate preventive measures is recommended to achieve and maintain normal body weight in children who receive therapy due to bronchitis.

CD151, a laminin receptor showing increased expression in asthmatic patients, contributes to airway hyperresponsiveness through calcium signaling

BACKGROUND

Airway smooth muscle (ASM) contraction underpins airway constriction; however, underlying mechanisms for airway hyperresponsiveness (AHR) remain incompletely defined. CD151, a 4-transmembrane glycoprotein that associates with laminin-binding integrins, is highly expressed in the human lung. The role of CD151 in ASM function and its relationship to asthma have yet to be elucidated.

OBJECTIVE

We sought to ascertain whether CD151 expression is clinically relevant to asthma and whether CD151 expression affects AHR.

METHODS

Using immunohistochemical analysis, we determined the expression of CD151 in human bronchial biopsy specimens from patients with varying asthma severities and studied the mechanism of action of CD151 in the regulation of ASM contraction and bronchial caliber in vitro, ex vivo, and in vivo.

RESULTS

The number of CD151⁺ ASM cells is significantly greater in patients with moderate asthma compared with those in healthy nonasthmatic subjects. From loss- and gain-of-function studies, we reveal that CD151 is required for and enhances G protein-coupled receptor (GPCR)-induced peak intracellular calcium release, the primary determinant of excitation-contraction coupling. We show that the localization of CD151 can also be perinuclear/cytoplasmic and offer an explanation for a novel functional role for CD151 in supporting protein kinase C (PKC) translocation to the cell membrane in GPCR-mediated ASM contraction at this site. Importantly, CD151^-/- mice are refractory to airway hyperreactivity in response to allergen challenge.

CONCLUSIONS

We identify a role for CD151 in human ASM contraction. We implicate CD151 as a determinant of AHR in vivo, likely through regulation of GPCR-induced calcium and PKC signaling. These observations have significant implications in understanding the mechanism for AHR and the efficacy of new and emerging therapeutics.

Epidemiology of bronchial asthma in school children (10-16 years) in Srinagar

Objectives:

To assess the epidemiological profile of asthma in school going children in Srinagar, Kashmir.

Study design:

Cross-sectional study.

Setting:

Thirty-one schools with proportionate representation from both government and private schools as well as from primary, middle, and high schools.

Participants:

School children aged 10–16 years with equal representation of sex and all ages.

Main Outcome Measure:

Prevalence of current and past asthma.

Methods and Results:

After administering a modified pretested questionnaire, peak expiratory flow measurement was carried. Children who had asthma-like symptoms or positive family history of asthma or physician-labeled asthma were subjected to spirometry and bronchodilator reversibility. Out of 806 children, bronchial asthma was seen in 60 (prevalence of 7.4%) which included 34 boys and 26 girls. Majority of asthmatic children (78.3% [n = 47]) had probable asthma; 6.7% (n = 4) had definite asthma; and 15% (n = 9) had physician-diagnosed asthma. Majority of children had intermittent asthma (78.3% [n = 47]). Mild persistent asthma was seen in 12.7% (n = 7) and 10% (n = 6) had moderate persistent asthma. None of the children had severe persistent asthma. The prevalence of current asthma was 3.2% (n = 26). On univariate analysis, the factors found to be statistically significant were family history of asthma (odds ratio [OR] =8.174; confidence interval [CI] =4.403–15.178), seasonal cough (OR = 4.266; CI = 2.336–7.791), allergic rhinitis (OR = 2.877; CI = 1.414–5.852), atopic dermatitis (OR = 6.597; CI = 2.72–16.004), and obesity (OR = 6.074; CI = 2.308–18.034). On multivariate analysis, family history, seasonal cough, allergic rhinitis, atopic dermatitis, and obesity were found to be significant independent risk factors.

Conclusions:

Srinagar qualifies as a low prevalence area for bronchial asthma in the age group of 10–16 years. Majority of children had mild intermittent asthma resulting in under diagnosis and wrong treatment.

Risk Factors Associated with Irreversible Airway Obstruction in Asthma: A Systematic Review and Meta-Analysis

Irreversible airway obstruction (IAO) is a subtype of asthma and relates to poorer prognosis in some asthma patients. However, the prevalence and risk factors for IAO are unknown. A systematic review regarding controlled clinical studies (cohort, case-control studies) on IAO asthma in adult and/or children affected by asthma/early wheeze was performed. Eighteen papers were identified in this study. It was reported that the incidence of IAO at random effects or fixed effects in severe asthma and nonsevere asthma was 0.54 (95% CI: 0.45–0.62) and 0.16 (95% CI: 0.12–0.20), respectively. In IAO asthma, the pooled odds ratio (OR) related to smoking exposure was 2.22 (95% CI: 1.82–2.73), the OR for male, smoking, and fractional exhaled nitric oxide (FENO) was 2.22 (95% CI: 1.82–2.7), 1.79 (95% CI: 1.46–2.19), and 2.16 (95% CI: 1.05–4.43), respectively, suggesting these factors increase the risk of IAO. However, a decreased OR in IAO asthma was observed due to rhinitis (OR = 0.31, 95% CI: 0.24–0.40), atopy (OR = 0.584, 95% CI: 0.466–0.732), and atopic dermatitis (OR = 0.60, 95% CI: 0.42–0.85), indicating these factors are associated with reduced risk of IAO. IAO in asthma is associated with gender, smoking, FENO, rhinitis, atopy, and atopic dermatitis.

