Relationship Among Pulmonary Function, Bronchial Hyperresponsiveness, and Atopy in Children with Clinically Stable Asthma

Pulmonary function testing plays a key role in the diagnosis and management of asthma in children. However, the literature does not clearly show whether children with clinically stable asthma have significantly reduced lung function when compared with normal children. We compared the lung function of 242 clinically stable asthmatic children who were initially diagnosed with mild intermittent or mild persistent asthma with the lung function of 100 nonasthmatic controls. The lung function was assessed using FEV₁, FEV₁/FVC, FEF_25–75 and PEF. In addition, we measured bronchial hyperresponsiveness (BHR) using the provocation concentration of methacholine needed to produce a 20% fall in FEV₁. All measures of pulmonary function were significantly decreased in the children with asthma. Pulmonary function was not influenced by atopy, serum IgE, or total eosinophil count (TEC). However, the likelihood ratio for trends revealed a significant association between our pulmonary parameters and the degree of BHR. Children with mild-to-severe BHR had greatly decreased lung function compared with those with normal BHR, the control group. In addition, a direct correlation was found between PC₂₀ and our pulmonary parameters in asthmatic children. However, only atopic children with asthma had a significant correlation between PC₂₀ and TEC. We found children with clinically stable asthma to have pulmonary obstruction, which associated strongly with their degree of BHR.     

Relationships Among Respiratory Infections, Triggers of Attacks, and Asthma Severity in Children

The present study of asthmatic children examined relationships among the frequencies of prior respiratory infections (i.e., those prior to the development of asthma) and recent (past year) respiratory infections, asthma severity, and the impacts of 12 common asthma triggers: air pollution, allergy problems, anger, cigarette smoke, excitement, high humidity, high or low environmental temperature, laughter, nighttime hours, physical activity, respiratory infection, and stress or worry. Data on these variables were obtained through a survey in which 325 families completed questionnaires; 121 families had asthmatic children who were 2-20 years of age. Pearson correlational analyses revealed many significant positive correlations: The frequencies of prior and recent infections were correlated. The frequency of prior infections was correlated with the impacts of all asthma triggers except allergy problems, but the frequency of recent infections was correlated only with the impacts of air pollution, cigarette smoke, respiratory infection, and nighttime hours as triggers of asthma attacks. Asthma severity was correlated with the frequencies of prior and recent respiratory infections and with the impact of respiratory infection as an asthma trigger.     

Long-Term Effects of Breastfeeding,Maternal Smoking During Pregnancy,and Recurrent Lower Respiratory Tract Infections on Asthma in Children

The effect of breastfeeding on asthma is controversial, which may be explained by related and interacting early childhood risk factors. We assessed the joint effects of a risk-triad consisting of maternal smoking during pregnancy, breastfeeding for less than 3 months, and recurrent lower respiratory tract infections (RLRTI) on physician-diagnosed childhood asthma. The association was assessed in the Isle of Wight birth cohort study (1989–1990) using a repeated measurement approach with data collection at birth, and at ages 1, 2, 4, and 10 years. The population consists of 1,456 children recruited between January 1989 and February 1990. Prenatal smoking, breastfeeding for less than 3 months, and recurrent lower respiratory infections (RLRTI) were combined into eight risk-triads. Relative risks (RR) and 95% confidence intervals were estimated with a log-linear model. The risk-triad involving RLRTI in infancy, maternal smoking during pregnancy, and breastfeeding for less than 3 months showed a stronger association with asthma at ages 4 and 10 compared to other risk-triads (RR of 5.79 for any asthma at ages 1, 2, 4, and 10; and 3.1 for asthma at ages 4 and 10). Of the three individual risk factors, RLRTI appeared to be the major driver of the combined effects in the risk-triads. The effect of RLRTI on asthma was modified by breastfeeding. Breastfeeding for ≥ 3 months also attenuated the effect of prenatal smoking on asthma in children without RLRTI. A high proportion of asthma cases in childhood can be prevented by promoting breastfeeding, by preventing smoking during pregnancy, and by avoidance of recurrent lower respiratory tract infections in early childhood.     

