The relationship between age and bronchial responsiveness: evidence from a population survey

The Impact of Climate Change on Pollen Season and Allergic Sensitization to Pollens

Pollens are a major cause of seasonal allergic diseases. Weather may alter the production of pollens. Increased atmospheric temperatures lead to earlier pollination of many plants and longer duration of pollination, resulting in extended pollen seasons, with early spring or late winter. Longer pollen seasons increase duration of exposure, resulting in more sensitization, and higher pollen concentrations may lead to more severe symptoms. Climate changes in contact to pollens may affect both allergic sensitization and symptom prevalence with severity. The future consequences of climate change, however, are speculative, because the influence on humans, is complex.

Asthma Over the Age of 65: All's Well That Ends Well

Asthma in older adults (often classified as those 65 years or older) is relatively common, underdiagnosed, and suboptimally treated. It is an important health problem, as the population of the United States continues to age. Unfortunately, asthma morbidity and mortality rates are highest in this age group. Alterations in the innate and adaptive immune responses occur with aging, and contribute to pathophysiologic differences and subsequent treatment challenges. The symptoms of asthma may differ from those in younger populations, and often include fatigue. There are unique factors that can complicate asthma management among older adults, including comorbidities, menopause, caregiver roles, and depression. Pharmacologic therapies are often not as effective as in younger populations, and may have greater side effects. Spirometry, peak flow measurements, and asthma education are typically underused, and may contribute to delays in diagnosis as well as worse outcomes. There are specific strategies that health care providers can take to improve the care of older adults with asthma.

Asthma in the elderly and late-onset adult asthma

Elderly asthmatics are at a higher risk for morbidity and mortality from their asthma than younger patients. There are important age-related physiologic and immunologic changes that complicate the presentation, diagnosis, and management of asthma in the aged population. Evidence suggests that elderly asthmatics are more likely to be underdiagnosed and undertreated. Additionally, elderly patients with asthma have highest rates of morbidity and mortality from their disease than younger patients. The underlying airway inflammation of asthma in this age group likely differs from younger patients and is felt to be non-type 2 mediated. While elderly patients are underrepresented in clinical trials, subgroup analysis of large clinical trials suggests they may be less likely to respond to traditional asthma therapies (ie, corticosteroids). As the armamentarium of pharmacologic asthma therapies expands, it will be critical to include elderly asthmatics in large clinical trials so that therapy may be better tailored to this at-risk and growing population.

An Official American Thoracic Society Workshop Report: Evaluation and Management of Asthma in the Elderly

Asthma in the elderly (>65 yr old) is common and associated with higher morbidity and mortality than asthma in younger patients. The poor outcomes in this group are due, in part, to underdiagnosis and undertreatment. There are a variety of factors related to aging itself that affect the presentation of asthma in the elderly and influence diagnosis and management. Structural changes in the aging lung superimposed on structural changes due to asthma itself can worsen the disease and physiologic function. Changes in the aging immune system influence the cellular composition and function in asthmatic airways. These processes and differences from younger individuals with asthma are not well understood. Phenotypes of asthma in the elderly have not been clearly delineated, but it is likely that age of onset and overlap with chronic obstructive pulmonary disease impact disease characteristics. Physiologic tests and biomarkers used to diagnose and follow asthma in the elderly are generally similar to testing in younger individuals; however, whether they should be modified in aging has not been established. Confounding influences, such as comorbidities (increasing the risk of polypharmacy), impaired cognition and motor skills, psychosocial effects of aging, and age-related adverse effects of medications, impact both diagnosis and treatment of asthma in the elderly. Future efforts to understand asthma in the elderly must include geriatric-specific methodology to diagnose, characterize, monitor, and treat their disease.

Urban residence is associated with bronchial hyperresponsiveness in Italian general population samples

BACKGROUND

The role of different risk factors for bronchial hyperresponsiveness (BHR), such as gender, atopy, IgE, and environmental factors (smoking, occupational exposure, infections), has been described. Indoor and outdoor pollution play an important role too, but few studies have analyzed the association with BHR. The aim of this study was to assess the effect of urban residence on BHR.