Childhood asthma and chronic obstructive pulmonary disease: outcomes until the age of 50

PURPOSE OF REVIEW

There has been recent interest in understanding the origins of chronic obstructive pulmonary disease. Epidemiological studies suggest that chronic obstructive pulmonary disease clearly has other causes apart from tobacco smoke.

RECENT FINDINGS

Cross-sectional studies of adult cohorts with chronic obstructive pulmonary disease highlight that childhood asthma is a risk factor. A recent longitudinal childhood cohort study of children from childhood to the age of 50 years describes that children with severe asthma are at increased risk of chronic obstructive pulmonary disease and that the deficit in lung function can be tracked back to early years.

SUMMARY

Children with severe asthma are at increased risk of developing chronic obstructive pulmonary disease.

Intermittent inhaled corticosteroid therapy versus placebo for persistent asthma in children and adults

BACKGROUND

International guidelines advocate using daily inhaled corticosteroids (ICS) in the management of children and adults with persistent asthma. However, in real world clinical settings, these medicines are often used at irregular intervals by patients. Recent evidence suggests that the use of intermittent ICS, with treatment initiated at the time of early symptoms, may still have benefits for reducing the severity of an asthma exacerbation.

OBJECTIVES

To compare the efficacy and safety of intermittent ICS versus placebo in the management of children and adults diagnosed with, or suspected to have, symptoms of mild persistent asthma.

SEARCH METHODS

We searched the Cochrane Airways Group Specialised Register of trials (CAGR), the ClinicalTrials.gov website and the World Health Organization (WHO) trials portal in March 2015.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) that compared intermittent ICS versus placebo in children and adults with symptoms of persistent asthma. No co-interventions were permitted other than rescue relievers and oral corticosteroids used during exacerbations.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trials for inclusion, methodological quality and extracted data. The primary efficacy outcome was the risk of asthma exacerbations requiring oral corticosteroids and the primary safety outcome was serious adverse health events. Secondary outcomes included exacerbations, lung function tests, asthma control, adverse effects, and withdrawal rates. Quality of the evidence was assessed using the GRADE criteria.

MAIN RESULTS

Six trials (representing 490 preschool children, 145 school-aged children and 240 adults) met the inclusion criteria. Study durations were 12 to 52 weeks. Results for preschool children were presented in a separate analysis as this represents a distinct clinical condition, not necessarily related to the development of long term asthma.There was a reduction in the risk of patients experiencing one or more exacerbations requiring oral corticosteroids in older children (145 participants, odds ratio (OR) 0.57; 95% confidence interval (CI) 0.29 to 1.12, low quality evidence) and adults with asthma (240 participants, OR 0.10; 95% CI 0.01 to 1.95, low quality evidence). These analyses were each based on the findings of a single study. No group difference was observed in the risk of serious adverse health events (385 participants; OR 1.00; 95% CI 0.14 to 7.25, moderate quality evidence). Compared to the placebo group, there was an insufficient number of participants to make firm conclusions whether the intermittent ICS group displayed any reduction in the rate of hospitalisations, day time and night time symptoms scores, or adverse events. Lung function tests reported by a single study favoured the use of ICS. There was no significant group difference in growth rate of children, or overall withdrawals.In preschool children with frequent wheezing episodes, the use of intermittent ICS at the onset of early symptoms reduced the likelihood of requiring rescue oral corticosteroids by half (490 participants; OR: 0.48; 95% CI 0.31 to 0.73, moderate quality evidence with minimal heterogeneity). Intermittent therapy was associated with fewer serious adverse events (439 participants; OR 0.42; 95% CI 0.17 to 1.02, low quality evidence). There was no significant difference in hospitalisations or in a single study measuring parent perceived quality of life. However, intermittent therapy was associated with improvements in both day time and night time symptoms. There was no increase in the rates of withdrawals, and overall and treatment-specific adverse events.

AUTHORS' CONCLUSIONS

In children and adults with mild persistent asthma, two studies have shown that the use of intermittent ICS at the time of exacerbation reduced the chances of needing oral corticosteroids by half. This result is statistically significant if we assume that the effect size is the same for each study population (fixed effects model), but is not statistically significant when using a random effects model. However, the paucity of published evidence limits our conclusions towards the 'as-needed' use of this medication. The small number of studies and participants were the major reasons for downgrading the overall quality of the findings. A corresponding result was found in preschool children with wheeze. In this age group, an improvement in day time and night time asthma symptoms score and parental perceived quality of life of children similarly favoured the ICS group. However, there was no statistical difference in hospitalisation rates in any group. This treatment was not associated with any significant increase in adverse events. There was no growth suppression noted with the use of intermittent ICS in either preschool or school-aged children. Considering the limited number of available studies, we emphasise the need for more randomised controlled studies in order to confirm these findings.

