RESUMO
BACKGROUND: The association between obesity and bronchial hyperreactivity (BHR) in children has not been fully demonstrated in cross-sectional or longitudinal studies, and no study has specifically addressed Latino children. METHODS: A cross-sectional study of 450 children (10-18 years) from public schools was conducted in Mexico city. Among this group, 260 met the study criteria (no chronic respiratory illnesses, including asthma and rhinitis; no acute respiratory infections; and no tobacco-exposure or endocrine or body dysmorphic disorders), and 229 performed reproducible pulmonary function and methacholine challenge tests and were fully analyzed. RESULTS: According to BMI percentiles, 40 were normal weight, 116 were obese, and 73 morbidly obese. Children in the morbidly obese group had significantly higher % FVC than those in the normal-weight group, and obese children had higher % PEF those in the morbidly obese and normal-weight groups. In the BHR methacholine challenge test, baseline FEV1 values among obese children were significantly lower than in the morbidly obese group. Using adjusted percentages for FEV1 , values were significantly lower among obese compared to morbidly obese children at metacholine concentrations of 0.25, 1, and 4 mg/ml. The proportion of positive BHR (PC20 ≤ 16 mg/ml) was higher in these two groups compared to normal-weight children (28.4%, 17.8%, and 12.5%, respectively), although differences were not significant. CONCLUSION: Our findings show that obesity by itself is not a sufficient condition to alter airway responsiveness to methacholine in a group of adolescents.
Assuntos
Hiper-Reatividade Brônquica/epidemiologia , Pulmão/fisiopatologia , Obesidade/epidemiologia , Adolescente , Hiper-Reatividade Brônquica/fisiopatologia , Testes de Provocação Brônquica , Broncoconstritores , Criança , Estudos Transversais , Feminino , Humanos , Masculino , Cloreto de Metacolina , México/epidemiologia , Obesidade Mórbida/epidemiologia , Testes de Função RespiratóriaRESUMO
BACKGROUND: The pattern of associations and the attributable fractions (AF) of atopic conditions due to specific sensitizations vary between countries. OBJECTIVE: To assess the level of associations and AF between sensitization to five allergens and atopic conditions in two settings. METHODS: We studied 2063 Brazilians and 1231 Chileans of both sexes using representative samples selected at birth in the 1970s. Information on asthma and rhinitis was based on the European Community Respiratory Health Survey questionnaire. We assessed bronchial hyperresponsiveness (BHR) to methacholine and sensitization to Dermatophagoides pteronyssinus, cat, dog, grass blend and Alternaria alternata. RESULTS: The prevalence of sensitization to one or more allergens was 50% in Brazilians and 22% in Chileans. The level of associations varied according to the outcome used. Strong associations between sensitization and asthma, defined as wheeze or awakening with breathlessness at night and positive BHR, were found for each of the five allergens in Chileans [varying from odds ratio (OR) 3.24, 95% confidence interval (CI) 1.47, 7.15 for D. pteronyssinus to 8.44, 95% CI 3.82, 18.66 for cat], whereas the level of associations was restricted to D. pteronyssinus, cat and dog in Brazilians and was somewhat weaker (highest OR 3.90, 95% CI 2.80-5.44). The AF of sensitization on asthma was 54% in Brazil and 44% in Chile. D. pteronyssinus and cat made an independent contribution to asthma in the two samples. The patterns of associations between sensitization and rhino-conjunctivitis were similar to those for asthma. CONCLUSION: The associations between sensitization, and asthma and rhinitis were high in Chile and moderately high in Brazil, but the AF were higher in Brazil, reflecting a higher prevalence of sensitization. In Brazil, dust mite had the greatest impact on atopic conditions while in Chile several allergens had an impact. Sensitization is as serious a problem in Chile and Brazil as in developed countries.
