Atopy May Be an Important Determinant of Subepithelial Fibrosis in Subjects with Asymptomatic Airway Hyperresponsiveness

The bronchial pathology of asymptomatic airway hyperreponsiveness (AHR) subjects is not well understood, and the role of atopy in the development of airway remodeling is unclear. The aim of this study was to evaluate whether atopy is associated with airway remodeling in asymptomatic AHR subjects. Five groups, i.e., atopic or non-atopic subjects with asymptomatic AHR, atopic or non-atopic healthy controls, and subjects with mild atopic asthma, were evaluated by bronchoscopic biopsy. By electron microscopy, mean reticular basement membrane (RBM) thicknesses were 4.3+/-1.7 micrometer, 3.4+/-1.8 micrometer, 2.5+/-1.5 micrometer, 2.6+/-1.1 micrometer, and 2.3+/-1.2 micrometer in the mild atopic asthma, atopic and non-atopic asymptomatic AHR, atopic and nonatopic control groups, respectively (p=0.002). RBM thicknesses were significantly higher in the mild atopic asthma group and in the atopic asymptomatic AHR group than in the other three groups (p=0.048). No significant difference in RBM thickness was observed between the atopic asymptomatic AHR group and the mild atopic asthma group (p>0.05), nor between non-atopic asymptomatic AHR group and the two control groups (p>0.05). By light microscopy, subepithelial layer thicknesses between the groups showed the same results. These findings suggest that RBM thickening occurs in subjects with atopic asymptomatic AHR, and that atopy plays an important role in airway remodeling.

Severe Airway Hyperresponsiveness in School-aged Boys with a High Body Mass Index

BACKGROUND: An association between obesity and asthma has been reported. The prevalence of airway hyperresponsiveness (AHR), results of skin prick tests, body mass index (BMI), and asthma symptoms were examined in schoolchildren. METHODS: The results of BMI (kg/m2) determination, skin prick testing, spirometry, asthma questionnaires, and methacholine challenge tests were obtained in a cross-sectional survey of 667 schoolchildren. The methacholine concentration causing a 20% fall in FEV1 (PC20) was used as the threshold of AHR. If the PC20 was less than 16 mg/mL, the subject was considered to have methachloine mediated AHR. RESULTS: The mean BMI was 17.1+/-0.09 kg/m2. The prevalence of AHR was 42.7%. The sensitization rate to common inhalant allergens was 30.3%. PC20 in children with BMIs >or=17.1 kg/m2 was significantly lower than that in children with BMIs 17.1 kg/m2. The mean BMIs of boys and girls were not significantly different. The levels of PC20 by sex were not different. The children were grouped by sex into percentile of BMI. PC20 in boys was lower in the obese group than in the non-weight and overweight groups (p<0.05). PC20 in boys and girls with atopy was significantly lower than in those without atopy. In a multiple logistic regression model that included all of the children and adjusted for confounding variables, independent associations with AHR were seen with BMI, asthma symptoms, and atopy . CONCLUSIONS: BMI had an association with AHR in school-age boys.

The Effect of Passive Smoking on Asthma Symptoms, Atopy, and Airway Hyperresponsiveness in Schoolchildren

Passive smoking is a major cause of respiratory morbidity, and is associated with increased bronchial responsiveness in children. To evaluate the effect of smoking by a parent on asthma symptoms, atopy, and airway hyperresponsiveness (AHR), we conducted a cross-sectional survey of 503 schoolchildren that involved questionnaires, spirometry, allergy testing, and a bronchial challenge test. If the PC20 methacholine was less than 16 mg/mL, the subject was considered to have AHR. The prevalence of a parent who smoked was 68.7%. The prevalence of AHR was 45.0%. The sensitization rate to common inhalant allergens was 32.6%. Nasal symptoms such as rhinorrhea, sneezing, nasal itching, and nasal obstruction were present in 42.7%. Asthma symptoms such as cough and wheezing were present in 55.4%. The asthma symptoms were significantly more prevalent in children who had a parent who smoked than in those whose parents did not. The nasal symptoms, atopy, and AHR did not differ according to whether a parent smoked. In a multiple logistic regression model, the asthma symptoms and atopy were independently associated with AHR, when adjusted for confounding variables. Passive smoking contributed to asthma symptoms in schoolchildren and was not an independent risk factor of airway hyperresponsiveness in an epidemiological survey.

The Validity of the ISAAC Written Questionnaire and the ISAAC Video Questionnaire (AVQ 3.0)for Predicting Asthma Associated with Bronchial Hyperreactivity in a Group of 13-14 Year Old Korean Schoolchildren

To validate the prevalence rate of symptoms of asthma produced by the phase I ISAAC (International Study of Asthma and Allergies in Childhood) study, hypertonic saline challenge test was carried out during the phase II study at a year after the phase I study. For the phase II study, six middle schools from three cities in the phase I study were selected. Finally, 499 children who responded to both studies were analyzed. All subjects were asked to complete the written questionnaire (WQ) first, followed by a video questionnaire (AVQ 3.0) during the phase I study. Of the 499 children, only 19 (3.8%) were positive to the hypertonic saline bronchial challenge test. The degree of agreement between responses to the two corresponding questions "wheezing at rest" and "nocturnal wheeze" in the AVQ 3.0 and WQ were moderate and weak with a Kappa indices of 0.45 and 0.23, respectively. The question on "severe wheeze" in the AVQ 3.0 had the highest Youden's index among the five questions related to asthma symptoms in the previous 12 months, but its specificity was low whereas it 's sensitivity was 1.0. There was no consistency of priority between the two questionnaires in predicting bronchial hyperreactivity in a group of Korean schoolchildren. Therefore we need to develop more appropriate WQ or AVQ to compare the prevalences of asthma to other countries.

Epidemiología del asma y su relación con nutrición / Asthma epidemiology and its relación with nutrition

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