METHODS

We studied two general population samples enrolled in two cross-sectional epidemiological studies performed in Northern Italy (Po Delta, rural area) and Central Italy (Pisa, urban area). We analyzed 2,760 subjects (age range, 8 to 74 years). We performed analysis of variance and logistic regression analysis using ln slope of the dose-response curve of the methacholine challenge test as dependent variable, and sex, age, smoking habits, respiratory symptoms, skin-prick test results, IgE value, residence, and airway caliber as independent variables.

RESULTS

The mean value of ln slope of the dose-response curve adjusted for initial airways caliber (by baseline FEV(1) percentage of predicted value) was significantly higher in female subjects, in smokers, in subjects with respiratory symptoms, in younger and older ages, in subjects with high values of IgE, and in subjects with positive skin-prick test results. After controlling for the independent effects of all these variables, living in urban area was an independent risk factor for having BHR (odds ratio, 1.41; 95% confidence interval, 1.13 to 1.76).

CONCLUSION

Living in urban area is a risk factor for increased bronchial responsiveness.

Exercise-induced bronchoconstriction in athletes-should we screen?

The fact that exercise-induced bronchoconstriction (EIB) may be both over- and underdiagnosed in athletes has led to calls for widespread screening for the condition. This article assesses such a strategy by employing the standard framework used when evaluating any screening policy. This approach highlights a number of concerns and allows recommendations to help optimize the success of such a strategy if it were to be implemented.

Overcoming gaps in the management of asthma in older patients: new insights

Asthma is under-recognised and undertreated in older populations. This is not surprising, given that one-third of older people experience significant breathlessness. The differential diagnosis commonly includes asthma, chronic obstructive pulmonary disease (COPD), heart failure, malignancy, aspiration and infections. Because symptoms and signs of several cardiorespiratory diseases are nonspecific in older people and diseases commonly co-exist, investigations are important. A simple strategy for the investigation of breathlessness in older people should include a full blood count, chest radiograph, ECG, peak flow diary and/or spirometry with reversibility as a minimum. If there are major abnormalities on the ECG, an echocardiogram should also be performed. Diurnal variability in peak flow readings >or=20% or >or=15% reversibility in forced expiratory volume in 1 second, spontaneously or with treatment, support a diagnosis of asthma. Distinguishing asthma from COPD is important to allow appropriate management of disease based on aetiology, accurate prediction of treatment response, correct prognosis and appropriate management of the chest condition and co-morbidities. The two conditions are usually readily differentiated by clinical features, particularly age at onset, variability of symptoms and nocturnal symptoms in asthma, supported by the results of reversibility testing. Full lung function tests may not necessarily help in differentiating the two entities, although gas transfer factor is characteristically reduced in COPD and usually normal or high in asthma. Methacholine challenge tests previously mainly used in research are now also used widely and safely to confirm asthma in clinical settings. Interest in exhaled nitric oxide as a biomarker of airways inflammation is increasing as a noninvasive tool in the diagnosis and monitoring of asthma. Regular inhaled corticosteroids (ICS) are the mainstay of treatment of asthma. Even in mild disease in older adults, regular preventive treatment should be considered, given the poor perception of bronchoconstriction by older asthmatic patients. If symptoms persist despite ICS, addition of long-acting beta(2)-adrenoceptor agonists (LABA) should be considered. Addition of LABA to ICS improves asthma control and allows reduction in ICS dose. However, older people have been grossly under-represented in trials of LABA, many trials having excluded those >or=65 years of age. On meta-analysis, beta(2)-adrenoceptor agonists (both short acting and long acting) are associated with increased cardiovascular mortality and morbidity in asthma and COPD. While the evidence for excess cardiovascular mortality is stronger for short-acting beta(2)-adrenoceptor agonists, it would be prudent to exercise particular care in using beta(2)-adrenoceptor agonists (long acting and short acting) in those at risk of adverse cardiovascular outcomes, including older people. Regular review of cardiovascular status (and monitoring of serum potassium concentration) in patients taking beta(2)-adrenoceptor agonists is crucial. The response to LABA should be carefully monitored and alternative 'add-on' therapy such as leukotriene receptor antagonists (LRA) should be considered. LRA have fewer adverse effects and in individual cases may be more effective and appropriate than LABA. Long-term trials evaluating beta(2)-adrenoceptor agonists and other bronchodilator strategies are needed particularly in the elderly and in patients with cardiovascular co-morbidities. There is no evidence that addition of anticholinergics improves control of asthma further, although the role of long-acting anticholinergics in the prevention of disease progression is currently being researched. Older patients need to be taught good inhaler technique to improve delivery of medications to lungs, minimise adverse effects and reduce the need for oral corticosteroids. Nurse-led education programmes that include a written asthma self-management plan have the potential to improve outcomes.

