Exercise-induced bronchoconstriction in children with asthma: An observational cohort study

Exercise-Induced Bronchoconstriction in Children: State of the Art from Diagnosis to Treatment

Exercise-induced bronchoconstriction (EIB) is a common clinical entity in people with asthma. EIB is characterized by postexercise airway obstruction that results in symptoms such as coughing, dyspnea, wheezing, chest tightness, and increased fatigue. The underlying mechanism of EIB is not completely understood. "Osmotic theory" and "thermal or vascular theory" have been proposed. Initial assessment must include a specific work-up to exclude alternative diagnoses like exercise-induced laryngeal obstruction (EILO), cardiac disease, or physical deconditioning. Detailed medical history and clinical examination must be followed by basal spirometry and exercise challenge test. The standardized treadmill running (TR) test, a controlled and standardized method to assess bronchial response to exercise, is the most adopted exercise challenge test for children aged at least 8 years. In the TR test, the goal is to reach the target heart rate in a short period and maintain it for at least 6 min. The test is then followed by spirometry at specific time points (5, 10, 15, and 30 min after exercise). In addition, bronchoprovocation tests like dry air hyperpnea (exercise and eucapnic voluntary hyperpnea) or osmotic aerosols (inhaled mannitol) can be considered when the diagnosis is uncertain. Treatment options include both pharmacological and behavioral approaches. Considering medications, the use of short-acting beta-agonists (SABA) just before exercise is the commonest option strategy, but daily inhaled corticosteroids (ICS) can also be considered, especially when EIB is not controlled with SABA only or when the patients practice physical activity very often. Among the behavioral approaches, warm-up before exercise, breathing through the nose or face mask, and avoiding polluted environments are all recommended strategies to reduce EIB risk. This review summarizes the latest evidence published over the last 10 years on the pathogenesis, diagnosis using spirometry and indirect bronchoprovocation tests, and treatment strategies, including SABA and ICS, of EIB. A specific focus has been placed on EIB management in young athletes, since this condition can not only prevent them from practicing regular physical activity but also competitive sports.

Exercise-induced bronchoconstriction, allergy and sports in children

Exercise-induced bronchoconstriction (EIB) is characterized by the narrowing of airways during or after physical activity, leading to symptoms such as wheezing, coughing, and shortness of breath. Distinguishing between EIB and exercise-induced asthma (EIA) is essential, given their divergent therapeutic and prognostic considerations. EIB has been increasingly recognized as a significant concern in pediatric athletes. Moreover, studies indicate a noteworthy prevalence of EIB in children with atopic predispositions, unveiling a potential link between allergic sensitivities and exercise-induced respiratory symptoms, underpinned by an inflammatory reaction caused by mechanical, environmental, and genetic factors. Holistic management of EIB in children necessitates a correct diagnosis and a combination of pharmacological and non-pharmacological interventions. This review delves into the latest evidence concerning EIB in the pediatric population, exploring its associations with atopy and sports, and emphasizing the appropriate diagnostic and therapeutic approaches by highlighting various clinical scenarios.

Is there cardiac autonomic dysfunction in children and adolescents with exercise-induced bronchospasm?

BACKGROUND

The pulmonary impairment in patients with bronchoconstriction induced by eucapnic voluntary hyperpnea(EVH) goes beyond the respiratory system, also impairing autonomic nervous modulation. This study aimed to evaluate the behavior of cardiac autonomic modulation in young asthmatics with and without EIB after the EVH test.

RESEARCH DESIGN AND METHODS

A cross-sectional study design using 54 asthmatics(51.9% female), aged between 10 and 19 years, investigated with the EVH test. Forced expiratory volume in one second(FEV1) was measured at 5, 10, 15, and 30 min after EVH. Heart rate variability(HRV) measures of time were assessed pre and 30 min-post EVH. The diagnosis of Exercise-Induced bronchoconstriction with underlying clinical asthma(EIBA) was confirmed by a fall in FEV1 ≥10% compared to baseline.

RESULTS

Thirty(55.5%) asthmatics had EIBA. Subjects with EIBA have reduced mean of the R-R intervals in relation to baseline until 15 minutes after EVH. Individuals without EIBA had increased parasympathetic activity compared to baseline(rMSSD) from 5 min after EVH(p < 0.05). This parasympathetic activity increase in relation to baseline was seen in individuals with EIBA after 25 minutes (rMSSD = 49.9 ± 5.3 vs 63.5 ± 7.2, p < 0.05).