Assuntos
Asma/etiologia , Hipersensibilidade Imediata/complicações , Hipersensibilidade Imediata/imunologia , Rinite Alérgica Perene/etiologia , Rinite Alérgica Sazonal/etiologia , Adulto , Alérgenos/imunologia , Alternaria/imunologia , Animais , Animais Domésticos/imunologia , Antígenos de Dermatophagoides/imunologia , Antígenos de Plantas/imunologia , Asma/epidemiologia , Brasil , Hiper-Reatividade Brônquica/epidemiologia , Hiper-Reatividade Brônquica/etiologia , Testes de Provocação Brônquica , Gatos , Chile , Conjuntivite Alérgica/epidemiologia , Conjuntivite Alérgica/etiologia , Estudos Transversais , Cães , Feminino , Humanos , Hipersensibilidade Imediata/epidemiologia , Masculino , Sons Respiratórios/etiologia , Rinite Alérgica Perene/epidemiologia , Rinite Alérgica Sazonal/epidemiologia , Testes Cutâneos , Adulto JovemRESUMO
OBJECTIVES: We assessed the effects of indoor risk factors, including smoking, on different types of cough and on cough and wheeze in combination. METHODS: Our sample was composed of 1232 men and women residing in a semirural area of Chile. We used a standardized questionnaire, sensitization to 8 allergens, and bronchial hyperresponsiveness to methacholine to assess cough and wheeze characteristics. Information was gathered on dampness, mold, ventilation, heating, housing quality, smoking, and environmental tobacco smoke exposure. RESULTS: Most exposures were associated with cough alone or cough in combination with wheeze. Smoking, past smoking, and environmental tobacco smoke exposure were strongly associated with dry cough and wheeze. The use of coal for heating was associated with dry cough. Leaks, mold, and lack of kitchen ventilation were associated with cough and wheeze. Nocturnal cough and productive cough were associated with specific types of sensitization, but dry cough was not. Productive cough was associated with hyperresponsiveness to methacholine. CONCLUSIONS: Several different types of indoor exposures, including environmental tobacco smoke exposure, are important contributors to morbidity associated with cough and wheeze. A vigorous preventive strategy designed to lower exposures to indoor risk factors would lower rates of respiratory morbidity.
Assuntos
Alérgenos , Hiper-Reatividade Brônquica/etiologia , Tosse/etiologia , Exposição Ambiental/efeitos adversos , Sons Respiratórios , Fumar/efeitos adversos , Adolescente , Adulto , Fatores Etários , Hiper-Reatividade Brônquica/epidemiologia , Chile/epidemiologia , Tosse/epidemiologia , Feminino , Humanos , Entrevistas como Assunto , Masculino , Fatores de Risco , Inquéritos e QuestionáriosRESUMO
BACKGROUND: Although global studies such as the International Study of Asthma and Allergies in Childhood (ISAAC) have provided valuable data on the prevalence of asthma in children in Latin America, there is little information on the relationship between asthma symptoms, pulmonary function, bronchial hyperresponsiveness (BHR) and atopy in the region. METHODS: This study examined the relationship between self-reported wheezing in the past 12 months, pulmonary function, airway responsiveness and atopy in children from a low income population in a neighbourhood of Santiago, Chile. Two random samples (100 each) of children aged 13-14 years who participated in ISAAC phase I were selected according to whether or not they reported wheezing in the past 12 months. Spirometry, the methacholine bronchial challenge test and the prick test were performed in all individuals. RESULTS: Children who reported current wheezing had significantly higher BHR to methacholine compared with those without wheezing (71.6% vs 52.6%; p = 0.007) and no significant difference was found in forced expiratory volume in 1 s (116.7 (12.3)% vs 120.3 (14.5%); p = 0.11). The prevalence of atopy was not significantly different between those children who reported wheezing compared with those who did not (44.2% vs 42.3%; p = 0.89). Multiple regression analysis showed that only BHR to methacholine (OR 2.72, 95% CI 1.25 to 4.13; p = 0.01) and maternal asthma (OR 3.1, 95% CI 1.2 to 8.3, p = 0.03) were significant risk factors for current wheezing. CONCLUSIONS: Our results support previous findings suggesting that in adolescents from underprivileged populations, self-reported current wheezing is related to BHR but not to atopy.
