Impact of climate variability on exercise-induced bronchospasm in adolescents living in a semi-arid region / Influência de alterações climáticas sobre a ocorrência do broncoespasmo induzido por exercício em adolescentes de uma região semiárida

ABSTRACT Objective: To examine the impact of climate variability on the occurrence of exercise-induced bronchospasm in the rainy and dry seasons of a Brazilian semi-arid region. Methods: This sample comprised 82 adolescents aged 15 to 18 years, who were submitted to exercise-induced bronchospasm assessment on a treadmill and outdoors, during the rainy and the dry season. Anthropometric variables, sexual maturity and forced expiratory volume in the first second were analyzed. Air temperature and humidity, decline in forced expiratory volume in the first second (%) and frequency of bronchospasm were compared between seasons using the independent Student's t test, the Wilcoxon and McNemar tests, respectively. The level of significance was set at p<0.05. Results: The mean age was 15.65±0.82 years. Air temperature, air humidity and decline in forced expiratory volume in the first second (%) differed between seasons, with higher air temperature and humidity in the rainy season (29.6ºC±0.1 and 70.8%±0.6 versus 28.5ºC±0.2 and 48.5%±0.6; p<0.05). The decline in forced expiratory volume in the first second (%) was greater in the dry season (9.43%±9.97 versus 12.94%±15.65; p<0.05). The frequency of bronchospasm did not differ between seasons. Conclusion: The dry season had a negative impact on forced expiratory volume in the first second in adolescents, with greater decrease detected during this period. Findings of this study suggested bronchospasm tends to be more severe under low humidity conditions.

RESUMO Objetivo: Verificar a influência das alterações climáticas sobre o broncoespasmo induzido por exercício, nos períodos chuvoso e seco de uma região do semiárido brasileiro. Métodos: Foram submetidos à avaliação do broncoespasmo em esteira ergométrica, em ambiente externo, nos períodos chuvoso e seco, 82 adolescentes, com idades de 15 a 18 anos. Foram avaliadas as variáveis antropométricas, a maturação sexual e o volume expiratório forçado no primeiro segundo. Para comparação da temperatura e umidade, queda do volume expiratório forçado no primeiro segundo (%) e frequência do broncoespasmo entre os períodos, foram utilizados o teste t de Student independente, o teste de Wilcoxon e o teste de McNemar, respectivamente. O nível de significância adotado foi p<0,05. Resultados: A média de idade foi 15,65±0,82 anos. A temperatura, a umidade e a queda do volume expiratório forçado no primeiro segundo (%) diferiram entre os períodos, com valores de temperatura e umidade maiores no período chuvoso (29,6ºC±0,1 e 70,8%±0,6 versus 28,5ºC±0,2 e 48,4%±0,6; p<0,05). A queda do volume expiratório forçado no primeiro segundo (%) foi maior no período seco (9,43%±9,97 versus 12,94%±15,65; p<0,05), e não foi encontrada diferença da frequência do broncoespasmo entre os períodos. Conclusão: O período seco influenciou negativamente no volume expiratório forçado no primeiro segundo de adolescentes, observando maior percentual de queda dessa variável nesse período. De acordo com os achados, propõe-se uma maior gravidade do broncoespasmo induzido por exercício em condições de baixa umidade.

Efecto agudo del ejercicio físico de intensidad moderada sobre las variables espirométricas en sujetos asmáticos broncodilatados. Prueba piloto / Acute effect of moderate-intensity exercise on spirometric variables in broncodilated asthmatic subjects. A pilot study

