Evidence Of Airflow Obstruction Research Articles

The Impact of an Electronic Health Record Intervention on Spirometry Completion in Patients with Chronic Obstructive Pulmonary Disease

Spirometry is necessary to diagnose chronic obstructive pulmonary disease (COPD), yet a large proportion of patients are diagnosed and treated without having received testing. This study explored whether the effects of interventions using the electronic health record (EHR) to target patients diagnosed with COPD without confirmatory spirometry impacted the incidence rates of spirometry referrals and completions. This retrospective before and after study assessed the impact of provider-facing clinical decision support that identified patients who had a diagnosis of COPD but had not received spirometry. Spirometry referrals, completions, and results were ascertained 1.5 years prior to and 1.5 years after the interventions were initiated. Inhaler prescriptions by class were also tallied. There were 10,949 unique patients with a diagnosis of COPD who were eligible for inclusion. 4,895 patients (44.7%) were excluded because they had completed spirometry prior to the cohort start dates. The pre-intervention cohort consisted of 2,622 patients, while the post-intervention cohort had 3,392. Spirometry referral rates pre-intervention were 20.2% compared to 31.6% post-intervention (p < 0.001). Spirometry completion rates rose from 13.2% pre-intervention to 19.3% afterwards (p < 0.001). 61.7% (585 of 948) had no evidence of airflow obstruction. After excluding patients with a diagnosis of asthma, 25.8% (126 of 488) patients who had no evidence of airflow obstruction had prescriptions for long-acting bronchodilators or inhaled steroids. A concerted EHR intervention modestly increased spirometry referral and completion rates in patients with a diagnosis of COPD without prior spirometry and decreased misclassification of disease.

Impaired Spontaneous Baroreceptor Reflex Sensitivity in Patients With COPD Compared to Healthy Controls: The Role of Lung Hyperinflation.

Background and Objectives: Patients with chronic obstructive pulmonary disease (COPD) are at increased risk for cardiovascular disease. This study aimed to investigate the relationship between pulmonary hyperinflation and baroreceptor reflex sensitivity (BRS), a surrogate for cardiovascular risk.Methods: 33 patients with COPD, free from clinical cardiovascular disease, and 12 healthy controls were studied. Participants underwent pulmonary function and non-invasive hemodynamic measurements. BRS was evaluated using the sequence method during resting conditions and mental arithmetic stress testing.Results: Patients with COPD had evidence of airflow obstruction [forced expiratory volume in 1 s predicted (FEV1%) 26.5 (23.3–29.1) vs. 91.5 (82.8–100.8); P < 0.001; geometric means (GM) with 95% confidence interval (CI)] and lung hyperinflation [residual volume/total lung capacity (RV/TLC) 67.7 (64.3–71.3) vs. 41.0 (38.8–44.3); P < 0.001; GM with 95% CI] compared to controls. Spontaneous mean BRS (BRSmean) was significantly lower in COPD, both during rest [5.6 (4.2–6.9) vs. 12.0 (9.1–17.6); P = 0.003; GM with 95% CI] and stress testing [4.4 (3.7–5.3) vs. 9.6 (7.7–12.2); P < 0.001; GM with 95% CI]. Stroke volume (SV) was significantly lower in the patient group [−21.0 ml (−29.4 to −12.6); P < 0.001; difference of the means with 95% CI]. RV/TLC was found to be a predictor of BRS and SV (P < 0.05 for both), independent of resting heart rate.Conclusion: We herewith provide evidence of impaired BRS in patients with COPD. Hyperinflation may influence BRS through alteration of mechanosensitive vagal nerve activity.

Spirometry performed as part of the Manchester community-based lung cancer screening programme detects a high prevalence of airflow obstruction in individuals without a prior diagnosis of COPD

BackgroundCOPD is a major cause of morbidity and mortality in populations eligible for lung cancer screening. We investigated the role of spirometry in a community-based lung cancer screening programme.MethodsEver smokers,...