Atopy and Pulmonary Function Abnormalities in Children with a History of Acute Bronchiolitis

To assess the relationship between acute viral bronchiolitis and subsequent development of asthma, we studied retrospectively 97 index children, aged between 9 and 14 years, and 52 controls. The bronchiolitis group showed significantly lower values for mean expiratory flow at 50% of vital capacity (MEF₅₀), higher incidence of atopy, and were more sensitive to methacholine than were controls, even if they had not shown recurrent wheezing episodes. It is suggested that an increased incidence of atopy, bronchial hyperresponsive-ness, and reduced expiratory flows may be detectable in children with a history of acute bronchiolitis, regardless of the fact that they did not develop subsequent clinical symptoms suggestive of bronchial asthma.     

Cigarette Smoking, But Not Sensitization to Alternaria, Is Associated with Severe Asthma in Urban Patients

Hereditary susceptibility and allergen exposure have been identified as general risk factors for asthma. However, risk factors for severe asthma still remain to be identified. To further assess and quantify risk factors associated with severe asthma in adult patients apart from clinical exacerbations, 306 randomly selected subjects (mean age 40 ± 17 years, 46% males) presenting to an inner city pulmonary practice between 1995 and 1996 were retrospectively investigated. Of these, 117 patients were atopic, 112 had current asthma, and 22 asthmatics had severe asthma. Risk factors associated with atopy were family history of atopy and any domestic pet ownership (OR: 3.1, 95% CI: 1.6-6.1). Asthma was generally associated with atopy (OR: 4.2, CI: 2.4-7.4) and pet ownership (OR: 2.4, CI: 1.2-4.6). Severe asthma was strongly associated with current smoking (OR: 4.8, CI: 1.3-18.3), and lung function was negatively correlated with the amount of consumed cigarettes per day (r = -0.61, p = 0.04). However, no association with sensitization to Alternaria was found in severe asthma. Cigarette smoking is an independent risk factor associated with severe asthma in urban patients, whereas sensitization to Alternaria is of less importance in these patients.     

Burden of Wheezing Illness Among U.S. Children Reported by Parents Not to Have Asthma

We examined the 12-month prevalence of asthma and wheezing among U.S. children and compared the illness-related burden of children who wheezed with and without an asthma diagnosis. Data were obtained in a cross-sectional telephone survey that tested the performance of a health interview designed to identify children with chronic health conditions. Respondents were 712 primary caretakers of 1388 children under 18 years old in a national probability sample selected by random-digit dialing. Although 51 children identified with asthma and wheezing had more episodes, sleep disturbances, and attacks that limited speech, and received more medical treatment for wheezing than 69 children with wheezing alone, the “undiagnosed” children appeared to be only somewhat less affected by their wheezing. Repeat episodes and burden experienced by children with wheezing alone suggest that the asthma prevalence may be underestimated if based only on the diagnostic label.     

Respiratory symptoms,asthma, atopy and Chlamydia pneumoniae IgG antibodies in a general population sample of young adults

Background: This study was designed to test the association of Chlamydia pneumoniae infection with respiratory symptoms and atopy. Methods: A general population sample of 369 young adults (aged 20-44 years) completed a questionnaire on respiratory symptoms and underwent skin prick testing. C pneumoniae IgG and IgM serum titers were measured by micro-immunofluorescence. Prior infection was defined by titers of IgG ≥ 1:32, acute infection by titers of IgG ≥ :512 and/or IgM ≥ 1:16. Results: The prevalence of cough and phlegm was higher in subjects with (19.0%) than in those without (11.4%) prior C. pneumoniae infection (p = 0.01). A similar difference was found for wheezing (14.3% vs 8.0%; p = 0.05), whereas the percentage of asthmatics was equally distributed between seropositive and seronegative subjects. IgG titers ≥ 1:128 were found more frequently in atopic subjects (p = 0.04). After adjusting for any confounding factors, cough and phlegm (but not wheezing) were found significantly associated with C. pneumoniae positivity, both for 1 : 32 (OR 1.80; 95% CI: 1.01-3.36; p = 0.05) and for 1 : 128 titers (OR 2.31; 95% CI: 1.20-4.42; p = 0.01). A significant association was also found for atopy, for titers ≥ 1 : 128 (OR 1.73; 95% CI: 1.01-3.20, p = 0.05). Acute infection was not associated with respiratory symptoms or asthma. Conclusion: We conclude that C. pneumoniae infection is associated with cough and phlegm and may have a role in the pathogenesis of chronic respiratory diseases. Moreover, our results indicate a relationship between atopy and C. pneumoniae infection. Received: October 9, 2001 · Revision accepted: March 3, 2002     