Allergic sensitization to indoor and outdoor allergens and relevance to bronchial hyperresponsiveness in younger and older subjects

BACKGROUND

Most previous epidemiological studies on the relationship between allergy and bronchial hyperresponsiveness (BHR) have made no distinction between sensitization to indoor and outdoor allergens. We studied the relationship between specific sensitization to allergen and BHR and further assessed whether this was different in young adults and older subjects.

METHODS

Specific IgE to indoor allergens (house dust mite and cat) and outdoor allergens (timothy grass and birch) were measured using the CAP System. BHR was defined as PD20 </= 2 mg methacholine. Multiple logistic regression analysis was performed to study independent relationships between BHR and specific IgE to indoor and outdoor allergens in 1018 young adults (20-44 years) and 909 older subjects (45-70 years).

RESULTS

In the older age group specific IgE to indoor allergens was associated with BHR at a lower level (class 2) than in young adults (class >/= 3). Young adults with multiple sensitization had the highest risk of BHR. Subjects who were exclusively sensitized to pollen did not show increased BHR in both age groups. Total IgE had, independently of sensitization, only a significant dose-response relationship with BHR in the oldest age group.

CONCLUSIONS

The association between sensitization and BHR is dependent on the nature of the allergen and the level of specific IgE. Furthermore, this study shows for the first time that total IgE is associated with BHR at older ages, independently of sensitization.

The prevalence of airways hyperresponsiveness in members of an exercise training facility

Athletes have a high prevalence (11-50%) of exercise-induced asthma, which may be caused by the hyperventilation accompanying repetitive bouts of strenuous exercise. We hypothesized that recreational exercisers would display a similar trend. Eucapnic voluntary hyperventilation (EVH) bronchoprovocation (breathing 21% O2, 5% CO2, and 74% N2 at 60% of MVV for 5 minutes) was performed to determine the prevalence of airways hyperresponsiveness (AHR) in adults (n=212, 146 males, mean +/- standard deviation, age 32 +/- 10 years) who exercised regularly (10 +/- 10 years, 31 +/- 28% of their lives): none had a previous diagnosis of asthma. AHR was defined by at least a 10%, 20%, or 25% decline in FEV1, FEF(25-75), or PEFR, respectively, by spirometry at 1, 5, 10, and 15 minutes post-EVH. Forty-one of 212 (19%) tested positive for AHR: 20 of 41 (49%) were positive by FEV1, 28 of 41 (68%) by FEF(25-75), and 27 of 41 (66%) by PEFR. Comparing responders with nonresponders: pre-EVH lung function was equivalent, except for FEV1, which was reduced (p<0.05) in responders (96 +/- 13 vs. 102 +/- 12% predicted). Mean maximal negative deflections for responders were: for FEV1, -17 +/- 7%; FEF(25-75), -31 +/- 10%; PEFR, -38 +/- 11%. Ranges of decline for responders were: FEV1, -10 to -33%; FEF(25-75), -20 to -59%; PEFR, -25- to -70%. We conclude that in these regular exercisers, the prevalence of AHR is high and comparable with some athletic populations.

Is asthma over- or under-diagnosed in athletes?