Cannabis use disorder and the lungs.

Cannabis is one of the world's most widely used recreational drugs and the second most commonly smoked substance. Research on cannabis and the lungs has been limited by its illegal status, the variability in strength and size of cannabis cigarettes (joints), and the fact that most cannabis users also smoke tobacco, making the effects difficult to separate. Despite these difficulties, the available evidence indicates that smoking cannabis causes bronchitis and is associated with changes in lung function. The pattern of effects is surprisingly different from that of tobacco. Whereas smoking cannabis appears to increase the risk of severe bronchitis at quite low exposure, there is no convincing evidence that this leads to chronic obstructive pulmonary disease. Instead, cannabis use is associated with increased central airway resistance, lung hyperinflation and higher vital capacity with little evidence of airflow obstruction or impairment of gas transfer. There are numerous reports of severe bullous lung disease and pneumothorax among heavy cannabis users, but convincing epidemiological data of an increased risk of emphysema or alveolar destruction are lacking. An association between cannabis and lung cancer remains unproven, with studies providing conflicting findings.

Constrictive (Obliterative) Bronchiolitis in Primary Sjögren Syndrome

SESSION TITLE: Systemic Disease and Pulmonary Manifestations SESSION TYPE: Original Investigation Poster PRESENTED ON: Wednesday, November 1, 2017 at 01:30 PM - 02:30 PM PURPOSE: Extraglandular involvement in Sjögren’s syndrome (SS) includes a broad spectrum of lung diseases. Constrictive (obliterative) bronchiolitis (CB) is a poorly understood pulmonary manifestation of SS. The purpose of this investigation is to understand the clinico-radiologic features and clinical course of primary SS-associated CB. METHODS: We retrospectively identified 11 patients with primary SS and constrictive bronchiolitis encountered at our institution during a 9-year period from 2007-2015. Clinical features, laboratory results and radiologic findings were analyzed. Treatment data was extracted and correlated with follow-up course including imaging and pulmonary function testing. RESULTS: Our patients were mostly women (91%), with a median age of 50 years (range, 22 to 76 years) at the time of SS diagnosis and 53 years (range, 31 to 76 years) at the time of pulmonary symptom onset. Average interval between diagnosis of SS and the onset of pulmonary symptoms was 4.4 years; four patients (36%) were diagnosed with SS after the onset of pulmonary symptoms. Most patients (64%) were nonsmokers. The majority of patients had positive serology to anti-nuclear antibodies (82%), rheumatoid factor (55%), anti-Ro/SS-A (82%) and anti-LA/SS-B (64%) antibodies. Patients most frequently presented with dyspnea (91%) and cough (36%). Chest radiographs were normal (67%) or demonstrated hyperinflation (33%). High-resolution CT chest revealed mosaic attenuation with air trapping in all patients. PFT demonstrated airflow obstruction in 7 patients (63%), 2 patients (18%) had an isolated reduction in diffusing capacity, 1 (9%) had mixed physiology and the remaining patient (9%) had normal PFT results. Surgical lung biopsy was performed in two patients and confirmed the diagnosis of CB; one additional patient underwent bronchoscopic lung biopsy which yielded nondiagnostic findings. Treatment was variable and included glucocorticoids, hydroxychloroquine, mycophenolate mofetil, and cyclophosphamide. Most patients remained stable or declined during follow-up (median 8 months; range 0-160); one patient treated with hydroxychloroquine and mycophenolate mofetil demonstrated improvement. There were no deaths or lung transplants. CONCLUSIONS: CB is an uncommon pulmonary manifestation in primary SS and manifests mosaic attenuation with air trapping on chest CT scan, usually associated with evidence of airflow obstruction on PFT. Optimal therapy remains to be identified. CLINICAL IMPLICATIONS: Constrictive bronchiolitis can be seen in patients with primary SS and can be identified by the presence of mosaic pattern with air trapping on chest CT. DISCLOSURE: The following authors have nothing to disclose: Elizabeth Wight, Misbah Baqir, Jay Ryu No Product/Research Disclosure Information

Sensitization to Aspergillus species is associated with frequent exacerbations in severe asthma.

