Definitions and classification of work-related asthma

The workplace can trigger or induce asthma and cause the onset of different types of work-related asthma (WRA). Based on current knowledge of clinical features, pathophysiologic mechanisms, and evidence supporting a causal relationship, the following conditions should be distinguished in the spectrum of WRA: (1) immunologic occupational asthma (OA), (2) nonimmunologic OA, (3) work-exacerbated asthma, and (4) variant syndromes, including eosinophilic bronchitis, potroom asthma, and asthmalike disorders caused by organic dusts. The rationale, issues, and controversies relating to this approach are critically reviewed to stimulate the development of a consensus on operational definitions of the various phenotypes of WRA.     

The Association of Lung Function,Bronchial Hyperresponsiveness,and Exhaled Nitric Oxide Differs Between Atopic and Non-atopic Asthma in Children

Purpose

Although many previous studies have attempted to identify differences between atopic asthma (AA) and non-atopic asthma (NAA), they have mainly focused on the difference of each variable of lung function and airway inflammation. The aim of this study was to evaluate relationships between lung function, bronchial hyperresponsiveness (BHR), and the exhaled nitric oxide (eNO) levels in children with AA and NAA.

Methods

One hundred and thirty six asthmatic children aged 5-15 years and 40 normal controls were recruited. Asthma cases were classified as AA (n=100) or NAA (n=36) from skin prick test results. Lung function, BHR to methacholine and adenosine-5''-monophosphate (AMP), eNO, blood eosinophils, and serum total IgE were measured.

Results

The AA and NAA cases shared common features including a reduced small airway function and increased BHR to methacholine. However, children with AA showed higher BHR to AMP and eNO levels than those with NAA. When the relationships among these variables in the AA and NAA cases were evaluated, the AA group showed significant relationships between lung function, BHR to AMP or methacholine and eNO levels. However, the children in the NAA group showed an association between small airway function and BHR to methacholine only.

Conclusions

These findings suggest that the pathogenesis of NAA may differ from that of AA during childhood in terms of the relationship between lung function, airway inflammation and BHR.     

Infancy predictors of preschool and post‐kindergarten executive function

Little is known about factors that promote optimal development of executive function (EF) skills. The focus of this study was associations among early maternal behaviors, infant frontal brain electrical activity, and child EF at age 4 and following kindergarten. Infant frontal electroencephalogram was collected from 56 infants at 10 months of age and maternal positive affect was observed. Children completed EF measures in the research laboratory at age 4; parental‐reported EF was obtained following children's kindergarten year. Maternal positive affect and infant frontal brain electrical activity measured when the children were 10 months jointly and uniquely predicted both preschool and post‐kindergarten EF. Findings suggest parenting behavior and brain development in infancy are precursors of later self‐regulatory EF abilities. © 2012 Wiley Periodicals, Inc. Dev Psychobiol 55: 530–538, 2013     

Long-term effects of a peer-led asthma self-management program on asthma outcomes in adolescent peer leaders

ObjectiveTo examine the long-term effects of a peer-led asthma self-management program on urban adolescent peer leaders with asthma.MethodsThis longitudinal study includes 51 adolescents (16?20 years) enrolled in an asthma self-management program implemented at a one-day camp as peer leaders. Study outcomes, including quality of life, asthma control, asthma knowledge, and attitudes toward asthma were collected for 15 months post-intervention. Mixed-effects models were conducted to estimate time effects, and effect sizes were calculated for each model.ResultsOf 51 enrolled, 41 completed the training, of which 35 successfully participated in the camp program. A total of 17 peer leaders withdrew between enrollment and 15-months follow-up. Quality of life, asthma control, and knowledge significantly improved after peer leader training and remained elevated for 15 months, while significant improvement in attitudes emerged immediately after camp, in which they served as leaders, and sustained for 15 months.ConclusionThis study demonstrates the long-term positive effects of a peer-led program on a wide range of asthma outcomes in urban adolescent peer leaders.Practice ImplicationsA peer-led approach to asthma education providing peer leaders with intense training and leadership experience can be effective and sustainable in improving asthma outcomes among urban adolescents.     

