Is asymptomatic bronchial hyperresponsiveness an indication of potential asthma? A two-year follow-up of young students with bronchial hyperresponsiveness

Fat mass index and airway hyperresponsiveness in Korean adults

OBJECTIVE

Airway hyperresponsiveness (AHR) is associated with asthma and obesity, which is defined as a high body mass index. Body mass mainly comprises fat mass (FM) and muscle mass (MM), which are independent of each other. We investigated the effect of changes in FM over time on the development of asymptomatic AHR in adults.

METHODS

This long-term longitudinal study included adults who were underwent health checkups at the Seoul National University Hospital Gangnam Center. The participants underwent two methacholine bronchial provocation tests with a follow-up period (between the first and second tests) of more than 3 years and bioelectrical impedance analysis (BIA) at all visits. FM index (FMI; FM normalized for height) and MM index (MMI; MM normalized for height) were calculated using BIA.

RESULTS

The study included 328 adult participants (61 women and 267 men). The mean number of BIA measurements was 6.96 and the follow-up duration was 6.69 years. In total, 13 participants showed a positive conversion of AHR. Multivariate analysis indicated that a high rate of change in FMI ([g/m²]/year), not MMI, was significantly associated with the risk of AHR development (P = 0.037) after adjustment for age, sex, smoking status, and FEV1 predicted.

CONCLUSION

A rapid gain of FM over time may be a risk factor for developing AHR in adults. Prospective studies are needed to confirm our results and evaluate the role of FM reduction in preventing AHR development in obese adults.

Perspectives and Management of Atypical Asthma in Chinese Specialists and Primary Care Practitioners-A Nationwide Questionnaire Survey

Background and objective: To evaluate the awareness/knowledge and clinical practice for the treatment of atypical asthma among respiratory specialists and primary care practitioners (PCPs) in China.

Methods: A total number of 1,997 physicians participated in the survey via WeChat. The questionnaire included six main items: physician demographic characteristics, awareness, diagnosis, medical prescription, assessment/education, and proposal.

Results: Cough variant asthma (CVA) was recognized by 97.51% of physicians (1,166 respiratory specialists and 799 PCPs), followed by chest tightness variant asthma (CTVA, 83.72%) and occult asthma (73.54%). Specialists were more likely to follow diagnostic recommendations than PCPs (P < 0.01); however, 34.15% of physicians reported the utility of bronchodilation tests, airway provocation tests, and peak expiratory flow monitoring. A total of 91.70% and 92.01% of physicians prescribed inhaled corticosteroids (ICS) or ICS plus long-acting beta-agonists (LABA) for CVA and CTVA, respectively. Physicians prescribed an ICS or ICS/LABA for 4 (2–8) or 8 (4–12) weeks for CVA and 4 (2–8) or 5 (4–12) weeks for CTVA, and the prescription durations were significantly shorter for PCPs than for specialists (P < 0.01). Further, 52.42% and 35.78% reported good control of CVA and CTVA, respectively, with significantly lower control rates for PCPs than for specialists (P < 0.01). Additionally, specialists exhibited better assessment and educational habits than PCPs.

Conclusion: While atypical asthma was identified by most specialists and PCPs, there remains a gap between management in real clinical practice and guideline recommendations, especially for PCPs. Further training of PCPs and clinical studies of atypical asthma are required to improve practice.

Bronchial challenge test in patients with a history suggestive of bronchial asthma with normal spirometric studies

Background

Bronchial hyper-responsiveness (BHR) is the hallmark of bronchial asthma, characterized by clinical features of cough, wheeze, breathlessness and chest tightness which are confirmed by spirometry showing obstructive pattern and reversibility to bronchodilators. In individuals having features of bronchial asthma but normal spirometry, demonstration of BHR with bronchial challenge test (direct or indirect) confirms/ rules out the diagnosis. The aim of this study was to assess BHR in patients (methacholine challenge) with a history suggestive of bronchial asthma but normal spirometry and its role in diagnosis of bronchial asthma.

Methods

This study was conducted at tertiary care respiratory center. Patients having clinical features of bronchial asthma but spirometry not confirming obstructive disorder and or reversibility were included in the study. After written consent, methacholine challenge test with methacholine chloride and exercise spirometry was done in all patients as per the American Thoracic Society protocol.

Results

A total of 50 (n) patients were included in the study. Among them, 42 patients had clinical features suggestive of bronchial asthma but having normal spirometry and eight patients were diagnosed as they had bronchial asthma in the past but asymptomatic and off drugs were included in the study. At PC20 4mg/ml 32 (64%) patients had a positive test, 28(66%) symptomatic patients and four (50%) asymptomatic asthmatics. There were no significant side effects with methacholine test.

Conclusion

Airway hyper-responsiveness is an important aspect of bronchial asthma and its demonstration with bronchial challenge (direct and indirect) test is an important diagnostic tool. Methacholine challenge test is a safe procedure to perform under supervision.

Methacholine bronchial provocation test for assessment of bronchial hyperresponsiveness in preschool children

Background

Bronchial hyperresponsiveness (BHR) has not been extensively performed in preschool children, possibly because of the difficulty in cooperating with the tests. We sought to determine the usefulness and safety of methacholine bronchial provocation test (MCh-BPT) for BHR assessment in preschool children.

Methods

We recruited 252 preschool children (190 healthy and 62 with wheezing) who underwent MCh-BPT at baseline. MCh-BPT was re-scheduled in case initial attempts failed. Forced expiratory volumes in 0.5 (FEV_0.5), 0.75 (FEV_0.75) and one second (FEV₁) were measured. We recorded the provocative dose causing 15% (PD₁₅) or 20% reduction (PD₂₀) in FEV_0.5, FEV_0.75 and FEV₁, thus allowing for comparison of the diagnostic value of PD₁₅ and PD₂₀.

Results

A total of 209 children [156 (82.1%) healthy, 53 (85.5%) with wheezing] successfully completed MCh-BPT. Compared with healthy children, a significantly greater proportion of children with wheezing had measurable PD₁₅FEV_0.5, PD₁₅FEV_0.75 and PD₁₅FEV₁ (P<0.01), and PD₂₀FEV_0.5, PD₂₀FEV_0.75 and PD₂₀FEV₁ (P<0.05). The sensitivity was 92.5% and 94.3% for PD₂₀FEV₁, and PD₁₅FEV₁ and the specificity was 93.6% and 93.6% respectively, for discriminating asthmatic from healthy children.

Conclusions

Most preschool children successfully and safely complete MCh-BPT, with higher success rate in larger age group. PD₂₀FEV_0.5 and PD₂₀FEV_0.75 can be surrogates of PD₂₀FEV₁ among children whose expiration lasted for less than one second. PD₁₅ has a good diagnostic value as PD₂₀ for diagnosing of BHR in preschool children, which are also more suitable for children five years old or elder.

Clinical phenotypes of bronchial hyperresponsiveness in school-aged children

BACKGROUND

Bronchial hyperresponsiveness (BHR), one of the key features of asthma, has a diverse natural course in school-aged children, but studies on BHR phenotypes are lacking.

OBJECTIVE

To classify BHR phenotypes according to onset age and persistence in children and investigate the characteristics and factors associated with each phenotype in a longitudinal study.

METHODS

This study analyzed 1,305 elementary school children from the Children's Health and Environmental Research (CHEER) study, a 4-year, prospective, follow-up study with 2-year intervals starting at a mean age of 7years. Total serum IgE levels and blood eosinophil counts were measured, and allergy workup, including methacholine challenge tests with the International Study of Asthma and Allergies in Childhood questionnaire, was performed at each survey.

RESULTS

The 4 BHR phenotypes were classified as non-BHR (n = 942 [72.2%]), early-onset transient BHR (n = 201 [15.4%]), late-onset BHR (n = 87 [6.7%]), and early-onset persistent BHR (n = 75 [5.7%]). Early-onset persistent BHR is characterized by an increased eosinophil count, total serum IgE level, sensitization rate, decreased lung function, and increased risk of newly diagnosed asthma during follow-up (adjusted odds ratio, 3.89; 95% confidence interval, 1.70-8.88). The 2 early-onset phenotypes were associated with peripheral airway dysfunction. The late-onset BHR phenotype was related to increased risks of allergic rhinitis symptoms at baseline and later sensitization against inhalant allergens.

CONCLUSION

The early-onset persistent BHR phenotype in school-aged children is associated with high atopic burden and increased risk of newly diagnosed asthma, whereas the late-onset BHR phenotype related with later sensitization and allergic rhinitis symptoms. Diverse BHR phenotypes in children have specific characteristics that require targeted follow-ups.