Japanese Guideline for Childhood Asthma 2014

The Japanese Guideline for the Diagnosis and Treatment of Allergic Diseases 2013 (JAGL 2013) describes childhood asthma after the Japanese Pediatric Guideline for the Treatment and Management of Asthma 2012 (JPGL 2012) by the Japanese Society of Pediatric Allergy and Clinical Immunology. JAGL 2013 provides information on diagnosis by age group from infancy to puberty (0-15 years of age), treatment for acute exacerbations, long-term management by anti-inflammatory drugs, daily life guidance, and patient education to allow non-specialist physicians to refer to this guideline for routine medical treatment. JAGL differs from the Global Initiative for Asthma Guideline (GINA) in that JAGL emphasizes early diagnosis and intervention at <2 years and 2-5 years of age. A management method, including step-up or step-down of long-term management drugs based on the status of asthma control levels, as in JAGL, is easy to understand, and thus the Guideline is suitable as a frame of reference for routine medical treatment. JAGL has also introduced treatment and management using a control test on children, recommending that the physician aim at complete control by avoiding exacerbation factors and by appropriate use of anti-inflammatory drugs.

Early origins of chronic obstructive lung diseases across the life course

Chronic obstructive lung diseases, like asthma and chronic obstructive pulmonary disease, have high prevalences and are a major public health concern. Chronic obstructive lung diseases have at least part of their origins in early life. Exposure to an adverse environment during critical periods in early life might lead to permanent developmental adaptations which results in impaired lung growth with smaller airways and lower lung volume, altered immunological responses and related inflammation, and subsequently to increased risks of chronic obstructive lung diseases throughout the life course. Various pathways leading from early life factors to respiratory health outcomes in later life have been studied, including fetal and early infant growth patterns, preterm birth, maternal obesity, diet and smoking, children's diet, allergen exposure and respiratory tract infections, and genetic susceptibility. Data on potential adverse factors in the embryonic and preconception period and respiratory health outcomes are scarce. Also, the underlying mechanisms how specific adverse exposures in the fetal and early postnatal period lead to chronic obstructive lung diseases in later life are not yet fully understood. Current studies suggest that interactions between early environmental exposures and genetic factors such as changes in DNA-methylation and RNA expression patterns may explain the early development of chronic obstructive lung diseases. New well-designed epidemiological studies are needed to identify specific critical periods and to elucidate the mechanisms underlying the development of chronic obstructive lung disease throughout the life course.

Trends in eczema, rhinitis, and rye grass sensitization in a longitudinal asthma cohort

BACKGROUND

Atopic conditions are prevalent in the Western world, with limited long-term data on atopic trends in patients with asthma.

OBJECTIVE

To describe the trends in eczema, rhinitis, and allergic sensitization in a longitudinal childhood asthma cohort.

METHODS

Four hundred eighty-four patients were recruited at 7 years of age and followed regularly to 50 years of age. Subjects completed an interviewer-administered questionnaire to define current eczema and rhinitis. Skin prick testing to rye grass also was performed.

RESULTS

The participation rate over the past 4 decades has been maintained at 72% to 91%. There was a decrease in the prevalence of eczema in the past 12 months in groups with viral-associated wheeze (21% to 8%, P = .002), asthma (47% to 18%, P < .001), and severe asthma (69% to 28%, P < .001) from 14 to 21 years of age. Conversely, there was an increase in the prevalence of rhinitis in the previous 12 months in groups without asthma (1% to 6%, P = .04; 1% to 20%, P = .008), with viral-associated wheeze (16% to 28%, P = .006; 16% to 49%, P < .001), and with asthma (45% to 56%, P = .2; 45% to 73%, P = .014) from recruitment to 10 and 14 years of age, respectively. There were 2 peaks in prevalence in the sensitization to rye grass in this cohort from 7 to 10 years of age and from 14 to 21 years of age in all groups.

CONCLUSION

The adolescence phase appears to be an important period in the body's response to allergens whereby eczema decreases in prevalence, whereas rhinitis and rye grass sensitization increase in prevalence.

Diagnosis, management, and prognosis of preschool wheeze

Preschool children (ie, those aged 5 years or younger) with wheeze consume a disproportionately high amount of health-care resources compared with older children and adults with wheeze or asthma, representing a diagnostic challenge. Although several phenotype classifications have been described, none have been validated to identify individuals responding to specific therapeutic approaches. Several risk factors related to genetic, prenatal, and postnatal environment are associated with preschool wheezing. Findings from several cohort studies have shown that preschool children with wheeze have deficits in lung function at 6 years of age that persisted until early and middle adulthood, suggesting increased susceptibility in the first years of life that might lead to persistent sequelae. Daily inhaled corticosteroids seem to be the most effective therapy for recurrent wheezing in trials of children with interim symptoms or atopy; intermittent high-dose inhaled corticosteroids are effective in moderate-to-severe viral-induced wheezing without interim symptoms. The role of leukotriene receptor antagonist is less clear. Interventions to modify the short-term and long-term outcomes of preschool wheeze should be a research priority.

Will symptom-based therapy be effective for treating asthma in children?

