Sensitization to individual allergens and bronchial responsiveness in the ECRHS. European Community Respiratory Health Survey.

Little is known about the relation of bronchial responsiveness (BHR) to sensitization to individual allergens, or its variation between countries. Data were obtained for BHR, specific immunoglobulin E and confounding variables from 11,215 subjects, aged 20-44 yrs at the start of the European Community Respiratory Health Survey, in 34 centres in 15 countries. The relation of BHR to sensitization to cat, house dust mite, timothy grass and Cladosporium was estimated by means of multiple regression for each centre, and combined across centres by random effects meta-analysis, controlling for baseline lung function, height, sex, season of testing, age, smoking and age/sex and age/smoking interactions. BHR was greater, on average, in those sensitized to cat (p=0.023), house dust mite (p<0.001) and timothy grass (p=0.018), but not to Cladosporium (p=0.60), and increased with degree of sensitization (p<0.001). All relations showed heterogeneity between centres, although to a lesser extent in the relation to sensitization to house dust mite. More variation in bronchial responsiveness was explained by sensitization and degree of sensitization to the individual allergens than by atopy defined as any positive test in each centre, but the relative importance of each allergen varied. The use of atopy as a single variable in relation to bronchial hyperresponsiveness may be misleading.     

Parental childhood respiratory illness and respiratory illness in their infants

Parental histories of childhood respiratory trouble (CRT) were examined as risk factors for lower respiratory tract illnesses in healthy infants enrolled in the Children's Respiratory Study, Tucson, Arizona. A parental history of childhood respiratory trouble before age 16 was a risk factor for infantile lower respiratory tract illnesses (LRIs). Early age of onset of the parental CRT and those illnesses described as asthma or bronchiolitis showed the greatest risk: odds ratio = 2.8, P < 0.05. After controlling for known and suspected confounders, a parental history of CRT described as asthma or bronchiolitis with onset before age 3 was associated with wheezing LRls in their children, with an odds ratio of 2.6, P < 0.05. A parental history of CRT described as bronchitis/croup was associated with nonwheezing LRls in their children: odds ratio = 2.2, P < 0.05. These findings suggest a familial component to childhood respiratory trouble which may have a hereditary basis. Pediatr Pulmonol. 1993; 16:275–280. © 1993 Wiley-Liss, Inc.     

Lower respiratory illness in early childhood and lung function and bronchial reactivity in adolescent males

We examined the relationship between lower respiratory illness (LRI) experience in early childhood and lung function and bronchial reactivity in 57 boys, 11 to 22 yr of age, whose histories of outpatient physician visits for wheezing and nonwheezing LRI had been documented prospectively during their first 6 yr of life. These boys were a subpopulation of 159 children whose early childhood LRI experience and spirometric performance had been studied an average of 4 yr previously. The majority of boys had been free of chronic respiratory symptoms in the 2 yr before evaluation. Boys with histories of 2 or more preschool wheezing illnesses had lower mean levels of performance for FEV1, FEF25-75, FEF50, FEF75, and FEV1/FVC than did boys who had zero or 1 preschool wheezing illness, replicating observations that had been made when the boys had been studied 4 yr previously. Boys with lower spirometric performance relative to the study population on initial testing continued to have lower relative levels of spirometric performance 4 yr later. Neither preschool wheezing nor nonwheezing illness experience was associated with the degree of methacholine sensitivity measured in adolescence. Increasing degrees of methacholine sensitivity were associated with lower levels of spirometric performance; however, preschool wheezing illness experience remained a significant correlate of spirometric performance after adjustment for level of methacholine sensitivity. We conclude that recurrent preschool wheezing illness in these adolescent boys was associated with persistently lower lung function, but not enhanced methacholine sensitivity, during the middle to late school years.     