Prevalence, Risk Factors and Cutoff Values for Bronchial Hyperresponsiveness to Provocholine in 7-Year-Old Children

Background

A US Food and Drug Administration (FDA)-approved drug methacholine chloride (Provocholine^®) was recently introduced to Korea where it is now widely used in clinical practice. We aimed to evaluate the prevalence, risk factors and cutoff value of bronchial hyperresponsiveness (BHR) to Provocholine in 7-year-old children.

Methods

Six hundred and thirty-three children from the Panel Study on Korean Children who visited 16 regional hospitals were evaluated. Skin prick tests, spirometry and bronchial provocation tests for Provocholine as well as a detailed history and physical examinations were performed. The bronchial provocation test was reliably performed on 559 of these children.

Results

The prevalence of ever-diagnosed asthma via medical records was 7.7%, and that of current asthma (wheezy episode in the last 12 months + diagnosed asthma by physicians) was 3.2%. The prevalence of BHR to Provocholine was 17.2% and 25.8%, respectively, for a PC20 < 8 and < 16 mg/mL. The risk factors for BHR (PC20 < 16 mg/mL) were atopic dermatitis diagnosis and current dog ownership, whereas those for current asthma were allergy rhinitis diagnosis, a history of bronchiolitis before the age of 3, recent use of analgesics/antipyretics and maternal history of asthma. The BHR prevalence trend showed an increase along with the increased immunoglobulin E (IgE) quartile. The cutoff value of PC20 for the diagnosis of current asthma in children at age 7 was 5.8 mg/mL (sensitivity: 47.1%, specificity: 87.4%).

Conclusions

BHR to Provocholine (PC20 < 8 mg/mL) was observed in 17.2% of 7-year-olds children from the general population and the cutoff value of PC20 for the diagnosis of current asthma was 5.8 mg/mL in this age group. The risk factors for BHR and current asthma showed discrepancies suggesting different underlying mechanisms. Bronchial provocation testing with Provocholine will be a useful clinical tool in the future.

Different cutoff values of methacholine bronchial provocation test depending on age in children with asthma

BACKGROUND

Bronchial hyperresponsiveness (BHR) is a fundamental pathophysiological characteristic of asthma. Although several factors such as airway caliber can affect BHR, no study has established age-dependent cutoff values of BHR to methacholine for the diagnosis of asthma in children. We investigated the cutoff values of the methacholine challenge test (MCT) in the diagnosis of asthma according to age.

METHODS

A total of 2383 individuals aged from 6 to 15 years old were included in this study. MCTs using the five-breath technique were performed in 350 children with suspected asthma based on symptoms by pediatric allergists and in 2033 healthy children from a general population-based cohort. We determined the provocative concentration of methacholine producing a 20% decrease in forced expiratory volume in 1 second from baseline (PC₂₀). A modified Korean version of the International Study of Asthma and Allergies in Childhood questionnaire was used to distinguish asthmatics and healthy subjects. Receiver-operator characteristic curve analysis was used to assess the cutoff value of PC₂₀ for the diagnosis of asthma.

RESULTS

Cutoff values of methacholine PC₂₀, which provided the best combination of diagnostic sensitivity and specificity, showed an increasing pattern with age: 5.8, 9.1, 11.8, 12.6, 14.9, 21.7, 23.3, 21.1, 21.1, and 24.6 mg/mL at ages 6, 7, 8, 9, 10, 11, 12, 13, 14, and 15 years, respectively.

CONCLUSION

The application of different cutoff values of methacholine PC₂₀ depending on age might be a practical modification for the diagnosis of asthma in children and adolescents with asthmatic symptoms.

Lower airway inflammation and hyperresponsiveness in non-asthmatic patients with non-allergic rhinitis

BACKGROUND

Potential associations between non-allergic rhinitis (NAR) and asthma have been verified epidemiologically, but these associations remain not very clear. It is necessary to further explore the possible implication of lower airway abnormities in NAR patients but without asthma. This study aims to determine lower airway hyperresponsiveness (AHR), inflammation and lung function in non-asthmatic patients with NAR.

METHODS

We recruited 262 non-asthmatic patients with NAR, 377 with AR and 264 healthy subjects. All subjects were non-smokers who underwent meticulous history taking, nasal examination, allergen skin prick test (SPT), blood routine test, measurement of fractional exhaled nitric oxide (FeNO), methacholine bronchial challenge test and induced sputum eosinophil count, in this order.

RESULTS

Compared with healthy subjects, non-asthmatic patients with NAR yielded markedly lower FEV1/FVC, maximal mid-expiratory flow (MMEF), mid-expiratory flow when 50% of FVC has been expired (MEF50%) and mid-expiratory flow when 75% of FVC has been expired (MEF25%) (P<0.05). Differences in spirometry between group AR and NAR were unremarkable (P>0.05). Patients with NAR yielded higher rate of AHR and higher FeNO levels than healthy subjects but lower than those with AR. The proportion of lower airways disorders (sputum eosinophilia, high FeNO levels or AHR) was highest in group AR (70.8%), followed by NAR (53.4%) and healthy subjects (24.2%) (P<0.01). However, sputum eosinophils in NAR patients were not higher compared with healthy subjects (P>0.05). Sputum eosinophils and FeNO had significant correlation with positive AHR and MMEF in group AR but not in NAR.

CONCLUSIONS

Non-asthmatic patients with NAR harbor lower AHR, small airways dysfunction and inflammation, despite being less significant than those with AR. This offers clues to unravel the link between NAR and asthma.

The correlation between the bronchial hyperresponsiveness to methacholine and asthma like symptoms by GINA questionnaires for the diagnosis of asthma

Background

In epidemiological studies of asthma, questionnaires to differentiate asthmatics from non-asthmatics have proven to be cost-effective and convenient. The aim of this study was to analyze the association between hyperresponsiveness to methacholine and the validity of five items for the asthma like questionnaire recommended by the Global Initiative for Asthma (GINA).

Methods

A total of 680 subjects who visited the pulmonology department with suspected symptoms of asthma were enrolled. All participants completed five items questionnaires and underwent methacholine bronchial provocation tests (MBPT). The diagnostic value of the questionnaire was assessed through analysis of the sensitivity, specificity, and positive and negative predictive values.

Results

Multivariate logistic regression analysis showed that questionnaires about wheezing, exercise induced dyspnea and pollution-induced dyspnea were useful for differentiating asthmatics from non-asthmatics (adjusted odds ratio (OR) =2.0, 95% confidence interval (CI) 1.3-3.0; OR =2.3, 95% CI 1.5-3.5; OR =2.0, 95% CI 1.3-3.0) respectively. A total symptom score of higher than 1 was associated with the highest sensitivity (98.4%) and lowest specificity (9.4%). In contrast, a total symptom score of more than 5 was associated with the highest specificity (91.9%) and lowest sensitivity (18.5%)

Conclusions

Although questionnaires are not a sufficiently accurate method for diagnosing asthma, properly selected questionnaire can be used as effective strategies in situations such as private clinics or large population based epidemiologic studies.

Correlation between eosinophil count and methacholine challenge test in asymptomatic subjects

BACKGROUND

Methacholine challenge test is used to identify airway hyperresponsiveness (AHR). Total eosinophil counts in peripheral blood reflect asthmatic activity and are useful for early detection of exacerbations. Correlation between the two is poorly defined, particularly in asymptomatic subjects.

OBJECTIVE

The aim is to define correlation between methacholine challenge test and peripheral blood eosinophilia.

METHODS

All flight academy candidates evaluated in the Israeli Air Force Aero Medical Center between the years 2010 and 2011 were included. Candidates were referred to methacholine challenge test based on a personal history of asthma or wheezing in childhood, a first-degree relative with the diagnosis of asthma, or an abnormal spirometry. All methacholine tests were analyzed retrospectively.

RESULTS

Asymptomatic subjects with a positive methacholine challenge test demonstrated significantly (p < .002) higher levels of absolute eosinophil count compared with the group with a negative methacholine test (0.46 ± 0.21 vs. 0.21 ± 0.01 K/μL). Total white blood cell and neutrophil counts were higher in the group with a positive methacholine test compared with the group with a negative methacholine test, but to a lesser extent (7.1 ± 0.25 vs. 6.6 ± 0.09 K/μL, p = .04 and 3.9 ± 0.24 vs. 3.5 ± 0.07 K/μL, p = .04, respectively). No association was demonstrated between eosinophil count and severity of AHR expressed by the methacholine concentration evoking a response.

CONCLUSION

There is a strong association between eosinophil count and AHR in asymptomatic subjects.

Airway hyper-responsiveness in young adults with asthma that remitted either during or before adolescence

BACKGROUND AND OBJECTIVE

More than 50% of patients with childhood asthma enter clinical remission by puberty, although 40-50% of these people will probably develop asthma symptoms during early adulthood. The mechanism of relapsing asthma in early adulthood remains unclear. This study determined the characteristics of young adults whose asthma remitted either during or before adolescence.