Age and the Impacts of Triggers in Childhood Asthma

This study examined the relationships among age (2-20 years) and the impacts of 12 common triggers in episodes of childhood asthma. The triggers were: air pollution, allergy problems, cigarette smoke, stress or worry, anger, excitement, laughter, high/low environmental temperature, high humidity, respiratory infection, nighttime hours, and physical activity. Data were analyzed from families with asthmatic children (n = 119) as part of a larger study of biological and psychosocial factors in asthma and other illnesses. Positive correlations were found for age and the trigger impacts of allergy problems (p = 0.025) and physical activity (p = 0.004); negative correlations were found for age and the trigger impacts of nighttime hours (p = 0.002) and respiratory infection (p = 0.002). Age was also negatively correlated with the frequency of recent respiratory infections (p = 0.000) and positively correlated with the intensity of hay fever episodes (p = 0.047). These findings indicate that as children with asthma get older, their asthma episodes are more likely to be influenced by allergy problems and physical activity, and less likely to be associated with nighttime hours and respiratory infections.     

Inhalant Allergens as Risk Factors for the Development and Severity of Mild-to-Moderate Asthma in Hong Kong Chinese Children

Sensitization to aeroallergens has been found to be a dominant risk factor for asthma in population-based studies. Similar results in asthmatic children being managed in hospital-affiliated outpatient clinic have not been established. We therefore conducted a case-control study on asthmatic children attending a university hospital-based outpatient clinic to investigate the pattern of aeroallergen sensitization, and to assess the correlation between asthma control and the presence of allergen-specific IgEs. Asthmatic patients underwent a questionnaire assessment of their asthma control, skin prick tests (SPT) for allergen sensitization, and spirometric evaluation. Peripheral blood was collected from all subjects for in vitro serum specific IgE assay (RAST) to common aeroallergens. One hundred and seventy asthmatics (aged 9.8 ± 3.7 years) and 57 age-matched control subjects were enrolled. Our patients had a median of two asthmatic attacks within 6 months prior to evaluation, and their median Disease Severity Score was 13. The median FEV₁ in our asthmatic children was 98%, whereas serum logarithmic total IgE concentrations in patients and controls were 2.57 and 2.09, respectively (p<0.0001). More than 85 % of our asthmatic children were sensitized to house-dust mite (HDM), and sensitization to HDM and cat, as well as elevated serum total IgE concentration, was a significant risk factor for the development of asthma in this cohort. Several objective measures of asthma severity, as well as FEV₁, correlated significantly with sensitization to HDM, pets, and cockroaches. In conclusion, indoor aeroallergens are one of the risk factors for the development and severity of mild-to-moderate asthma in Chinese children in Hong Kong.     

Hypnosis and Asthma: A Critical Review

Asthma is among the most common chrome diseases of the western world and has significant effects on patients' health and quality of life. Asthma is typically treated with pharmaceutical products, but there is interest in finding nonphar-maceutical therapies for this condition. Hypnosis has been used clinically to treat a variety of disorders that are refractive to pharmaceutical-based therapies, including asthma, but relatively little attention has been given recently to the use of clinical hypnosis as a standard treatment for asthma. Significant data suggest that hypnosis may be an effective treatment for asthma, but it is premature to conclude that hypnosis is unequivocally effective. Studies conducted to date have consistently demonstrated an effect of hypnosis with asthma. More and larger randomized, controlled studies are needed. Existing data suggest that hypnosis efficacy is enhanced in subjects who are susceptible to the treatment modality, with experienced investigators, when administered over several sessions, and when reinforced by patient autohypnosis. Children in particular appear to respond well to hypnosis as a tool for improving asthma symptoms.     