The relationship of nonspecific bronchial responsiveness to respiratory symptoms in a random population sample

The relationship of airway responsiveness to respiratory symptom prevalence has been studied in a cross-sectional analysis of a random subpopulation from a large-scale population study on chronic obstructive pulmonary disease (COPD) being conducted in the Netherlands. In 1,905 subjects with complete data on age, sex, area of residence, smoking habits, and respiratory symptom prevalence, airway responsiveness was assessed by a histamine challenge test. Subjects with a decrease in FEV1 of greater than or equal to 10% at a histamine concentration of less than or equal to 16 mg/ml were considered to be responders. Bronchial hyperresponsiveness appeared to be age dependent, with the proportion of responders increasing from 13% in those 14 to 24 yr of age to 40% in those 55 to 64 yr of age (p less than 0.001). Respiratory symptom outcomes included chronic cough, chronic phlegm, dyspnea, bronchitic episodes, persistent wheeze, and asthmatic attacks. Respiratory symptom prevalence rates were significantly higher in responders (p less than 0.001 for all symptoms). Cigarette smoking is known to be related to respiratory symptom prevalence and possibly to bronchial responsiveness. Because of these associations, we examined the relationship of bronchial responsiveness to respiratory symptoms within cigarette smoking categories. For all respiratory symptoms, it was found that, regardless of smoking category, responders were more likely to be symptomatic than were nonresponders. Odds ratios ranged from 1.7 for chronic cough to 4.4 for asthmatic attacks.(ABSTRACT TRUNCATED AT 250 WORDS)     

The daily variability of bronchial responsiveness to methacholine

Ten mild atopic asthmatics on inhaled beta 2-agonists alone were studied in order to determine the repeatability of methacholine inhalation provocation tests at 24 h intervals over a period of 5 days. Such patients are most frequently studied in therapeutic trials of anti-asthmatic medications. There were no significant differences in results obtained on any of the days and no evidence for the development of tolerance to methacholine in this group of patients at one day intervals. The 95% confidence interval for repeatability of the results was +/- 1.05 doubling doses of methacholine, and 95% range +/- 2.36 doubling doses, comparable to the results obtained by other investigators on similar patients. Some investigators have produced more highly repeatable results but these have generally been obtained using highly selected groups of patients.     

The relationship between respiratory illness in childhood and chronic air-flow obstruction in adulthood

This review evaluates the hypothesis that lower respiratory infection in childhood is a risk factor for chronic air-flow obstruction (CAO) in adulthood. Clinical CAO appears to result from a lengthy and initially asymptomatic loss of function that correlates with the development of peripheral airways abnormalities and emphysema. The relative functional silence of the small airways, the apparent vulnerability of the child's lung to injury, and the demonstration of functional abnormalities after several types of viral respiratory infection are consistent with the proposed role of lower respiratory infection. Relevant epidemiologic studies, however, have provided conflicting results, and many are flawed by recall bias. The observed association in children between lower respiratory infection and impaired ventilatory function may be noncausal and not a direct consequence of infection. A complete test of the hypothesis would require follow-up of study subjects from birth to adulthood with monitoring of respiratory infections and pulmonary function.     

Lung function and bronchial responsiveness after Mycoplasma pneumoniae infection in early childhood

Mycoplasma (M.) pneumoniae has been associated with exacerbation of symptoms in asthmatic school children and adults; and an etiological role in asthma has been suggested. The purpose of this study was to investigate whether infection with M. pneumoniae in early childhood has a long-term influence on lung function and bronchial responsiveness. In a retrospective, clinical cohort-study children younger than 5 years-of-age when PCR-tested for M. pneumoniae were enrolled. Sixty-five children with clinical symptoms suggesting infection with M. pneumoniae during an epidemic season completed a clinical follow-up examination including lung function testing (28 PCR-positive and 37 PCR-negative). In addition to the PCR-test for M. pneumoniae all respiratory tract specimens were additionally tested for other atypical bacteria and for viruses by PCR. Lung function was measured as specific airway resistance by whole-body plethysmography and bronchial hyperresponsiveness was assessed by cold, dry air hyperventilation. Neither baseline lung function nor bronchial response to cold dry air hyperventilation differed between M. pneumoniae-positive and -negative children: mean baseline lung function were 1.17 versus 1.21 (kPa sec), P = 0.45; and mean change in specific resistance was 13% versus 9%, P = 0.42. In conclusion, M. pneumoniae infection in early childhood was not associated with long-term effects on lung function and bronchial hyperresponsiveness 2 years after infection.     

