Exercise-induced bronchospasm in obese adolescents

Obesity is a risk factor for exercise-induced bronchospasm in asthmatic adolescents

INTRODUCTION

Exercise-induced bronchospasm (EIB) is common in young asthmatics and obesity is becoming an epidemic in this population. Both conditions can give rise to or worsen respiratory symptoms upon exercise and may interfere with recreational and sports activities.

OBJECTIVE

To investigate the association between obesity and the risk and severity of EIB in asthmatic children and adolescents.

METHODS

This study included data from asthmatic patients aged between 7 and 19 years undergoing treadmill running tests to evaluate EIB, defined as a reduction greater than or equal to 10% in forced expiratory volume in the first second (FEV₁ ) compared to baseline. Eutrophic, obese, and overweight individuals were categorized according to body mass index z-score (eutrophic, -0.5 < z ≤ 1; overweight, 1 < z < 2; and obese, z ≥ 2).

RESULTS

Of the 156 individuals studied (42% female), 58% were eutrophic, 22% overweight, and 19% obese. Seventy-three individuals (47%) presented with EIB, with higher risk among obese (OR, 2.86; 95% CI, 1.00-8.14; P = .05). Asthma severity was another independent risk factor for EIB (OR, 2.95; 95% CI, 1.36-6.42; P = .006). The number of patients in whom FEV₁ returned to baseline values (difference less than 10% from baseline) at the 13th minute after challenge was lower in obese individuals compared to eutrophic and overweight ones (P = .04). Baseline FEV₁ , gender, or age were not found to be risk factors for EIB in any of the groups.

CONCLUSION

Obese youngsters with asthma present a greater risk for EIB with slower recovery than their nonobese peers. Clinicians should be aware of this association, especially in those with more severe disease, for adequate recognition and treatment.

Exercise-induced bronchoconstriction update-2016

The first practice parameter on exercise-induced bronchoconstriction (EIB) was published in 2010. This updated practice parameter was prepared 5 years later. In the ensuing years, there has been increased understanding of the pathogenesis of EIB and improved diagnosis of this disorder by using objective testing. At the time of this publication, observations included the following: dry powder mannitol for inhalation as a bronchial provocation test is FDA approved however not currently available in the United States; if baseline pulmonary function test results are normal to near normal (before and after bronchodilator) in a person with suspected EIB, then further testing should be performed by using standardized exercise challenge or eucapnic voluntary hyperpnea (EVH); and the efficacy of nonpharmaceutical interventions (omega-3 fatty acids) has been challenged. The workgroup preparing this practice parameter updated contemporary practice guidelines based on a current systematic literature review. The group obtained supplementary literature and consensus expert opinions when the published literature was insufficient. A search of the medical literature on PubMed was conducted, and search terms included pathogenesis, diagnosis, differential diagnosis, and therapy (both pharmaceutical and nonpharmaceutical) of exercise-induced bronchoconstriction or exercise-induced asthma (which is no longer a preferred term); asthma; and exercise and asthma. References assessed as relevant to the topic were evaluated to search for additional relevant references. Published clinical studies were appraised by category of evidence and used to document the strength of the recommendation. The parameter was then evaluated by Joint Task Force reviewers and then by reviewers assigned by the parent organizations, as well as the general membership. Based on this process, the parameter can be characterized as an evidence- and consensus-based document.

Obesity, Asthma, and Exercise in Child and Adolescent Health

Obesity increases the risk of asthma throughout life but the underlying mechanisms linking these all too common threats to child health are poorly understood. Acute bouts of exercise, aerobic fitness, and levels of physical activity clearly play a role in the pathogenesis and/or management of both childhood obesity and asthma. Moreover, both obesity and physical inactivity are associated with asthma symptomatology and response to therapy (a particularly challenging feature of obesity-related asthma). In this article, we review current understandings of the link between physical activity, aerobic fitness and the asthma-obesity link in children and adolescents (e.g., the impact of chronic low-grade inflammation, lung mechanics, and direct effects of metabolic health on the lung). Gaps in our knowledge regarding the physiological mechanisms linking asthma, obesity and exercise are often compounded by imprecise estimations of adiposity and challenges of assessing aerobic fitness in children. Addressing these gaps could lead to practical interventions and clinical approaches that could mitigate the profound health care crisis of the increasing comorbidity of asthma, physical inactivity, and obesity in children.

