Relationships between duration of asthma and asthma severity among children in the Childhood Asthma Management Program (CAMP)

Epithelial-Mesenchymal Transition Mechanisms in Chronic Airway Diseases: A Common Process to Target?

Epithelial-to-mesenchymal transition (EMT) is a reversible process, in which epithelial cells lose their epithelial traits and acquire a mesenchymal phenotype. This transformation has been described in different lung diseases, such as lung cancer, interstitial lung diseases, asthma, chronic obstructive pulmonary disease and other muco-obstructive lung diseases, such as cystic fibrosis and non-cystic fibrosis bronchiectasis. The exaggerated chronic inflammation typical of these pulmonary diseases can induce molecular reprogramming with subsequent self-sustaining aberrant and excessive profibrotic tissue repair. Over time this process leads to structural changes with progressive organ dysfunction and lung function impairment. Although having common signalling pathways, specific triggers and regulation mechanisms might be present in each disease. This review aims to describe the various mechanisms associated with fibrotic changes and airway remodelling involved in chronic airway diseases. Having better knowledge of the mechanisms underlying the EMT process may help us to identify specific targets and thus lead to the development of novel therapeutic strategies to prevent or limit the onset of irreversible structural changes.

Mild asthma: Lessons learned and remaining questions

Patients living with mild disease represent the largest proportion of asthma patients. There are significant challenges in proposing a definition that would best describe these patients, while also accurately identifying at-risk individuals. Current literature suggests considerable inflammatory and clinical heterogeneity within this group. Research has shown that these patients are at risk of poor control, exacerbations, lung function decline, and death. Despite conflicting data on its prevalence, eosinophilic inflammation appears to be a predictor of poorer outcomes in mild asthma. There is an immediate need to better understand phenotypic clusters in mild asthma. It is also important to understand factors that influence disease progression and remission, as it is evident that both vary in mild asthma. Guided by robust literature that supports inhaled corticosteroid-based strategies over short-acting beta-agonist (SABA) reliant regimens, the management of these patients has evolved considerably. Unfortunately, SABA use remains high in clinical practice despite strong advocacy from the Global Initiative for Asthma. Future mild asthma research should explore the role of biomarkers, develop prediction tools based on composite risk scores, and explore targeted therapies at least for at-risk individuals.

Airway remodeling heterogeneity in asthma and its relationship to disease outcomes

Asthma affects an estimated 262 million people worldwide and caused over 461,000 deaths in 2019. The disease is characterized by chronic airway inflammation, reversible bronchoconstriction, and airway remodeling. Longitudinal studies have shown that current treatments for asthma (inhaled bronchodilators and corticosteroids) can reduce the frequency of exacerbations, but do not modify disease outcomes over time. Further, longitudinal studies in children to adulthood have shown that these treatments do not improve asthma severity or fixed airflow obstruction over time. In asthma, fixed airflow obstruction is caused by remodeling of the airway wall, but such airway remodeling also significantly contributes to airway closure during bronchoconstriction in acute asthmatic episodes. The goal of the current review is to understand what is known about the heterogeneity of airway remodeling in asthma and how this contributes to the disease process. We provide an overview of the existing knowledge on airway remodeling features observed in asthma, including loss of epithelial integrity, mucous cell metaplasia, extracellular matrix remodeling in both the airways and vessels, angiogenesis, and increased smooth muscle mass. While such studies have provided extensive knowledge on different aspects of airway remodeling, they have relied on biopsy sampling or pathological assessment of lungs from fatal asthma patients, which have limitations for understanding airway heterogeneity and the entire asthma syndrome. To further understand the heterogeneity of airway remodeling in asthma, we highlight the potential of in vivo imaging tools such as computed tomography and magnetic resonance imaging. Such volumetric imaging tools provide the opportunity to assess the heterogeneity of airway remodeling within the whole lung and have led to the novel identification of heterogenous gas trapping and mucus plugging as important predictors of patient outcomes. Lastly, we summarize the current knowledge of modification of airway remodeling with available asthma therapeutics to highlight the need for future studies that use in vivo imaging tools to assess airway remodeling outcomes.

Estimating ambient air pollution mortality and disease burden and its economic cost in Barcelona

BACKGROUND

The new WHO air quality guidelines indicate that the air pollution disease burden is greater than previously reported. We aimed to estimate the air pollution disease burden and its economic cost in Barcelona to inform local action.

METHODS

We used a quantitative health impact assessment to estimate the non-accidental mortality and incidence of childhood asthma and lung cancer attributable to long-term air pollution exposure in the city of Barcelona (Spain) in 2018-2019. We used the population weighted mean of PM_2.5 and NO₂ assigned at the geocoded address during the study period and the 2021 WHO air quality guidelines as counterfactual scenario to estimate new annual cases attributable to each pollutant separately and combined. We estimated the social cost of attributable deaths and the health care cost of childhood asthma and lung cancer attributable cases. We also estimated attributable mortality by city district and the mortality avoidable by achieving the WHO air quality interim targets.

RESULTS

Mean exposure was 17 μg/m³ for PM_2.5 and 39 μg/m³ for NO₂. Total combined air pollution attributable mortality was 13% (95%CI = 9%-17%), corresponding to 1,886 deaths (95%CI = 1,296-2,571) and a social cost of €1,292 million (95%CI = 888-1,762) annually. Fifty-one percent (95%CI = 21%-71%) and 17% (95%CI = 7%-29%) of new cases of childhood asthma and lung cancer were attributable to air pollution with a health care cost of €4.3 and €2.7 million, respectively. Achieving the first unmet WHO air quality interim targets for PM_2.5 and for NO₂ would avoid 410 deaths and €281 million annually.

CONCLUSION

Air pollution in Barcelona represents a huge disease and economic burden, which is greater than previous estimates. Much stronger measures to reduce PM_2.5 and NO₂ levels are urgently needed. Until the WHO air quality guidelines are met in the city, achieving each WHO air quality interim targets would avoid hundreds of deaths each year.

Poor Asthma Control in Schoolchildren May Lead to Lower Lung Function Trajectory from Childhood to Early Adulthood: A Japanese Cohort Study

Purpose

Although childhood asthma is a risk factor for adult lung function disorders, the correlation between childhood asthma control level and lung function growth remains unclear in Japan. The correlation between childhood asthma control and early adulthood lung function growth was investigated in this study.

Patients and Methods

We included 505 children with asthma from the Omuta City Air Pollution-Related Health Damage Cohort Program. The characteristics and lung function of girls and boys aged 6–11 years and 12–17 years were compared between poor and good asthma control groups.

Results

Among the 505 children, 214 (42.4%) showed poor asthma control. The mean percentage forced expiratory volume in 1 second predicted for girls and boys aged 6–11 years (80.2% and 79.2%, respectively) and 12–17 years (80.0% and 81.1%, respectively) in the poor control group was significantly lower than those of girls and boys aged 6–11 years (87.9% and 87.3%, respectively) and 12–17 years (88.1% and 87.8%, respectively) in the good control group. However, a linear regression model did not reveal between-group differences in the slopes of lung function growth for both sexes. Girls (24.6%, P < 0.0001) and boys (24.4%, P = 0.0026) in the poor control group had a significantly higher proportion of young adults with obstructive ventilatory patterns than girls (1.4%) and boys (8.1%) in the good control group.

Conclusion

Our findings revealed that poor childhood asthma control leaded to lung function disorders, which suggest the importance of early asthma control in school children.

COPD in Smoking and Non-Smoking Community Members Exposed to the World Trade Center Dust and Fumes

Background: The characteristics of community members exposed to World Trade Center (WTC) dust and fumes with Chronic Obstructive Pulmonary Disease (COPD) can provide insight into mechanisms of airflow obstruction in response to an environmental insult, with potential implications for interventions. Methods: We performed a baseline assessment of respiratory symptoms, spirometry, small airway lung function measures using respiratory impulse oscillometry (IOS), and blood biomarkers. COPD was defined by the 2019 GOLD criteria for COPD. Patients in the WTC Environmental Health Center with <5 or ≥5 pack year smoking history were classified as nonsmoker-COPD (ns-COPD) or smoker-COPD (sm-COPD), respectively. Main Results: Between August 2005 and March 2018, 467 of the 3430 evaluated patients (13.6%) fit criteria for COPD. Among patients with COPD, 248 (53.1%) were ns-COPD. Patients with ns-COPD had measures of large airway function (FEV1) and small airway measures (R5−20, AX) that were less abnormal than those with sm-COPD. More ns-COPD compared to sm-COPD had a bronchodilator (BD) response measured by spirometry (24 vs. 14%, p = 0.008) or by IOS (36 vs. 21%, p = 0.002). Blood eosinophils did not differ between ns-COPD and sm-COPD, but blood neutrophils were higher in sm-COPD compared to ns-COPD (p < 0.001). Those with sm-COPD were more likely to be WTC local residents than ns-COPD (p = 0.007). Conclusions: Spirometry findings and small airway measures, as well as inflammatory markers, differed between patients with ns-COPD and sm-COPD. These findings suggest potential for differing mechanisms of airway injury in patients with WTC environmental exposures and have potential therapeutic implications.