RESUMEN Introducción: el broncoespasmo inducido por el ejercicio (BIE) ocurre entre el 70 y 80 % de los asmáticos y su aparición es más frecuente al terminar una sesión de ejercicio físico, principalmente de intensidad vigorosa. Objetivo: evaluar el efecto agudo que puede tener el ejercicio físico de intensidad moderada sobre las variables espirométricas en sujetos asmáticos broncodilatados. Metodología: se realizó un estudio cuasi-experimental de tipo antes y después. Se incluyeron diez sujetos (edad promedio = 23 ± 4 años), los cuales fueron divididos en dos grupos: cinco sujetos asmáticos y cinco sanos. Los dos grupos realizaron 10 minutos de calentamiento, 20 minutos de ejercicio en banda sin fin al 60 % de la frecuencia cardíaca de entrenamiento, seguido de 5 minutos de recuperación. La función pulmonar fue evaluada antes del ejercicio y 15 minutos después del ejercicio. Resultados: se encontraron diferencias estadísticamente significativas entre grupos (con asma 6 % vs. sin asma -1 %, p = 0,03) en los cambios pre y pos del ejercicio de la relación del volumen espiratorio forzado en el primer segundo (VEF1) sobre la capacidad vital forzada (CVF). El análisis multivariado mostró que la CVF post ejercicio en el grupo con asma fue significativamente menor que el del grupo sin asma, ajustado por evaluación basal y masa corporal total. Conclusión: el ejercicio de intensidad moderada en banda sin fin, no mostró diferencias clínicamente significativas sobre los cambios del pre y post ejercicio de las variables espirométricas estudiadas, puesto que estos cambios en VEF1 o CVF no superaron el 10 % teniendo como referencia la evaluación basal.

SUMMARY Background: Exercise-Induced Bronchospasm (BIE) occurs in 70 % to 80 % of asthmatics and its occurrence is more frequent at the end of a session of physical exercise, mainly of vigorous intensity. Objective: To evaluate the acute effect of moderateintensity physical exercise on spirometric variables in asthmatic subjects. Methodology: A before-and-after type quasi-experimental design. Ten subjects were included (mean age= 23 ± 4 years), which were divided into two groups: five asthmatic subjects and five healthy subjects. Both groups performed 10 min of warm-up, 20 min of treadmill exercise at an intensity of 60 % of the Heart Rate Reserve, and a final cool-down of 5 minutes. Lung function was assessed before and 15 minutes after exercise. Results: There were statistically significant differences between groups (with asthma = 6 % vs. without asthma = -1 %, p = 0.03) in the pre-post-exercise changes of the ratio of the forced expiratory volume in one second and the forced vital capacity (FEV1/FVC). The multivariate analysis showed that post-exercise FVC in subjects with asthma was significantly lower than in subjects without asthma, after adjusting for the baseline assessment and total body mass. Conclusion: Moderate-intensity exercise on a treadmill did not shows clinically significant differences on the changes pre-post exercise of the studied spirometric variables, since the changes on FEV1 or FVC did not exceed 10 % having as reference the baseline evaluation.

The association of forced expiratory volume in one second and forced expiratory flow at 50% of the vital capacity, peak expiratory flow parameters, and blood eosinophil counts in exercise-induced bronchospasm in children with mild asthma

BACKGROUND: Exercise-induced bronchoconstriction (EIB), which describes acute airway narrowing that occurs as a result of exercise, is associated with eosinophilic airway inflammation, bronchial hyperresponsiveness. The forced expiratory volume in one second (FEV₁) is the most commonly used spirometric test in the diagnosis of EIB in exercise challenge in asthma. Other parameters such as forced expiratory flow at 50% of the vital capacity (FEF(50%)) and peak expiratory flow (PEF) are used less often in the diagnosis of EIB. OBJECTIVE: The purpose of this study is to evaluate the association of FEV₁ and FEF(50%), PEF parameters, blood eosinophil counts in EIB in children with mild asthma. METHODS: Sixty-seven children (male: 39, female: 28) with mild asthma were included in this study. Pulmonary functions were assessed before and at 1, 5, 10, 15, and 20 minutes after exercise. The values of spirometric FEV₁, FEF50(%), PEF, and blood eosinophil counts were evaluated in EIB in children with mild asthma. RESULTS: There was a positive correlation between FEV₁ with FEF(50%) and PEF values (p < 0.05; FEF(50%), r=0.68; PEF, r=0.65). Also, a positive correlation was found between blood eosinophil counts and the values of spirometric FEV₁, FEF(50%), and PEF (p < 0.05; FEV₁, r=0.54; FEF(50%), r=0.42; PEF, r=0.26). In addition to these correlations, in the exercise negative group for FEV₁, the FEF(50%) and PEF values decreased more than the cutoff values in 3, and 2 patients, respectively. CONCLUSION: According to the presented study, eosinophil may play a major role in the severity of EIB in mild asthma. FEF(50%) and PEF values can decrease in response to exercise without changes in FEV₁ in mild asthmatic patients.