METHODS

A comparative study was performed on 24 students whose childhood asthma had gone into clinical remission by puberty (remission group), 25 atopic students with no history of asthma (atopy group) and 19 non-atopic students without allergic diseases (control group). Examinations included spirometry, levels of serum-specific IgE-antibodies, airway responsiveness to methacholine, exhaled nitric oxide (eNO) and evidence of airway inflammation in induced sputum.

RESULTS

Airway responsiveness (P < 0.01), eosinophil counts in sputum (P < 0.05) and the prevalence of sensitization to Dermatophagoides forinae (P < 0.01) were significantly higher, and FEF(25-75%) and FEF(75%) (P < 0.01) were significantly lower in the remission group than in the atopy and control groups. Furthermore, 50% and 33% of the remission group had airway hyper-responsiveness (AHR) and sputum eosinophilia, respectively. The eNO levels in the remission (P < 0.01) and atopy (P < 0.05) groups were significantly higher than in controls. Remission group members with AHR had a significantly longer period of childhood asthma, a shorter period of remission and greater airway eosinophilic inflammation than those without AHR (P < 0.05).

CONCLUSION

One half of young adults with childhood asthma that remitted either during or before adolescence continued to have evidence of AHR and airway eosinophilic inflammation, and might be at risk of future relapse.

Predictive value of sGaw, FEF(25-75), and FEV1 for development of asthma after a negative methacholine challenge test

BACKGROUND

A 20% change in forced expiratory volume in 1 second (FEV(1)) during methacholine challenge testing (MCT) is a reliable marker of asthma. When the FEV(1) decrease is < 20%, there is controversy whether other changes in flows and conductance may be useful. We conducted this study to determine whether changes in sGaw, FEF(25 - 75), and FEV(1) in a negative MCT could predict future occurrence of asthma over a 3-year period.

METHODS

A total of 100 consecutive patients with clinical suspicion of asthma but who had a negative MCT per ATS FEV(1) criteria (< 20% FEV(1) decline at 16 mg/mL of methacholine) performed by the 5-breath dosimeter method were analyzed. Two pulmonary fellows, blinded to MCT results, reviewed the patients' medical records. Patients were classified into one of three categories: asthmatic, unclear, and not asthmatic. Decreases in sGaw, FEF(25 - 75), and FEV(1) in the five groups were then retrieved. Analysis of variance (ANOVA) was used for data analysis.

RESULTS

Of 100 patients, 23 were excluded owing to lack of a 3-year follow-up. After complete data review, the number of patients (n) in each group was as follows: asthmatic (n = 15), unclear (n = 7), and not asthmatic (n = 55). sGaw and FEF(25 - 75) decreases from the negative MCT could not predict asthma; however, decreases in FEV(1) were associated with future asthma occurrence (sGaw p = 0.21, FEF25-75 p = 0.07, FEV(1) p = 0.0009). Forty-three percent of the patients who had a 10% to 20% decline in FEV(1) eventually developed asthma.

CONCLUSION

Up to 20% of patients who have symptoms suggestive of asthma but a negative MCT can still develop asthma. Declines in sGaw and FEF(25 - 75) in a negative MCT appear to have no clinical significance. A decrease in FEV(1), especially 10% to 20%, is associated with the diagnosis of future asthma.

[Symptoms, physical findings and bronchial hypersensitivity in patients with bronchial asthma and normal spirometry]

BACKGROUND/AIM

The diagnosis of bronchial asthma, a chronic inflammatory disease of the respiratory tract, is made on the basis of anamnesis, pathologic auscultatory findings of the lungs, lung function disturbances, skin tests, as well as the basic indices of immunologic condition in bronchial trunk. The aim of the study was to find out correlation of objective indices of the disease and than relation with the symptoms in the patients with bronchial asthma.

METHODS

The study included 60 young male non smokers with long lasting symptoms of bronchial asthma including shortness of breath, wheezing, hard breathing, nonproductive or productive cough, weakness and night hard breathing. There were no symptoms of respiratory infection over the past two months and lung radiography and spirometry were normal Based on the results of nonspecific bronchoprovocative test two groups of the patients were formed, group I (n=30) with positive histamine test (average value of the inhaled histamine concentration with FEV1 drop by 20% in regard with the initial value (PC20) = 2.99 +/- 0.51 mg/ml of histamine) and group II (n=30) with negative histamine test (PC20(a) = 14.58 +/- 6.34 mg/ml of histamine).

RESULTS

The obtained spirometry results revealed a statistically significant difference in values of FEV1 between groups: I group--FEV1 3.2%; II group--EV1 = 101.8%; (p .05, Wilcoxon test), although all the FEV1 values were normal Regarding the presence of the most common symptoms there was not statistically significant difference between the groups (p>0.05, chi-square test). Pathologic auscultatory lung findings were found in 73.4% of the patients in the group I and 27.5% of the patients in the group II. There was statistically significant difference (p<0.05, chi-squared test). A positive correlation between the degree of hypersensitivity and lung physical findings was confirmed (p<0.05 Spearman's rho), but there was no correlation with FEV1 values.

CONCLUSION

There is a correlation with lung pathologic physical findings, lower values of FEV1 (in a range of normal values) and the degree of nonspecific bronchial sensitivity as objective indices of activity of bronchial asthma. There is no correlation of these parameters with patient's symptoms as subjective indices of bronchial asthma.

Mechanisms of airway hyperresponsiveness in asthma

Airway hyperresponsiveness (AHR) is a fundamental abnormality in asthma. There are many potential factors contributing to the excessive airway response demonstrable on airway challenge. These range from abnormalities of airway smooth muscle, airway remodelling and airway inflammation to abnormalities in the neural control of airway calibre. None of these by themselves fully explains the abnormalities seen on the dose response curves of the asthmatic. In this review, the main mechanisms are described, together with recent evidence providing a pathway by which a number of these mechanisms may interact to cause AHR through abnormality in ventilation distribution and airway closure. There is now evidence for a close relationship between ventilation heterogeneity and AHR which could be exploited clinically.

Rhinitis and onset of asthma: a longitudinal population-based study

BACKGROUND

A close relation between asthma and allergic rhinitis has been reported by several epidemiological and clinical studies. However, the nature of this relation remains unclear. We used the follow-up data from the European Community Respiratory Health Survey to investigate the onset of asthma in patients with allergic and non-allergic rhinitis during an 8.8-year period.

METHODS

We did a longitudinal population-based study, which included 29 centres (14 countries) mostly in western Europe. Frequency of asthma was studied in 6461 participants, aged 20-44 years, without asthma at baseline. Incident asthma was defined as reporting ever having had asthma confirmed by a physician between the two surveys. Atopy was defined as a positive skin-prick test to mites, cat, Alternaria, Cladosporium, grass, birch, Parietaria, olive, or ragweed. Participants were classified into four groups at baseline: controls (no atopy, no rhinitis; n=3163), atopy only (atopy, no rhinitis; n=704), non-allergic rhinitis (rhinitis, no atopy; n=1377), and allergic rhinitis (atopy+rhinitis; n=1217). Cox proportional hazards models were used to study asthma onset in the four groups.

FINDINGS

The 8.8-year cumulative incidence of asthma was 2.2% (140 events), and was different in the four groups (1.1% (36), 1.9% (13), 3.1% (42), and 4.0% (49), respectively; p<0.0001). After controlling for country, sex, baseline age, body-mass index, forced expiratory volume in 1 s (FEV(1)), log total IgE, family history of asthma, and smoking, the adjusted relative risk for asthma was 1.63 (95% CI 0.82-3.24) for atopy only, 2.71 (1.64-4.46) for non-allergic rhinitis, and 3.53 (2.11-5.91) for allergic rhinitis. Only allergic rhinitis with sensitisation to mite was associated with increased risk of asthma independently of other allergens (2.79 [1.57-4.96]).

INTERPRETATION

Rhinitis, even in the absence of atopy, is a powerful predictor of adult-onset asthma.

Sputum eosinophilia, airway hyperresponsiveness and airway narrowing in young adults with former asthma

BACKGROUND

30-80% of outgrown asthma subjects develop symptoms again later in life. We investigated inflammation and function of lower airway in adolescents with former asthma.

METHODS

326 never-smoking young adults (mean age 24.0 years) were interviewed with special emphasis on history of asthma. Diagnosis of asthma was based on GINA guidelines. Former asthma subjects consisted of ones with a history of physician-diagnosed childhood asthma, who had been free of asthma symptoms without the use of medication for at least 10 years prior to the study. Provocative concentration of methacholine causing a 20% fall in forced expiratory volume in 1 second (FEV(1))(PC(20)) and eosinophil percentage in induced sputum were measured.