CONCLUSION

Young asthmatics with EIBA present a delay in the increase of the parasympathetic component after EVH when compared to asthmatics without EIBA.

Impulse Oscillometry (IOS) for Detection of Exercise Induced Bronchoconstriction in Children with Asthma Ages 6-15 years

OBJECTIVES

To determine the discriminatory value of various impulse oscillometry (IOS) parameters, and to find the cutoff value of the appropriate parameter for identifying exercise-induced bronchoconstriction (EIB) in children with asthma.

METHODS

This cross-sectional study was conducted in India from October 2016 to March 2018 in children with asthma who were 6-15 years of age. One hundred and five children were enrolled and subjected to pre-exercise IOS and spirometry followed by free running treadmill test as an exercise challenge. All children could achieve minute ventilation >17.5-21 times of FEV₁ during the exercise challenge test. Then, IOS and spirometry were performed at 10 ± 2, 20 ± 2, and 30 ± 2 min post-exercise challenge. EIB was defined as reduction of FEV₁ ≥10% within 30 min of exercise. For purposes of analysis, the children were grouped into two categories: "EIB Present" or "EIB Absent".

RESULTS

The prevalence of EIB in our study was 20.95% (n = 22). ΔR5max percentage within 30 min post-exercise (AUC 0.74; 95% CI: 0.64, 0.84) had the best discriminating capacity among all IOS parameters for identifying EIB. A cutoff value of 14.1% increase in R5 within 30 min post-exercise was obtained for detection of EIB (sensitivity-95.45%, specificity-50.6%, PPV-33.87% and NPV-97.67%).

CONCLUSIONS

A percentage change in R5 with a cutoff value of 14.1% increase post-exercise had the best discriminatory capacity among all IOS parameters for detection of EIB in children with asthma. However, low positive predictive value (PPV) with high negative predictive value (NPV) made this cutoff value more apt to rule out EIB.

An Overview on the Primary Factors That Contribute to Non-Allergic Asthma in Children

The prevalence of non-allergic asthma in childhood is low, peaking in late adulthood. It is triggered by factors other than allergens, like cold and dry air, respiratory infections, hormonal changes, smoke and air pollution. In the literature, there are few studies that describe non-allergic asthma in pediatric age. Even though it is a less common disorder in kids, it is crucial to identify the causes in order to keep asthma under control, particularly in patients not responding to conventional treatments. In this review, we discuss non-IgE-mediated forms of asthma, collecting the latest research on etiopathogenesis and treatment.

Exercise-Induced Bronchoconstriction in Children

Exercise-induced bronchoconstriction (EIB) is a transient airflow obstruction, typically 5-15 min after physical activity. The pathophysiology of EIB is related to the thermal and osmotic changes of the bronchial mucosa, which cause the release of mediators and the development of bronchoconstriction in the airways. EIB in children often causes an important limitation to physical activities and sports. However, by taking appropriate precautions and through adequate pharmacological control of the condition, routine exercise is extremely safe in children. This review aims to raise awareness of EIB by proposing an update, based on the latest studies, on pathological mechanisms, diagnosis, and therapeutic approaches in children.

Mortality and morbidity of asthma and chronic obstructive pulmonary disease associated with ambient environment in metropolitans in Taiwan

Background

This study investigated risks of mortality from and morbidity (emergency room visits (ERVs) and outpatient visits) of asthma and chronic obstructive pulmonary disease (COPD) associated with extreme temperatures, fine particulate matter (PM_2.5), and ozone (O₃) by sex, and age, from 2005 to 2016 in 6 metropolitan cities in Taiwan.

Methods

The distributed lag non-linear model was employed to assess age (0–18, 19–39, 40–64, and 65 years and above), sex-cause-specific deaths, ERVs, and outpatient visits associated with extreme high (99^th percentile) and low (5^th percentile) temperatures and PM_2.5 and O₃ concentrations at 90^th percentile. Random-effects meta-analysis was adopted to investigate cause-specific pooled relative risk (RR) and 95% confidence intervals (CI) for the whole studied areas.