Broncoespasmo induzido por exercício em corredores brasileiros de longa distância de elite / Exercise-induced bronchoconstriction in elite long-distance runners in Brazil

OBJETIVO: Determinar a prevalência de broncoespasmo induzido por exercício em corredores brasileiros de longa distância de elite e se há uma diferença na carga de treinamento entre atletas com e sem broncoespasmo induzido por exercício. MÉTODOS: Estudo transversal com corredores de longa distância de elite sem sintomas atuais de asma e sem diagnóstico de broncoespasmo induzido por exercício. Todos os participantes foram submetidos ao teste de hiperventilação voluntária eucápnica e ao teste cardiopulmonar de esforço máximo e responderam a questionários sobre sintomas de asma e atividade física para monitorizar sua carga de treinamento semanal. RESULTADOS: Dos 86 atletas do sexo masculino recrutados, 20 concordaram em participar do estudo, dos quais 5 (25%) foram diagnosticados com broncoespasmo induzido por exercício. Não foram evidenciadas diferenças entre os atletas com e sem broncoespasmo induzido por exercício em relação a características antropométricas, consumo de oxigênio de pico, valores basais de função pulmonar ou sintomas de asma relatados. A carga de treinamento semanal foi significativamente menor nos atletas com broncoespasmo induzido por exercício do que naqueles sem esse diagnóstico. CONCLUSÕES: Nesta amostra de corredores de longa distância brasileiros, a prevalência de broncoespasmo induzido por exercício foi alta.

OBJECTIVE: To determine the prevalence of exercise-induced bronchoconstriction among elite long-distance runners in Brazil and whether there is a difference in the training loads among athletes with and without exercise-induced bronchoconstriction. METHODS: This was a cross-sectional study involving elite long-distance runners with neither current asthma symptoms nor a diagnosis of exercise-induced bronchoconstriction. All of the participants underwent eucapnic voluntary hyperpnea challenge and maximal cardiopulmonary exercise tests, as well as completing questionnaires regarding asthma symptoms and physical activity, in order to monitor their weekly training load. RESULTS: Among the 86 male athletes recruited, participation in the study was agreed to by 20, of whom 5 (25%) were subsequently diagnosed with exercise-induced bronchoconstriction. There were no differences between the athletes with and without exercise-induced bronchoconstriction regarding anthropometric characteristics, peak oxygen consumption, baseline pulmonary function values, or reported asthma symptoms. The weekly training load was significantly lower among those with exercise-induced bronchoconstriction than among those without. CONCLUSIONS: In this sample of long-distance runners in Brazil, the prevalence of exercise-induced bronchoconstriction was high.

Desempenho de uma escala analógica visual legendada na determinação do grau de dispneia durante teste de broncoespasmo induzido por exercício em crianças e adolescentes asmáticos / Performance of a word labeled visual analog scale in determining the degree of dyspnea during exercise-induced bronchoconstriction in children and adolescents with asthma