Assuntos
Hiper-Reatividade Brônquica/epidemiologia , Adolescente , Asma/diagnóstico , Asma/epidemiologia , Asma/fisiopatologia , Hiper-Reatividade Brônquica/diagnóstico , Testes de Provocação Brônquica/métodos , Broncoconstritores , Chile/epidemiologia , Feminino , Humanos , Hipersensibilidade Imediata/diagnóstico , Hipersensibilidade Imediata/epidemiologia , Renda , Masculino , Cloreto de Metacolina , Prevalência , Sons Respiratórios/diagnóstico , Sons Respiratórios/etiologia , Fatores de Risco , Testes Cutâneos/métodos , Fatores Socioeconômicos , Espirometria/métodosRESUMO
BACKGROUND: An asthma score was proposed in the European Community Respiratory Health Survey (ECRHS) framework, as dichotomous definitions could be less appropriate in the study of chronic diseases. The aims of this study were to assess the value of this asthma score in comparison with other definitions of asthma in another population setting, using as criteria bronchial hyperresponsiveness (BHR) to methacholine and diagnosed asthma, and the association of these definitions to known risk factors of asthma. METHODS: We used the ECRHS questionnaire on 2063 Brazilians, aged 23-25 years, and measured their BHR. We assessed the positive and negative likelihood ratios (PLR and NLR) of the asthma score (0-8), a three question score (ECRHS definition) and single asthma symptoms in relation to BHR and diagnosed asthma. RESULTS: The PLR were relatively low for all asthma definitions with odd ratios varying from 1.47 for asthma score to 5.50 for wheeze and waking with breathlessness without a cold. The NLR were near 1. The PLR were lower for assessments using the score than for dichotomous assessments or the ECRHS definition. The PLR increased with asthma scores, but the prevalence with higher scores was too low for useful analysis. The asthma score was slightly better for identifying associations from a set of known risk factors than the other two approaches. CONCLUSION: Our study provided little support for a greater validity of this asthma score over other asthma definitions, and only marginal advantage for identifying risk factors.
Assuntos
Asma/diagnóstico , Asma/epidemiologia , Inquéritos Epidemiológicos , Cloreto de Metacolina , Índice de Gravidade de Doença , Adulto , Asma/classificação , Brasil/epidemiologia , Hiper-Reatividade Brônquica/diagnóstico , Hiper-Reatividade Brônquica/epidemiologia , Estudos de Coortes , Estudos Transversais , Dispneia/diagnóstico , Feminino , Volume Expiratório Forçado , Humanos , Masculino , Cloreto de Metacolina/efeitos adversos , Prevalência , Sons Respiratórios/diagnóstico , Fatores de Risco , Testes Cutâneos , Inquéritos e QuestionáriosRESUMO
OBJECTIVE: To assess the prevalence of asthma symptoms and their association with sensitisation to eight allergens and bronchial hyperresponsiveness (BHR) to methacholine. SETTING: A random sample of 1232 adults, aged 22 to 28 years, studied in a Chilean semi-rural area. DESIGN: A cross-sectional design for the purpose of this analysis. RESULTS: The prevalence of wheeze was 27.4% (95%CI 24.9-29.9) and waking with breathlessness 13.7% (95%CI 11.8-15.6), higher than the results of a multi-centre European study. Only 7.8% (95%CI 6.3-9.3) had a positive BHR (< or =8 mg/ml) and 26.3% (95%CI 23.8-28.8) were atopic. The Youden index of asthma symptoms in non-atopic subjects varied from 0.184 to 0.259 when using BHR as gold standard for asthma, and increased from 0.379 to 0.504 among those with positive atopy. Only 4.5% reported asthma, and the Youden index was slightly higher in comparison to the asthma symptom groups. CONCLUSION: The prevalence of asthma symptoms in young adults was high, but only a small proportion of these were sensitised or had a positive BHR. We believe that aetiological studies of asthma should analyse subjects with asthma symptoms separately from those with positive atopic status or positive BHR.