Bronchodilator responsiveness in wheezy infants predicts continued early childhood respiratory morbidity

Objective: Spirometry including bronchodilator responsiveness is considered routine in the workup of asthma in older children. However, in wheezy infants the existence of bronchodilator responsiveness and its prognostic significance remain unclear. Methods: Infants (< 2 years) with chronic or recurrent wheezing or coughing were evaluated by infant pulmonary function testing (PFT). Maximal expiratory flow at the point of functional residual capacity (V?_maxFRC) was measured before and 20 minutes after salbutamol administration. Only infants with an obstructive profile (V?_maxFRC < 80% predicted) were included. The infants were divided into two groups with regard to whether or not a response to salbutamol was observed on PFT. A response was defined as a mean V?maxFRC after salbutamol administration exceeding the upper confidence interval limit of individual pre-bronchodilator V?_maxFRC measurements. Follow-up data was gathered after a mean of 2 years. Measurements and Main Results: Sixty infants were included in the study of which 32 (53%) demonstrated responsiveness to bronchodilators. The infants in the responsive group had a significantly higher frequency of physician visits for wheezing than the non-responders (3.0 mean visits/yr vs. 1.5 respectively, P = 0.03), and had a higher likelihood of having received asthma medication in the last year of the follow-up period (84% vs. 50% respectively, RR: 1.68[1.10–2.56]). At the end of the follow-up period, more parents in the responsive group reported continued respiratory disease (71% vs. 22%, RR:3.21[1.30–7.95]). Conclusions: Bronchodilator responsiveness can be demonstrated by infant PFT in infants with recurrent wheezing and can predict increased respiratory morbidity until 3 years of age.     

The relationship of nonspecific bronchial responsiveness to the occurrence of respiratory symptoms and decreased levels of pulmonary function. The Normative Aging Study

Nonspecific bronchial responsiveness was assessed by an abbreviated methacholine challenge test in 458 male participants of the Normative Aging Study, who also completed a respiratory questionnaire and spirometry. A positive response to the methacholine challenge test was defined as a greater than or equal to 20% decline in FEV1 during the test. Cigarette smoking was significantly associated with a positive methacholine response (p less than 0.001). Logistic regression analyses indicated that there was a significant association between a positive response to methacholine and both any wheeze (p = 0.002) and persistent wheeze (p less than 0.001) after taking into account smoking status and age; an association between responsiveness and chronic cough was of borderline significance (p = 0.06). Multiple linear regression analyses indicated that positive methacholine responsiveness was independently associated with lower levels of FEV1 (p less than 0.001) and FEF25-75 (p less than 0.001). Using the log of the dose-response slope rather than a dichotomous variable to characterize responder status yielded very similar results in the linear and logistic models. The findings of this cross-sectional study suggest that increased level of nonspecific responsiveness is significantly associated with wheeze and cough symptoms and decreased levels of pulmonary function in adult men. Longitudinal follow-up of these men should shed light on the importance of nonspecific responsiveness as a risk factor for the subsequent development of chronic obstructive pulmonary disease.     

Risk factors from childhood to adulthood for bronchial responsiveness at age 32-42 yr.

Bronchial responsiveness (BR) is an important risk factor for the development and outcome of asthma. This study assessed childhood risk factors for both the severity of BR in adulthood and either improvement or worsening of BR over time. Finally, we studied cross-sectional risk factors of BR in adulthood. Between 1966 and 1969, 119 allergic asthmatic children (5-14 yr of age) were studied. Of these, 101 (85%) subjects were reinvestigated at age 22-32 yr (visit 2), and at age 32-42 yr (visit 3). Spirometry, PC10 histamine, skin tests, blood eosinophils, and serum total IgE were measured and a questionnaire was used. Higher FEV1 values in childhood were associated with less severe BR at age 32-42 yr independent of other potential risk factors. Larger increases in FEV1 values both from visit 1 to 2 and from visit 2 to 3, a longer time interval from visit 1 to 3, and having pets in childhood were associated with less severe BR at age 32-42 yr. The same factors were found to be associated with less deterioration of BR from visit 2 to 3. In nonsmokers a higher IgE level at visit 2 was a risk factor for an increase in BR. At age 32-42 yr, a low level of lung function and the presence of asthma symptoms were associated with more severe BR, and older age and having pets were associated with less severe BR. IgE was related to more severe BR only in nonsmokers. Conclusions: A lower lung function in childhood and less improvement in FEV1 over time were associated with more severe BR in adulthood.     