OBJETIVO: Existe uma relação indireta entre a obstrução das vias aéreas em asma e a intensidade de falta de ar (dispneia). Uma escala visual analógica legendada de dispneia com escore de 0-3 pontos tem sido amplamente utilizada na avaliação da broncoconstrição, embora a percepção de tal obstrução seja muito variável. O objetivo deste estudo foi determinar se crianças e adolescentes são capazes de perceber a broncoconstrição aguda induzida por exercício (BAIE), bem como medir o poder discriminatório de uma escala visual analógica legendada de dispneia em relação à intensidade de BAIE. MÉTODOS: Estudo transversal com 134 crianças e adolescentes asmáticos que foram submetidos a um teste de broncoespasmo induzido por seis minutos de exercício em um cicloergômetro. A intensidade da dispneia foi determinada utilizando-se uma escala visual analógica legendada de dispneia antes de cada determinação de VEF1. A escala tem um escore de 0-3 pontos, com desenhos em uma sequência lógica variando entre "sem sintomas" e "dispneia grave". As variáveis foram determinadas no momento basal, assim como em 5, 10 e 20 minutos após o término do teste de exercício. A acurácia da escala de dispneia em detectar o grau de BAIE foi determinada através de curvas ROC para a queda de VEF1 após o exercício, usando pontos de corte de 10 por cento, 20 por cento, 30 por cento e 40 por cento. RESULTADOS: Dos pacientes selecionados, 111 completaram o estudo, e 52 (46,8 por cento) apresentaram BAIE. A área sob a curva ROC progressivamente aumentou com o aumento do grau de broncoconstrição. CONCLUSÕES: Em crianças e adolescentes asmáticos, a acurácia desta escala de dispneia melhora com o aumento do percentual de queda em VEF1 após o exercício. Entretanto, o valor preditivo da escala é subótimo quando a porcentagem de queda em VEF1é menor.

OBJECTIVE: There is an indirect relationship between airway obstruction in asthma and the intensity of breathlessness (dyspnea). A word labeled visual analog dyspnea scale with a 0-3 score has been widely used for the assessment of the degree of bronchoconstriction, although the perception of such obstruction varies considerably. The objective of this study was to determine whether children and adolescents are able to perceive acute exercise-induced bronchoconstriction (EIB), as well as to measure the discriminatory power of a word labeled visual analog dyspnea scale in relation to the intensity of the EIB. METHODS: A cross-sectional study involving 134 children and adolescents with asthma and submitted to a six-minute steady-state exercise test on a cycle ergometer. The intensity of dyspnea was determined using a word labeled visual analog dyspnea scale prior to each determination of FEV1. The scale is scored from 0 to 3, with a logical sequence of pictures, ranging from "no symptoms" to "severe dyspnea". Variables were determined at baseline, as well as at 5, 10, and 20 min after the exercise test. The accuracy of the dyspnea scale in identifying the degree of EIB was determined by means of ROC curves for the post-exercise fall in FEV1, using cut-off points of 10 percent, 20 percent, 30 percent, and 40 percent. RESULTS: Of the patients selected, 111 finished the study, and 52 (46.8 percent) presented with EIB. The area under the ROC curve increased in direct proportion to increases in the degree of bronchoconstriction. CONCLUSIONS: Among children and adolescents with asthma, the accuracy of this dyspnea scale improves as the post-exercise percentage fall in FEV1 increases. However, the predictive value of the scale is suboptimal when the percentage fall in FEV1 is lower.

Broncoespasmo induzido pelo exercício em adolescentes asmáticos obesos e não-obesos / Exercise-induced bronchospasm in obese and non-obese asthmatic adolescents

OBJETIVO: Avaliar e comparar a frequência e intensidade do broncoespasmo induzido pelo exercício (BIE) em adolescentes asmáticos obesos e não-obesos. MÉTODOS: Estudo transversal e descritivo realizado com 39 adolescentes de ambos os sexos, com idade entre dez e 16 anos, divididos em dois grupos conforme o histórico clínico de asma e/ou rinite alérgica e o índice de massa corporal: asmáticos obesos (n=18); asmáticos não-obesos (n=21). Utilizou-se o teste de broncoprovocação com exercício para a avaliação do BIE, considerando-se positiva uma diminuição do volume expiratório forçado no primeiro segundo (VEF1) >15 por cento do valor pré-exercício. Para avaliar a intensidade e a recuperação do BIE, foram calculadas a queda percentual máxima do VEF1 (QM por centoVEF1) e a área acima da curva (AAC0-30). A análise estatística utilizou o teste exato de Fischer para comparar a frequência de BIE e o teste de Mann-Whitney para a intensidade e recuperação. Rejeitou-se a hipótese de nulidade se p<0,05. RESULTADOS: Não houve diferença significativa na frequência de BIE entre os grupos de asmáticos obesos (50 por cento) e não-obesos (38 por cento). Entretanto, a queda máxima do VEF1 e a AAC0-30 foram maiores nos asmáticos obesos em comparação aos não-obesos (respectivamente 37,7 por cento e 455 versus 24,5 por cento e 214, p<0,03). CONCLUSÕES: A obesidade não contribuiu para o aumento da frequência do BIE em asmáticos e não-asmáticos, entretanto, a obesidade contribuiu para o aumento da intensidade e do tempo de recuperação da crise de BIE em asmáticos.