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.

Changes in Type 2 Biomarkers After Anti-IL5 Treatment in Patients With Severe Eosinophilic Asthma

Patients with severe eosinophilic asthma (SEA) suffer from frequent asthma exacerbations, where eosinophils are major effector cells in airway inflammation, and anti-interleukin (IL)-5 becomes an effective treatment modality to control eosinophilic inflammation of SEA. Fifteen patients with SEA who had been treated with anti-IL5 (reslizumab, 100 mg monthly intravenously) for 6 months at Ajou University Hospital (Suwon, Korea) were enrolled in this study. Clinical parameters, including total blood eosinophil count (TEC), FEV1%, fractional exhaled nitric oxide (FeNO) levels, and serum biomarkers such as eosinophil-derived neurotoxin (EDN), periostin (PON), and transforming growth factor-β1 (TGF-β1), were analyzed. EDN levels and TEC decreased significantly after 1 month of treatment (P < 0.05 for both), while no changes were noted in FeNO/PON/TGF-β1 levels. FEV1% increased after 2 months of treatment (P < 0.05). A positive correlation was observed between TEC and EDN levels (r = 0.60, P = 0.02). Significant negative correlations were noted between age and TEC/EDN levels (r = -0.57, P = 0.02 and r = -0.56, P = 0.03, respectively). Baseline TEC was higher in the EDN-responder group (≥75% decrease) than in the non-responder group (P = 0.06) with a positive correlation between %reduction in EDN and TEC (r = 0.67, P = 0.01). The onset age was younger and asthma duration was longer in the FEV1%-non-responder group (<12% increase) than in the FEV1%-responder group (P = 0.07 and P = 0.007, respectively). In conclusion, changes in the serum EDN level may be a potential biomarker for monitoring eosinophilic inflammation after anti-IL5 treatment in SEA, which is affected by onset age and asthma duration.

Performance Characteristics of Spirometry With Negative Bronchodilator Response and Methacholine Challenge Testing and Implications for Asthma Diagnosis

BACKGROUND

In patients with a history suggestive of asthma, diagnosis is usually confirmed by spirometry with bronchodilator response (BDR) or confirmatory methacholine challenge testing (MCT).

RESEARCH QUESTION

We examined the proportion of participants with negative BDR testing who had a positive MCT (and its predictors) result and characteristics of MCT, including effects of controller medication tapering and temporal variability (and predictors of MCT result change), and concordance between MCT and pulmonologist asthma diagnosis.

STUDY DESIGN AND METHODS

Adults with self-reported physician-diagnosed asthma were recruited by random-digit dialing across Canada. Subjects performed spirometry with BDR testing and returned for MCT if testing was nondiagnostic for asthma. Subjects on controllers underwent medication tapering with serial MCTs over 3 to 6 weeks. Subjects with a negative MCT (the provocative concentration of methacholine that results in a 20% drop in FEV₁ [PC₂₀] > 8 mg/mL) off medications were examined by a pulmonologist and had serial MCTs after 6 and 12 months.

RESULTS

Of 500 subjects (50.5 ± 16.6 years old, 68.0% female) with a negative BDR test for asthma, 215 (43.0%) had a positive MCT. Subjects with prebronchodilator airflow limitation were more likely to have a positive MCT (OR, 1.90; 95% CI, 1.17-3.04). MCT converted from negative to positive, with medication tapering in 18 of 94 (19.1%) participants, and spontaneously over time in 25 of 165 (15.2%) participants. Of 231 subjects with negative MCT, 28 (12.1%) subsequently received an asthma diagnosis from a pulmonologist.

INTERPRETATION

In subjects with a self-reported physician diagnosis of asthma, absence of bronchodilator reversibility had a negative predictive value of only 57% to exclude asthma. A finding of spirometric airflow limitation significantly increased chances of asthma. MCT results varied with medication taper and over time, and pulmonologists were sometimes prepared to give a clinical diagnosis of asthma despite negative MCT. Correspondingly, in patients for whom a high clinical suspicion of asthma exists, repeat testing appears to be warranted.

Defective Fibrillar Collagen Organization by Fibroblasts Contributes to Airway Remodeling in Asthma

Rationale: Histologic stains have been used as the gold standard to visualize extracellular matrix (ECM) changes associated with airway remodeling in asthma, yet they provide no information on the biochemical and structural characteristics of the ECM, which are vital to understanding alterations in tissue function.Objectives: To demonstrate the use of nonlinear optical microscopy (NLOM) and texture analysis algorithms to image fibrillar collagen (second harmonic generation) and elastin (two-photon excited autofluorescence), to obtain biochemical and structural information on the remodeled ECM environment in asthma.Methods: Nontransplantable donor lungs from donors with asthma (n = 13) and control (n = 12) donors were used for the assessment of airway collagen and elastin fibers by NLOM, and extraction of lung fibroblasts for in vitro experiments.Measurements and Main Results: Fibrillar collagen is not only increased but also highly disorganized and fragmented within large and small asthmatic airways compared with control subjects, using NLOM imaging. Furthermore, such structural alterations are present in pediatric and adult donors with asthma, irrespective of fatal disease. In vitro studies demonstrated that asthmatic airway fibroblasts are deficient in their packaging of fibrillar collagen-I and express less decorin, important for collagen fibril packaging. Packaging of collagen fibrils was found to be more disorganized in asthmatic airways compared with control subjects, using transmission electron microscopy.Conclusions: NLOM imaging enabled the structural assessment of the ECM, and the data suggest that airway remodeling in asthma involves the progressive accumulation of disorganized fibrillar collagen by airway fibroblasts. This study highlights the future potential clinical application of NLOM to assess airway remodeling in vivo.

Persistent Asthma from Childhood to Adulthood Presents a Distinct Phenotype of Adult Asthma

BACKGROUND

In approximately 30% of children with asthma, the condition persists into adulthood. The longer duration of asthma in these patients is a risk factor for poor asthma control. However, the characteristics of adult patients with asthma that has persisted since childhood are not well documented.

OBJECTIVE

We sought to compare the clinical characteristics among patients with adult-onset asthma, patients who outgrew childhood asthma but relapsed, and patients with persistent asthma since childhood.

METHODS

We conducted a cross-sectional study of adult patients with asthma who visited our hospital. We classified them into 3 groups: those with adult-onset asthma (adult-onset), those who had remitted childhood asthma that relapsed (relapsed), and those who had asthma that had persisted since childhood (persistent). The clinical characteristics of these groups were compared.

RESULTS

A total of 1443 patients were enrolled. The persistent group was younger and included fewer patients with a smoking history. There were statistically significant differences among the 3 groups in the percentages of patients with a family history of asthma and comorbidities of allergic rhinitis and atopic dermatitis. The proportion of patients with severe asthma differed among the 3 groups (31% in the adult-onset group, 34% in the relapsed group, and 40% in the persistent group; P = .015). The values of forced expiratory flow at 75% of vital capacity were lower in the persistent group than the relapsed or adult-onset group. A multivariable logistic regression analysis (dependent variable: severe asthma) in each group revealed that the factors associated with severe asthma differed among the adult-onset, relapsed, and persistent groups. When we established an overall model that included interaction terms of cohort-by-other factors, there was a trend that comorbidity of allergic rhinitis affected the severity of asthma differently in the relapsed group compared with the other groups.

CONCLUSION

The clinical phenotype of asthma that persists from childhood to adulthood seems to be a distinct phenotype of adult asthma.

What is the impact of outdoor pollution on children's asthma?

Outdoor pollution is a complex mix of more than 200 air contaminants. Among these pollutants, ozone, nitrogen dioxide and fine particles may generate bronchial inflammation and hyperreactivity. The hypothesis that pollution contributes to the development of asthma in children is based on epidemiological, clinical and experimental data. Many risk factors during the in utero and postnatal period have been identified in the aetiology of childhood asthma. During pregnancy, outdoor pollution was identified as a causal factor of respiratory disease in neonatal cohort studies. Several epidemiological studies also demonstrate that outdoor pollution is a trigger of asthma exacerbations. This review aims to highlight the current knowledge on outdoor pollution and asthma.

Trajectory of spirometric and exhaled nitric oxide measurements in Chinese schoolchildren with asthma

BACKGROUND

Lung function growth occurs in most asthmatic children. A subgroup has subnormal lung function trajectory, but such data are limited in children. This prospective study characterized longitudinal changes of spirometric indices and fractional exhaled nitric oxide level (FeNO) among asthmatic children and identified their genetic and environmental determinants.