RESULTS

31 subjects were former asthma subjects (FBA), 11 subjects were current asthma subjects (CBA) and 284 subjects had no history of asthma (non-BA). PC(20) and FEV(1)/FVC ratio were significantly lower in the FBA group than in the non-BA group (P < 0.01). Maximal mid-expiratory flow (MMF) was significantly lower in the FBA group than in the non-BA group (P < 0.05). Sputum eosinophil percentage was significantly increased in the FBA group compared with the non-BA group (P < 0.01). PC(20) was significantly lower in the CBA group than in the FBA and non-BA groups (P < 0.01). FEV(1), FEV(1)/FVC ratio and MMF were significantly lower in the CBA group than in the FBA group (P < 0.05, P < 0.05 and P < 0.05, respectively) and the non-BA group (P < 0.01, P < 0.01 and P < 0.05, respectively). Sputum eosinophils were significantly higher in the CBA group than in the FBA and non-BA groups (P < 0.01).

CONCLUSIONS

This study shows that subjects with long-term outgrown asthma continue to have airway eosinophilic inflammation, airway hyperresponsiveness and airway narrowing.

Abnormal spirometry in children with persistent allergic rhinitis due to mite sensitization: the benefit of nasal corticosteroids

Inflammatory processes affecting nasal and bronchial mucosa are similar in nature. The purpose of this study was to examine whether children with perennial allergic rhinitis, without underlying asthma, have impaired pulmonary function. We also investigated whether nasal corticosteroids and loratidine would improve the pulmonary function tests of those children with impaired lung function. Fifty subjects with moderate/severe persistent allergic rhinitis due to exclusively dust mite sensitization and no past medical history suggestive of asthma were assessed. The control group consisted of 26 matched healthy subjects. Subjects with airway obstruction, as detected by forced expiratory volume/1 s (FEV1) or forced expiratory flow from 25/% to 75% (FEF(25-75)) values <80% of those predicted, were treated with loratidine, once a day for 10 days, and daily nasal budesonide for 3 months. We found that 11 of 50 patients (22%) with perennial allergic rhinitis had impaired pulmonary function (FEF(25-75) values <80%), compared to 1/26 (3.8%) of the control group (p < or = 0.05). Reversibility was observed in 9/11 (81.8%), mean 24.7% +/- 10.3%. Within 3 months of treatment, 7/10 had FEF(25-75) > 80% of their predicted values as well as significant improvements in their FEV1 (p = 0.04), and FEV1/FVC (p = 0.04). We conclude that a substantial proportion of children with perennial allergic rhinitis have diminished FEF (25-75) values and reversible airway obstruction. Nasal corticosteroids improve the pulmonary function tests of these children with impaired lung function.

Asthma

Asthma has been recognized as a disease since the earliest times. In the Corpus Hippocraticum, Hippocrates used the term “ασθμα” to indicate any form of breathing difficulty manifesting itself by panting. Aretaeus of Cappadocia, a well-known Greek physician (second century A.D.), is credited with providing the first detailed description of an asthma attack [13], and to Celsus it was a disease with wheezing and noisy, violent breathing. In the history of Rome, we find many members of the Julio-Claudian family affected with probable atopic respiratory disorders: Caesar Augustus suffered from bronchoconstriction, seasonal rhinitis as well as a highly pruritic skin disease. Claudius suffered from rhinoconjunctivitis and Britannicus was allergic to horse dander [529]. Maimonides (1136–1204) warned that to neglect treatment of asthma could prove fatal, whereas until the 19th century, European scholars defined it as “nervous asthma,” a term that was given to mean a defect of conductivity of the ninth pair of cranial nerves.

Prevalence of lower airway diseases in patients with chronic rhinosinusitis

CONCLUSION

There is high prevalence of lower airway diseases in patients with chronic rhinosinusitis and frequently co-existing lower airway diseases have not been diagnosed before.

OBJECTIVES

To examine the prevalence of lower airway diseases in patients with chronic rhinosinusitis.

METHODS

Seventy-three consecutive patients with chronic rhinosinusitis were enrolled in this prospective study. With routine physical examination, spirometry and methacholine bronchial provocation test were performed and chest simple radiograph or chest computed tomography was taken.

RESULTS

Thirty patients (41.1%) had lower airway diseases. There were 8 patients with asthma, 5 with asymptomatic bronchial hyperresponsiveness, 11 with small airway disease, 2 with chronic obstructive pulmonary disease and 4 with bronchiectasis. Of these 30 patients, 21 patients (70.0%) were first diagnosed as having lower airway diseases in this study.

Airway hyperresponsiveness and risk of chest symptoms in an occupational model

BACKGROUND

The clinical outcome of asymptomatic airway hyperresponsiveness (AHR) remains unclear. A study was undertaken to evaluate the incidence of respiratory symptoms in a cohort of asymptomatic subjects with AHR at baseline.

METHODS

A 3 year prospective study involving methacholine challenge tests and serially administered questionnaires was undertaken in 769 apprentices exposed to high molecular weight allergens. Analyses were performed on 428 initially asymptomatic subjects.

RESULTS

Thirty eight subjects (8.9%) were airway hyperresponsive (PC(20) < or =8 mg/ml) and asymptomatic at the start of the study. Forty four apprentices (10.3%) developed two or more respiratory symptoms unrelated to work, 13 (34.2%) in the AHR group and 31 (7.9%) in the non-AHR group (risk ratio (RR) 7.88 (95% CI 2.53 to 24.55) among subjects with AHR). The RR of developing two or more respiratory symptoms increased as the degree of PC(20) decreased with a significant trend (p<0.001). In a multivariate analysis, AHR (RR 8.33, 95% CI 2.65 to 26.16) and self-reported rhinitis on exposure to pollen through an interaction with a family history of asthma (RR 6.3, 95% CI 1.29 to 31.89) were associated with the incidence of two or more respiratory symptoms; atopy was not a significant covariate.

CONCLUSION

AHR in asymptomatic subjects is an important determinant for the development of respiratory symptoms outside the workplace among apprentices exposed to high molecular weight allergens in their training environment.

Association between nonspecific airway hyperresponsiveness and Arg16Gly beta2-adrenergic receptor gene polymorphism in asymptomatic healthy Japanese subjects

BACKGROUND

Nonspecific airway hyperresponsiveness (AHR), a cardinal feature of asthma, is thought to result from several genetic and environmental factors. Asymptomatic AHR in nonasthmatic healthy subjects might be a risk factor for the development of asthma. Genetic variations in codons 16 and 27 of the human beta(2)-adrenergic receptor (beta(2)-AR) alter receptor function in vitro and are associated with various asthma-related phenotypes, including asthma severity and AHR. To date, however, few reports have examined the impact of beta(2)-AR gene polymorphism on AHR in asymptomatic healthy subjects.

OBJECTIVE

To determine whether polymorphism of the beta(2)-AR gene (Arg16Gly and Gln27Glu) might influence nonspecific AHR in asymptomatic healthy Japanese subjects.

DESIGN AND PARTICIPANTS

A cohort of 120 asymptomatic healthy subjects was analyzed using a stepwise linear regression model. Nonspecific airway responsiveness was measured using a continuous methacholine inhalation method (Astograph; Chest; Tokyo, Japan). We used values of the cumulative dose of inhaled methacholine measured at the inflection point at which respiratory conductance starts to decrease (Dmin) as an index of AHR. Genotyping to identify polymorphisms at codons 16 and 27 was conducted using an assay combining kinetic real-time quantitative polymerase chain reaction with allele-specific amplification.

RESULTS

The Gly16Gly genotype was associated with lower Dmin values. The log Dmin value of asymptomatic healthy subjects carrying the Arg16 allele (Arg16/Arg or Arg16/Gly, n = 90) was 1.09 +/- 0.56 (mean +/- SD), while those homozygous for the Gly16 allele (n = 30) yielded a log Dmin value of 0.85 +/- 0.56 (p < 0.05).

CONCLUSION

This study indicates that a specific beta(2)-AR polymorphism at codon 16 might be a genetic determinant of AHR, as judged by methacholine-induced bronchoconstriction in asymptomatic healthy subjects.