Comparison of questionnaire and diary methods in acute childhood respiratory illness surveillance

We compared two prospective survey methods, an interviewer-administered questionnaire and a daily diary, used concurrently to record acute respiratory illness experience over a 2-yr period in 422 children 5 to 11 yr of age from East Boston, Massachusetts. Respondents contributed more months of data with the questionnaire than with the diary method. Respiratory symptom and illness rates, as determined for the first year by each of the methods, were compared for 277 children who had less than 4 months of missing data. Respondents from families with more children tended to report a lower total respiratory illness rate by the diary than by the questionnaire method (p = 0.006). Although upper respiratory illness rates did not differ by method, lower respiratory illnesses were reported more frequently (p = 0.0001) by questionnaire than by diary. In the group of 49 children who were identified as having had greater than one lower respiratory illness, 25% of the illnesses reported as having been lower respiratory by questionnaire were reported as having been another form of respiratory illness by diary. For this group the ratio of 3:1 of boys to girls for the diary as compared with 1.5:1 for the questionnaire suggests the presence of reporting bias and no comparability of methods. Standardization of an acute respiratory illness questionnaire would provide greater opportunity than use of diaries for synthesis of prospective data from different epidemiologic studies.     

Acute lower respiratory illness in childhood as a predictor of lung function and chronic respiratory symptoms

This study investigated the relationship of acute lower respiratory illness (LRI) to level and change in level of forced expiratory volumes in a cohort of 801 children, followed longitudinally for a maximum of 13 yr. The co-occurrence of respiratory illness before 2 yr of age and two or more LRI during a single surveillance year was associated with a 20.3% lower mean cross-sectional level of FEF25-75, and with reduced longitudinal change in level of FEF25-75. The effect of LRI on lung function was uniformly stronger for boys than for girls. Of the children with illness before 2 yr of age and two or more LRI, six of 14 were male asthmatics with mean levels of FEF25-75 that were lower than those of other asthmatic children. Pneumonia and/or hospitalization for respiratory illness prior to the onset of study were associated with lower cross-sectional levels of forced expiratory volumes at entry to the study, even when asthmatics/persistent wheezers were eliminated from the analysis (6.1% lower level of FEV1 for a nonasthmatic boy with previous hospitalization versus a nonasthmatic boy without hospitalization). In the longitudinal analysis, pneumonia and/or hospitalization were associated with slower increase in level of forced expiratory volumes, even after adjusting for "ever diagnosis of asthma/current any wheeze" (starting at the same leve, after eight years a boy with hospitalization would develop a 5.0% lower FEV1 than a boy without hospitalization). Acute LRI also was evaluated as a predictor of chronic respiratory symptoms.(ABSTRACT TRUNCATED AT 250 WORDS)     

Treating childhood respiratory illness in developing countries: mist therapy without electricity

We have developed an effective and well-accepted method of providing mist for children with acute respiratory distress. This method can be especially useful in areas of the world where resources are limited.     

The effects of osmotic challenge on bronchial responsiveness to methacholine in non-asthmatic subjects

We have measured the airway responses to methacholine on three days in sixteen non-asthmatic subjects. On the first day the methacholine challenge alone was performed. The other two days were randomized between pretreatment with distilled water or hypertonic saline administered by ultrasonic nebulizer. Distilled water and hypertonic saline did not affect baseline specific conductance (sGaw). Provocative dose producing a 35% fall in sGaw (PD35sGaw) was slightly reduced by both distilled water and hypertonic saline (15.83 to 8.55 mumol with distilled water and to 11.80 mumol with hypertonic saline). Six out of 16 subjects reached a plateau of maximal response with methacholine. The level of this plateau was not affected by pretreatment with distilled water or hypertonic saline. These results show that distilled water and 3.6% saline produced small increases in non-specific reactivity in normal subjects and confirm that substantial osmotic challenge does not change airway calibre in non-asthmatic subjects.     

合并呼吸道感染的支气管哮喘诊治

呼吸道感染与支气管哮喘有密切关系.呼吸道感染可使许多支气管哮喘患者诱发喘息,或使支气管哮喘的临床症状加重.支气管哮喘患者支气管的异常和部分平喘药物均易于引起呼吸道和肺部感染.呼吸道合胞病毒、鼻病毒等可引起喘息症状.该文讨论了呼吸道病毒感染诱发支气管哮喘的机制、临床特点和诊治方法.