METHODS

Chinese asthmatic children recruited from pediatric clinics underwent 5-year follow-up for pre-bronchodilator spirometric indices and FeNO. Fourteen asthma-associated single nucleotide polymorphisms (SNPs) were genotyped. Generalized estimating equation was used to analyze longitudinal changes of spirometric indices and FeNO.

RESULTS

One hundred and ninety-three asthmatic children, aged 9.7 (1.9) years, had significant annual decline of 1.3% for forced vital capacity (FVC) and annual increase of 1.2% and 3.6% for FEV₁ /FVC and FEF_25-75 , respectively. Patients who received inhaled corticosteroid (ICS) had 2.4% lower baseline FEV₁ /FVC but 0.81% higher annual increase in FEV₁ . Body mass index (BMI) was associated inversely with FEV₁ /FVC but positively with FEV₁ % and FVC% changes. Asthma exacerbation was associated with lower FEV₁ % and FVC% but not their longitudinal changes. When classified by FEV₁ curve, one-quarter of patients had reduced lung function growth which was associated with female gender and lower spirometric and higher FeNO values at baseline. IL33_rs1342326 was associated with spirometric indices and FeNO, whereas GSDMB_rs2305480 was significantly associated with FEV₁ /FVC change.

CONCLUSION

Asthmatic children have annual decline in FVC and increase in FEV₁ /FVC and FEF_25-75 . Their lung function trajectory is influenced by gender, ICS treatment, BMI, and asthma exacerbations. IL33 and GSDMB may be candidate genes for their lung function growth.

Level of asthma control and risk factors for poor asthma control among clinic patients seen at a Referral Hospital in Addis Ababa, Ethiopia

OBJECTIVE

Uncontrolled asthma negatively impacts patients, families, and the community. The level of symptom control among asthmatics in Ethiopia has not been well studied. We investigated the level of asthma control and risk factors for poor asthma control in clinic patients seen in the largest public hospital in Ethiopia.

RESULTS

In this cross-sectional study, we studied all 182 consecutive subjects with a physician diagnosis of asthma who were seen in chest clinic at Tikur Anbessa Specialized Hospital between July and December 2015. Of the 182 subjects, 68.1% were female. The mean age was 52 ± 12 years and the median duration of asthma was 20 ± 12.7 years. One hundred and seventeen subjects (64.3%) had nighttime awakening due to asthma. Fifty-eight (31%) were not using controller medications and 62 (34.6%) had improper inhaler technique. Only 44 (24.2%) subjects had well-controlled asthma. On multivariate analysis, variables associated with uncontrolled asthma included: use of biomass fuel for cooking, longer duration of asthma (> 30 year), incorrect inhalation technique, and asthma exacerbation in the last 12 months. Most asthmatics attending in the largest public hospital in Ethiopia, had uncontrolled asthma. Several risk factors for poor asthma control were identified. Improved asthma control is possible through directed interventions.

Contributing factors to the development of childhood asthma: working toward risk minimization

Asthma is the most common chronic disease in childhood, and considerable research has been undertaken to find ways to prevent its development and reduce its prevalence. For such interventions to be successful, risk factors for asthma emergence should be identified and clearly defined. Data are robust for some of them, including atopy, viral infections and exposure to airborne irritants, whereas it is less conclusive for others, such as aeroallergen exposure and bacterial infections. Several interventions for asthma prevention, including avoidance and pharmacotherapy, have been attempted. However, most of them have furnished equivocal results. Various issues hinder the establishment of risk factors for asthma development and reduce the effectiveness of interventions, including the complexity of the disease and the fluidity of the developing systems in childhood. In this review, we revisit the evidence on pediatric asthma risk factors and prevention and discuss issues that perplex this field.

Early life environmental predictors of asthma age-of-onset

Prevention strategies that delay the onset of asthma may improve clinical outcomes. To identify early life environmental exposures associated with asthma age-of-onset and potential genetic modifiers of these exposures, we studied 1085 subjects with physician-diagnosed asthma and disease onset at or after age two. Subjects reported retrospectively on their exposure to 17 environmental factors before the age of two. The presence of individual or combinations of these early life exposures was then tested for association with variation in asthma age-of-onset. For exposures significantly associated with age-of-onset, we tested if 26 single nucleotide polymorphisms (SNP) with an established association with allergic disease significantly modified the effect of the exposure. Five environmental exposures were significantly associated with variation in asthma age-of-onset after correction for multiple testing: carpet at home (P = 6 × 10⁻⁵), a serious chest illness (P = 10⁻⁴), father a cigarette smoker (P = 6 × 10⁻⁴) and direct exposure to father's smoking (P = 3 × 10⁻⁴). Individuals with early childhood asthma onset, between the ages of two and six, were 1.4-fold (CI 1.1–1.9) more likely to report having lived in a house with carpet and 2.1-fold (CI 1.3–3.5) more likely to report suffering a serious chest illness before the age of two, than asthmatics with later disease onset. We further found these individual risks to increase to 3.2-fold (CI 1.7–6.0) if carpet exposure and suffering a serious chest illness co-occurred before age two. Paternal smoking exposures were less likely to be reported by asthmatics with early when compared to later disease onset (OR 0.5, CI 0.3–0.7). There were no significant SNP interactions with these environmental exposures after correction for multiple testing. Our results suggest that disease onset in individuals at a high-risk of developing asthma can potentially be delayed by avoiding exposure to carpet at home and preventing serious chest illnesses during the first 2 years of life.

Pharmacological approach to wheezing in preschool children

INTRODUCTION

Wheezing disorders are very common during childhood (particularly among preschool children), and represent a significant burden for patients, their families, the healthcare system, and society as a whole. Identifying wheezing phenotypes, and recognizing the risk factors associated with each, may help to predict long-term outcomes, distinguish high-risk children who may benefit from secondary prevention measures, and ensure that the most effective therapy is prescribed for each case.

AREAS COVERED

The main aim of this review is to analyze the characteristics of the drugs currently used to treat wheezing in preschool children, and discuss the results obtained in children with different wheezing phenotypes.

EXPERT OPINION

The continuous or intermittent administration of various oral or inhaled drugs could theoretically be effective in preventing or controlling wheezing in preschool children. However, the optimal management of acute preschool wheezing episodes has not yet been determined mainly because of their phenotypical heterogeneity.

Assessing asthma severity among children and adults with current asthma

BACKGROUND

Asthma severity is a key indicator to assess asthma care and management. Severity status may vary over time. Assessing asthma severity periodically is important for monitoring the health and well-being of people with asthma.

OBJECTIVE

To assess population-based asthma severity and to identify related-risk factors among children and adults with asthma.

METHODS

We used the 2006-2010 BRFSS child and adult Asthma Call-back Survey. Asthma severity was classified as intermittent or persistent. We performed multivariate logistic regression to identify related-risk factors.

RESULTS

Overall, 63.8% of persons with asthma had persistent asthma. Persistent asthma was more prevalent among children aged 0-4 years (71.8%; prevalence rate ratio [PR] = 1.3). Among adults with current asthma, persistent asthma was more prevalent among those who were 45 years or older (aged 45-54: 69.4%; PR = 1.1, aged 55-64: 72.6%; PR = 1.2, and aged 65+: 77.8%; PR = 1.3); annual household incomes of <$15 000 (74.1%; PR = 1.1); and first diagnosed at age 55 years or older (first diagnosed at age 55-64: 80.4%; PR = 1.1, at age 65 + : 81.5%; PR = 1.1). The prevalence of persistent asthma was also higher among current smokers who were also exposed to secondhand smoke (SHS) (74.7%; PR = 1.1); and among those with Chronic Obstructive Pulmonary Disease (COPD) (77.1%; PR = 1.2).

CONCLUSIONS

Nearly two-thirds of children and adults with asthma had persistent asthma. Identifying related-risk factors could help improve targeted interventions or strategies to reduce modifiable predictors (low income, smoking, and SHS) of increased asthma severity. Such strategies could improve asthma care and quality of life.

Acute asthma exacerbations in childhood: risk factors, prevention and treatment

Asthma is a heterogeneous disease more appropriately seen as a syndrome rather than a single pathologic entity. Although it can remain quiescent for extended time periods, the inflammatory and remodeling processes affect the bronchial milieu and predispose to acute and occasionally severe clinical manifestations. The complexity underlying these episodes is enhanced during childhood, an era of ongoing alterations and maturation of key biological systems. In this review, the authors focus on such sudden-onset events, emphasizing on their diversity on the basis of the numerous asthma phenotypes.

Long-term follow-up after two years of asthma treatment guided by airway responsiveness in children

INTRODUCTION

Children with persistent asthma may have diminished lung function in early adulthood. In our previous study ('CATO') we showed preservation of lung function in asthmatic children, during 2 years of treatment that was guided by airway hyperresponsiveness (AHR). The aim of the present prospective follow up study was to investigate whether the positive effect of the AHR strategy on lung function had persisted beyond the duration of the intervention study, after several years of usual care by paediatrician and general practitioner.