BackgroundSevere asthma is a largely heterogeneous disease with varying phenotypic profiles. The relationship between specific allergen sensitization and asthma severity, particularly in Asia, remains unclear. We aim to study the prevalence of specific allergen sensitization patterns and investigate their association with outcomes in a severe asthma cohort in an Asian setting.MethodsWe conducted a cross-sectional study of patients receiving step 4 or 5 Global Initiative for Asthma treatment. Univariate and multivariate analyses were performed to assess the association between sensitization to a specific identifiable allergen by skin prick test (SPT) and uncontrolled asthma (defined in our study as the use of ≥2 steroid bursts or hospitalization in the past year, a history of near-fatal asthma or evidence of airflow obstruction on spirometry).ResultsTwo hundred and six severe asthma patients (mean age 45±17 years, 99 [48.1%] male) were evaluated. Of them, 78.2% had a positive SPT to one or more allergens. The most common allergen to which patients were sensitized was house dust mites (Blomia tropicalis, Dermatophagoides pteronyssinus and Dermatophagoides farinae). Also, 11.7% were sensitized to Aspergillus species. On multivariate analysis, Aspergillus sensitization was associated with uncontrolled asthma (odds ratio 6.07, 95% confidence interval 1.80–20.51). In particular, Aspergillus sensitization was independently associated with the use of ≥2 steroid bursts in the past year (odds ratio 3.05, 95% confidence interval 1.04–8.95). No similar associations of uncontrolled asthma with sensitization to any other allergens were found.ConclusionHigh allergen, specifically Aspergillus sensitization was observed in the Asian population with severe asthma by SPT. Aspergillus sensitization was specifically associated with frequent exacerbations and a greater corticosteroid requirement. An improved understanding of the severe asthma with Aspergillus sensitization phenotype is warranted, which is likely a subgroup of severe asthma with fungal sensitization.

Clinical current and structural changes of pulmonary tissue at children with a bronchopulmonary dysplasia in the anamnesis

Bronchopulmonary dysplasia is currently the most common chronic lung disease in preterm infants. Since the initial description of the disease, more than forty years ago, new treatments and technologies have improved the outcome for preterm infants with very - low and extremely - low - birth - weight. As a result, the survival of extremely premature infants has increased but, despite of the improvement in neonatal care, the incidence of bronchopulmonary dysplasia continues to grow. At the same time the consequences of this disease for life has not yet been determined. The aim of the study to determine the clinical course, structural and functional changes in the lungs. In this study we surveyed 44 primary school children and adolescents who have had bronchopulmonary dysplasia in infancy. The children was carried out computed tomography of the lungs, research of function of external breath by methods of impulse oscillometry, spirometry, a body plethysmography, and also research of diffusion lung capacity. The features of the clinical course at different ages, the functional state of the respiratory system, as well as structural changes in the lung tissue. In school children and adolescents with a history of bronchopulmonary dysplasia found long - term structural changes in the lungs as inhomogeneity of ventilation and fibrotic changes on computed tomography of the thorax and also had evidence of airflow obstruction in the result of pulmonary function tests, in the absence of significant clinical signs of respiratory disease.

Why act early in COPD?