Effect of one hour of passive cigarette smoking on lung function and airway responsiveness in adults and children with asthma

Summary We exposed 18 adults with bronchial asthma, 16 healthy controls and 11 children with asthma for 1 h either to ambient air (AA) or to environmental tobacco smoke (ETS). Exposure was performed at rest in an exposure chamber. Before and after exposure symptom scores and lung function were determined. After exposure bronchoprovocation tests with methacholine (adults) or histamine (children) were performed to determine the concentrations causing a 100% increase in SRaw (PC₁₀₀SRaw), and a 20% fall in FEV₁ (PC_2OFEV₁). In adult asthmatics mean (SD) SRaw before and after Sham was 8.8 (3.6) and 8.4 (3.6) cmH₂O · s, and mean FEV₁ (SD) was 3.18 (0.97) and 3.14 (0.9) 1, respectively. Before and after passive smoking mean SRaw (SD) was 7.5 (3.0) and 7.2 (2.7) cmH₂O · s, and mean FEV₁ (SD) was 3.31 (1.0) and 3.21 (0.88) 1, respectively. Geometric mean (SD) PC₁₀₀SRaw and PC_2OFEV₁ after Sham were 0.38 (4.5) and 0.29 (4.1) mg/ml, after passive smoking 0.39 (5.1) and 0.36 (4.7) mg/ ml, respectively. In healthy controls there was no consistent effect on the respective parameters during exposure. In children mean (SD) SRaw before and after Sham was 8.7 (3.6) and 9.0 (3.2) cmH₂O · s, and mean FEV₁ (SD) was 1.97 (0.32) and 1.98 (0.40) 1, respectively. Before and after passive smoking mean SRaw (SD) was 10.4 (5.3) and 9.4 (3.3) cmH₂O · s, and mean FEV₁ (SD) was 1.95 (0.37) and 1.94 (0.35) 1, respectively. Geometric mean (SD) PC₁₀₀SRaw and PC₂₀FEV₁ after Sham were 1.39 (3.0) and 0.70 (2.7) mg/ml, and after passive smoking 1.65 (2.5) and 0.96 (2.3) mg/ml, respectively. There were no significant differences in lung function and airway responsiveness between exposure to ambient air or ETS. The main symptoms during passive smoking were eye and nasopharyngeal irritation. Our observations suggest that in children and adults with mild to moderate bronchial asthma, 1 h of passive cigarette smoking does not cause airway obstruction or con sistent changes in bronchial responsiveness.Abbreviations AA ambient air (Sham) - ETS environmental tobacco smoke - SRaw specific airway resistance - FEV₁a one-second forced expiratory volume - PC₂₀FEV₁a provocative concentrations of histamine/methacholine to decrease FEV₁ by 20% - PC₁₀₀SRaw provocative concentrations of histamine/methacholine to increase SRaw by 100% Supported by Forschungsrat Rauchen und Gesundheit, Hamburg, Federal Republic of Germany     

Serum eosinophil cationic protein in relation to bronchial asthma in a young Swedish population

How are the serum concentration of eosinophil cationic protein (S-ECP) and the blood eosinophil count (B-Eos) related to symptoms of asthma, allergy, and bronchial hyperresponsiveness (BHR)? We measured S-ECP, B-Eos, and total and specific IgE in serum in blood samples from 699 randomly selected persons 20–44 years old. They also underwent a structured interview, spirometry, a methacholine provocation test, and skin prick tests as part of the European Community Respiratory Health Survey. B-Eos and S-ECP were found to be closely related to asthma symptom score (P < 0.001), total IgE (P < 0.001), and BHR (P < 0.001). On the basis of the results, the subjects were divided into four groups: healthy controls, patients with allergic rhinitis, patients with nonallergic asthma, and patients with allergic asthma. There were significant differences in both B-Eos and S-ECP among the groups (P < 0.001), the highest values being found in the allergic asthma group. B-Eos and S-ECP each had an additive value in predicting the occurrence of asthma. Among persons with high concentrations of both variables, asthma was eight times more common than in those with low concentrations. Allergy and BHR were also found to be independently related to B-Eos and S-ECP levels. Furthermore, both B-Eos and S-ECP showed good correlation to subjective and objective measures of asthma activity. We conclude that both B-Eos and S-ECP and their interrelationship may be of value in assessing the activity of asthma. However, their role in disease management was not established in this cross-sectional study.     