Bronchial hyper-responsiveness predicts the development of mild clinical asthma within 2 yr in school children with hay-fever

In children with mild asthma, symptoms are not always apparent. Therefore, results of tests play an important role for the diagnosis. First, to investigate whether children with bronchial hyper-responsiveness (BHR) but no symptoms of asthma in 1992 had developed clinical asthma at follow up in 1994. The second aim was to find out the diagnostic properties of tests for asthma/allergic inflammation, using either doctor diagnosed asthma (DDA), self-assessed symptoms of asthma or iso-capnic hyperventilation of cold air (IHCA), as the standard, to diagnose asthma in a group of children with hay fever. Twenty-eight children with pollinosis, 12 of them with a history of asthma for the first time during the season 1992, were studied during the birch pollen season and in the autumn of 1994. During both periods, the bronchial hyper-reactivity was estimated by methacholine bronchial provocation tests (MBPT), bronchial variability by peak expiratory flow rate variability, subjective symptoms of asthma by visual analogue scale (VAS) and bronchial inflammation by serum and urine levels of inflammatory mediators. In 1994 IHCA was added during both seasons. Eight of 16 children with BHR but without clinical asthma in 1992 had developed asthma in 1994, 14 of 16 reacted to IHCA and 13 to MBPT. All 12 children with DDA in 1992 had still asthma in 1994 and 14 children with BHR in 1992 had persistent BHR in 1994. Of 23 children with BHR in 1992, 17 had DDA in 1994 and all maintained their BHR. Furthermore, 20 of them reacted to IHCA in 1994. In 1994, 24 of 28 hay-fever children had a positive IHCA tests and 24 had positive MBPT. In relation to VAS, the sensitivity of IHCA and MBPT to predict present asthma was high, but the specificity low, whereas the specificity of most other tests was high, but based on few individuals. In relation to DDA both the IHCA test (65-80%) and the MBPT test (79-85%) had a high sensitivity and it was three to six times more likely to find a positive test among asthmatics than in non-asthmatics. Children with hay fever without clinical asthma have a high risk of developing asthma within 2 yr. In relation to DDA, inhalation of cold air and the MBPT showed a high sensitivity.

Clinical features and airway inflammation in mild asthma versus asymptomatic airway hyperresponsiveness

RATIONALE

We still do not know why some subjects with airway hyperresponsiveness (AHR) experience no respiratory symptoms.

OBJECTIVES

Our aim was to compare pulmonary function, perception of bronchoconstriction, and airway inflammation in atopic subjects with mild recently diagnosed (<5 years, n=30) or longer-standing (5 years or more, n=30) symptomatic asthma in comparison with atopic subjects with asymptomatic AHR (n=27).

METHODS

All subjects had measurements of expiratory flows, PC(20) methacholine, perception of breathlessness and induced sputum cell differential, eosinophil cationic protein and alpha(2)-macroglobulin levels.

RESULTS

Compared with the other groups, PC(20) was significantly lower in longer-standing asthma and perception score for breathlessness at 20% fall in FEV(1) was lower in asymptomatic subjects. Markers of airway inflammation were similar in all groups. There were no significant correlations between sputum eosinophils, alpha(2)-macroglobulin and/or eosinophil cationic protein levels and FEV(1), FVC or PC(20) in either group.

CONCLUSION

Subjects with mild asthma or asymptomatic AHR are similar in regard to induced sputum markers of airway inflammation. Although perception of bronchoconstriction was slightly lower in asymptomatic subjects, additional factors are probably involved to explain why they report no respiratory symptoms. Further studies are needed to determine why these last are asymptomatic.

Asthma in remission: can relapse in early adulthood be predicted at 18 years of age?

STUDY OBJECTIVE

To determine the frequency of relapse of asthma in young adults in remission at 18 years of age, during a follow-up period of 8 years, and to identify possible prognostic markers for relapse.

DESIGN

Longitudinal study of birth cohort (n = 1,037) born in New Zealand in 1972-1973.

SETTING

University hospital research clinic.

MEASUREMENTS

Participants were assessed at 9, 11, 13, 15, 18, 21, and 26 years of age using a respiratory questionnaire (all ages), spirometry (all ages), bronchodilator response (18 years and 26 years of age), methacholine challenge (9, 11, 13, 15, and 21 years of age), and allergen skin-prick testing (13 years and 21 years of age).

RESULTS

Approximately one third of study members (35%) with asthma in remission at 18 years of age relapsed by 21 years or 26 years of age. Atopy and lower FEV(1)/FVC ratio at 18 years of age were significant independent prognostic factors for relapse in multiple logistic regression analyses. Increased responsiveness to methacholine (provocative concentration < 8 mg/mL) or bronchodilator (improvement in FEV(1) >/= 10%) at 21 years of age were more common among those with relapse, but the positive and negative predictive values for a previous positive methacholine challenge test result at 15 years of age were low. Asthma after relapse was generally mild (mean FEV(1) 97.1% predicted). Totally new adult asthma developed by 26 years of age in 9% of study members who had no asthma or wheezing at any time up to 18 years of age.

CONCLUSIONS

Subsequent relapse of previously diagnosed asthma in remission at 18 years of age occurs in one in three young adults. Such relapse is not easily predicted, especially by measurements of airway responsiveness. A history of asthma currently in remission should not be used to prejudice employment opportunities for young adults.

Bronchial hyperresponsiveness in children with atopic rhinitis: a 7-year follow-up

BACKGROUND

A high prevalence of bronchial hyperresponsiveness (BHR) was found in atopic subjects with rhinitis. Those subjects may be at higher risk for developing bronchial asthma. We evaluated, in a 7-year follow-up, BHR and atopy in a homogeneous population of nonasthmatic children with allergic rhinitis (AR), and their role in asthma development.

METHODS

Twenty-eight children (6-15 years) with AR were studied. At enrollment (T(0)), skin tests, total serum IgE assay, peak expiratory flow (PEF) monitoring and methacholine (Mch) bronchial challenge were performed. BHR was computed as the Mch dose causing a 20% forced expiratory volume (FEV)(1) fall (PD(20)FEV(1)) and as dose-response slope (D(RS)). Subjects were reassessed after 7 years (T(1)) using the same criteria.

RESULTS

At T(0), 13 children (46%), showing a PD(20)FEV(1) <1526 microg of Mch, had BHR (Mch+), although PEF variability (PEFv) was within normal limits. None of the children with negative methacholine test developed bronchial asthma after 7 years. Of the 13 Mch+, only two reported asthma symptoms after 7 years. No significant change was seen in the other parameters of atopy considered.

CONCLUSION

Children with allergic rhinitis present a high prevalence of BHR. Nevertheless, their PEFv is normal and the rate of asthma development low.

Beta 2-adrenergic receptor polymorphisms and haplotypes are associated with airways hyperresponsiveness among nonsmoking men

STUDY OBJECTIVE

To investigate the relationship of common single nucleotide polymorphisms (SNPs) of the beta(2)-adrenergic receptor (AR) gene at codons 16 and 27, and the intermediate phenotype of airways hyperresponsiveness.

DESIGN

A case-control study in 543 white men (152 case patients and 391 control subjects), who were nested in an ongoing longitudinal cohort.

SETTING

Subjects were selected from the Normative Aging Study, an ongoing longitudinal cohort of healthy aging.

PARTICIPANTS

Case patients were defined as those having a positive response to methacholine challenge testing. Control subjects were selected among those who did not have a diagnosis of asthma and who had no response to methacholine.

RESULTS

There was a trend for an association of the Arg16 SNP genotype with airways hyperresponsiveness (odds ratio, 1.25; 95% confidence interval, 0.96 to 1.64 [in an additive model]). In stratified analyses, the effect of the Arg16 variant was seen mainly among nonsmokers. Smokers had increased risks for airway hyperresponsiveness regardless of genotype at either SNP. Using a program to estimate haplotype frequencies, three common haplotypes were identified. Adjusting for age, baseline FEV(1), serum IgE level, and smoking status, the Gly16/Gln27 haplotype was negatively associated with airways hyperresponsiveness in the full complement of case patients and control subjects (score statistic, - 2.43; p = 0.02). The effect of the beta(2)-AR haplotypes was much stronger among lifelong nonsmokers, among whom the Gly16/Gln27 haplotype remained negatively associated with airways hyperresponsiveness (score statistic, - 3.114; p = 0.002), whereas the Arg16/Gln27 haplotype was positively associated with airways hyperresponsiveness (score statistic, 3.142; p = 0.002). No effects were seen among ever-smokers.

CONCLUSIONS

In this cohort of middle-aged to older white men, beta(2)-AR polymorphisms were associated with airways hyperresponsiveness, particularly among lifelong nonsmokers. Our results illustrate an instance in which greater power is obtained by performing haplotype analyses as opposed to single SNP analysis.