METHODS

With a mean interval of 4.4 y after the last visit, 137 subjects (67% of the original CATO population) participated in this follow-up study. Evaluation consisted of spirometry (n = 137), a methacholine challenge test (n = 83), data on inhaled steroid treatment and asthma exacerbations (n = 137), and an asthma symptom diary during 6 weeks (n = 90).

RESULTS

At follow-up, lung function, % symptom-free days and exacerbation rates of both treatment strategy groups was similar. The mean dose of inhaled corticosteroids had diminished from 550 μg/day at the end of CATO to 235 μg/day at follow-up. The decrease in AHR measured at the end of CATO was maintained at follow-up for both treatment strategy groups.

CONCLUSION

The beneficial effect on lung function of 2 years treatment guided by AHR was lost after 3-7 years of usual care. This suggests that an AHR-guided treatment strategy may need to be sustained in order to preserve lung function.

Intermittent versus daily inhaled corticosteroids for persistent asthma in children and adults

BACKGROUND

Daily inhaled corticosteroids (ICS) are the recommended mainstay of treatment in children and adults with persistent asthma. However, often, ICS are used intermittently by patients or recommended by physicians to be used only at the onset of exacerbations.

OBJECTIVES

The aim of this review was to compare the efficacy and safety of intermittent versus daily ICS in the management of children and adults with persistent asthma and preschool-aged children suspected of persistent asthma.

SEARCH METHODS

We searched the Cochrane Airways Group Specialised Register of trials (CAGR) and the ClinicalTrials.gov web site up to October 2012.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) that compared intermittent ICS versus daily ICS in children and adults with 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 number of patients with one or more exacerbations requiring oral corticosteroids and the primary safety outcome was the number of patients with serious adverse health events. Secondary outcomes included exacerbations, lung function tests, asthma control, adverse effects, withdrawal rates and inflammatory markers. Equivalence was assumed if the risk ratio (RR) estimate and its 95% confidence interval (CI) were between 0.9 and 1.1. Quality of the evidence was assessed using GRADE.

MAIN RESULTS

Six trials (including one trial testing two relevant protocols) met the inclusion criteria for a total of seven group comparisons. The four paediatric trials (two involving preschool children and two school-aged children) and two adult parallel-group trials, lasting 12 to 52 weeks, were of high methodological quality. A total of 1211 patients with confirmed, or suspected, persistent asthma contributed to the meta-analyses. There was no statistically significant group difference in the risk of patients experiencing one or more exacerbations requiring oral corticosteroids (1204 patients; RR 1.07; 95% CI 0.87 to 1.32; the large confidence interval translates into a risk of exacerbations in the intermittent ICS group varying between 17% and 25%, assuming a 19% risk with daily ICS). Age, severity of airway obstruction, step-up protocol used during exacerbations and trial duration did not significantly influence the primary efficacy outcome. No group difference was observed in the risk of patients with serious adverse health events (1055 patients; RR 0.82; 95% CI 0.33 to 2.03). Compared to the daily ICS group, the intermittent ICS group displayed a smaller improvement in change from baseline peak expiratory flow rate (PEFR) by 2.56% (95% CI -4.49% to -0.63%), fewer symptom-free days (standardised mean difference (SMD) -0.15 (95% CI -0.28 to -0.03), fewer asthma control days -9% (95% CI -14% to -4%), more use of rescue β2-agonists by 0.12 puffs/day (95% CI 0 to 0.23) and a greater increase from baseline in exhaled nitric oxide of 16.80 parts per billion (95% CI 11.95 to 21.64). There was no significant group difference in forced expiratory volume in one second (FEV1), quality of life, airway hyper-reactivity, adverse effects, hospitalisations, emergency department visits or withdrawals. In paediatric trials, intermittent ICS (budesonide and beclomethasone) were associated with greater growth by 0.41 cm change from baseline (532 children; 95% CI 0.13 to 0.69) compared to daily treatment.

AUTHORS' CONCLUSIONS

In children and adults with persistent asthma and in preschool children suspected of persistent asthma, there was low quality evidence that intermittent and daily ICS strategies were similarly effective in the use of rescue oral corticosteroids and the rate of severe adverse health events. The strength of the evidence means that we cannot currently assume equivalence between the two options.. Daily ICS was superior to intermittent ICS in several indicators of lung function, airway inflammation, asthma control and reliever use. Both treatments appeared safe, but a modest growth suppression was associated with daily, compared to intermittent, inhaled budesonide and beclomethasone. Clinicians should carefully weigh the potential benefits and harm of each treatment option, taking into account the unknown long-term (> one year) impact of intermittent therapy on lung growth and lung function decline.

Intermittent versus daily inhaled corticosteroids for persistent asthma in children and adults

BACKGROUND

Daily inhaled corticosteroids (ICS) are the recommended mainstay of treatment in children and adults with persistent asthma. Yet often, ICS are used intermittently by patients or recommended by physicians to be used only at the onset of exacerbations.

OBJECTIVES

The aim of this review was to compare the efficacy and safety of intermittent versus daily ICS in the management of children and adults with persistent asthma and preschool-aged children suspected of persistent asthma.

SEARCH METHODS

We searched the Cochrane Airways Group Specialised Register of trials (CAGR) and the ClinicalTrials.gov website up to December 2011.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) that compared intermittent ICS versus daily ICS in children and adults with 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 number of patients with one or more exacerbations requiring oral corticosteroids and the primary safety outcome was the number of patients with serious adverse health events. Secondary outcomes included exacerbations, lung function tests, asthma control, adverse effects, withdrawal rates and inflammatory markers. Equivalence was assumed if the risk ratio (RR) estimate and its 95% confidence interval (CI) were between 0.9 and 1.1.

MAIN RESULTS

Six trials (including one trial testing two relevant protocols) met the inclusion criteria for a total of seven group comparisons. The four paediatric trials (two involving preschool children and two school-aged children) and two adult parallel-group trials, lasting 12 to 52 weeks, were of high methodological quality. A total of 1211 patients with confirmed, or suspected, persistent asthma contributed to the meta-analyses. There was no statistically significant group difference in the risk of patients experiencing one or more exacerbations requiring oral corticosteroids (1204 patients; RR 1.07; 95% CI 0.87 to 1.32). The patients' age, severity of airway obstruction, step-up protocol used during exacerbations and trial duration did not significantly influence the primary efficacy outcome. No group difference was observed in the risk of patients with serious adverse health events (1055 patients; RR 0.82; 95% CI 0.33 to 2.03). Compared to the daily ICS group, the intermittent ICS group displayed a smaller improvement in change from baseline peak expiratory flow rate (PEFR) by 2.56% (95% CI -4.49% to -0.63%), fewer symptom-free days (standardised mean difference (SMD) -0.15 (95% CI -0.28 to -0.03), fewer asthma control days -9% (95% CI -14% to -4%), more use of rescue β(2)-agonists by 0.12 puffs/day (95% CI 0 to 0.23) and a greater increase from baseline in exhaled nitric oxide of 16.80 parts per billion (95% CI 11.95 to 21.64). There was no significant group difference in forced expiratory volume in one second (FEV(1)), quality of life, airway hyper-reactivity, adverse effects, hospitalisations, emergency department visits or withdrawals. In paediatric trials, intermittent ICS (budesonide and beclomethasone) were associated with greater growth by 0.41 cm change from baseline (532 children; 95% CI 0.13 to 0.69) compared to daily treatment.

AUTHORS' CONCLUSIONS

In children and adults with persistent asthma and in preschool children suspected of persistent asthma, intermittent and daily ICS strategies did not significantly differ in the use of rescue oral corticosteroids and the rate of severe adverse health events, neither did they reach equivalence. Daily ICS was superior to intermittent ICS in several indicators of lung function, airway inflammation, asthma control and reliever use. Both treatments appeared safe, but a modest growth suppression was associated with daily, compared to intermittent, inhaled budesonide and beclomethasone. The clinician should carefully weigh the potential benefits and harm of each treatment option, taking into account the unknown long-term (> one year) impact of intermittent therapy on lung growth and lung function decline.

House dust mite sensitization in toddlers predict persistent wheeze in children between eight to fourteen years old

BACKGROUND

Identifying toddlers at increased risk of developing persistent wheeze provides an opportunity for risk-reducing interventions. House dust mite (HDM) allergen sensitization might identify this group of high-risk children.

OBJECTIVE

We examined whether a positive skin prick test (SPT) to at least 1 of the 3 HDMs in wheezing toddlers, would serve as a predictor for persistent wheeze at age 8 to 14 years old.