Family patterns of asthma, atopy and airway hyperresponsiveness: an epidemiological study

BACKGROUND: The patterns of inheritance of asthma have largely been explored using data of symptom history collected by questionnaires which are subject to bias and which may therefore distort the measured relationship. OBJECTIVE: The purpose of this study was to examine family patterns of allergic disease using objective measurements of atopy and of airway hyperresponsiveness (AHR). METHODS: A large random sample of children aged 8-11 years was studied and 3 months later, their parents were also invited for study. Of the sample of 1655 children, both parents of 661 children were studied. In all subjects, respiratory illness history was measured by questionnaire, atopy by skin tests and AHR by responsiveness to histamine. RESULTS: The odds ratio for a child to have AHR if either parent had the same condition was approximately 2. 0, which was the same as the odds ratio for wheeze or diagnosed asthma in the presence of the same condition in either parent. The odds ratio for atopy was smaller (approximately 1.4, NS) but the risk of a nonatopic child having AHR if the parent had AHR was 3.0 (P = 0.01). The correlation between weal size in the child and parent was poor and the severity of AHR in the child was only modestly correlated with the severity of AHR in the parent (R = 0.51, P = 0.04). CONCLUSION: The use of objective measurements did not strengthen the association between atopic or asthmatic conditions in the parent and child, but did suggest that atopy and AHR are inherited independently.     

Diagnosis and management of early asthma in preschool-aged children

Asthma is a common disease in young children and is associated with significant morbidity and an increasing prevalence over time. Early childhood wheezing and asthma are heterogeneous disorders; thus identifying phenotypes of asthma remains a goal to identify high-risk children who might benefit from specific therapies or secondary prevention interventions. The typical pattern of illness in preschool-aged children consists of short but recurrent exacerbations of cough and wheeze usually triggered by viral respiratory tract infections. Documenting reversible airflow obstruction on lung function, allergen sensitization, increased IgE levels, or blood eosinophilia is helpful in establishing a diagnosis of asthma in preschool-aged children, if present; however, the diagnosis is most often based on symptom patterns, presence of risk factors, and therapeutic responses. The preschool-aged asthmatic population tends to be characterized as exacerbation prone with relatively limited impairment, unlike older children and adolescents who have more impairment-dominant disease. However, management of persistent disease is based largely on expert opinion and extrapolation from studies in older children given the relative lack of data in this age group. Strategies used to manage intermittent disease include daily and intermittent controller therapy. Management strategies for persistent asthma include daily inhaled corticosteroids, daily leukotriene receptor antagonists, and combination therapies. Finally, regular monitoring of symptom control and medication side effects is important along with titrating controllers to the minimally effective dose.     

豚鼠实验性支气管哮喘时支气管肺泡灌洗液及血浆中IL-8水平的检测

目的:探讨IL-8在哮喘气道炎症中的作用。方法:将20只豚鼠随机分为2组:①哮喘组(n=10):用卵蛋白雾化诱导哮喘模型;②正常对照组(n=10)。用酶联免疫吸附试验(ELISA)测血浆和支气管肺泡灌洗液(BALF)中IL-8水平,用呼吸生理学方法观察豚鼠气道反应性。结果:①哮喘组BALF中IL-8水平显著高于正常对照组(P<0.01);②哮喘组PC₂₀值显著低于正常对照组(P<0.01);③BALF中IL-8水平与中性粒细胞的百分比和嗜酸性粒细胞的百分比均呈显著正相关(r=0.65、0.68,P<0.01),与PC₂₀值呈显著负相关(r=-0.48,P<0.01)。结论:实验性哮喘时IL-8水平增高,后者可能参与气道炎症及气道高反应性过程。     

Absence of relationship between tuberculin reactivity and asthmatic symptoms, level of FEV1 and bronchial hyperresponsiveness in BCG vaccinated young adults

BACKGROUND: Some recent studies have suggested that bacillus Calmette-Guérin (BCG) vaccination or mycobacterial infection early in life is inversely related to asthma. We wondered if an increase in tuberculin reactivity was inversely related to commonly used indices of asthma in a population of young adults who were BCG vaccinated at age 14. METHODS: Men and women aged 20-44 years, randomly selected from the general population, were tuberculin tested with the epinephrine-Pirquet method with Norwegian-produced synthetic medium tuberculin (n = 588). In addition they were interviewed using eight questions on asthma symptoms and medication. Lung function and bronchial responsiveness were also tested. RESULTS: Altogether 95% of those studied had been BCG vaccinated at age 14 (n = 558). In the 386 subjects with complete examinations, there was no relationship between a positive tuberculin reaction (> or = 4 mm) and asthma symptoms or use of asthma medication. Furthermore we did not observe any relationship between a positive tuberculin reaction and the level of forced expiratory volume (FEV1) or a positive bronchial responsiveness test, assessed as the percent of predicted of FEV1 and PD20 < 2 mg methacholine, respectively. In multiple logistic regression analyses neither respiratory symptoms, level of FEV1, nor bronchial hyperresponsiveness were related to tuberculin reactivity after adjustment for age, gender and smoking habits. CONCLUSIONS: In this young adult population who were BCG vaccinated at the age of 14 no significant relationship existed between tuberculin reactivity and asthmatic symptoms, level of FEV1 or bronchial hyperresponsiveness. Our data does not support the hypothesis that BCG immunization is beneficial in reducing asthmatic symptoms and disease in young adults.     