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Repeatability of induced sputum measurements in moderate to severe asthma

Novel therapies are being developed for patients with moderate to severe asthma. These patients may have neutrophilic airway inflammation. Induced sputum is commonly used as an endpoint in clinical trials of asthma therapies. We have performed repeated induced sputum sampling in moderate to severe asthma patients to understand the variability of cell counts, including neutrophils, and performed power calculations for studies in this group of patients. Nineteen patients with moderate to severe asthma with evidence of airflow obstruction (FEV1 ≤ 80% predicted) and suboptimal control (ACQ ≥ 1) performed repeated induced sputum separated by 1 month. The Ri of neutrophil percentage and absolute eosinophil count demonstrated good (0.61) and moderate (0.56) repeatability respectively, but there was a poor level of agreement for eosinophil percentage and absolute neutrophil counts. The within subject SD for sputum neutrophil percentage was 15.8. In cross over studies, sample sizes of n = 14 and n = 54 are required to detect changes in neutrophil percentages by 20 and 10 % respectively at 90% power. Sputum neutrophil percentage has good reproducibility in patients with moderate to severe asthma.

COPD phenotypes in a lung cancer screening population.

COPD (chronic obstructive pulmonary disease) is a very heterogeneous disease, and phenotypic categorization of a high-risk population has many potential benefits. The present study uses a symptom questionnaire, low-dose computed tomography (LDCT) and pulmonary function tests (PFT) to phenotypically subgroup a high-risk population. Study group consisted of current or former smokers who underwent lung cancer screening with LDCT as a subgroup of Pittsburgh Lung Screening Study. In addition to LDCT, PFT and a symptom query questionnaire were obtained from each patient. The study group consisted of 3183 subjects (age 50-79) subdivided into eight groups according to presence of symptoms, obstruction on PFT and presence of emphysema on LDCT. A total of 501 (15.7%) subjects were asymptomatic, with no airflow obstruction or evidence of emphysema. There were 866 (27.2%) subjects with both obstruction on PFT and emphysema on LDCT, but only 660 (20.7%) had symptoms. Five hundred thirty (16.6%) of the subjects had no emphysema on LDCT but had obstruction on PFT, although only 370 (11.6%) had symptoms. Four hundred seventy-four (14.9%) of subjects had emphysema on LDCT, but no airflow obstruction, with 312 (9.8%) symptomatic. Finally, 812 (25.5%) of subjects had no evidence of airflow obstruction on PFT or emphysema on LDCT, but had symptoms. Combining LDCT with PFT and a comprehensive questionnaire allows subgroup classification of COPD phenotypes in a high-risk population and may lead to earlier intervention and an improved framework for future studies.

Measuring and imaging small airways dysfunction in asthma

Asthma is a chronic inflammatory disorder of the airways causing typical symptoms, and the diagnosis is supported by evidence of airflow obstruction which is variable, reversible or inducible. However, standard assessment of lung function with spirometry does not measure dysfunction in small airways which are < 2 mm in diameter towards the periphery of the lung. These airways make only a small contribution to airway resistance under normal circumstances. Nevertheless, there is mounting evidence that pathology and dysfunction in these small airways are implicated in the pathogenesis and natural history of asthma. Using forced oscillation and the multibreath nitrogen washout techniques, uneven ventilation (ventilation heterogeneity) due to small airways dysfunction has been shown to be an important marker of asthma disease activity, even in the absence of abnormalities in standard spirometric measurements. Recent advances in imaging research, particularly with hyperpolarised gas magnetic resonance imaging, have also given insights into the significance and dynamic nature of ventilation heterogeneity in asthma. The challenge is to integrate these new physiological and imaging insights to further our understanding of asthma and facilitate potential new treatments.

Cross-sectional analysis of the utility of pulmonary function tests in predicting emphysema in ever-smokers.

Emphysema is largely an under-diagnosed medical condition that can exist in smokers in the absence of airway obstruction. We aimed to determine the sensitivity and specificity of pulmonary function tests (PFTs) in assessing emphysema using quantitative CT scans as the reference standard. We enrolled 224 ever-smokers (current or former) over the age of 40. CT of thorax was used to quantify the low attenuation area (% emphysema), and to measure the standardized airway wall thickness. PFTs were used individually and in combination to predict their ability to discriminate radiographic emphysema. Significant emphysema (>7%) was detected in 122 (54%) subjects. Twenty six (21%) emphysema subjects had no evidence of airflow obstruction (FEV1/FVC ratio <70%), while all subjects with >23% emphysema showed airflow obstruction. The sensitivity and specificity of spirometry for detecting radiographic emphysema were 79% and 75%, respectively. Standardized airway wall thickness was increased in subjects with airflow obstruction, but did not correlate with emphysema severity. In this cohort of lifetime ever-smokers, PFTs alone were inadequate for diagnosing emphysema. Airway wall thickness quantified by CT morphometry was associated with airflow limitation, but not with emphysema indicating that the heterogeneous nature of lung disease in smokers may represent distinct phenotypes.