METHODS

A cohort of 78 children, who had wheezing episodes, and underwent SPT to 3 HDMs between the ages of 2 to 5 years old, were enrolled. SPT results were obtained from the National University Hospital database. Four to 9 years later, the children, currently between 8 to 14 years old, were re-assessed for persistence of asthma symptoms and other atopic disorders via a telephone interview. A validated questionnaire on current wheezing and asthma, developed by the International Study of Asthma and Allergies in Childhood, was used. Fisher's exact test was used to evaluate the association between persistence of asthma and a positive SPT.

RESULTS

Of the 78 children who participated in the study, 42 (53.8%) had a positive SPT and 36 (46.2%) had a negative SPT. Of these, 18 (42.9%) of SPT positive and 7 (19.4%) of SPT negative children had persistence of asthma symptoms. There is a significant association between a positive SPT during the preschool years, and persistence of asthma (p = 0.0314 [<0.05]).

CONCLUSION

HDM sensitization at ages 2 to 5 years old in wheezing children predicts persistence of asthma after 4 to 9 years. This in turn may have benefits for management of asthma in this high-risk group.

Genome-wide association study of the age of onset of childhood asthma

BACKGROUND

Childhood asthma is a complex disease with known heritability and phenotypic diversity. Although an earlier onset has been associated with more severe disease, there has been no genome-wide association study of the age of onset of asthma in children.

OBJECTIVE

We sought to identify genetic variants associated with earlier onset of childhood asthma.

METHODS

We conducted the first genome-wide association study of the age of onset of childhood asthma among participants in the Childhood Asthma Management Program (CAMP) and used 3 independent cohorts from North America, Costa Rica, and Sweden for replication.

RESULTS

Two single nucleotide polymorphisms (SNPs) were associated with earlier onset of asthma in the combined analysis of CAMP and the replication cohorts: rs9815663 (Fisher P= 2.31 × 10(-8)) and rs7927044 (P= 6.54 × 10(-9)). Of these 2 SNPs, rs9815663 was also significantly associated with earlier asthma onset in an analysis including only the replication cohorts. Ten SNPs in linkage disequilibrium with rs9815663 were also associated with earlier asthma onset (2.24 × 10(-7)

CONCLUSIONS

We have identified 2 SNPs associated with earlier onset of childhood asthma in 4 independent cohorts.

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Key Words

• asthma
• pediatrics
• age of onset
• asthma genetics
• c1orf100
• genome-wide association study
• pediatric asthma

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MESH Headings

• Adolescent
• Age of Onset
• Asthma/epidemiology
• Asthma/genetics
• Child
• Cohort Studies
• Costa Rica/epidemiology
• Female
• Genetic Predisposition to Disease
• Genome-Wide Association Study/methods
• Genotype
• Humans
• Linkage Disequilibrium
• Male
• North America/epidemiology
• Polymorphism, Single Nucleotide/genetics
• Sweden/epidemiology

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Grants

• R00 HL096840 NHLBI NIH HHS
• N01-HR-16051 NHLBI NIH HHS
• M01 RR002719 NCRR NIH HHS
• N01-HR-16044 NHLBI NIH HHS
• N01-HR-16048 NHLBI NIH HHS
• M01 RR000036 NCRR NIH HHS
• N01-HR-16045 NHLBI NIH HHS
• M01RR02719-14 NCRR NIH HHS
• M01 RR000051 NCRR NIH HHS
• HL66289 NHLBI NIH HHS
• R01 HL066289 NHLBI NIH HHS
• N01HR16044 NHLBI NIH HHS
• N01-HR-16047 NHLBI NIH HHS
• WT084703MA Wellcome Trust
• N01-HR-16046 NHLBI NIH HHS
• N02-HL-6-4278 NHLBI NIH HHS
• K01 HL004370 NHLBI NIH HHS
• N01-HR-16049 NHLBI NIH HHS
• RR00036 NCRR NIH HHS
• N01-HR-16052 NHLBI NIH HHS
• R37 HL066289 NHLBI NIH HHS
• N01-HR-16050 NHLBI NIH HHS
• Wellcome Trust
• M01RR00051 NCRR NIH HHS
• M01RR0099718-24 NCRR NIH HHS

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Affiliation(s)

Erick Forno Channing Laboratory, Brigham and Women’s Hospital, Boston, MA Division of Pediatric Pulmonology, Dept. of Pediatrics, University of Miami, Miami, FL Harvard Medical School, Boston, MA
Jessica Lasky-Su Channing Laboratory, Brigham and Women’s Hospital, Boston, MA Harvard Medical School, Boston, MA
Blanca Himes Channing Laboratory, Brigham and Women’s Hospital, Boston, MA Harvard Medical School, Boston, MA
Judie Howrylak Channing Laboratory, Brigham and Women’s Hospital, Boston, MA
Clare Ramsey Dept. of Medicine, University of Manitoba, Winnipeg, Canada
John Brehm Channing Laboratory, Brigham and Women’s Hospital, Boston, MA Division of Pulmonary/Critical Care Medicine, Dept. of Medicine, Brigham and Women’s Hospital, Boston, MA Harvard Medical School, Boston, MA
Barbara Klanderman Channing Laboratory, Brigham and Women’s Hospital, Boston, MA
John Ziniti Channing Laboratory, Brigham and Women’s Hospital, Boston, MA
Erik Melén Channing Laboratory, Brigham and Women’s Hospital, Boston, MA Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden Astrid Lindgren Children’s Hospital, Karolinska University Hospital, Stockholm, Sweden
Goran Pershagen Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden
Magnus Wickman Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden Sachs Children’s Hospital, Stockholm, Sweden
Fernando Martinez Department of Pediatrics, University of Arizona, Tucson, AZ
Dave Mauger Penn State Hershey College of Medicine, Hershey, PA
Christine Sorkness University of Wisconsin, Madison, WI
Kelan Tantisira Channing Laboratory, Brigham and Women’s Hospital, Boston, MA Division of Pulmonary/Critical Care Medicine, Dept. of Medicine, Brigham and Women’s Hospital, Boston, MA Harvard Medical School, Boston, MA
Benjamin A. Raby Channing Laboratory, Brigham and Women’s Hospital, Boston, MA Division of Pulmonary/Critical Care Medicine, Dept. of Medicine, Brigham and Women’s Hospital, Boston, MA Harvard Medical School, Boston, MA
Scott T. Weiss Channing Laboratory, Brigham and Women’s Hospital, Boston, MA Harvard Medical School, Boston, MA
Juan C. Celedón Division of Pediatric Pulmonary Medicine, Allergy and Immunology, Dept. of Pediatrics, Children’s Hospital of Pittsburgh of UPMC, University of Pittsburgh School of Medicine, Pittsburgh, PA

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Lung effects of inhaled corticosteroids in a rhesus monkey model of childhood asthma

BACKGROUND

The risks for infants and young children receiving inhaled corticosteroid (ICS) therapy are largely unknown. Recent clinical studies indicate that ICS therapy in pre-school children with symptoms of asthma result in decreased symptoms without influencing the clinical disease course, but potentially affect postnatal growth and development. The current study employs a primate experimental model to identify the risks posed by ICS therapy.

OBJECTIVE

To (1) establish whether ICS therapy in developing primate lungs reverses pulmonary pathobiology associated with allergic airway disease (AAD) and (2) define the impact of ICS on postnatal lung growth and development in primates.

METHODS

Infant rhesus monkeys were exposed, from 1 through 6 months, to filtered air (FA) with house dust mite allergen and ozone using a protocol that produces AAD (AAD monkeys), or to FA alone (Control monkeys). From three through 6 months, the monkeys were treated daily with ICS (budesonide) or saline.

RESULTS

Several AAD manifestations (airflow restrictions, lavage eosinophilia, basement membrane zone thickening, epithelial mucin composition) were reduced with ICS treatment, without adverse effects on body growth or adrenal function; however, airway branching abnormalities and intraepithelial innervation were not reduced. In addition, several indicators of postnatal lung growth and differentiation: vital capacity, inspiratory capacity, compliance, non-parenchymal lung volume and alveolarization, were increased in both AAD and Control monkeys that received ICS treatment.

CONCLUSIONS AND CLINICAL RELEVANCE

Incomplete prevention of pathobiological changes in the airways and disruption of postnatal growth and differentiation of airways and lung parenchyma in response to ICS pose risks for developing primate lungs. These responses also represent two mechanisms that could compromise ICS therapy's ability to alter clinical disease course in young children.

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.