Traditionally, symptoms are important patient-oriented outcomes in asthma treatment, and assessment of symptoms is an essential component of assessing asthma control. However, variable airways obstruction, airways hyperresponsiveness and chronic inflammation are key components of the asthma syndrome, and correlations among these hallmarks and symptoms are weak or even absent. Therefore, it might be questioned if symptom-based therapy is effective for treating asthma in (all) children. To date, there is no firm indication that monitoring asthma based on repetitive lung function measurement or markers of airway inflammation is superior to monitoring based on symptoms only. In the majority of patients, symptom-based asthma management may well be sufficient, and in preschool children, symptoms are presently the only feasible outcome. Nevertheless, there is some evidence that selected groups might benefit from an approach that takes into account individual phenotypic characteristics. In patients with poor perception, those with a discordant phenotype and those with persistent severe asthma, considering lung function, airways hyperresponsiveness and inflammatory markers in treatment decisions might improve outcomes.

Outcomes of childhood asthma to the age of 50 years

BACKGROUND

In 1964, The Melbourne Asthma Study was established to describe the spectrum and natural history of childhood asthma.

OBJECTIVE

To describe the clinical and lung function outcome of childhood asthma to the age of 50 years.

METHOD

Subjects were invited to complete an interviewer-administered questionnaire, skin prick testing, and measurement of lung function from the age of 7 years to the age of 50 years at 7-year intervals.

RESULTS

Of 458 survivors (from the original 484 subjects at recruitment), 346 subjects (76%) participated, of whom, 197 completed lung function measurement. Asthma remission at the age of 50 years was 64% in those with wheezy bronchitis, 47% for those with persistent asthma, and 15% for those with severe asthma in childhood. Multivariable analysis identified severe asthma in childhood (odds ratio [OR] 11.9 [95% CI, 3.4-41.8]), female sex (OR 2.0 [95% CI, 1.1-3.6]), and childhood hay fever (OR 2.0 [95% CI, 1.0-4.0]) as risk factors for "current asthma" at age 50 years. There was no evidence of a difference in the rate of decline in FEV1 (mL/y, 95% CI) between the severe asthma group (15 mL/y [95% CI, 9-22 mL/y]) and all the other recruitment groups: control (16 mL/y [95% CI, 12-20 mL/y]), mild wheezy bronchitis (14 mL/y [95% CI, 8-19 mL/y]), wheezy bronchitis (16 mL/y [95% CI, 11-20 mL/y]), and persistent asthma (19 mL/y [95% CI, 13-24 mL/y]).

CONCLUSION

The clinical and lung function outcome in adult life is strongly determined by asthma severity in childhood. The reduced lung function seen in adults is established in childhood and does not appear to decline more rapidly in adult years despite continuing symptoms.

The course of asthma in young adults: a population-based nine-year follow-up on asthma remission and control

Background

Only few longitudinal studies on the course of asthma among adults have been carried out.

Objective

The aim of the present prospective study, carried out between 2000 and 2009 in Italy, is to assess asthma remission and control in adults with asthma, as well as their determinants.

Methods

All the subjects with current asthma (21–47 years) identified in 2000 in the Italian Study on Asthma in Young Adults in 6 Italian centres were followed up. Asthma remission was assessed at follow-up in 2008–2009 (n = 214), asthma control at baseline and follow-up. Asthma remission and control were related to potential determinants by a binomial logistic and a multinomial logistic model. Separate models for remission were used for men and women.

Results

The estimate of the proportion of subjects who were in remission was 29.7% (95%CI: 14.4%;44.9%). Men who were not under control at baseline had a very low probability of being in remission at follow-up (OR = 0.06; 95%CI:0.01;0.33) when compared to women (OR = 0.40; 95%CI:0.17;0.94). The estimates of the proportion of subjects who were under control, partial control or who were not under control in our sample were 26.3% (95%CI: 21.2;31.3%), 51.6% (95%CI: 44.6;58.7%) and 22.1% (95%CI: 16.6;27.6%), respectively. Female gender, increasing age, the presence of chronic cough and phlegm and partial or absent asthma control at baseline increased the risk of uncontrolled asthma at follow-up.

Conclusion

Asthma remission was achieved in nearly 1/3 of the subjects with active asthma in the Italian adult population, whereas the proportion of the subjects with controlled asthma among the remaining subjects was still low.

The potential to predict the course of childhood asthma

Many children experience pre-school or early childhood wheezing. In a significant proportion symptoms disappear as the child grows, but others have persistent and troublesome asthma which can be life-long. Tools to predict course of disease in young children are a priority for families and clinicians. This review summarizes evidence from several longitudinal population-based birth-cohort studies that have identified risk factors for persistence and remission of childhood asthma. These factors include clinical characteristics, environmental and other exposures, familial factors, biomarkers of allergic inflammation, measurements of lung function and airway responsiveness, and genetic variants. This review also introduces the concept of polygenic risk and genetic risk scores, and describes results from a recent study that suggests promise for the use of genetic information in predicting the course of childhood asthma. We conclude with a discussion of implications and future directions.

Relevance of birth cohorts to assessment of asthma persistence

The definition of persistent asthma in longitudinal studies reflects symptoms reported at every assessment with no substantive asymptomatic periods. Early-childhood wheezing may be transient, especially if it is of viral etiology. Longitudinal studies provide greater opportunity to confirm the diagnosis by variability of symptoms, objective measurements, and therapeutic responses. Several clinical phenotypes of childhood asthma have been identified, with general consistency between cohorts. Persistent wheezing is often associated with loss of lung function, which is evident from early-childhood and related to persistent inflammation and airway hyperresponsiveness. Female sex, atopy, airway responsiveness, and personal smoking, but not exposure to environmental tobacco smoke, are risk factors for persistence of childhood asthma into adulthood. The effect of breastfeeding remains controversial, but gene-environment interactions may partly explain outcomes. Understanding the natural history and underlying causes of asthma may lead to development of strategies for primary prevention.