Usefulness of bronchial reactivity analysis in the diagnosis of bronchial asthma in patients with bronchial hyperresponsiveness

We examined the usefulness of some bronchial reactivity indices to identify bronchial asthma in patients with airway hyperresponsiveness. Eighty-eight consecutive patients with positive response to histamine bronchial challenge (> or = 20% fall in FEV1) were included in the study. Dose-response curves were characterised by their sensitivity (PD20) and reactivity. Dose-response slope, continuous index of responsiveness (CIR) and bronchial reactivity index (BRI) with respect to baseline and post-diluent baseline values were determined as reactivity indices. The clinical diagnosis remaining in the case history 2 years after the bronchial challenge was considered the definitive diagnosis. Asthmatic patients had higher baseline BRI (12.121+/-0.412 vs. 11.615+/-0.201; P<0.001) and post-diluent baseline BRI (12.054+/-0.368 vs. 11.563+/-0.531; P = 0.003) than other subjects. Area beneath their receiver operating characteristic (ROC) curve was 82.68% (standard error: 0.77) for the baseline BRI and 81.73 (standard error: 0.76). By multiple logistic regression analysis, baseline BRI was the only independent variable identified as a predictor for diagnosis of bronchial asthma (r = 0.387, P = 0.0007). A cut-off of 11.76 for baseline BRI reached an 87.2% sensitivity and an 80% specificity for bronchial asthma diagnosis. In conclusion, BRI calculated with respect to baseline FEV1 should be useful in identifying asthmatic patients among subjects with airway hyperresponsiveness.

Determinants of maximally attained level of pulmonary function

This study investigated the determinants of sex-specific maximally attained levels of FEV(1), VC, and the ratio of FEV(1) to VC. Subjects were between the ages of 15 and 35 years (1,818 males and 1,732 females), participating in the Vlagtwedde/Vlaardingen study in The Netherlands. The subjects were followed (3-year intervals) with questionnaire, spirometry, peripheral blood eosinophil counts, and testing for airway responsiveness to histamine. Skin tests were performed only at study onset. Regression splines were used to assess the effects of these variables on levels of FEV(1), VC, and the ratio of FEV(1) to VC, with adjustment for age, height, and area of residence. Current (-44 ml/pack/day) and cumulative (-85 ml/10 packs/year) cigarette smoking were significant predictors of reduced maximal level of FEV(1) in males but not in females. The presence of respiratory symptoms (-114 ml in males, -106 ml in females), increased eosinophils (-128 ml [males], -53 ml [females]), and increased airway responsiveness (-225 ml [males], -213 ml [females]) were all significant predictors of reduced level of FEV(1). To the degree that these factors diminished plateau phase pulmonary function, they may be important predictors of chronic obstructive pulmonary disease in later life.

The natural history of asthma in a primary care cohort

BACKGROUND

We examined the natural history of asthma in a primary care cohort of patients 10 years after the cohort was stratified for asthma risk by responses to a questionnaire and bronchial hyperresponsiveness (BHR) testing.

METHODS

Children and young adults who were born between 1967 and 1979 within 1 of 4 affiliated family practices of the Nijmegen Department of Family Medicine, The Netherlands, were asked to participate in an asthma study in 1989. Of 926 patients available, 581 (63%) agreed to participate. Their family physicians' diagnoses of upper and lower respiratory tract disease and asthma were prospectively collected during the next 10 years and were analyzed.

RESULTS

BHR or the presence of asthma symptoms at screening did not result in a significantly disproportionate number of physician visits during the next 10 years for 4 or more upper or lower respiratory tract infections when compared with patients who did not have these findings at the beginning of the study. The presence of asthma symptoms correlated with an increased risk of an asthma diagnosis or allergic rhinitis in the group of patients who did not have asthma diagnosed at start of the study. One half of the known asthmatic patients at the onset of the study (21 of 44) had no further visits to their physicians for treatment of asthma during the next 10 years.

CONCLUSIONS

In primary care, BHR testing has limited value in predicting subsequent respiratory tract disease for patients who have asthma diagnosed by a physician. The use of symptom questionnaires can be of clinical use in predicting asthma.

Prevalence of asthmatic phenotypes and bronchial hyperresponsiveness in Turkish schoolchildren: an International Study of Asthma and Allergies in Childhood (ISAAC) phase 2 study

BACKGROUND

Numerous epidemiologic studies have revealed that bronchial asthma affects populations without regard to frontiers. However, standardized methodological approaches are necessary to compare these populations.

OBJECTIVE

To investigate objective markers of childhood asthma on an epidemiologic basis and to include Turkish children in international comparisons.

METHODS

Parental questionnaires were collected and skin prick tests performed on fourth grade primary schoolchildren, aged 8 to 11 years, residing in Ankara, Turkey. Pulmonary function tests and bronchial challenge with hypertonic saline (HS) were conducted in children selected from this cohort with a stratified random sampling according to the presence of current wheezing.

RESULTS

A total of 3,041 questionnaires were included in the evaluation. Skin prick tests were performed on 2,774 children (97.1%). A total of 347 children from this cohort underwent pulmonary function and bronchial challenge tests. In 18 (5.1%) of the 347 children, bronchial challenge tests could not be successfully completed. The prevalence values were 11.5% for current wheezing, 6.9% for physician-diagnosed asthma, and 7.7% for physician-diagnosed recurrent bronchitis. Population-based weighted prevalence of bronchial hyperresponsiveness (BHR) was 21.8%. Frequency of responses to HS was 38.6% among physician-diagnosed asthma cases and 30.5% among patients with current wheezing. Skin test positivity was present in 38.7% of the children with a diagnosis of asthma or asthmatic bronchitis, 35.0% of current asthmatic patients, and 19.2% of patients with current wheezing.

CONCLUSIONS

Objective markers, in addition to the questionnaire-based prevalence figures, need to be used in epidemiologic surveys for asthma, especially in countries with inadequate health care facilities or problems with interpretation of the wheeze concept.

Rhinoconjunctivitis, bronchial responsiveness, and atopy as determinants for incident non-work-related asthma symptoms in apprentices exposed to high-molecular-weight allergens

OBJECTIVE

The aim of this study was to explore the role of rhinoconjunctivitis (RC), taking into account atopy and the level of bronchial responsiveness to methacholine, on the incidence of respiratory symptoms and in the development and/or worsening of asthma.

METHODS

We examined data from a prospective study in 769 students starting exposure to high-molecular-weight occupational allergens and who were serially followed for up to 44 months.

RESULTS

The presence of RC symptoms at baseline was significantly associated with an increased risk of developing shortness of breath and wheezing in atopic subjects regardless of PC20 level and in subjects with a PC20 <or= 32 mg/ml regardless of atopic status. RC symptoms were significantly associated with the development of exercise-induced respiratory symptoms. Multivariate analyses indicated that having a measurable PC20 was significantly associated with the incidence of all respiratory symptoms studied, whereas baseline seasonal RC was associated only with incident exercise-induced respiratory symptoms; atopy played a minimal role, and only through an interaction with seasonal RC.

CONCLUSION

Of the three potential factors for the development of respiratory symptoms that we considered, i.e. RC symptoms, having a measurable PC20 and atopy, having a measurable PC20 is the most significant one.

Hypertonic saline challenge tests in the diagnosis of bronchial hyperresponsiveness and asthma in children

The hypertonic saline challenge test is the recommended method to assess bronchial hyperresponsiveness in the International Study of Asthma and Allergies in Childhood (ISAAC). The sensitivity of this procedure to assess asthma symptoms, however, has been reported to vary among study centers. The purpose of our study was to evaluate the value of this provocation test in an epidemiological survey in children, and to relate the degree of bronchial hyperresponsiveness to the severity of asthma symptoms. All 11-13-year-old children from 16 randomly selected schools in Linköping, Sweden received a questionnaire regarding respiratory symptoms and allergic disease. Skin prick tests with eight inhalant allergens were performed. In addition, all children with wheeze over the past 12 months (current wheeze) and a random sample of children without current wheeze were invited to perform hypertonic saline provocation tests. A complete data set was available for 170 children, including 50 with and 120 without current wheeze. Bronchial hyperresponsiveness (BHR) was defined as at least 15% decline in FEV1. The degree of BHR was represented by the response/dose ratio, i.e. the fall in FEV1 divided by total dose of inhaled saline. The severity of asthma symptoms was classified by the number of wheezing episodes over the past 12 months. 'Asthma ever' was defined by a combination of symptoms in the questionnaires. Children with 'asthma ever' and current wheeze were considered as having current asthma. Current atopic asthma was defined as current asthma with at least one positive skin prick test. The sensitivity of the procedure to detect 'asthma ever', current asthma and current atopic asthma was 62, 61 and 83%, and the specificity 83, 81 and 60%, respectively. The positive challenge rate was 52, 34, 13 and 7% among current wheezers, previous wheezers, non-wheezers with a history of allergy and healthy children. The degree of bronchial hyperresponsiveness increased with the number of wheezing episodes. Thus, the median and range of the response/dose ratio were 4.8%/ml (2.1-14.8), 2.6%/ml (0.7-8.6) and 1.3%/ml (0.8-2.7), respectively, for children with >/= 4 episodes, 1-3 episodes and no wheezing episodes over the past 12 months (p<0.001). In conclusion, hypertonic saline provocation test is useful as a tool to detect asthma in epidemiological studies in children. The degree of bronchial hyperresponsiveness, as represented by the response/dose ratio, reflects the severity of asthma symptoms.