Development of a Non-Invasive Dynamic Pulmonary Function Monitor

Characterizing the complexity of airflow limitation in diagnosing and assessing disease severity in asthma, COPD, cystic fibrosis, and other respiratory diseases can help guide clinicians toward the most appropriate treatments. Current technologies allow obstructive lung disease to be measured with about 5%−10% precision. A noninvasive dynamic pulmonary function monitor (DPFM) can quantify ventilation inhomogeneities, such as those originating in partially blocked or constricted small airways, with 1% precision if inert gas concentrations can be measured accurately and precisely over three to four decades of sensitivity. We have studied the precision and linearity of a commercially available mass spectrometer, sampling the gas exhaled by a mechanical lung analog, mimicking a multibreath inert gas washout measurement. The root mean square deviation of the inert gas concentration measured for each “breath,” compared to the expected value for a purely exponential decay, is found to be about 1.1% over three decades of concentration. The corresponding overall impairment, a specific measure of ventilation inhomogeneity, is found to be about 0.2%, which indicates that were inhomogeneities observed, the corresponding impairment could be measured with 1% precision.

Novel severe wheezy young children phenotypes: boys atopic multiple-trigger and girls nonatopic uncontrolled wheeze

BACKGROUND

Recurrent wheezing during infancy is a heterogeneous disorder that has been associated with early-onset asthma.

OBJECTIVE

To identify phenotypes of severe recurrent wheezing and therapeutic approaches.

METHODS

We performed cluster analysis with 20 variables of 551 children with active asthma, younger than 36 months old, and enrolled in the Trousseau Asthma Program.

RESULTS

We identified 3 independent clusters of children with wheezing. Cluster 1, mild episodic viral wheeze (n= 327), consisted of children with wheezing related only to colds (71%), mild disease (76%), and mainly normal chest x-ray results. Cluster 2, nonatopic uncontrolled wheeze (n = 157), was characterized by moderate to severe disease (91%), uncontrolled wheezing despite high doses of inhaled corticosteroids (55%), parents with asthma, and increased levels of ferritine. Cluster 3, atopic multiple-trigger wheeze (n = 67), included more children with multiple-trigger wheeze (68%) than did clusters 1 or 2; eczema (75%); a positive result from the Phadiatop Infant test (90%); increased levels of IgE, IgA, and IgG; and abnormal results from chest x-rays. In separate analysis, 1 parameter for boys (increased total level of IgE) and 2 parameters for girls (wheezing severity and increased total level of IgE) properly classified 90% of boys and 83% of girls in the appropriate cluster. Significant associations were found between overcrowding, molds and cockroaches at home, and atopic multiple-trigger wheeze and between day-care attendance and nonatopic uncontrolled wheeze in other parts.

CONCLUSION

We identified different phenotypes of recurrent wheezing in young children by using cluster analysis with usual variables. These phenotypes require confirmation in longer, follow-up studies.

Biomarkers in chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is a complex disease with multiple phenotypes that cannot be identified through measurement of lung function alone. The importance of COPD risk assessment, phenotype identification, and diagnosis of exacerbation magnify the need for validated biomarkers in COPD. A large number of potential biomarkers have already been assessed and some appear promising, in particular fibrinogen, which is likely to be the first COPD biomarker presented to the Food and Drug Administration for qualification in the drug approval process. Blood fibrinogen and c-reactive protein (CRP) have been associated with the presence of COPD and, in some instances, future risk of developing COPD in targeted populations. Sputum neutrophil counts have been used preliminarily as biomarkers of favorable response to therapy in COPD, but use in clinical settings may be limited. Other potential blood biomarkers include pulmonary and activation-regulated chemokine (PARC/CCL-18) and the clara cell secretory protein 16 (CC-16). Integrative indices, such as the BODE index, provide a framework to determine prognosis, predict outcome, and may be responsive to therapeutic interventions. Computed tomography provides a means to assess phenotypes and identify the relative extents of small airways disease and emphysema, which themselves may inform prognosis and therapeutic decision making. Fibrinogen and other markers of systemic inflammation are elevated in the context of acute COPD exacerbations and may also identify those at risk of accelerated lung function decline and hospitalization. So far, no single biomarker in COPD warrants wide acceptance emphasizing the need for future investigation of biomarkers in large-scale longitudinal studies.

Recurrent, severe wheezing is associated with morbidity and mortality in adults with sickle cell disease

Prior studies of asthma in children with sickle cell disease (SCD) were based on reports of a doctor-diagnosis of asthma with limited description of asthma features. Doctor-diagnoses of asthma may represent asthma or wheezing unrelated to asthma. Objectives of this study were to determine if asthma characteristics are present in adults with a doctor-diagnosis of asthma and/or wheezing, and to examine the relationship between doctor-diagnosis of asthma, wheezing and SCD morbidity. This was an observational cohort study of 114 adults with SCD who completed respiratory symptom questionnaires and had serum IgE measurements. A subset of 79 participants completed pulmonary function testing. Survival analysis was based on a mean prospective follow-up of 28 months and data were censored at the time of death or loss to follow-up. Adults reporting a doctor-diagnosis of asthma (N = 34) were more likely to have features of asthma including wheeze, eczema, family history of asthma, and an elevated IgE level (all P < 0.05). However, there was no difference in pain or ACS rate, lung function, or risk of death between adults with and without a doctor-diagnosis of asthma. In contrast, adults who reported recurrent, severe episodes of wheezing (N = 34), regardless of asthma, had twice the rates of pain and ACS, decreased lung function and increased risk of death compared with adults without recurrent, severe wheezing. Asthma features were not associated with recurrent, severe wheezing. Our data suggest that wheezing in SCD may occur independently of asthma and is a marker of disease severity.

Spirometry use among pediatric primary care physicians

OBJECTIVE

This study explores the use of spirometry in primary care settings.

METHODS

A 4-page survey was mailed to a national, random sample of office-based family physicians and pediatricians. Survey items addressed knowledge, attitudes, and practices regarding spirometry and standardized clinical vignettes. Data were analyzed by using χ2 tests and multivariate logistic regression.

RESULTS

Among the 360 respondents who provided care to children with asthma, 52% used spirometry in clinical practice, whereas 80% used peak flow meters and 10% used no lung function tests. Only 21% routinely used spirometry for all guideline-recommended clinical situations. More family physicians than pediatricians reported using spirometry (75% vs 35%; P<.0001), and family physicians were more comfortable in interpreting spirometric results (50% vs 25%; P<.0001). Only one-half of respondents interpreted correctly the spirometric results in a standardized clinical vignette, and the frequency of underrating asthma severity increased with the inclusion of spirometric results. The most common barriers to the use of spirometry, that is, time and training, were cited more often by physicians who did not use spirometry. Two-thirds of respondents agreed that they would want additional training regarding implementing spirometry in their clinical practices.

CONCLUSIONS

The use of spirometry in primary care settings for children with asthma does not conform to national guidelines. Widespread implementation of national asthma guidelines likely would require a major educational initiative to address deficiencies in spirometry interpretation and other barriers.

Using genetics to predict the natural history of asthma?

Clinical practice reminds us that there is considerable variability in the course of asthma over time. Treatment of patients with asthma would be considerably improved if one could accurately predict the likely course of disease over the life course. Recently, with the advent of the era of genome-wide association studies, there has been a monumental shift in our understanding of the genetic factors that underlie inherited susceptibility to asthma. Genes have been identified that modulate many aspects of the natural history of asthma, such as susceptibility to atopy, altered lung development, and susceptibility to more severe disease. Heritability studies have even suggested a role for genetic factors in remission of asthma. However, although the discovery of novel genetic factors underlying disease susceptibility has undoubtedly improved our understanding of disease pathogenesis, whether these advances have improved the ability to predict the natural history in individual patients is questionable, and the application of genetic testing to clinical practice remains some way off.

Effect of fluticasone on markers of inflammation and quality of life in steroid-naive patients with mild asthma

BACKGROUND AND AIMS

Patients with mild asthma may adapt to symptoms that may be neglected at a medical consultation. Despite active airway inflammation, indicating need for treatment symptoms may be poorly perceived and influence on quality of life. The aim was to find out if markers of asthma activity and quality of life are influenced by inhaled steroids in patients who regard themselves as free of symptoms.

METHODS

Seventy steroid-free patients with mild asthma were treated with inhaled fluticasone (250 microg twice daily) or placebo for 3 months in a randomised, double-blind, study. Spirometry with reversibility test, exhaled nitric oxide (NO), bronchial responsiveness to methacholine and eucapnic dry air hyperventilation and quality of life [(Asthma Quality of Life Questionnaire (AQLQ)] were assessed before and after treatment.

RESULTS

Fluticasone, but not placebo, decreased methacholine responsiveness. Bronchial responsiveness to dry air and exhaled NO levels was significantly lowered by fluticasone compared with placebo. Quality-of-life scores were high already before treatment and were not significantly altered by treatment.

CONCLUSION

Treatment with an inhaled steroid in mild asthmatics altered bronchial responsiveness and exhaled NO levels but did not improve quality of life. In mild asthma, there is thus a space for improvement with regard to inflammatory parameters in patients who have only minor symptoms that are not influenced by treatment. In a long-term perspective, the indication for treatment of surrogate markers remains, however, unclear.