Results

Only the mortality risk of COPD in the elderly men was significantly associated with the extreme low temperatures. Exposure to the 90^th percentile PM_2.5 was associated with outpatient visits for asthma in 0–18 years old boys [RR = 1.15 (95% CI: 1.09–1.22)]. Meanwhile, significant elevation of ERVs of asthma for females aged 40–64 years was associated with exposure to ozone, with the highest RR of 1.21 (95% CI: 1.05–1.39).

Conclusions

This study identified vulnerable subpopulations who were at risk to extreme events associated with ambient environments deserving further evaluation for adaptation.

Pulmonary function as a limiting factor of middle distance race performance

Exercise induced bronchoconstriction (EIB) is common and underdiagnosed phenomenon of yet largely unknown etiology. This study aimed to estimate prevalence of EIB in response to highly demanding skyscraper race and to test its association with race performance and hypothetical predisposing factors. Healthy participants (26 males, 8 females; 31.5 +/- 6.3 years) from mostly running-based amateur sports were measured for forced expiratory volume in first 1 s (FEV1) before and then repeatedly within 10 min after the completion of the 114 m skyscraper upstairs race. Allergy questionnaire (AQUA) data were collected and post-exercise blood lactate was measured. Over 40% of the participants developed >10% decrement in FEV1 shortly after all-out exercise. While EIB response was not associated with questionnaire-based atopic status, training background, gender, age, anthropometrics, pacing and exertion (estimated from the accumulated blood lactate values), participants exhibiting <10% decrement in FEV1 were faster, especially over the later stages of the race. In conclusion, nearly every other participant of the skyscraper race develops EIB not associated with training, demographic, anthropometric and atopic status, pacing and exertion (estimated from postexercise blood lactate), but the responders (FEV1 decrement >10%) were slower indicative of poorer fitness due to EIB developing during the exercise already.

Exercise Limitation in Children and Adolescents With Severe Refractory Asthma: A Lack of Asthma Control?

Background

Patients with severe refractory asthma (SRA), even when using high doses of multiple controller medications in a regular and appropriate way, can have persistent complaints of exercise limitation.

Methods

This was a cross-sectional study involving patients with SRA (treated with ≥ 800 μg of budesonide or equivalent, with ≥ 80% adherence, appropriate inhaler technique, and comorbidities treated), who presented no signs of a lack of asthma control other than exercise limitation. We also evaluated healthy controls, matched to the patients for sex, age, and body mass index. All participants underwent cardiopulmonary exercise testing (CPET) on a cycle ergometer, maximum exertion being defined as ≥ 85% of the predicted heart rate, with a respiratory exchange ratio ≥ 1.0 for children and ≥ 1.1 for adolescents. Physical deconditioning was defined as oxygen uptake (VO₂) < 80% of predicted at peak exercise, without cardiac impairment or ventilatory limitation. Exercise-induced bronchoconstriction (EIB) was defined as a forced expiratory volume in one second ≥ 10% lower than the baseline value at 5, 10, 20, and 30 minutes after CPET.

Results

We evaluated 20 patients with SRA and 19 controls. In the sample as a whole, the mean age was 12.9 ± 0.4 years. The CPET was considered maximal in all participants. In terms of the peak VO₂ (VO_{2 peak}), there was no significant difference between the patients and controls, (P = 0.10). Among the patients, we observed isolated EIB in 30%, isolated physical deconditioning in 25%, physical deconditioning accompanied by EIB in 25%, and exercise-induced symptoms not supported by the CPET data in 15%.

Conclusion and Clinical Relevance

Physical deconditioning, alone or accompanied by EIB, was the determining factor in reducing exercise tolerance in patients with SRA and was not therefore found to be associated with a lack of asthma control.

Determinants of exercise capacity in children and adolescents with severe therapy-resistant asthma

OBJECTIVE

To evaluate the exercise capacity of children and adolescents with severe therapy resistant asthma (STRA) aiming to identify its main determinants.

METHODS

Cross-sectional study including individuals aged 6-18 years with a diagnosis of STRA. Clinical (age and gender), anthropometric (weight, height and body mass index) and disease control data were collected. Lung function (spirometry), cardiopulmonary exercise testing (CPET) and exercise-induced bronchoconstriction (EIB) test were performed.