Outcome in adulthood of asymptomatic airway hyperresponsiveness in childhood: a longitudinal population study

The clinical outcome of asymptomatic airway hyperresponsiveness (AHR) first detected in childhood is sparsely reported, with conflicting results. We used a birth cohort of 1,037 children followed to age 26 years to assess the clinical outcome of asymptomatic AHR to methacholine first documented in study members at age 9 years. Of 547 study members who denied wheezing symptoms ever at age 9 years, 41 (7.5%) showed AHR. Forty showed methacholine responsiveness, with a provocation concentration of methacholine that elicited a 20% drop in forced expired volume in 1 sec (PC(20)) < or = 8 mg/mL, and one had baseline airway obstruction with a bronchodilator response exceeding 10%. Of these 41 study members, 18 (44%), 11 (27%), and 4 (10%) maintained AHR in 1, 2, and 3 later assessments, respectively, while 23 (56%) manifested AHR only at age 9. Compared with asymptomatic study members without AHR, those with asymptomatic AHR at age 9 years were more likely to report asthma and wheeze at any subsequent assessment, were more likely to have high IgE levels and eosinophils at ages 11 and 21, and more often demonstrated positive responses to skin allergen testing at ages 13 and 21 years. Persistent AHR at later assessments increased these likelihoods further.In conclusion, asymptomatic children with AHR are more likely to develop asthma and atopy later in life compared with asymptomatic children without AHR. Persistent AHR, even though initially asymptomatic, was associated with an even greater increased risk of development of asthma. We suggest that rather than considering AHR as a marker of asthma, it should be regarded as a parallel pathological process that may lead to subsequent symptoms and clinical evidence of asthma.

Increasing prevalence of bronchial hyperresponsiveness in three selected areas in East Germany. Bitterfeld Study Group

The prevalence of asthma, bronchial hyperresponsiveness (BHR) and allergic rhinitis in children was lower in East Germany compared to West Germany. The reasons for this difference are still not understood. This study tested the hypothesis that prevalence of BHR increased in East German children after reunification. Two consecutive cross-sectional surveys of schoolchildren aged 8-14 yrs from three communities in East Germany were carried out in 1992-1993 and 1995-1996. A subsample of 530 and 790 children with complete lung function and cold air challenge data was analysed. The prevalence of BHR increased from 6.4%, in 1992-1993 to 11.6% in 1995-1996 (odds ratio (OR): 2.0, 95% confidence interval (CI): 1.3-3.0, adjusted for age, sex, season, community and parental education). No changes were found for asthma, allergic rhinitis or allergic sensitization. In contrast, physician diagnosed bronchitis, pneumonia and frequent colds decreased significantly. The observed increase in the prevalence of BHR was reduced (OR: 1.5, 95% CI: 0.95-2.3) after adjustment for several indoor factors. In conclusion, while the prevalence of nonallergic respiratory diseases seems to decrease, the prevalence of bronchial hyperresponsiveness might be a first indicator of the suspected increase of asthma prevalence in East Germany. The present results give indirect evidence, that less respiratory infections may be associated with higher bronchial hyperresponsiveness.

Association of airway responsiveness with asthma and persistent wheeze in a Chinese population

STUDY OBJECTIVES

Data from a cross-sectional study were analyzed to examine the association of increased airway responsiveness with physician-diagnosed asthma and persistent wheeze.

DESIGN

Two methods for calculating the provocative dose that decreases the airflow rate by 20% (PD(20)) were used as indexes for increased airway responsiveness: (1) a 20% drop in FEV(1) calculated from baseline FEV(1) (PD(20)b), and (2) a 20% drop in FEV(1) from FEV(1) measurements after inhalation of saline solution (PD(20)s). Both PD(20)b and PD(20)s were measured through induction by varying doses of methacholine.

SETTING

Anqing, Anhui Province, China.

PARTICIPANTS

Study subjects were 8 to 74 years of age and were classified into four groups: children (< 15 years old), young adults (15 to 29 years old), adults (30 to 44 years old), and older adults (> or 5 years old).

INTERVENTIONS

The differences in estimated odds ratios of airway hyperresponsiveness with asthma and wheeze, sensitivity and specificity, and coefficients of variation were compared between PD(20)b and PD(20)s. The sample for analysis consisted of 10,284 subjects from 2,663 nuclear families with complete data on wheeze, asthma, and major potential confounding factors.

MEASUREMENTS AND RESULTS

The prevalence of asthma in this sample was lowest in subjects with no demonstrable PD(20) and had a reverse dose-response relationship with PD(20) across all age groups. Using the receiver operating characteristic, the sensitivity and specificity of the PD(20)s or PD(20)b were found to be almost identical. A similar trend was found for persistent wheeze, although the estimated odds ratios for persistent wheeze appeared slightly smaller than those for physician-diagnosed asthma.

CONCLUSIONS

This study demonstrates a dose-response relationship between increased airway responsiveness and asthma and wheeze in this Chinese population. PD(20)s or PD(20)b yielded virtually indistinguishable results, which indicated that either of the two tests could serve as an index of airway hyperresponsiveness.

Development of bronchial hyperresponsiveness during childhood

Bronchial hyperresponsiveness (BHR) produces the characteristic pathological abnormalities seen in asthma and clearly plays a central role in the pathophysiology of asthma. The presence of BHR has been demonstrated in infants with asthma, as has the possibility of BHR persisting through the childhood period. The level of BHR may not only reflect the state of the airways, as a marker of airway dysfunction, but may also predict the persistent prognosis of the disease. Thus, measurement of BHR may provide important information about the symptoms and lung function in children with asthma. In view of multiple pathophysiological mechanisms, BHR does not seem to have a single cause. Many potential confounding variables, such as age, gender and genetic status, and some environmental factors, such as allergens, infections, and pollutants, could be responsible for the establishment of childhood BHR. There may be differences between the mechanisms that induce transient BHR and the mechanisms that induce persistent BHR. Also, there may be differences between the causes that induce BHR in the infantile period and the causes that maintain persistent BHR during childhood asthma. There is also disagreement as to the most suitable method to measure BHR in children, especially in infants. The assessment of BHR in young children has not been uniformly successful, and measurements of BHR changes over the childhood period (are associated with a number of problems. To resolve these problems, there may be two ways to study childhood BHR. One is to use age-matched specific techniques to clarify the precise BHR in each age group; the other is to use simple techniques that can be performed over the childhood period on a large number of subjects. In studies of infantile respirator, dysfunction the ultimate goal is to establish a simple, noninvasive method by which measurements of respiratory function may be obtained in infants. Further investigations and acceptable methods will be needed to clarify, the mechanisms involved in the establishment of asthma throughout the childhood period.

Effects of specific immunotherapy in allergic rhinitic individuals with bronchial hyperresponsiveness

Allergic rhinitis can be associated with bronchial hyperresponsiveness (BHR), and carries an increased risk for the development of asthma. The aim of this study was to evaluate the ability of specific immunotherapy (SIT) to reduce the progression of allergic rhinitis to asthma and prevent the associated increase in BHR. Forty-four subjects monosensitized to Dermatophagoides pteronyssinus, with perennial rhinitis and BHR to methacholine, were randomly assigned to receive SIT or placebo in a double-blind study conducted over a period of 2 yr. After 1 yr of treatment, a 2.88-fold increase in the provocative dose of methacholine producing a 20% decrease in FEV(1) (PD(20)FEV(1)) was recorded in the SIT-treated group (95% confidence interval [CI]: 3.98- to 2.09-fold; p < 0.001), with a further increase to fourfold at the end of Year 2 (95% CI: 2.9- to 5.7-fold; p < 0.001). At the end of the study, the methacholine PD(20)FEV(1) was within the normal range in 50% of treated subjects (p < 0.0001), and was significantly higher in this group than in the group receiving placebo (p < 0.0001). In contrast, no changes in methacholine PD(20)FEV(1) were found in the placebo group throughout the study. Although 9% of subjects given placebo developed asthma, none of those treated with SIT did. This study suggests that SIT, when administered to carefully selected, monosensitized patients with perennial allergic rhinitis, reduces airway responsiveness in subjects with rhinitis, and may be an appropriate prophylactic treatment for rhinitic patients with hyperreactive airways.

Bronchial hyperresponsiveness before and after the diagnosis of bronchial asthma in children

OBJECTIVE

To assess at what age bronchial hyperresponsiveness (BHR) is acquired in children with asthma.