Airway remodelling in asthma: from benchside to clinical practice

Airway remodelling refers to the structural changes that occur in both large and small airways relevant to miscellaneous diseases including asthma. In asthma, airway structural changes include subepithelial fibrosis, increased smooth muscle mass, gland enlargement, neovascularization and epithelial alterations. Although controversial, airway remodelling is commonly attributed to an underlying chronic inflammatory process. These remodelling changes contribute to thickening of airway walls and, consequently, lead to airway narrowing, bronchial hyper-responsiveness, airway edema and mucous hypersecretion. Airway remodelling is associated with poor clinical outcomes among asthmatic patients. Early diagnosis and prevention of airway remodelling has the potential to decrease disease severity, improve control and prevent disease expression. The relationship between structural changes and clinical and functional abnormalities clearly deserves further investigation. The present review briefly describes the characteristic features of airway remodelling observed in asthma, its clinical consequences and relevance for physicians, and its modulation by therapeutic approaches used in the treatment of asthmatic patients.

Impact of innate and environmental factors on wheezing persistence during childhood

BACKGROUND

Persistent asthma in adults starts often early in childhood and is associated with alterations in respiratory function that occur early in life.

OBJECTIVES

The aim of this study was to evaluate the importance of innate and environmental factors associated with occurrence of asthma during childhood in a population of recurrent wheezing infants followed prospectively.

METHODS

A cohort of infants less than 30 months old with recurrent wheezing was established in order to assess severity of respiratory symptoms and to look for the presence of atopy and environmental risk factors. At the age of 6 years, they were reevaluated with respect to remission or persistence of wheezing over the previous 12-month period.

RESULTS

Data were available for 219 subjects aged 15 +/- 5 months. In 27% of the infants with recurrent wheeze, wheezing persisted until the age of 6 years. In multivariate analysis, stepwise logit analysis showed that the risk factors for persistent wheezing are eosinophilia >or=470/mm(3), allergenic sensitization, and a father with asthma. Environmental factors present during the first year of life that protect from persistence of wheezing are ( 1 ) breastfeeding for longer than 3 months, ( 2 ) pets at home, and ( 3 ) >or=3 siblings. The detection rate for persistent wheezing in this model is 72%. The persistence score showed good specificity 91% but low sensitivity 35%.

CONCLUSION

This study confirms the role of atopic host factors on wheezing persistence during childhood and detected protective environmental factors.

Impact of a novel nutritional formula on asthma control and biomarkers of allergic airway inflammation in children

BACKGROUND

A novel nutritional formula (NNF) enriched in eicosapentaenoic (EPA) and gamma-linolenic fatty acids and antioxidants reduces airway inflammation and improves clinical outcomes in critically ill patients, but NNF has not been evaluated in chronic inflammatory diseases such as persistent asthma.

OBJECTIVE

To evaluate the efficacy, compliance, and safety of NNF in asthmatic children.

METHODS

Children, 6-14 years of age, with mild to moderate persistent asthma, on as needed albuterol alone, were randomized to receive daily NNF (n=23) or control formula (n=20) for 12 weeks, with multiple assessments of asthma control, spirometry, measures of airway inflammation, formula tolerance, and adverse events.

RESULTS

Daily consumption of either NNF or a control formula showed improvement in asthma-free days over time (P=0.04) but there was no difference between groups. However, the NNF group had lower exhaled nitric oxide levels compared with the control group at weeks 4, 8, and 12 (P<0.05). An overall group difference in log FEV1 PC20 (P=0.05) was found in favour of the NNF group as well. Significantly higher levels of EPA in plasma (P<0.01) and peripheral blood mononuclear cell (PBMC) (P<0.01) phospholipids in the NNF group compared with control group within 2 weeks indicated good adherence with daily NNF intake. There were no differences in adverse events for NNF vs. control after 12 weeks.

CONCLUSIONS

Both NNF and control groups demonstrated improvement in asthma-free days. NNF-treated group had reduced biomarkers of disease activity. Rapid PBMC fatty acid composition changes reflected an anti-inflammatory profile. Dietary supplementation with NNF was safe and well tolerated (ClinicalTrials.gov number NCT01087710).

Identifying problematic severe asthma in the individual child--does lung function matter?

AIM

Measures of lung function (usually FEV(1) <80% predicted) are used to classify asthma severity in both adults and children, despite evidence that lung function impairment is less pronounced in the paediatric asthma population. The present study assesses the relevance of lung function measurements as discriminators of severe childhood asthma.

METHODS

Fifty-one school-aged children with problematic severe asthma, 37 mild-to-moderate asthmatics and 29 healthy controls underwent a comprehensive clinical work-up. Problematic severe asthma was defined in patients exhibiting poor asthma control despite high-dose inhaled corticosteroid treatment and at least one other asthma controller drug. Mild-to-moderate asthmatic children used low-dose inhaled steroids and reported minimal asthma symptoms.

RESULTS

Baseline FEV(1) values were significantly reduced in children with problematic severe asthma, yet FEV(1) <80% predicted showed a low sensitivity (41%) for discriminating severe vs. mild-to-moderate asthma. Receiver-operated characteristic analysis estimated the optimal cut-off of FEV(1) to be 90% predicted in this population (sensitivity 61%, specificity 83%). Baseline FEV(1)/FVC and FEF(25-75) values were not superior to FEV(1) in discriminating problematic severe asthma, and neither exhaled nitric oxide levels nor bronchial hyperresponsiveness differentiated between the two asthmatic study populations.

CONCLUSION

Spirometric measurements are insensitive discriminators of problematic severe asthma in childhood.

Association of Atopy to Asthma Severity and Medication Use in Children

The importance of aeroallergens as triggers for asthma is well recognized, but the relationship between asthma severity and atopic profiles in childhood has not been elucidated. This study assessed the relationship of allergen sensitization to asthma severity in a study of 114 asthmatic children followed for 8 weeks in three Southern California areas. Increased controller medication and beta-agonist use were positively associated with number of positive skin tests and allergy to mold and pollens. Mold was associated with increased asthma symptoms. Degree of atopy and reactivity to mold and pollens plays a significant role in asthma severity in asthmatic children.

Wheezing and Asthma in childhood: an epidemiology approach

Wheezing/asthma in children is a complex problem due to its heterogeneous condition, with different pathogenic mechanisms, variations in duration and in severity; that make it difficult to totally understand. This relation between wheezing in infants and later development of asthma will be the result of alterations in the immune system maturation and congenital or acquired modifications of the airway. Several longitudinal studies have given us important information about the different phenotypes of wheezing/asthma that coexist in children. In this review, we analyse the recent potential mechanisms and risk factors for each of the three classic wheezing phenotypes presenting in children: transient, non-atopic and atopic; and we propose for consideration a fourth phenotype: overweight/obese girls with early menarche. A better understanding of those risk factors would be useful for the development of new strategies in wheezing/asthma management.

Effect of 17q21 variants and smoking exposure in early-onset asthma

BACKGROUND

A genomewide association study has shown an association between variants at chromosome 17q21 and an increased risk of asthma. To elucidate the relationship between this locus and disease, we examined a large, family-based data set that included extensive phenotypic and environmental data from the Epidemiological Study on the Genetics and Environment of Asthma.

METHODS

We tested 36 single-nucleotide polymorphisms (SNPs) in the 17q21 region in 1511 subjects from 372 families for an association with asthma. We also tested for genetic heterogeneity according to the age at the onset of asthma and exposure to environmental tobacco smoke in early life.

RESULTS

Eleven SNPs were significantly associated with asthma (P<0.01), of which three (rs8069176, rs2305480, and rs4795400) were strongly associated (P<0.001). Ordered-subset regression analysis led us to select an onset at 4 years of age or younger to classify patients as having early-onset asthma. Association with early-onset asthma was highly significant (P<10(-5) for four SNPs), whereas no association was found with late-onset asthma. With respect to exposure to environmental tobacco smoke in early life, we observed a significant association with early-onset asthma only in exposed subjects (P<5x10(-5) for six SNPs). Under the best-fitting recessive model, homozygous status (GG) at the most strongly associated SNP (rs8069176) conferred an increase in risk by a factor of 2.9, as compared with other genotypes (AG and AA) in the group exposed to environmental tobacco smoke (P=2.8x10(-6); P=0.006 for the test for heterogeneity of the SNP effect on early-onset asthma between groups with tobacco exposure and those without such exposure).

CONCLUSIONS

This study shows that the increased risk of asthma conferred by 17q21 genetic variants is restricted to early-onset asthma and that the risk is further increased by early-life exposure to environmental tobacco smoke. These findings provide a greater understanding of the functional role of the 17q21 variants in the pathophysiology of asthma.