P179 Lung-based assessment in Anderson Fabry Disease (AFD) demonstrates differential α galactosidase a enzyme (GLA) activity at blood and tissue sites

Introduction and ObjectivesAFD is an X-linked lysosomal storage disorder caused by mutations of the GLA gene. Lack of enzyme results in storage material accumulation within lysosomes, leading to multi-organ pathology....

The problem of preschool wheeze: new developments, new questions

Preschool wheeze is a common and often difficult to treat symptom. It may rarely be the first presentation of a severe underlying condition. Preschool wheeze is clearly a syndrome, not a single entity, and thus ripe for phenotyping. A number of approaches to phenotyping have been adopted. Epidemiology, based on the temporal patterns of symptoms, has taught us a lot about the medium and long-term implications of early life events, but is not useful for treatment planning. Atopic status is also not useful. Instead, symptom pattern (episodic (viral) and multiple trigger) should be used to decide on treatment. Reduced lung function at birth is associated with a number of maternal factors, including smoking (both by direct and epigenetic mechanisms), atopic status, and pregnancy complications; these children tend to have transient wheeze. Children whose symptoms persist into mid-childhood are born with normal lung function, but have evidence of airflow obstruction at 4–6 years of age. Early atopic sensitization is important in this group. Treatment of pre-school wheeze should be based on relief of present symptoms; there is no known therapy which prevents progression from episodic to multiple trigger symptoms and asthma. Episodic (viral) wheeze is a neutrophilic disease and should be treated with intermittent therapy. Options include inhaled anticholinergics or short-acting β-2 agonists, oral leukotriene receptor antagonists and short-course, high-dose inhaled corticosteroids. Prophylactic inhaled corticosteroids are not useful. Neither prophylactic nor inhaled corticosteroids are effective in preventing progression from an episodic viral to a multiple-trigger pattern. Multipletrigger wheeze may merit a three-step trial (trial period, stop if apparent response, restart only if symptoms return) of prophylactic inhaled corticosteroids or leukotriene receptor antagonists. Recent data have shown that prednisolone should not be a routine treatment for acute exacerbations of episodic (viral) wheeze, but should only be used for really severe excacerbations, defined as being more severe than a routine admission and likely needing high dependency care. This is especially true in the setting of multiple trigger wheeze. Keywords: asthma, inhaled corticosteroid, leukotriene, neutrophil, prednisolone

Prevalence and risk factors of airflow obstruction in an elderly Chinese population

It is common practice to use a forced expiratory volume in one second (FEV(1))/ forced vital capacity (FVC) ratio of <70% as evidence of airflow obstruction. As the FEV(1)/FVC ratio falls with age, the lower limit of normal range (LLN), defined as the bottom 5% in a health reference population, of FEV(1)/FVC ratio has been suggested as a better index to reduce over-diagnosis of chronic obstructive pulmonary disease (COPD), particularly in the elderly. However, there are no large scale studies that focus on the diagnosis of COPD in the elderly based on these definitions. The present prospective epidemiological study involved 1,149 elderly subjects aged > or =60 yrs in the community. Detailed questionnaires, pre- and post-bronchodilator spirometry were performed. In total, 1,008 subjects (mean age 74.2+/-6.4 yrs; 271 males) completed satisfactory spirometry testing. Airflow obstruction was present in 25.9% as defined by the post-bronchodilator FEV(1)/FVC ratio of <70% and in 12.4% defined by the LLN of FEV(1)/FVC ratio. Moderate COPD, at least, was found in 14.0% of patients according to the post-bronchodilator FEV(1)/FVC ratio of <70% and in 8.5% of patients according to LLN of FEV(1)/FVC ratio. In the present elderly Chinese population (mostly females, with low education level and previous exposure to biomass during formative years), the prevalence of chronic obstructive pulmonary disease varied markedly depending on definitions adopted. Further longitudinal studies are needed to determine the precise definition of chronic obstructive pulmonary disease.