BACKGROUND

A relationship between BHR and infantile wheezing diseases has been reported. Infants with a genetic predisposition to atopy are more likely to wheeze with respiratory viral infection or bronchiolitis, and it is suspected that the continued BHR after the first attack of asthma may be induced or triggered by some viral infections. Also, recent studies have reported the existence of atopic and BHR-related genes. However, whether BHR is congenital or acquired after asthma attacks, and when BHR in children with asthma is established or acquired remain unclear.

METHODS

We performed methacholine inhalation challenge using a transcutaneous oxygen pressure (tcPO(2)) monitoring system in 205 children without asthma from 6 months to 6 years of age. During follow-up, 18 of these participants were diagnosed with asthma (group N-A). This group and 15 age-matched children without asthma (group N-N) were tested twice using methacholine inhalation challenge. For comparison, 39 age-matched atopic-type asthmatic children (group A-A) were also given the inhalation challenge twice. Methacholine inhalation challenge using a tcPO(2) monitoring system was performed while the participants were asleep in the supine position. Sequential doses of inhaled methacholine delivered by oxygen mask were doubled until a 10% decrease in tcPO(2) from the baseline was reached. The cumulative dose of methacholine at the inflection point of tcPO(2) (minimal dose of methacholine [Dmin]-PO(2)) was considered to represent BHR.

RESULTS

In groups N-N and A-A, there was no difference in Dmin-PO(2) between the first and second challenge. However, the Dmin-PO(2) in group N-A significantly decreased from the first challenge to the second challenge. There was no significant difference between the Dmin-PO(2) in group N-N and the first Dmin-PO(2) in group N-A; or between the Dmin-PO(2) in group A-A and the second Dmin-PO(2) in group N-A.

CONCLUSIONS

These data suggest that BHR in many infants with asthma is acquired after several asthma attacks.bronchial hyperresponsiveness, childhood asthma, methacholine inhalation challenge, transcutaneous oxygen pressure.

Bronchial responsiveness to methacholine is increased in citrus red mite (Panonychus citri)-sensitive children without asthmatic symptoms

BACKGROUND

A recent investigation has suggested that citrus red mite (Panonychus citri, CRM) is a common sensitizing allergen among children living around citrus farms.

OBJECTIVE

A cross-sectional survey was performed to evaluate the bronchial responsiveness to methacholine in CRM-sensitive children without asthmatic symptoms.

SUBJECTS AND METHODS

A total of 375 children living around citrus farms were enrolled in this study. There were 201 boys and 174 girls with a mean age of 12.5 (range 7-16) years. Each subject was evaluated by a questionnaire, a skin prick test with 13 common inhalant allergens including CRM, and a methacholine bronchial provocation test (MBPT).

RESULTS

Positive rate of MBPT (PC20-methacholine < 25 mg/mL) was higher in atopic rhinitic and atopic control children than in nonatopic rhinitic and nonatopic control subjects (41.3% and 33.3% vs 17.2% and 15.4%, respectively, both P < 0.05). Slope of dose-response curve (DRS, %/mg/mL) was higher in atopic rhinitic children than in nonatopic rhinitic, atopic control and nonatopic control subjects (14.3 +/- 0.87 vs 9.4 +/- 0.72, 10.0 +/- 1.37 and 9.2 +/- 1.51, P < 0.05, respectively). Both the positive rate of MBPT and the DRS were increased in children with positive skin response to CRM than in those without sensitization (48.2% vs 22.9%, P = 0.0001; 15.6 +/- 1.26 vs 10.2 +/- 0.65, P = 0.0001).

CONCLUSION

Bronchial responsiveness is increased in citrus red mite-sensitive children even if they have no asthmatic symptoms.

Trends in bronchial hyperresponsiveness, respiratory symptoms and lung function among adults: West and East Germany. INGA Study Group. Indoor Factors and Genetics in Asthma

Previous studies have shown higher prevalences of bronchial hyperresponsiveness (BHR), respiratory symptoms and atopic sensitization among adults in Western Germany than in Eastern Germany. One of the aims of the joint project INGA (INdoor Factors and Genetics in Asthma) is to assess incidence, prevalence and trends for asthma, BHR and atopic diseases over a time period of 11 years (1990-2001) in the former West (Hamburg) and East Germany (Erfurt), with special reference to indoor exposure. INGA was designed as a case-control study following a cross-sectional study performed from 1990 to 1992 within the European Community Respiratory Health Survey (ECRHS). The database consisted of 1159 subjects in Hamburg and 731 subjects in Erfurt from the ECRHS (age 20-44). In 1995-1996, 107 cases (diagnosed asthma, positive specific serum IgE, positive skin prick or PD20FEV1< or =2.0 mg methacholine at ECRHS) and 106 controls (none of the previous findings) participated in Hamburg (115 cases and 109 controls in Erfurt). The methodology was identical to the ECRHS and dose-response slopes (DRS) of the methacholine challenge were calculated as an index of responsiveness. In the control group, median values of DRS were 0.028% mg(-1) (1990-1992) and 0.044 (1995-1996) (P<0.01) in Erfurt. Corresponding values for Hamburg were 0.028 and 0.022 (NS). Corresponding values within the case groups were 0.041 and 0.049 (NS) for Erfurt, and 0.069 and 0.052 (P<0.05) for Hamburg. Thus, 4 years after the first survey, we found an increased BHR in the Erfurt control group while the bronchial responsiveness remained unchanged for the Hamburg group. These trends in BHR, which indicate the expected converging tendency between East and West Germany, have to be confirmed within the next INGA-survey in 2000-2001.

Impact of airway lability, atopy, and tobacco smoking on the development of asthma-like symptoms in asymptomatic teenagers

AIM

To investigate the impact of airway lability, atopy, and tobacco smoking on the development of asthma-like symptoms in asymptomatic subjects.

METHODS

In this prospective, community-based study, 271 asymptomatic adolescents with an average age at inclusion of 13.9 years were followed for 6.4 years. Airway lability was assessed at baseline by three tests, including exercise challenge, airway provocation with methacholine, and monitoring of peak expiratory flow. Atopy was defined by one or more positive reactions (> or = 3-mm weal) to 10 common aeroallergens by skin prick testing. The influence of airway lability, atopy, and smoking on the development of asthma-like symptoms was assessed by logistic regression.

RESULTS

During the 6-year study period, 68 of the previously asymptomatic teenagers (25%) developed asthma-like symptoms. Among those, 50% reported cough only, 29% reported wheezing only, and 21% reported both wheezing and coughing. Hyperresponsiveness to methacholine (odds ratio [OR], 3.5; 95% confidence interval [CI], 1.1 to 11.6), smoking (OR, 2.1; 95% CI, 1. 2 to 3.8), and atopy (OR, 3.5; 95% CI, 1.8 to 6.8) each contributed independently to explain symptom development (wheezing and cough together). Girls, but not boys, with airway lability were less likely to take up smoking, compared with subjects of that set with no airway lability (32% vs 51%; p < 0.05). No effect of airway lability on the likelihood of giving up smoking could be demonstrated, nor did the presence of atopy have any significant impact on smoking behavior.

CONCLUSION

Hyperresponsiveness to methacholine, atopy, and smoking were independent risk factors for the development of asthma-like symptoms during adolescence. The presence of airway lability may prevent girls from taking up smoking.

Airway hyperresponsiveness and symptoms of asthma in a six-year follow-up study of childhood asthma

BACKGROUND AND AIM

In an inception cohort study of 457 asthmatic children diagnosed at the age of 3 to 4 years, airway hyperresponsiveness (AHR) was assessed 6 years after first diagnosis in a subgroup of 84 children. Our objective was to associate the level of AHR with the symptomatic asthma status at follow-up.

METHODS

Information on respiratory symptoms and medication use for the previous 6 years was obtained. Children with reported wheezing episodes during the previous year (n = 169) or for > or = 2 years at any time during the follow-up period (n = 85) were eligible for the challenge test.

RESULTS

Among the 254 eligible children, 166 were randomly selected. The parents of 88 of them consented to have their child participate. At the time of assessment of AHR, 19 children (22%) were asymptomatic and 24 others (29%) had symptoms but did not use any medication. Forty-one children (49%) were symptomatic and required medication, including antiinflammatory preparations in 26 instances (31%). All but two children had significant AHR. There was no significant association between the level of AHR and graded symptomatic and medication score. Twenty-four of the 70 children (34%) with greatly enhanced AHR used no medication.

CONCLUSIONS

This study shows that (1) almost all children first diagnosed with asthma 6 years ago and with persisting but not necessarily current symptoms of asthma have increased AHR, which satisfies a proposed epidemiologic definition of asthma; (2) AHR was present in 95% of the 20 currently asymptomatic children; and (3) one third of children with greatly enhanced AHR did not use any treatment.