The interplay between the effects of lifetime asthma, smoking, and atopy on fixed airflow obstruction in middle age

RATIONALE

The contribution by asthma to the development of fixed airflow obstruction (AO) and the nature of its effect combined with active smoking and atopy remain unclear.

OBJECTIVES

To investigate the prevalence and relative influence of lifetime asthma, active smoking, and atopy on fixed AO in middle age.

METHODS

The population-based Tasmanian Longitudinal Health Study cohort born in 1961 (n = 8,583) and studied with prebronchodilator spirometry in 1968 was retraced (n = 7,312) and resurveyed (n = 5,729 responses) from 2002 to 2005. A sample enriched for asthma and chronic bronchitis underwent a further questionnaire, pre- and post-bronchodilator spirometry (n = 1,389), skin prick testing, lung volumes, and diffusing capacity measurements. Prevalence estimates were reweighted for sampling fractions. Multiple linear and logistic regression were used to assess the relevant associations.

MEASUREMENTS AND MAIN RESULTS

Main effects and interactions between lifetime asthma, active smoking, and atopy as they relate to fixed AO were measured. The prevalence of fixed AO was 6.0% (95% confidence interval [CI], 4.5-7.5%). Its association with early-onset current clinical asthma was equivalent to a 33 pack-year history of smoking (odds ratio, 3.7; 95% CI, 1.5-9.3; P = 0.005), compared with a 24 pack-year history for late-onset current clinical asthma (odds ratio, 2.6; 95% CI, 1.03-6.5; P = 0.042). An interaction (multiplicative effect) was present between asthma and active smoking as it relates to the ratio of post-bronchodilator FEV(1)/FVC, but only among those with atopic sensitization.

CONCLUSIONS

Active smoking and current clinical asthma both contribute substantially to fixed AO in middle age, especially among those with atopy. The interaction between these factors provides another compelling reason for atopic individuals with current asthma who smoke to quit.

House dust allergy and immunotherapy

HDM allergy is associated with asthma, allergic rhinitis and atopic dermatitis. In many countries childhood asthma is predominantly found in HDM-allergic children with their probability of developing disease being proportional to their IgE antibody titers and the early development of Th2 responses. While the pathogenesis is complex and increasingly linked to infection the immunologically-based allergen immunotherapy and anti-IgE antibody therapy are highly beneficial. Immunotherapy could be a short-term treatment providing lifelong relief but the current regimens depend on repeated administration of allergen over years. Immunological investigations point to a contribution of responses outside the Th2 pathway and multiple potential but unproven control mechanisms. Over half of the IgE antibodies are directed to the group 1 and 2 allergens with most of remainder to the group 4, 5, 7 and 21 allergens. This hierarchy found in high and low responders provides a platform for introducing defined allergens into immunotherapy and defined reagents for investigation.

Severe asthma in childhood: recent advances in phenotyping and pathogenesis

PURPOSE OF REVIEW

Children with severe asthma have a high degree of respiratory morbidity despite treatment with high doses of inhaled corticosteroids and are therefore very difficult to treat. This review will discuss phenotypic and pathogenic aspects of severe asthma in childhood, as well as remaining knowledge gaps.

RECENT FINDINGS

As a group, children with severe asthma have a number of distinct phenotypic features compared with children with mild-to-moderate asthma. Clinically, children with severe asthma are differentiated by greater allergic sensitization, increased exhaled nitric oxide, and significant airflow limitation and air trapping that worsens as a function of age. These findings are accompanied by structural airway changes and increased and dysregulated airway inflammation and oxidant stress which may explain the differential nature of corticosteroid responsiveness in this population. Because children with severe asthma themselves are a heterogeneous group, current efforts are focused on improved definition and sub-phenotyping of the disorder. Whereas the clinical relevance of phenotyping approaches in severe asthma is not yet clear, they may provide important insight into the mechanisms underlying the disorder.

SUMMARY

Improved classification of severe asthma through unified definitions, careful phenotypic analyses, and mechanism-focused endotyping approaches may ultimately advance knowledge and personalized treatment.

Epithelial-mesenchymal transition in the pathophysiology of airway remodelling in asthma

PURPOSE OF REVIEW

We currently understand little about the mechanisms that lead to airway remodeling in asthma. The origin of the mesenchymal cells that contribute to fibrosis of the airway is poorly understood. However, emerging evidence suggests that the airway epithelium could contribute to airway remodeling through the process of epithelial-mesenchymal transition (EMT) following environmental challenge. In this review, we will discuss the mechanistic features of EMT and highlight recent descriptions of EMT in the airway to further define the role of the airway epithelium in the pathogenesis of asthma.

RECENT FINDINGS

Growth factors, inflammatory mediators, and matricellular proteins expressed following exposure to environmental insults are known to induce downregulation of epithelial cell-cell adhesions and promote mesenchymal gene expression programs both in vitro and in vivo. These results demonstrate that the plastic and dynamic airway epithelium may contribute to airway remodeling via EMT in asthma.