RESULTS

Twenty-four patients aged 11.5 ± 2.6 years were included. The mean forced expiratory volume in one second (FEV₁) was 91.3 ± 9.2%. EIB occurred in 54.2% of patients. In CPET, the peak oxygen uptake (VO_2peak) was 34.1 ± 7.8 mL kg^-1 min^-1. A significant correlation between ventilatory reserve and FEV₁ (r = 0.57; p = 0.003) was found. Similarly, there was a significant correlation between CPET and percent of FEV₁ fall in the EIB test for both V_E/VO₂ (r = 0.47; p = 0.02) and V_E/VCO₂ (r = 0.46; p = 0.02). Patients with FEV₁<80% had lower ventilatory reserve (p = 0.009). In addition, resting heart rate correlated with VO_2peak (r=-0.40; p = 0.04), V_E/VO₂ (r = 0.46; p = 0.02) and V_E/VCO₂ (r = 0.48; p = 0.01).

CONCLUSIONS

Exercise capacity is impaired in approximately 30% of children and adolescents with STRA. The results indicate that different aspects of aerobic fitness are influenced by distinct determinants, including lung function and EIB.

Pulmonary function evaluation in pediatric patients with primary immunodeficiency complicated by bronchiectasis

BACKGROUND

Primary immunodeficiency (PID) accompanying with recurrent respiratory infections is thought to have a devastating effect on lung function. However, the associations between the airway structural abnormalities on chest computed tomography (CT), severity of dyspnea, and deterioration of pulmonary function test (PFT) have not been fully addressed.

METHODS

Children diagnosed with PID in a tertiary referred center in northern Taiwan were enrolled. Demographic and clinical data including age, sex, age at diagnosis of PID, and follow-up period were collected. Chest CT images (modified Reiff scores), parameters of PFT, and life quality questionnaires (mMRC dyspnea scale) were analyzed and correlated using Spearman's rank correlation test.

RESULTS

A total of nineteen children with PID were enrolled and thirteen patients were diagnosed as having bronchiectasis based on chest CT scans. Modified Reiff scores of chest CT scan were negatively correlated with FEV₁ (% predicted) and FEV₁/FVC ratio (P < 0.05). A strongly negative correlation was found between the mMRC dyspnea scale and FEV₁ (% predicted) and FVC (% predicted), but positively correlated with RV (% predicted) and RV/TLC ratio (P < 0.05). Furthermore, there was a negative correlation between FVC (% predicted) with increasing follow-up period (P < 0.05).

CONCLUSIONS

In pediatric patients with PID, chest CT scan appears to be a good tool for not only the diagnosis of bronchiectasis, but also the degree of pulmonary function impairment. Further quality of life impairments could be particularly due to the airflow obstruction and air trapping related to bronchiectasis.

Tai Chi Chuan Exercise Improves Lung Function and Asthma Control through Immune Regulation in Childhood Asthma

Background

Tai Chi Chuan (TCC) is an exercise of low to moderate intensity with key features of mindfulness, structural alignment, and flexibility to relax the body and mind in adults. Our previous study showed that TCC could improve the quality of life (QoL), pulmonary function, and fractional exhaled nitric oxide in asthmatic children. We further investigated whether the benefits induced by TCC were associated with immune regulation.

Method

Six- to twelve-year-old children diagnosed with mild to severe persistent asthma for at least one year according to the Global Initiative for Asthma guidelines were enrolled from a tertiary pediatric allergy center in Taiwan. Asthmatic children were divided into two groups based on their choice: (1) the TCC group had a 60-minute TCC exercise session once weekly led by an instructor and (2) the control group kept their original activity levels. All other exercises were encouraged as usual. Pulmonary function tests, laboratory tests, standardized pediatric asthma QoL questionnaire (PAQLQ(S)), and childhood asthma control test (C-ACT) were performed before and after the TCC program (12 weeks). Data on medications and exacerbations were collected from medical records.