Assessment of Pulmonary Function in COPD

Pulmonary function testing is used in the diagnosis of chronic obstructive pulmonary disease (COPD) and the staging of COPD severity. The current diagnostic criterion for airflow obstruction is a ratio of forced expiratory volume in 1 second (FEV (1)) to forced vital capacity (FVC) < 70%. However this absolute definition can lead to false-negative determinations in younger patients and false-positive determinations in the elderly. Nevertheless, screening spirometry is advocated and becomes feasible in the physician office setting with the availability of compact, relatively affordable apparatus that meets the appropriate technical specifications. Spirometry should be complemented by measurement of lung volumes using body plethysmography in those with evidence of airflow obstruction. Small airways disease can be detected by various techniques that measure airway and total respiratory system resistance. There is renewed interest in the forced oscillation technique and impulse oscillometry because of their noninvasiveness and potential ability to distinguish small from larger airway disease. Finally, pulmonary function testing has an important role in preoperative risk assessment; for example, in patients being considered for lung volume reduction surgery or resection of a lung nodule.

Subjective benefit of inhaled therapies in patients with bronchiectasis: a questionnaire study.

The objectives of this study were to obtain information about the use and subjective benefits of inhaled therapies in patients with bronchiectasis and to determine if these benefits were related to the presence of airflow obstruction. One hundred and twenty patients completed a questionnaire on inhaled therapies and performed spirometry. Inhalers were used daily by 85/120 patients with bronchiectasis and 42/120 patients had a nebuliser. Inhaled therapies were used extensively in patients with (FEV1 < 80%) and without (FEV1 > 80%) evidence of airflow obstruction. The majority of patients reported subjective benefits from their inhaled therapies. Chi2 analysis showed that there was no association between perceived benefits of short acting bronchodilators (SAB), long acting bronchodilators (LAB), corticosteroids or nebulisers and degree of airflow obstruction. This study provides information about the subjective benefits of inhaled therapies which could facilitate a more comprehensive assessment of the net benefit of inhaled therapies in patients with bronchiectasis with and without airflow obstruction.

Beta2-agonists for acute bronchitis.