Bronchial Hyperresponsiveness in Farmers: Relation to Respiratory Symptoms, Lung Function, and Atopy

There is only limited information on the factors associated with nonspecific bronchial hyperresponsiveness (BHR) in farmers. Our purpose was to examine the relationship between BHR and respiratory symptoms, atopy, and abnormalities of lung function in a sample of French farmers. Farmers scheduled for a preventive medicine check-up in northeastern France were examined. Occupational exposure, respiratory symptoms, and work-related symptoms were assessed by questionnaire, sensitization to 34 common and agricultural allergens by skin prick tests, and BHR by the single-dose (1,200 μg) acetylcholine (ACh) challenge test. Data were obtained from 741 farmers (95% of those invited). Seventy-seven subjects (10.3%) had BHR defined as a fall in forced expiratory volume in 1 s (FEV₁) ≥ 10% after the inhalation of ACh or, for those with a poor lung function, an increase in FEV₁ > 10% and > 200 ml after the inhalation of 200 μg of salbutamol. The proportion of asthmalike symptoms, especially wheeze during work, positive skin tests to acarian (storage mites) and cereal dust allergens, and low levels of lung function was significantly greater among reactors than among nonreactors. Stepwise logistic regression analysis showed a significant and independent association between BHR and wheezing during work (OR = 4.99; 95% CI = 2.29–10.89; p= 0.0001) and baseline FEV₁ (OR = 1.49; 95% CI = 1.05–2.20; p= 0.026). In conclusion, hyperreactive farmers had significantly more asthmalike symptoms, positive skin tests, and abnormal lung function than normoreactive farmers. Work-related wheeze and low baseline FEV₁ were significantly and independently associated with BHR. Accepted for publication: 26 January 1999     

A Review of Asthma and Scuba Diving

An increasing number of asthmatics participate in recreational scuba diving. This activity presents unique physical and physiological challenges to the respiratory system. This review addresses the susceptibility of divers with asthma to diving accidents, acute asthmatic attacks, and long-term exacerbation of their disease. Recommendations on fitness to dive with asthma and airway hyperresponsiveness are provided.     

运动诱发气道痉挛与特应质的关系

目的 调查运动诱发气道痉挛( EIB)和特应质之间的关系.方法 采取整群抽样的方法选取北京市城区和郊区各1所中学学生,利用运动筛查试验的方法调查EIB的发生率,通过血清总IgE水平和皮肤过敏原点刺结果判断特应质,根据支气管激发试验判断气道高反应性.将发生EIB的学生(EIB组)与正常学生(对照组)进行配对分析,均接受皮肤过敏原点刺、血清总IgE水平测定和支气管激发试验,利用相关分析方法判断EIB和特应质的关系,分析EIB学生气道高反应的发生情况.结果 共773名10～13岁学生(男389名,女384名)参加研究,其中89名学生(EIB组,男43名、女46名)运动筛查试验阳性,EIB发生率为11.5％ (89/773);EIB组89名学生中,16人血清总IgE水平和皮肤过敏原点刺结果超过正常上限,对照组70名学生中,10人血清总IgE水平和皮肤过敏原点刺结果超过正常上限.通过x2检验发现,特应质与EIB之间无明显相关;50名接受支气管激发试验的EIB组学生中,只有1名呈阳性结果.结论 特应质与EIB发病无明显相关.绝大多数EIB学生不存在气道高反应.     

Effects of Early Intervention with Inhaled Sodium Cromoglycate in Childhood Asthma

International and Japanese guidelines classify childhood asthma as mild, moderate, or severe, and recommend treatment with “as needed” bronchodilators, inhaled sodium cromoglycate, and inhaled corticosteroids, respectively. Alternatively, some investigators proposed inhaled corticosteroids as first-line therapy to prevent airway inflammatory obstruction. This article describes a clinical study assessing the effect of early intervention with inhaled sodium cromoglycate in childhood asthma. This was a retrospective study of 189 asthmatic children treated with inhaled sodium cromoglycate for five years and whose age of onset of asthma was six year of age or younger. An end-of-study questionnaire completed the examination. Children administered oral or inhaled corticosteroids simultaneously with sodium cromoglycate, were excluded. Asthma scores as defined by the Japanese Pediatric Allergic Committee, were reduced continuously during the five years after the start of sodium cromoglycate treatment. The frequency of emergency department visits and hospitalizations also decreased. Significant between-period intervention differences showed improvement of clinical outcomes for children with severe asthma during the five years of sodium cromoglycate inhalation. The early intervention regime of starting sodium cromoglycate inhalation within two years of the onset of asthma shows a large improvement in the long-term prognosis of childhood asthma, especially for children with severe asthma. It is possible that starting inhaled sodium cromoglycate earlier than the present recommendation of corticosteroids could further improve clinical outcomes, but a prospective study should be performed to verify our results.     