Metabolic origins of childhood asthma

Childhood obesity and incidence of asthma are increasing globally. The parallel increase of the two suggests that obesity and asthma may be related and that abnormalities in the lipid and/or glucose metabolism may contribute to the pathogenesis of asthma. The clinical presentation of obese asthma is distinct from other asthma phenotypes and depending on age of onset of symptoms. Asthma in obese people tends to be more severe, not typically associated with allergy, and less responsive to standard anti-inflammatory therapy, including corticosteroids. Obesity and obesity-related comorbidities may lead to asthma via a number of mechanisms including changes in lung mechanics, the nitric oxide metabolism, and by causing inflammation. Furthermore, evidence suggests that nutrition during pregnancy contributes to intrauterine immune and metabolic programming in the offspring, which may have major influences on predisposition to cardiovascular, metabolic, and allergic diseases, including asthma, later in life. This review will highlight some suggested mechanistic links between obesity and diabetes with asthma.

Effects of dietary induced weight loss on exercise-induced bronchoconstriction in overweight and obese children

RATIONALE

Previous studies showed that obesity in asthmatic children is associated with more severe exercise-induced bronchoconstriction (EIB), compared with non-obese asthmatic children. This study investigates the effect of weight loss on EIB in overweight and obese asthmatic children.

METHODS

In this intervention study, children aged 8-18 years with EIB and moderate to severe overweight, followed a diet based on healthy daily intake for 6 weeks. Before and after the diet period they underwent an exercise challenge test in cold air. Primary outcome was change in exercise-induced fall in FEV1 and relation between weight loss and EIB. Secondary outcomes were changes in recovery of FEV1 ("area under the curve"; AUC), fraction of exhaled nitric oxide (FeNO) and scores of the Pediatric Asthma Quality of Life Questionnaire (PAQLQ) and Asthma Control Questionnaire (ACQ).

RESULTS

Twenty children completed the study. After the diet period, weight, and body mass index (BMI) were significantly reduced (changes respectively -2.6% and -1.5 kg/m(2), P < 0.01). There was a significant improvement of the percentage exercise-induced fall in FEV1 (30.6% vs. 21.8%, P < 0.01), AUC and PAQLQ score. The reduction in BMI z-score was significantly related to the reduction in the percentage exercise-induced fall in FEV1 in children that lost weight (r = 0.53, P = 0.03). There were no changes in FeNO and ACQ.

CONCLUSIONS

Dietary induced weight loss in overweight and obese asthmatic children leads to significant reduction in severity of EIB and improvement of the quality of life. The reduction in BMI z-score is significantly related to the improvement of EIB.

Childhood obesity and risk of allergy or asthma

The simultaneous increment in the prevalence of obesity and allergic diseases suggests a possible link between them. This review focuses on the consequences of obesity on allergic diseases, especially asthma in children and adolescents, and evaluates the available evidence on the possible mechanisms. Obesity is related more strongly to nonatopic than atopic asthma, suggesting non-eosinophilic inflammation and Th1 polarization. Among other allergic diseases, the association is more consistent with eczema compared to allergic rhinitis/rhinoconjunctivitis. The mechanisms of asthma in obese individuals could involve mechanical effects of obesity on lung function, adipokines-mediated inflammation, shared factors (diet, genetics, sedentary lifestyle) and comorbidities.

Pediatric allergy and immunology in Brazil

The subspecialty of pediatric allergy and immunology in Brazil is in its early years and progressing steadily. This review highlights the research developed in the past years aiming to show the characteristics of allergic and immunologic diseases in this vast country. Epidemiologic studies demonstrated the high prevalence of asthma in infants, children, and adolescents. Mortality rates and average annual variation of asthma hospitalization have reduced in all pediatric age groups. Indoor aeroallergen exposure is excessively high and contributes to the high rates of allergy sensitization. Prevalence of food allergy has increased to epidemic levels. Foods (35%), insect stings (30%), and drugs (23%) are the main etiological agents of anaphylaxis in children and adolescents. Molecular diagnosis of primary immunodeficiencies (PID) showed a high incidence of fungal infections including paracoccidioidomycosis in X-linked hyper-IgM syndrome, and the occurrence of BCG adverse reactions or other mycobacterial infections in patients with chronic granulomatous disease. Education in pediatric allergy and immunology is deficient for medical students, but residency programs are effective in training internists and pediatricians for the practice of allergy. The field of PID requires further training. Last, this review is a tribute to Prof. Dr. Charles Naspitz, one of the pioneers of our specialty in Brazil.