SUMMARY

It is becoming increasingly clear that the airway epithelium orchestrates inflammatory and remodeling responses of the airway. Understanding the regulatory mechanisms involved in epithelial plasticity will be crucial to determine effective therapies to halt the progression of airway remodeling in asthma.

Long-term outcomes of early-onset wheeze and asthma

Evidence from longitudinal cohort studies demonstrates that wheezing that begins in early life and continues into the school years generally persists into adulthood. This persistent wheezing is associated with lung function deficits and airways hyperresponsiveness that appear to be established in the first few years of life. Allergic sensitization early in life, early-life infection with rhinovirus, or colonization with any of a number of bacteria have been associated with increased risk of persistent wheeze. Early life, whether in utero or in the first few years of life, presents a window of vulnerability during which airway injury results in persistent airways dysfunction. Available data further suggest that a second such window of vulnerability might be present in the preadolescent and adolescent years. Lung function growth patterns established by age 6 years generally continue into early adulthood to middle adulthood, typically leaving groups of subjects with wheezing that persists into or relapses during adulthood with a mean FEV(1) of about 10% of predicted value less than their peers who do not wheeze. Subgroups of patients with persistent asthma, however, can have progressive decreases in lung function and enter adulthood with even lower lung function. The concern exists that these deficits in lung function apparent in early adulthood might put subjects at risk for the later development of chronic obstructive pulmonary disease.

Fetal and infant origins of asthma

Previous studies have suggested that asthma, like other common diseases, has at least part of its origin early in life. Low birth weight has been shown to be associated with increased risks of asthma, chronic obstructive airway disease, and impaired lung function in adults, and increased risks of respiratory symptoms in early childhood. The developmental plasticity hypothesis suggests that the associations between low birth weight and diseases in later life are explained by adaptation mechanisms in fetal life and infancy in response to various adverse exposures. Various pathways leading from adverse fetal and infant exposures to growth adaptations and respiratory health outcomes have been studied, including fetal and early infant growth patterns, maternal smoking and diet, children's diet, respiratory tract infections and acetaminophen use, and genetic susceptibility. Still, the specific adverse exposures in fetal and early postnatal life leading to respiratory disease in adult life are not yet fully understood. Current studies suggest that both environmental and genetic factors in various periods of life, and their epigenetic mechanisms may underlie the complex associations of low birth weight with respiratory disease in later life. New well-designed epidemiological studies are needed to identify the specific underlying mechanisms. This review is focused on specific adverse fetal and infant growth patterns and exposures, genetic susceptibility, possible respiratory adaptations and perspectives for new studies.

The course of asthma activity: a population study

BACKGROUND

Unlike most chronic diseases, which tend to progress over time, asthma is known to persist, possibly resolve, and/or present with any combination of remissions and relapses. As a result, its course has been difficult to characterize and its prognosis difficult to predict.

OBJECTIVE

To quantify the proportion of individuals with asthma who have active disease and, of those, the proportion who experience significant gaps in their asthma activity; and to determine factors associated with asthma activity.

METHODS

Universal population health administrative databases were used to identify all individuals with asthma living in Ontario, Canada, in 1993 and follow them for 15 years. Active asthma was indicated by 1 or more physician claims for asthma.

RESULTS

Of 613,394 individuals with asthma in 1993, 504,851 (82.3%) had active disease in subsequent years. Of those who had complete follow-up, 74.6% experienced a gap of 2 or more years in their asthma activity. Previous asthma claims, older and younger age, and a codiagnosis of chronic obstructive pulmonary disease correlated with greater asthma activity.

CONCLUSION

Over 15 years, most individuals with asthma in Ontario, Canada, had active disease that was interspersed by periods of inactivity when they did not require medical attention and were likely in remission. These analyses offer insight into the natural course of asthma activity that may help improve the ability to predict an individual's course of disease.

Patterns of inhaled corticosteroid use and asthma control in the Childhood Asthma Management Program Continuation Study

BACKGROUND

Daily controller medication use is recommended for children with persistent asthma to achieve asthma control.

OBJECTIVE

To examine patterns of inhaled corticosteroid (ICS) use and asthma control in an observational study of children and adolescents with mild-to-moderate asthma (the Childhood Asthma Management Program Continuation Study).

METHODS

We assessed patterns of ICS use during a 12-month period (consistent, intermittent, and none) and asthma control (well controlled vs poorly controlled). Multivariate logistic regression examined the association between pattern of ICS use and asthma control.

RESULTS

Of 914 patients enrolled, 425 were recommended to continue receiving ICS therapy in the Childhood Asthma Management Program Continuation Study. Of these patients, 46% reported consistent ICS use and 20% reported no ICS use during year 1. By year 4, consistent ICS use decreased to 20%, whereas no ICS use increased to 57%; poorly controlled asthma was reported in 18% of encounters. In multivariate models controlling for age, sex, forced expiratory volume in 1 second, and asthma severity assessment, patients reporting consistent ICS use during a 12-month period were more likely to report poor asthma control (odds ratio, 1.6; 95% confidence interval, 1.2-2.1) compared with those reporting no ICS use.