Respiratory Muscle Overloading and Dyspnoea During Bronchoconstriction in Asthma: Protective Effects of Fenoterol

Whether, and to what extent, β₂-agonists protect against respiratory muscle overloading and breathlessness during bronchoconstriction remains to be defined in patients with asthma. In a double blind placebo-controlled study, 100 μg of fenoterol were administered to six stable asthmatics before a bronchial provocation test, performed by inhaling doubling concentrations of histamine from a Devilbiss 646 nebulizer. We recorded breathing pattern (tidal volume V_T, inspiratory time T_I, total time of the respiratory cycle T_TOT), inspiratory capacity (IC), dynamic pleural pressure swing (P_plsw), total lung resistance (R_L) and FEV₁. V_Twas expressed both in actual values and as % of IC. Changes in V_T(%IC) during histamine inhalation reflected changes in dynamic end-inspiratory lung volume (EILV). P_plswwas expressed as % of maximal (the most negative in sign) pleural pressure, obtained under control conditions during a sniff manoeuvre (P_plsn). P_plsw(%P_plsn) is an index of inspiratory muscle effort. The test ended when the concentration of histamine which caused a decrease in FEV₁of ≥40% post-saline was reached. Dyspnoea rating was scored by a modified Borg scale. At the ultimate degree of bronchoconstriction (UDB) with histamine: (i) decrease in FEV₁was similar after placebo and fenoterol, while increase in R_Lwas lower after fenoterol (P<0.005); (ii) V_T(%IC) increased less after fenoterol (P<0.027); (iii) increases in P_plsw(%P_plsn) was lower after fenoterol (P<0.001); (iv) ΔBorg (from saline) was lower (P<0.01) after fenoterol; (v) differences in ΔBorg, from placebo to fenoterol, related to concurrent changes in V_T(%IC) (r²=0.67). In conclusion, at UDB 100 μg of fenoterol produced a beneficial effect on the degree of inspiratory muscle loading and breathlessness, an effect greater than it would be expected from measuring FEV₁alone.     

Endothelial Dysfunction in Patients with Asthma: The Role of Polymorphisms of ACE and Endothelial NOS Genes

Both atopy and asthma are claimed to be associated with a Th-2 cytokine pattern. We sought to determine the contribution of atopy and asthma to the observed Th-2/Th-1 imbalance in these conditions. Of 60 children aged 6–16 years that were included in the study, 13 were nonatopic nonasthmatic, 15 atopic nonasthmatic, 14 nonatopic asthmatic, and 18 atopic asthmatic. Atopic children had positive skin prick tests to grass pollens only. All children were studied after an asymptomatic and drug-free period of at least three months. Total IgE was measured in serum. Peripheral blood mononuclear cells were cultured and stimulated in vitro with phytohemagglutinin and interferongamma (IFN-γ) and interleukin-4 (IL-4) measured in the supernatants. Total IgE was significantly higher in atopic asthmatics compared to nonatopic asthmatics (p = 0.004), and nonatopic nonasthmatics (p = 0.001), but was not different from atopic nonasthmatics (p > 0.05). On the other hand, IL-4 was significantly elevated in atopic asthmatics and in nonatopic asthmatics compared to nonatopic nonasthmatics (p = 0.037 and p = 0.009, respectively). Although atopic asthmatics had lower IFN-γ values than nonatopic asthmatics, the difference did not reach statistical significance. No correlation was detected between any two parameters. Our results suggest that both atopy and asthma contribute to the increased levels of IL-4 and that, whereas nonatopic asthma is associated with increases in both IL-4 and IFN-γ release by mononuclear cells, only atopic asthma is characterized by a Th-2 type cytokine dominance.     

Persistent Asthma: Patient Characteristics, Courses of Asthma, and Utility of Salmeterol

Applications of National Asthma and Education and Prevention Program (NAEPP) guidelines for the diagnosis and management of asthma may reduce the morbidity of this disorder. Medical records and questionnaires from a series of 177 outer-city adolescents and adults with persistent asthma were audited according to NAEPP guidelines and for utility of salmeterol (Serevent®). Allergic sensitivity and exposure to indoor allergens house-dust mite (66% of patients), fungi (42%), cat (20%) and/or dog (14%) were of dominant importance to persistent asthma. Patients who continued salmeterol over 1 year had reduced severity of disease, improved forced expiratory flow at 25%-75% of vital capacity, and reduced usage of systemic, but not inhaled, corticosteroid.