Respostas fisiológicas em adolescentes obesos submetidos à broncoprovocação com solução salina hipertônica

INTRODUÇÃO: A hiper-responsividade brônquica é a resposta do aumento dos mecanismos fisiológicos protetores das vias aéreas em indivíduos atópicos e não atópicos. Além disso, a magnitude da hiperresponsividade aérea apresenta influência conforme o grau de obesidade. OBJETIVO: Avaliar as respostas fisiológicas em adolescentes obesos submetidos a hiper-responsividade brônquica a solução salina hipertônica. MATERIAIS E MÉTODOS: Estudo descritivo, transversal e correlacional composto por 15 adolescentes obesos, de ambos os gêneros. O diagnóstico de asma foi realizado por meio de histórico clínico e questionário ISAAC, e a obesidade pelo IMC acima do percentil 95. Utilizou-se o teste de broncoprovocação por solução salina hipertônica para avaliação da hiper-responsividade brônquica, considerando positiva uma diminuição do volume expiratório forçado no primeiro segundo (VEF1) > 15% do valor pré-solução salina e a intensidade da hiper-responsividade brônquica foi calculada pela queda percentual máxima do VEF1 (% Queda máxVEF1). Foram utilizados o teste t independente ou U de Mann-Whitney e a correlação de Spearman rho (p < 0,05). RESULTADOS: Não foram encontradas diferenças significativas entre os asmáticos e não asmáticos para as variáveis antropométricas, espirométricas, lipídicas e hemodinâmicas. Verificaram-se moderadas correlações positivas e diferenças significativas entre o % Queda máxVEF1 com o IMC (p = 0,040) e IMC escore-Z (p = 0,028). Foram detectadas correlações negativas e diferenças significativas para a Queda máxVEF1 e leucócitos (p = 0,005) e para o % Queda máxVEF1 com o sulfato de dehidropiandrosterona (p = 0,032). CONCLUSÃO: Pode-se concluir que os adolescentes obesos submetidos a hiper-responsividade brônquica apresentam alterações espirométricas que estão associadas às inflamações sistêmicas da obesidade.

Influence of asthma definition on the asthma-obesity relationship

Background

Epidemiological studies suggest an association between obesity and asthma in adults and children. Asthma diagnosis criteria are different among studies. The aim of this study was to test the influence of asthma definition on the asthma-obesity relationship.

Methods

In a cross-sectional analysis of 1922 men and women, subjects completed a translated questionnaire from the European Community Respiratory Health Survey and underwent spirometry and a bronchial challenge test. Weight, height and waist circumference were measured. Multiple logistic regression analysis was carried out to assess the association of variables related to obesity and asthma. Asthma was defined either by the presence of symptoms with bronchial hyperresponsiveness (BHR) or by a self-report of a physician-made diagnosis. The following variables were separately tested for associations with asthma: socioeconomic characteristics, schooling, physical activity, smoking status, anthropometry and spirometry.

Results

No association was detected between asthma confirmed by BHR and obesity indicators, odds ratio (OR) = 1.08 (95% confidence interval: 0.69 - 1.68) for obesity assessed by body mass index ≥ 30 kg/m²; OR = 1.02 (0.74 - 1.40) for obesity assessed by abnormal waist-to-height ratio; and, OR = 0.96 (0.69 - 1.33) for abnormal waist circumference. On the contrary, a previous diagnosis of asthma was associated with obesity, OR = 1.48 (1.01 - 2.16) for body mass index ≥ 30 kg/m²; OR = 1.48 (1.13 - 1.93) for abnormal waist-to-height ratio; and, OR = 1.32 (1.00 – 1.75) for abnormal waist circumference. Female gender, schooling ≥ 12 years and smoking were associated with BHR-confirmed asthma. Physically inactive subjects were associated with a previous diagnosis of asthma.

Conclusions

Our findings indicate that the relationship between asthma and obesity in epidemiological studies depends on the definition adopted. Certain components of asthma, for instance, symptoms may be more prone to the obesity influence than other ones, like bronchial hyperresponsiveness.

Reduction in the leptin concentration as a predictor of improvement in lung function in obese adolescents

OBJECTIVE

To assess the effects of weight loss on adipokines, asthma-related symptoms, exercise-induced bronchospasm (EIB) and lung function, and to evaluate the role of leptin and adiponectin levels on lung function after treatment in obese adolescents.