A high prevalence of asthma has been reported in athletes. However, studies in this population usually show an even higher prevalence of airway hyperresponsiveness (AHR) and exercise-induced bronchoconstriction (EIB). This report compares studies on self-reported or physician-diagnosed asthma in athletes with those using objective measures of airflow limitation or airway responsiveness. The higher prevalence of AHR (or EIB) measured in athletes, when compared with the prevalence of self-reported or physician-diagnosed asthma, suggests that abnormal airway responses are common in athletes, although they are infrequently associated with troublesome respiratory symptoms. This may indicate underdiagnosis of asthma in athletes, possibly due to an underreporting of respiratory symptoms or a reduction in perception of nociceptive sensations with repeated exercise over time, or it may simply mean that high-level training is associated with asymptomatic AHR. In athletes, as in the general population, the use of subjective methods such as surveys and questionnaires results in an underestimation ofthe prevalence of airway dysfunction when compared with objective measurements. The significance of these observations is unknown, and there is a need to determine their long-term consequences for athletes.

Serum cytokine levels, cigarette smoking and airway responsiveness among pregnant women

BACKGROUND

Five to twenty percent of healthy, nonasthmatic individuals exhibit airway hyperreactivity. Because cytokines are important intermediates in airway responses, we investigated the relationship between serum cytokines and airway responsiveness in a well-characterized population of pregnant women.

METHODS

We analyzed serum levels of interleukin-4 (IL-4), IL-5, IL-6, interferon-gamma (IFN-gamma), and granulocyte-macrophage colony-stimulating factor (GM-CSF) in frozen sera from 240 pregnant nonasthmatic subjects from a previous study of airway responsiveness and preterm labor for their relationship to methacholine challenge test results.

RESULTS

Serum IFN-gamma and GM-CSF levels were significantly related to levels of methacholine airway responsiveness among nonasthmatics in this population. Nonasthmatics with PD(20) <8 micromol (the highest level of airway responsiveness) had the highest mean serum levels of IFN-gamma and GM-CSF, those with 8 <or= PD(20) <or= >50 micromol had intermediate levels, and those with PD(20) >>50 mol had the lowest levels. Both serum IFN-gamma and GM-CSF levels were also significantly related to the log dose-response slope for methacholine responsiveness. These relationships were confirmed in a multiple linear regression analysis controlling for age, ethnic background, and cigarette smoking. Current smoking was uniformly associated with decreased cytokine levels.

CONCLUSION

IFN-gamma, GM-CSF, and other cytokines may be useful serum markers in population studies of airway responsiveness.

Changes in FVC during methacholine-induced bronchoconstriction in elderly patients with asthma: bronchial hyperresponsiveness and aging

STUDY OBJECTIVE

We evaluated whether aging may produce changes in bronchial hyperresponsiveness, risk of enhanced bronchoconstriction, and changes of bronchoconstriction perception.

SETTING

Each subject underwent a methacholine bronchial challenge. Methacholine challenge was stopped when one of the following conditions occurred: (1) plateau of bronchoconstriction; (2) decrease of FEV(1) > 40%; (3) FEV(1) drop below 1 L; or (4) excessive respiratory discomfort. Methacholine dose-response curves were plotted both for FVC and FEV(1). The provocative dose of methacholine causing a 20% decrease in FEV(1) with respect to baseline (PD(20)) and the fall in FVC (DeltaFVC) at PD(20) were computed. The Borg scale was used for scoring the perception of respiratory discomfort.

PATIENTS

We compared 17 young asthmatic patients (aged 22 to 45 years) with 17 older asthmatic patients (aged 63 to 78 years) selected on the basis of similar baseline pulmonary function and disease duration.

RESULTS

No significant between-group difference was found in PD(20) and in plateau development. Conversely, DeltaFVC was significantly higher in the older group (mean +/- SD, 15.5 +/- 3.9% vs 11.6 +/- 5.5% in younger patients). In addition, DeltaFVC showed a positive linear relationship with age (p = 0.0026). Elderly subjects were less aware of bronchoconstriction during the methacholine challenge (p = 0.04).

CONCLUSIONS

In elderly patients with asthma having comparable pulmonary function and disease duration, bronchial responsiveness is not different from that observed in younger asthmatic patients. Nevertheless, in such patients, an age-related tendency to an enhanced bronchoconstriction and a reduced perception of the degree of bronchoconstriction exist.