Prevalence of childhood asthma based on questionnaires and methacholine bronchial provocation test in Korea

Background In most epidemiological survey studies, only subjective symptoms and past medical history of asthma have been used as diagnostic criteria. Even though a questionnaire survey can be performed in a large population study at low cost, limitations such as lack of objectivity and poor predictability in non-specific bronchial hyperresponsiveness cannot be avoided. Objectives The purpose of this study was to elucidate the prevalence of current asthma based on questionnaires and methacholine bronchial provocation test, and the prevalence of atopy in Korea. Methods We performed modified ATS respiratory questionnaires and allergen skin-prick test with 10 common inhalant allergens among 3219 subjects aged 7–19 years in Seoul and a rural part of a small city, Chungju in Korea. Methacholine bronchial provocation tests were also performed among those who had asthma symptoms according to the questionnaire. The criteria of asthma was presence of both asthma symptoms and non-specific bronchial hyperresponsiveness. Atopy was defined as when an allergen induced weal size is same or larger than that caused by histamine. Results The prevalence of asthma based on questionnaires and methacholine bronchial provocation tests was 4.6%, while the prevalence of wheeze was 8.2% and 19.3% of total population complained of one or more respiratory symptoms related to asthma on the questionnaires. There was no significant difference according to age, sex and living area. The mean prevalence of atopy was 35.0% and the most common allergens were Dermatophagoides farinae (30.9%), Dermatophagoides pteronyssinus (27.5%), cat fur (20.4%) and cockroach (11.8%). The atopy prevalence in Chungju area was higher than that in Seoul and males showed a higher prevalence than females. The asthma prevalence was higher among atopies (6.8%) than among non-atopies (2.7%). None of questionnaire items were enough to predict the presence of bronchial hyperresponsiveness in terms of sensitivity, specificity and positive predictive value. Conclusion The prevalence rate of current asthma in Korea was 4.6% and the prevalence rate of atopy in Korea was 35.0%. Questionnaire-based surveys are not enough to predict the actual prevalence of asthma.     

Interactions between breast-feeding, specific parental atopy, and sex on development of asthma and atopy

BACKGROUND: The influence of breast-feeding on the risk of developing atopy and asthma remains controversial. OBJECTIVE: To examine asthma and atopy outcomes by sex, reported specific parental history of atopy, and breast-feeding. METHODS: In a birth cohort, we examined childhood asthma and atopy (positive skin prick tests) by sex and breast-feeding in relation to maternal and paternal atopy. Interactions were explored in logistic regression models. RESULTS: For boys, breast-feeding (odds ratio [OR], 1.63; 95% CI, 0.93-2.87; P = .09) and maternal atopy (OR, 1.95; 95% CI, 0.93-4.08; P = .08) were each associated with atopy at age 13 years. Breast-feeding increased the risk for atopy among boys with paternal atopy (OR, 7.39; 95% CI, 2.21-24.66) compared with non-breast-fed boys with paternal atopy, but did not significantly further increase risk among subjects with maternal atopy. For girls, breast-feeding (OR, 0.74; 95% CI, 0.41-1.31) and maternal and paternal atopy were not independent risk factors for atopy at age 13 years. However, breast-feeding increased the risk for atopy in girls with maternal atopy (OR, 3.13; 95% CI, 1.20-8.14) compared with non-breast-fed girls with maternal atopy. There was no such effect among subjects with paternal atopy. Results for the outcome of asthma followed a similar pattern. CONCLUSION: The influence of breast-feeding on development of atopy and asthma differs by sex and by maternal and paternal atopy, and is most significant among subjects at lower baseline risk. CLINICAL IMPLICATIONS: Analyses of environmental risk factors for asthma and atopy should be stratified by specific parental atopy and sex.