METHODS

84 postpubertal obese adolescents were enrolled and distributed in quartiles according to weight loss (low (<2.5 kg), low to moderate (>2.5 and <8 kg), moderate (<8 and <14 kg) and massive (<14 kg)). Body composition was measured by plethysmography, and visceral and subcutaneous fat were detected by ultrasound. Serum levels of adiponectin and leptin were analyzed. Lung function, asthma and EIB were evaluated according to the American Thoracic Society criteria. Patients were submitted to 1 year of interdisciplinary intervention consisting of physiotherapy, medical, nutritional, exercise, and psychological therapy.

RESULTS

After treatment the moderate and massive weight loss promoted an increase in adiponectin and adiponectin/leptin (A/L) ratio as well as a decrease in leptin levels and a reduction in EIB frequency and asthma-related symptoms. Furthermore, the reduction in leptin levels was a predictor factor to improvement in lung function.

CONCLUSION

Interdisciplinary therapy was able to decrease EIB and asthma-related symptoms and to improve pro/anti-inflammatory adipokines. Additionally, the leptin concentration was a predictor factor to explain changes in lung function.

Prevalence rate of exercise-induced bronchoconstriction in Annaba (Algeria) schoolchildren

BACKGROUND

We studied the prevalence rate of exercise-induced bronchoconstriction (EIB) in Annaba schoolchildren. No previous assessment of this syndrome had ever been done in Algeria.

METHODS

EIB was evaluated using the 6 min free running test (6MFRT) on 286 children, 87.4% of whom were 10-12 years old. They performed the test in the morning, during the autumn-winter season. Peak expiratory flow rate (PEFR) was measured before, and then 5 and 10 min after the 6MFRT, a 15% or more decrease in post-exercise PEFR being defined as significant.

RESULTS

EIB was much more frequent in asthmatic than in nonasthmatic children (47.0% vs. 13.9%, p < .001) and the drop in PEFR was more marked among the former. EIB was observed more often in a cool temperature (<8°C). There were relatively more children who were either eutrophic or overweight among those presenting an EIB. Past histories of nocturnal wheezing and rhinoconjunctivitis presented respectively the best specificity (96.7%) and sensitivity (84.8%). Children of unemployed workers presented the highest occurrence of EIB. Passive smoking appeared as the only factor being related to EIB among the indoor pollutants. The prevalence rate of asthma (6.7%) was higher than in a previous cross-sectional epidemiological survey study performed in the Maghreb. The prevalence rate of EIB (13.9%) was situated in the upper range of the results given worldwide.

CONCLUSIONS

These features of a fairly high bronchial hyperresponsiveness could be facilitated by the polluted environment of the city.

Serum leptin and adiponectin levels correlate with exercise-induced bronchoconstriction in children with asthma

BACKGROUND

Exercise-induced bronchoconstriction (EIB), a form of bronchial hyperresponsiveness (BHR), is common in children with asthma or obesity. Epidemiological studies have shown that asthma and obesity are increasing in parallel, but obesity- and adipokine-related effects on inflammation and BHR have not yet been demonstrated in the human airway.

OBJECTIVE

To address the relationship between leptin and adiponectin and EIB in children with asthma.

METHODS

Eighty-five prepubertal children between the ages of 6 and 10 years were included in our study. They comprised obese with asthma (n = 19), normal weight with asthma (n = 23), obese without asthma (n = 23), and healthy (n = 20). We measured serum leptin and adiponectin levels. We also performed pulmonary function tests: baseline, postbronchodilator inhalation, methacholine inhalation, and exercise. The area under the forced expiratory volume in 1 second (FEV(1))-time curve quantified the severity of EIB over a 20-minute period after exercise (AUC(20)).

RESULTS

The obese children had significantly elevated levels of leptin and reduced levels of adiponectin. The maximum decreases in %FEV(1) and AUC(20) after exercise were positively correlated with leptin levels and negatively with serum adiponectin levels in children with asthma. The odds for having EIB were incrementally and significantly higher for children with higher levels of serum leptin.

CONCLUSIONS

Levels of the adipocyte-derived hormones leptin and adiponectin are significantly correlated with BHR induced by exercise challenge in children with asthma. Further studies are needed to elucidate whether the changes in leptin and adiponectin levels bear a causal relationship to the EIB/BHR.