Daily versus as-needed inhaled corticosteroid for mild persistent asthma (The Helsinki early intervention childhood asthma study)

OBJECTIVE

To compare the effect of inhaled budesonide given daily or as-needed on mild persistent childhood asthma. Patients, design and

INTERVENTIONS

176 children aged 5-10 years with newly detected asthma were randomly assigned to three treatment groups: (1) continuous budesonide (400 microg twice daily for 1 month, 200 microg twice daily for months 2-6, 100 microg twice daily for months 7-18); (2) budesonide, identical treatment to group 1 during months 1-6, then budesonide for exacerbations as needed for months 7-18; and (3) disodium cromoglycate (DSCG) 10 mg three times daily for months 1-18. Exacerbations were treated with budesonide 400 microg twice daily for 2 weeks.

MAIN OUTCOME MEASURES

Lung function, the number of exacerbations and growth.

RESULTS

Compared with DSCG the initial regular budesonide treatment resulted in a significantly improved lung function, fewer exacerbations and a small but significant decline in growth velocity. After 18 months, however, the lung function improvements did not differ between the groups. During months 7-18, patients receiving continuous budesonide treatment had significantly fewer exacerbations (mean 0.97), compared with 1.69 in group 2 and 1.58 in group 3. The number of asthma-free days did not differ between regular and intermittent budesonide treatment. Growth velocity was normalised during continuous low-dose budesonide and budesonide therapy given as needed. The latter was associated with catch-up growth.

CONCLUSIONS

Regular use of budesonide afforded better asthma control but had a more systemic effect than did use of budesonide as needed. The dose of ICS could be reduced as soon as asthma is controlled. Some children do not seem to need continuous ICS treatment.

Effect of long-term corticosteroid use on bone mineral density in children: a prospective longitudinal assessment in the childhood Asthma Management Program (CAMP) study

OBJECTIVE

Systemic corticosteroids are known to induce osteoporosis and increase the risk for fractures in adults and children. Inhaled corticosteroids have been shown to increase the risk for osteoporosis and fractures in adults at risk; however, long-term prospective studies of children to assess risks of multiple short courses of oral corticosteroids and chronic inhaled corticosteroids have not been performed. Thus, we assessed the effects of multiple short courses of oral corticosteroids and long-term inhaled corticosteroids on bone mineral accretion over a period of years.

METHODS

This was a cohort follow-up study for a median of 7 years of children who had mild-to-moderate asthma and initially were randomly assigned into the Childhood Asthma Management Program trial. Serial dual-energy radiograph absorptiometry scans of the lumbar spine for bone mineral density were performed for all patients. Annual bone mineral accretion was calculated for 531 boys and 346 girls who had asthma and were aged 5 to 12 years at baseline (84% of the initial cohort).

RESULTS

Oral corticosteroid bursts produced a dosage-dependent reduction in bone mineral accretion (0.052, 0.049, and 0.046 g/cm(2) per year) and an increase in risk for osteopenia (10%, 14%, and 21%) for 0, 1 to 4, and >or=5 courses, respectively, in boys but not girls. Cumulative inhaled corticosteroid use was associated with a small decrease in bone mineral accretion in boys but not girls but no increased risk for osteopenia.

CONCLUSIONS

Multiple oral corticosteroid bursts over a period of years can produce a dosage-dependent reduction in bone mineral accretion and increased risk for osteopenia in children with asthma. Inhaled corticosteroid use has the potential for reducing bone mineral accretion in male children progressing through puberty, but this risk is likely to be outweighed by the ability to reduce the amount of oral corticosteroids used in these children.

Clinical assessment of asthma progression in children and adults

Asthma is a heterogeneous disorder with a variable course, characterized by episodes of cough, wheezing and shortness of breath, reversible airflow limitation, and bronchial hyperresponsiveness. It begins early in life in many subjects with intermittent symptoms occurring with viral respiratory tract infections. Over time, and in genetically susceptible children (those with an atopic predisposition), the disease becomes more persistent with symptoms occurring in the absence of respiratory tract infections. Children with persistent wheezing are eventually diagnosed with asthma, with those at greatest risk having developed allergic sensitization early in life. Among children with asthma, some will have lifelong asthma with active symptoms and progressive loss of lung function over time, whereas other children will undergo asthma remission in adolescence. Once in remission, the disease may remain quiescent, or it may relapse in midadult life. This review focuses on studies that have enhanced our understanding of the progression of asthma from infancy to adulthood. Studies evaluating progressive loss of lung function, the best-studied measure of asthma progression, are also reviewed, followed by a brief discussion of whether asthma progression can be modified by inhaled glucocorticoid therapy.

Lack of eosinophilia can predict remission in wheezy infants?

BACKGROUND

Early wheezing in infants is a potential risk factor for persistence of asthma into adulthood. Moreover, a personal or familial history of atopy are risk factors associated with persistence of pre-existing wheezing during childhood. However, their relative importance remains unclear.

OBJECTIVES

Firstly to determine the critical thresholds of common biological markers of atopy in wheezy infants associated with persistence of wheezing into childhood and secondly to rank these biological markers together with clinical parameters according to the strength of their association with wheezing persistence.

METHODS

A cohort of infants less than 30 months old with recurrent wheezing was established in order to assess severity of respiratory symptoms and to look for the presence of atopy. At the age of 6 years, they were re-evaluated regarding remission of wheezing over the previous 12-months period.

RESULTS

Data were available for 219 subjects. In 27% of them, wheezing persisted at 6 years of age. Critical biological thresholds associated with the risk of wheezing persistence were: (1) a blood eosinophilia count >or=470/mm(3) (defining eosinophilia), and (2) a total serum IgE level >or=45 IU/mL (defining elevated IgE) during infancy. A multiple component factorial analysis identified a dimension associating eosinophilia, elevated IgE and allergic sensitization on the one hand with persistent wheezing at 6 years of age on the other (lambda=0.15). According to a segmentation analysis, the main discriminative parameter of wheezing persistence was eosinophilia. Thus a lack of eosinophilia alone could account for 91% of infants in remission, and when combined with absence of allergic sensitization, remission was correctly discriminated in 96.9% of the study population.

CONCLUSION

Our data strongly suggest that the lack of eosinophilia in wheezy infants without ongoing infection could predict future remission of wheezing in a large majority of cases.

Ethnic-specific differences in bronchodilator responsiveness among African Americans, Puerto Ricans, and Mexicans with asthma

Socioeconomic and environmental differences do not fully explain differences in asthma prevalence, morbidity, and mortality among Puerto Ricans, African Americans, and Mexican Americans. Differences in response to albuterol may be a factor. We compared bronchodilator responsiveness between these three populations. All groups demonstrated below expected responsiveness. Puerto Ricans of all ages and African American children with moderate-to-severe asthma demonstrated the lowest responsiveness overall. Among subjects with moderate-to-severe asthma, children were even less likely than adults to show the expected bronchodilator response. We conclude that ethnic-specific differences in bronchodilator drug responsiveness exist between Mexicans, Puerto Ricans, and African Americans with asthma. This may be of importance in asthma management.

Association between candidate genes and lung function growth in Chinese asthmatic children

BACKGROUND

Asthma is caused by a complex interaction between multiple candidate genes and environmental factors. The Childhood Asthma Management Program reported lung function decline in a significant proportion of Caucasian asthmatic children, but such a relation has not been studied in other populations. Our group recently reported that interleukin-13 (IL13), interleukin-4 receptor-alpha and thymus and the activation-regulated chemokine interacted to influence asthma and raised plasma total IgE. However, there has not been any study that has addressed the genetic influences for longitudinal lung function growth.

OBJECTIVE

We studied the longitudinal changes in spirometric variables in Chinese asthmatic children, and investigated the influence and interactions between eight different loci in six candidate genes as well as environmental factors affecting lung function growth in these children.

METHODS

Spirometry was performed at baseline and study completion. Genotyping was performed by restriction fragment length polymorphism. Multi-factor dimensionality reduction (MDR) was used to detect any gene-gene or gene-environment interaction.

RESULTS

We prospectively followed 131 Chinese children, aged 9.9 (3.0) years, for 4.5 (0.8) years. Their mean (standard deviation) baseline forced expiratory volume in 1 s (FEV1) was 98.6 (20.6)% of predicted, and FEV1 to forced vital capacity (FVC) ratio was 77.8 (11.3)%. FEV1 and FVC increased by 210 (115) and 248 (148) mL/year during this study, and these changes were significantly larger among males (P<0.0001). Univariate analysis revealed a significant association between annual FEV1 change and C1570T of signal transducer and activator of transcription 6 gene (STAT6; P=0.009). Linear regression confirmed this finding (P=0.041). Using MDR, we detected a significant 3-locus interaction between IL13 R130Q, ADRB2 R16G and STAT6 C1570T for determining change in FVC (P=0.045).

CONCLUSION

Our data suggest that STAT6 may influence lung function growth in asthmatic children. We also found significant interactions among several atopy-related genetic polymorphisms for influencing FVC change.