CONCLUSIONS

In this observational study of children and adolescents with mild-to-moderate asthma, most did not report continued use of ICS. Patients recommended to continue receiving ICS therapy and reporting consistent ICS use were less likely to report well-controlled asthma even after controlling for markers of asthma severity. Although residual confounding by severity cannot be ruled out, many children and adolescents may not achieve well-controlled asthma despite consistent use of ICS.

A disease model for wheezing disorders in preschool children based on clinicians' perceptions

BACKGROUND

Wheezing disorders in childhood vary widely in clinical presentation and disease course. During the last years, several ways to classify wheezing children into different disease phenotypes have been proposed and are increasingly used for clinical guidance, but validation of these hypothetical entities is difficult.

METHODOLOGY/PRINCIPAL FINDINGS

The aim of this study was to develop a testable disease model which reflects the full spectrum of wheezing illness in preschool children. We performed a qualitative study among a panel of 7 experienced clinicians from 4 European countries working in primary, secondary and tertiary paediatric care. In a series of questionnaire surveys and structured discussions, we found a general consensus that preschool wheezing disorders consist of several phenotypes, with a great heterogeneity of specific disease concepts between clinicians. Initially, 24 disease entities were described among the 7 physicians. In structured discussions, these could be narrowed down to three entities which were linked to proposed mechanisms: a) allergic wheeze, b) non-allergic wheeze due to structural airway narrowing and c) non-allergic wheeze due to increased immune response to viral infections. This disease model will serve to create an artificial dataset that allows the validation of data-driven multidimensional methods, such as cluster analysis, which have been proposed for identification of wheezing phenotypes in children.

CONCLUSIONS/SIGNIFICANCE

While there appears to be wide agreement among clinicians that wheezing disorders consist of several diseases, there is less agreement regarding their number and nature. A great diversity of disease concepts exist but a unified phenotype classification reflecting underlying disease mechanisms is lacking. We propose a disease model which may help guide future research so that proposed mechanisms are measured at the right time and their role in disease heterogeneity can be studied.

The irreversible component of persistent asthma

Irreversible airflow obstruction or limitation occurs in some patients with asthma, can develop early in life, and becomes more common as asthma becomes more severe. Efforts to understand irreversible airflow obstruction or limitation have been hampered by the lack of a standardized definition of the phenotype and by the lack of appropriate research models. Unfortunately, it appears that currently available asthma treatments do not prevent this important asthma complication. Herein, the evidence of an irreversible component of asthma, its underlying pathology, and the limitations of current asthma treatments are reviewed.

Natural history of asthma: persistence versus progression-does the beginning predict the end?

Environmental exposures during the early years and airway obstruction that develops during this time, in conjunction with genetic susceptibility, are important factors in the development of persistent asthma in childhood. Established risk factors for childhood asthma include frequent wheezing during the first 3 years, a parental history of asthma, a history of eczema, allergic rhinitis, wheezing apart from colds, and peripheral blood eosinophilia, as well as allergic sensitization to aeroallergens and certain foods. Risk factors for the development of asthma in adulthood remain ill defined. Moreover, reasons for variability in the clinical course of asthma--persistence in some individuals and progression in others--remain an enigma. The distinction between disease persistence and disease progression suggests that these are different entities or phenotypes. There is currently no consensus on whether disease progression requires either airway inflammation or airway remodeling or the combination of the two. For patients with irreversible airway obstruction, inflammation might, in part, be necessary but perhaps not entirely sufficient to induce the irreversible component, some of which could be attributed to alterations in the structure of the bronchial wall. Intervening with intermittent or daily inhaled corticosteroids in high-risk infants and children does not prevent disease progression or impaired lung growth. These findings, however, might not apply to adults, and further study in adults is needed to determine the effect of inhaled corticosteroid therapy on disease progression.

Clinical, functional, and epidemiological differences between atopic and nonatopic asthmatic children from a tertiary care hospital in a developing country

BACKGROUND

Differences between children with atopic asthma (AA) and nonatopic asthma (non-AA) have been shown in epidemiologic studies. In developing countries, even when non-AA is more prevalent than AA among schoolchildren, no data are available regarding clinical, functional, and epidemiological differences between these 2 groups.

OBJECTIVE

To evaluate differences between Chilean children with AA and non-AA.

METHODS

In this cross-sectional study, skin prick tests were performed on all patients (age range, 4-14 years) admitted to our tertiary care hospital with the diagnosis of asthma who were consequently classified as having AA or non-AA. Demographic characteristics, spirometry results, exercise bronchial challenge test results, and eosinophil counts measured in the last 12 months were recorded.

RESULTS

Among the 237 asthmatic children, 62.5% had AA. Non-AA children had a significantly earlier onset of asthma and a more frequent history of pneumonia and tobacco consumption at home. Children with AA had higher nasal eosinophilia levels and a higher prevalence of dermatitis and severe exacerbation episodes of asthma in the past year (emergency department consultation and oral corticosteroids courses). Lung function was similar in both groups. After the multivariate analysis, only the number of oral steroid courses was significantly different between the groups and was associated with AA.

CONCLUSIONS

In this selected population of asthmatic schoolchildren, the prevalence of non-AA (37.6%) is not negligible, and some differences between AA and non-AA children exist.