Results

There were no differences between the TCC (n = 25) and control (n = 15) groups at baseline, except that the C-ACT showed significantly lower results in the TCC group (p=0.045). After 12 weeks, the number of leukocytes (p=0.041) and eosinophils (p=0.022) decreased, while regulatory T cells increased significantly (p=0.008) only in the TCC group. Lung functions (FEV₁ and PEFR) were significantly improved in both the TCC (p < 0.001) and control (p=0.045 and 0.019, respectively) groups, while the PAQLQ(S) and C-ACT (p < 0.001) showed improvement only in the TCC group. Moreover, compared to the control group, the exacerbations within 12 weeks after the study were significantly decreased in the TCC group (p=0.031). After multiple regression by a conditional forward method, the factors that were significantly associated with exacerbation within 12 weeks after study is the practice of TCC and exacerbation within 24 weeks before study (p=0.013 and 0.015, respectively) after adjusting for age, sex, asthma severity, PEF, FEV₁, C-ACT, PAQLQ(S), and medication score at baseline.

Conclusion

TCC exercise may improve pulmonary functions, asthma control, and QoL and prevent exacerbations in asthmatic children through immune regulation. Further research on detailed mechanisms is mandated.

Treatment of allergic rhinitis reduces acute asthma exacerbation risk among asthmatic children aged 2-18 years

BACKGROUND/PURPOSE

Asthma and allergic rhinitis (AR) frequently coexist in the same individuals in childhood and adolescence. We evaluated whether AR had an impact on acute exacerbation (AE) and whether intranasal corticosteroid (INCS) and second-generation antihistamines (SGH) for AR modified the association of AR with AE in asthmatics aged 2-6 years and 7-18 years.

METHODS

Using the National Health Research Institutes (NHRI) Database 2005 of Taiwan, we investigated patients who had been diagnosed with asthma in the years 2000 through 2012 and who had then been followed-up with for at least one year. The risk factors of AE were evaluated using multiple Cox proportional hazards regression analysis.

RESULTS

The incidence of AE was higher in the preschool group than the older group (adj. HR: 1.68, 95% CI: 1.44-1.95). The AR with INCS and/or SGH group was found to have a lower risk of AE than the non-AR group (adj. HR: 0.32, 0.44 and 0.30), but the AR without treatment group did not have a significant difference with the non-AR group. After propensity score matching, the use of INCS and/or SGH was associated with a significant reduction in the occurrence of AE among AR patients aged 2-6 years old (adj. HR: 0.38, 0.57 and 0.45) and 7-18 years old (adj. HR: 0.50, 0.52 and 0.35).

CONCLUSION

The preschool patients had a higher incidence of AE than the older patients in general. Adequate treatment with INCS and/or SGH in asthma with AR patients is important for reducing the incidence of AE of asthma.

Associations between environmental heavy metal exposure and childhood asthma: A population-based study

BACKGROUND/PURPOSE

The health risks of environmental heavy metals have been of concern are well known. The greater likelihood of heavy metal contamination in the physical environment increases the risk of asthma, especially in children. This cross-sectional, population-based study sought to investigate associations between heavy metal exposure and childhood asthma or wheezing.

METHODS

Data from 5866 subjects, stratified into age groups of 2-5, 6-11, and 12-15 years, from the National Health and Nutrition Examination Survey 2007-2012 conducted by the Centers for Disease Control and Prevention were analyzed retrospectively. The primary outcome was active asthma. Variables included demographics, anthropometric, and clinical data. Univariate and multivariate logistic regression analyses were used to identify associations between blood heavy metal concentrations and adjusted odds (aORs) of active asthma.

RESULTS

Higher concentration of blood lead was associated with higher adjusted odds of having asthma (aOR = 1.08, 95% CI = 1.00-1.16), but no significant effect was shown for current wheezing or whistling. Age-stratified analysis showed that higher blood lead concentration was associated with higher risk for active asthma (aOR = 1.24, 95% CI = 1.08-1.42) and current wheezing or whistling (aOR = 1.19, 95% CI = 1.04-1.38) in the 6-11 years age group, while higher blood mercury concentration was associated with lower risk of current wheezing or whistling (aOR = 0.95, 95% CI = 0.90-0.99). The medium concentration of blood lead was associated with decreased risks of current wheezing or whistling (aOR = 0.54, 95% CI = 0.30-0.96) in the 2-5 years age group.

CONCLUSION

Higher concentrations of blood lead are associated with higher odds of asthma in children aged 2-15 years.