The optimal treatment for acute bronchitis is not clear. Because many patients with acute bronchitis have airflow limitation as well as cough, beta2-agonists may be useful. To determine whether beta2-agonists improve the symptoms of acute bronchitis in patients who do not have underlying pulmonary disease. The Cochrane Library (through August 2000), MEDLINE (1966 to 2000), EMBASE (1974 to 2000), and Conference Proceedings using "bronchodilator (exp)", "adrenergic beta-agonist (exp)", or "sympathomimetics (exp)" and "bronchitis" or "cough"; Science Citation Index for referenced publications; and letters to manufacturers of beta2-agonists. An updated search of the Cochrane Central Register of Controlled Trials (CENTRAL) (issue 3, 2003); MEDLINE (January 2000 to July 2003); EMBASE (January 2000 to July 2003) was run in July 2003. Trials in which patients (adults or children over two years of age) without known pulmonary disease who were diagnosed with acute bronchitis or acute cough without other cause were randomized to beta2-agonist versus placebo, no treatment, or alternative treatment. Three reviewers independently first selected outcomes and evaluated trial quality while blinded to study results, and then extracted data. Trials in children and in adults were analyzed separately. Two trials in children (n = 109) with acute cough and no evidence of airway obstruction did not find any benefits from beta2-agonists. Combined data did not show a significant difference in daily cough scores between patients given oral beta2-agonists and those in the control groups. Five trials in adults (n = 418) with acute cough or acute bronchitis had mixed results, but overall summary statistics did not reveal any significant benefits from oral (three trials) nor inhaled (two trials) beta2-agonists. There were no significant differences in daily cough scores nor in the number of patients still coughing after seven days (control rate 73%; RR = 0.77, 95% CI 0.54-1.09). Subgroups of patients with evidence of airflow limitation had lower symptom scores if given beta2-agonists in one trial; and the trials that did note quicker resolution of cough in patients given beta2-agonists were those that had a higher proportion of patients with wheezing at baseline. Patients given beta2-agonists were more likely to report tremor, shakiness, or nervousness than patients in the control groups (for trials in children control rate 0%; RR 6.76, 95% CI 0.86 to 53.12, NNH 9, 95% CI 5 to 100; for trials in adults, control rate 11%; RR 7.94, 95% CI 1.17 to 53.94, NNH 2.3, 95% CI 2 to 3). There is no evidence to support using beta2-agonists in children with acute cough who do not have evidence of airflow obstruction. There is also little evidence that the routine use of beta2-agonists for adults with acute cough is helpful. These agents may reduce symptoms, including cough, in patients with evidence of airflow obstruction; but this potential benefit is not well-supported by the available data and must be weighed against the adverse effects associated with beta2-agonists.

Spirometric findings among school-aged First Nations children on a reserve: a pilot study.

Asthma and chronic obstructive pulmonary disease (COPD) are increasing concerns for First Nations peoples in Canada. Although hospital utilization for asthma and COPD among First Nations peoples has been increasing, the prevalence of asthma or wheezing is comparable to national averages. A pilot study was conducted to determine the prevalence of impaired lung function in school-aged First Nations children. A First Nations community in northern Alberta was selected to participate. Consent forms and a school health survey were completed by parents or guardians. Children with consent completed spirometry at school, and results were compared with predicted values. A total of 36 children participated (response rate 70.6%). Of these, 19.4% of parents reported that their child had received a physician diagnosis of asthma at some point in their life; only 28.6% had a parental report of still having asthma. Parents smoked in 73.1% of the children's homes. The mean (+/- SD) percentage of forced expiratory volume in 1 s (FEV1) over forced vital capacity (FVC) was 82.6%+/-6.9% (94.4%+/-0.08% of predicted). Evidence of airflow obstruction was found in 25% of the children. Parental report of the child ever having asthma was associated with impaired lung function (OR 3.20; P=0.033). Children in a home with reported mold exposure were less likely to have impaired lung function (OR 0.68; P=0.030). Many children in this study already have established airflow obstruction and may be at increased risk for asthma or COPD. Exposure to mold appeared to be protective. Further research is needed to evaluate the lung health concerns of this population.

Airway Hyperresponsiveness

Airway hyperresponsiveness is a characteristic feature of asthma and consists of an increased sensitivity of the airways to an inhaled constrictor agonist, a steeper slope of the dose-response curve, and a greater maximal response to the agonist. Measurements of airway responsiveness are useful in making a diagnosis of asthma, particularly in patients who have symptoms that are consistent with asthma and who have no evidence of airflow obstruction. These tests can be performed quickly, safely, and reproducibly. Certain inhaled stimuli, such as environmental allergens, increase airway inflammation and enhance airway hyperresponsiveness. These changes in airway hyperresponsiveness are of much smaller magnitude than those seen when asthmatic patients with persistent airway hyperresponsiveness are compared to healthy subjects. They are, however, similar to changes occurring in asthmatic patients that are associated with worsening asthma control. The mechanisms of the transient allergen-induced airway hyperresponsiveness are not likely to fully explain the underlying mechanisms of the persistent airway hyperresponsiveness in asthmatic patients.