OBJECTIVE: To assess and compare the frequency and severity of exercise-induced bronchospasm (EIB) in obese and non-obese asthmatic adolescents. METHODS: Cross-sectional and descriptive study with 39 subjects aged ten to 16 years of both genders divided into two groups according to clinical history of asthma and/or allergic rhinitis and body mass index, as follows: asthmatic obese (n=18) and asthmatic non-obese (n=21). An exercise bronchoprovocation test was applied to diagnose EIB and was considered positive if the forced expiratory volume in one second (FEV1) decreased >15 percent in relation to pre-exercise FEV1. Maximum percent of fall in FEV1 (MF percentFEV1) and the area above the curve (AAC0-30) were calculated to evaluate the intensity and recovery of EIB. Fisher exact test was used to compare the frequency of EIB and Mann-Whitney test to compare the severity and recovery of EIB. Null hypothesis was rejected when p<0.05. RESULTS: No significant difference was found in the frequency of EIB between the asthmatic obese (50 percent) and non-obese (38 percent) adolescents. However, the MF percentFEV1 and AAC0-30 were significantly higher in the asthmatic obese as compared to the asthmatic non-obese patients (respectively, 37.7 percent and 455 versus 24.5 percent e 214, p<0.03). CONCLUSIONS: Obesity did not contribute to the increase of the frequency of EIB in asthmatic and non-asthmatic patients. However, obesity contributed to the increase of severity and recovery time of EIB in asthmatics.

Increased Releasability of Skin Mast Cells after Exercise in Patients with Exercise-induced Asthma

The role of lung mast cells in exercise-induced asthma (EIA) is controversial. To investigate whether the skin mast cell releasability is increased after exercise in EIA, 49 young atopic men with or without asthma took part in a free-running test for 6 min and were given skin prick tests using morphine, a mast cell secretagogue, before and after the exercise. The mean diameters of the wheal induced by morphine in patients with EIA were not significantly different from those in patients without EIA before exercise, although the baseline lung function was significantly lower and the airway hyperresponsiveness, the peripheral blood eosinophil count, and the size of the wheal in response to Dermatophagoides pteronyssinus were significantly higher in patients with EIA. However, the differences of the morphine-induced wheal diameter between patients with EIA and those without EIA became significant at 120 min after exercise (p<0.05), while the responses to histamine were not significantly different. These results suggest that exercise increases the releasability of skin mast cells in EIA patients whose asthma/allergy are relatively severe.

Acute and Chronic Changes of Vascular Endothelial Growth Factor (VEGF)in Induced Sputum of Toluene Diisocyanate (TDI)-induced Asthma Patients

Vascular endothelial growth factor (VEGF) is a multi-functional cytokine involved in inflammation, repair and angiogenesis in asthmatic airway. This study aimed to evaluate the role of VEGF in immediate bronchoconstriction induced by TDI inhalation, and in chronic TDI-asthma patients. 11 newly diagnosed TDI-asthma patients (group I), 12 chronic TDI-asthma patients with persistent asthma symptoms followed for >4 yr and 15 unexposed healthy controls were enrolled. In group I, induced sputum and serum were collected before and 7 hr after placebo- and TDI-bronchoprovocation test (BPT). In group II, induced sputum and serum were collected every 2 yr. VEGF levels were measured by ELISA. There were no significant differences in sputum and serum VEGF levels between patients and controls. Before and after placebo and TDI-BPT, no significant changes were noted in sputum and serum VEGF levels of group I. In group II patients, sputum VEGF showed variable changes at 1-yr, then decreased significantly at 2-yr (p<0.05), while serum VEGF showed variable changes at 2-yr, which decreased significantly at 4-yr (p<0.05). These results suggest that VEGF may play a minor role in immediate bronchoconstriction after TDI-BPT. In chronic TDI-asthma, VEGF may be involved to 2 yr after the diagnosis and the contribution may decrease after then.