The role of epithelial injury and repair in the origins of asthma

PURPOSE OF REVIEW

We currently understand little about the mechanisms that lead to asthma. The bronchial epithelium is the first cell layer of contact with the environment and as such is an especially attractive target in which to identify novel mechanisms and new therapeutic strategies in disease development. We discuss the role of epithelial injury and wound repair in the origins of asthma.

RECENT FINDINGS

The presence of inflammation, thickening of the basement membrane and angiogenesis have been described in bronchial biopsies from asthmatic children. We and others have demonstrated the utility of bronchial brushings from children for the isolation, characterization and culture of primary epithelial cells. The results of these experiments suggest that intrinsic differences exist between asthmatic and nonasthmatic epithelial cells.

SUMMARY

It is becoming increasingly clear from studies involving adults and, more recently, children, that the epithelium orchestrates inflammatory and remodeling responses of the airway. Equally clear is that the asthmatic epithelium responds inappropriately to challenge and displays signs of dysregulated repair. Understanding the regulatory mechanisms involved in these processes, including the role of resident/recruited progenitor cells, is crucial if we are to halt the progression of asthma when the disease first manifests in childhood.

Variations in genetic influences on the development of asthma throughout childhood, adolescence and early adult life

PURPOSE OF REVIEW

Asthma is likely to be due to many aetiological factors, the effect of each varying considerably with age. Now that there are well established candidate genes for asthma, using genetics to examine age-related susceptibility to asthma offers a new approach to understanding the basic underlying mechanisms.

RECENT FINDINGS

Since few long-term, longitudinal asthma studies exist, opportunities to examine age-related genetic susceptibility have been limited, but have produced some specific findings. The CCR5Delta32 polymorphism renders the chemokine receptor nonfunctional and is associated with reduced asthma susceptibility in children but not adults. In CD14 C-159T, the -159C allele has been associated with increased atopy in mid-childhood, but not in young adults. IL-12beta is a promoter polymorphism associated with reduced lung function in girls but not boys in mid-childhood only. Regarding the beta(2)adrenoceptor, results from three studies suggest that Arg16 can be associated with impaired airway function in infancy and Gly16 with asthma and wheeze in mid-childhood.

SUMMARY

Age-related genetic susceptibility studies are likely to make a major contribution to understanding basic mechanisms in asthma, but the limited number of suitable cohorts has meant that to date few studies have been reported.

Progression of pulmonary hyperinflation and trapped gas associated with genetic and environmental factors in children with cystic fibrosis

BACKGROUND

Functional deterioration in cystic fibrosis (CF) may be reflected by increasing bronchial obstruction and, as recently shown, by ventilation inhomogeneities. This study investigated which physiological factors (airway obstruction, ventilation inhomogeneities, pulmonary hyperinflation, development of trapped gas) best express the decline in lung function, and what role specific CFTR genotypes and different types of bronchial infection may have upon this process.

METHODS

Serial annual lung function tests, performed in 152 children (77 males; 75 females) with CF (age range: 6-18 y) provided data pertaining to functional residual capacity (FRCpleth, FRCMBNW), volume of trapped gas (VTG), effective specific airway resistance (sReff), lung clearance index (LCI), and forced expiratory indices (FVC, FEV1, FEF50).

RESULTS

All lung function parameters showed progression with age. Pulmonary hyperinflation (FRCpleth > 2SDS) was already present in 39% of patients at age 6-8 yrs, increasing to 67% at age 18 yrs. The proportion of patients with VTG > 2SDS increased from 15% to 54% during this period. Children with severe pulmonary hyperinflation and trapped gas at age 6-8 yrs showed the most pronounced disease progression over time. Age related tracking of lung function parameters commences early in life, and is significantly influenced by specific CFTR genotypes. The group with chronic P. aeruginosa infection demonstrated most rapid progression in all lung function parameters, whilst those with chronic S. aureus infection had the slowest rate of progression. LCI, measured as an index of ventilation inhomogeneities was the most sensitive discriminator between the 3 types of infection examined (p < 0.0001).

CONCLUSION

The relationships between lung function indices, CFTR genotypes and infective organisms observed in this study suggest that measurement of other lung function parameters, in addition to spirometry alone, may provide important information about disease progression in CF.

The development of lung damage in asthma is confined to infancy and early childhood

In addition to its symptomatic impact, asthma may be associated with structural lung damage, which is reflected in impairment of lung function. An important and to some extent neglected aspect of the adverse effects of asthma on lung function has been their course: when do they first occur, and how do they progress? For example, does lung function progressively deteriorate, as it does in chronic obstructive pulmonary disease? These questions have in part been addressed by a number of prospective, longitudinal studies of asthma, including the Melbourne Asthma study (Australia), the Dunedin (New Zealand) and the Tucson study (Arizona, USA). Based on these three studies, I propose that the pathological changes which affect lung function occur in infancy and early childhood. The window of opportunity for preventing the development of these changes, and thus modify the course of the disease, is confined to this early period of life.

Susceptibility genes in severe asthma

Asthma is a common complex disease with a very wide spectrum of severity. Although part of this may be due to differing environmental interactions and inadequate treatment, there is increasing evidence that in addition to susceptibility genes for asthma onset, there are also important genetic influences over the disease severity, response to treatment, and natural history. In this review, we bring together recent literature in the field of genetic influences over disease severity and discuss some of the clinical implications in terms of drug discovery and personalized medicine.