Assuntos
Asma/epidemiologia , Hiper-Reatividade Brônquica/epidemiologia , Hipersensibilidade Imediata/epidemiologia , Adulto , Chile/epidemiologia , Estudos Transversais , Feminino , Humanos , Masculino , Prevalência , Saúde da População RuralRESUMO
STUDY OBJECTIVES: Rhinitis and asthma are considered to be synchronic or sequential forms of the same allergic syndrome. Treating the inflammation associated with allergic rhinitis influences the control of asthma. However, few studies have investigated the effect of treating perennial rhinitis on persistent asthma and vice versa. We determined the effects of inhaled or topical nasal beclomethasone dipropionate (BDP) administered separately or in combination on the control of asthma and bronchial hyperresponsiveness (BHR) in patients with the rhinitis/asthma association. DESIGN: A double-blind, parallel, three-group study. SETTING: Outpatient clinic of Pulmonary Division/Heart Institute (InCor) and the Division of General Internal Medicine, University of Sao Paulo Medical School, Sao Paulo, Brazil. PATIENTS: Seventy-four patients with mild-to-moderate asthma and allergic rhinitis (median age, 25 years). INTERVENTIONS: Patients received nasal or inhaled BDP separately or in combination for 16 weeks after a 2-week placebo run-in period. MEASUREMENTS AND RESULTS: Nasal and pulmonary symptoms, as well as pulmonary function and BHR, were compared among the three groups after 4 weeks and 16 weeks of treatment. Patients in all three groups demonstrated a progressive and significant decrease in nasal and pulmonary symptoms, which started after 4 weeks (p < 0.05) and continued through the end of treatment (p < 0.001). Clinical improvement was similar and parallel in the three groups. Asthma-related morbidity, evaluated by quantifying absence from work, emergency department visits, and nighttime awakenings, also decreased in the three groups (p < 0.05). CONCLUSIONS: Failure to consider treatment of rhinitis as essential to asthma management might impair clinical control of asthma. Furthermore, these data suggest that asthma and rhinitis in some patients can be controlled by the exclusive use of nasal medication.
Assuntos
Asma/epidemiologia , Beclometasona/uso terapêutico , Glucocorticoides/uso terapêutico , Rinite Alérgica Perene/tratamento farmacológico , Rinite Alérgica Perene/epidemiologia , Adolescente , Adulto , Beclometasona/administração & dosagem , Hiper-Reatividade Brônquica/epidemiologia , Método Duplo-Cego , Feminino , Glucocorticoides/administração & dosagem , Humanos , Masculino , Análise Multivariada , Rinite Alérgica Perene/fisiopatologiaRESUMO
El aumento de la prevalencia del asma en los últimos años y la diversidad en su presentación han generado la búsqueda de posibles explicaciones etiológicas. No existen dudas que el asma tiene una base genética y en el momento actual se hacen esfuerzos en dilucidar estos mecanismos. Sin embargo, el aumento de la prevalencia de asma en un período corto, sólo puede tener explicaciones ambientales. En este artículo se explora el potencial etiológico de una serie de factores relacionados tradicionalmente a nutrición. Esta presentación se hace fundamentalmente a través de investigación llevada a cabo en el departamento del autor de esta revisión. Se demuestra que desigualdad social, consumo de sal, resultantes de nutrición uterina, antioxidantes y obesidad tienen un impacto sobre la función pulmonar o los síntomas de asma. Otros autores han explorado otros factores y han sugerido que la falta de alimentación materna y los tipos de consumo de grasa también pueden tener un efecto protector en la etiología del asma. Considerando los múltiples factores que aparecen estar relacionados al asma, la comprobación de estos hallazgos y la magnitud de las asociaciones que se encuentren serán determinantes en descartar o confirmar el papel de estos factores en la etiología de esta enfermedad