Evaluation of emphysema in asthma patients using high-resolution CT / 대한내과학회지

BACKGROUND: Bronchial asthma is a clinical syndrome characterized by reversiblity of airway obstruction. however, many asthma patients have evidence of residual airway obstruction. It has become evident that the repair of chronic inflammatory process can lead to various irreversible changes. It is generally accepted that the most common cause for change is cigarette smoking but it is controversial whether asthma progresses to emphysema. High resolution computed tomography (HRCT) is more sensitive and more accurate than chest plain films in determining the type and extent of emphysema. This study was carried out to determine whether asthma can be a cause of emphysema without the effect of cigarette smoking and to evaluate clinical characterics in asthma patients with emphysema. METHODS: We studied 58 asthmatic patients with reversible airway obstruction and evaluated the presence of emphysema using HRCT and pulmonary function test. According to HRCT findings, they were divided into 2 groups: Asthma patients with and without emphysema. RESULTS: Of the 58 patients, 7 were judged to have emphysema. (1) 6 asthma patients with emphysema were smokers, but one patient was nonsmoker. (2) Highly significant differences between patients with and without emphysema were found in cigarette smoking (p<0.01), smoking consumption (p<0.01). (3) There was no significant differences in the duration of asthma, age or sex between patients with and without emphysema. (4) There was no significant differences in FEV1 (%), FEV1/FVC (%), diffusing capacity for carbon monoxide (DLco) (%), DLco/alveolar volume between patients with and without emphysema (5) Differences between asthma patients without emphysema and those with emphysema were found to be significant in bronchial wall thickening (p<0.05) and in total Ig E (p=0.07). CONCLUSION: These results indicate that smoking is a main factor to cause emphysema in the patient with asthma.

Evaluation of emphysema in asthma patients using high-resolution CT / 대한내과학회지

BACKGROUND: Bronchial asthma is a clinical syndrome characterized by reversiblity of airway obstruction. however, many asthma patients have evidence of residual airway obstruction. It has become evident that the repair of chronic inflammatory process can lead to various irreversible changes. It is generally accepted that the most common cause for change is cigarette smoking but it is controversial whether asthma progresses to emphysema. High resolution computed tomography (HRCT) is more sensitive and more accurate than chest plain films in determining the type and extent of emphysema. This study was carried out to determine whether asthma can be a cause of emphysema without the effect of cigarette smoking and to evaluate clinical characterics in asthma patients with emphysema. METHODS: We studied 58 asthmatic patients with reversible airway obstruction and evaluated the presence of emphysema using HRCT and pulmonary function test. According to HRCT findings, they were divided into 2 groups: Asthma patients with and without emphysema. RESULTS: Of the 58 patients, 7 were judged to have emphysema. (1) 6 asthma patients with emphysema were smokers, but one patient was nonsmoker. (2) Highly significant differences between patients with and without emphysema were found in cigarette smoking (p<0.01), smoking consumption (p<0.01). (3) There was no significant differences in the duration of asthma, age or sex between patients with and without emphysema. (4) There was no significant differences in FEV1 (%), FEV1/FVC (%), diffusing capacity for carbon monoxide (DLco) (%), DLco/alveolar volume between patients with and without emphysema (5) Differences between asthma patients without emphysema and those with emphysema were found to be significant in bronchial wall thickening (p<0.05) and in total Ig E (p=0.07). CONCLUSION: These results indicate that smoking is a main factor to cause emphysema in the patient with asthma.