Childhood asthma in adult life: a further study at 28 years of age

Transition for Adolescents and Young Adults With Asthma

Asthma is a complex, heterogenous medical condition which is very common in children and adults. The transition process from pediatric to adult health care services can be a challenge for young people with chronic medical conditions. The significant changes in physical and mental health during this time, as well as the many unique developmental and psychosocial challenges that occur during adolescence can complicate and impede transition if not adequately addressed and managed. The transition period can also be a challenging time for health professionals to assess readiness for transition and manage some of the complications which are particularly common during this time, including poor adherence to therapy, smoking, drug use, and emerging mental health conditions. The natural history, presentation, symptoms, and management of asthma is often significantly different when comparing pediatric and adult practice. In addition, management in infants, toddlers, school aged children, and adolescents differs significantly, offering an additional challenge to pediatric physicians managing asthmatic children and young people. Despite these challenges, if the transition process for young people with asthma is planned and performed in a formalized manner, many of these issues can be addressed, allowing the transition to occur smoothly despite changes that may occur in medical and psychosocial domains.

Asthma in Children and Adults-What Are the Differences and What Can They Tell us About Asthma?

Asthma varies considerably across the life course. Childhood asthma is known for its overall high prevalence with a male predominance prior to puberty, common remission, and rare mortality. Adult asthma is known for its female predominance, uncommon remission, and unusual mortality. Both childhood and adult asthma have variable presentations, which are described herein. Childhood asthma severity is associated with duration of asthma symptoms, medication use, lung function, low socioeconomic status, racial/ethnic minorities, and a neutrophilic phenotype. Adult asthma severity is associated with increased IgE, elevated FeNO, eosinophilia, obesity, smoking, and low socioeconomic status. Adult onset disease is associated with more respiratory symptoms and asthma medication use despite higher prebronchodilator FEV1/FVC. There is less quiescent disease in adult onset asthma and it appears to be less stable than childhood-onset disease with more relapses and less remissions.

Clinical Mimics: An Emergency Medicine-Focused Review of Asthma Mimics

BACKGROUND

Asthma is a common diagnosis or preexisting condition, and many patients with acute asthma exacerbation may present to the emergency department with wheezing and respiratory distress. However, many conditions may mimic this presentation.

OBJECTIVES

This review provides an overview of common asthma mimics and an approach to evaluation and management.

DISCUSSION

Asthma is characterized by an obstructive pulmonary disease with recurrent exacerbations. The disease may present with a variety of symptoms, including wheezing, chest tightness, shortness of breath, and even respiratory failure. Mimics include anaphylaxis, angioedema, central airway obstruction, heart failure, allergic reaction, foreign body aspiration, pulmonary embolism, and vocal cord dysfunction. The approach to evaluation and management of these patients includes assessment for life-threatening conditions while treatment and resuscitation is underway. Providers should assess for red flags, including no history of asthma, lack of severe asthma, and no improvement with standard treatments. Focused assessment with history, physical examination, chest imaging, electrocardiogram, and laboratory studies may provide benefit. Through consideration of these mimics and treatment, providers can provide rapid management.

CONCLUSIONS

While asthma is a common disease, many asthma mimics exist. Through consideration of other diseases with wheezing and assessing for red flags, such as patients presenting without a history of asthma or patients with a history of only mild asthma presenting with severe symptoms, emergency providers may decrease the chance of early diagnostic closure and anchoring while improving the care of these patients.

Strengths, Pitfalls, and Lessons from Longitudinal Childhood Asthma Cohorts of Children Followed Up into Adult Life

Asthma is a common problem worldwide and longitudinal studies of children followed up into adult life enable the assessment of clinical outcomes, examine the pattern of lung function outcomes, and importantly provide insight into aetiology and prognosis for patients with asthma. The aim of this review is to examine the major childhood asthma cohort studies which have continued into adult life, describing the strengths and weaknesses and the lessons that can be learnt regarding pathophysiology and potential future directions for research.

Predicting and reducing risk of exacerbations in children with asthma in the primary care setting: current perspectives

Childhood asthma is a very common condition in western countries and is becoming more prevalent worldwide. Asthma attacks (or exacerbations) affect the quality of life for child and parent, can rarely result in death, and also come at a cost for health care providers and the economy. The aims of this review were to 1) describe the burden of asthma exacerbations, 2) describe factors that might predict a child at increased risk of having an asthma attack, and 3) explore what interventions might be delivered in primary care to reduce the risk of a child having an asthma attack. Asthma attacks are more common in younger children and those with more severe asthma, although prevalence varies between countries. Many factors are associated with asthma attacks including environmental exposures, patient–clinician relationship, and patient factors. Currently, the best predictor of an asthma attack is a history of an attack in the previous 12 months, and the more attacks, the greater the risk. Looking ahead, it is likely that surveillance of routinely collected primary care data can be used to identify an individual at increased risk. Stratified (or personalized) treatment, which might involve physiological monitoring and genetic analysis, offers the potential to reduce an individual’s risk of asthma attack. Whatever the future holds, the relationship between patient and clinician will remain central to asthma management.

Childhood asthma and chronic obstructive pulmonary disease: outcomes until the age of 50

PURPOSE OF REVIEW

There has been recent interest in understanding the origins of chronic obstructive pulmonary disease. Epidemiological studies suggest that chronic obstructive pulmonary disease clearly has other causes apart from tobacco smoke.

RECENT FINDINGS

Cross-sectional studies of adult cohorts with chronic obstructive pulmonary disease highlight that childhood asthma is a risk factor. A recent longitudinal childhood cohort study of children from childhood to the age of 50 years describes that children with severe asthma are at increased risk of chronic obstructive pulmonary disease and that the deficit in lung function can be tracked back to early years.

SUMMARY

Children with severe asthma are at increased risk of developing chronic obstructive pulmonary disease.

Trends in eczema, rhinitis, and rye grass sensitization in a longitudinal asthma cohort

BACKGROUND

Atopic conditions are prevalent in the Western world, with limited long-term data on atopic trends in patients with asthma.

OBJECTIVE

To describe the trends in eczema, rhinitis, and allergic sensitization in a longitudinal childhood asthma cohort.

METHODS

Four hundred eighty-four patients were recruited at 7 years of age and followed regularly to 50 years of age. Subjects completed an interviewer-administered questionnaire to define current eczema and rhinitis. Skin prick testing to rye grass also was performed.

RESULTS

The participation rate over the past 4 decades has been maintained at 72% to 91%. There was a decrease in the prevalence of eczema in the past 12 months in groups with viral-associated wheeze (21% to 8%, P = .002), asthma (47% to 18%, P < .001), and severe asthma (69% to 28%, P < .001) from 14 to 21 years of age. Conversely, there was an increase in the prevalence of rhinitis in the previous 12 months in groups without asthma (1% to 6%, P = .04; 1% to 20%, P = .008), with viral-associated wheeze (16% to 28%, P = .006; 16% to 49%, P < .001), and with asthma (45% to 56%, P = .2; 45% to 73%, P = .014) from recruitment to 10 and 14 years of age, respectively. There were 2 peaks in prevalence in the sensitization to rye grass in this cohort from 7 to 10 years of age and from 14 to 21 years of age in all groups.

CONCLUSION

The adolescence phase appears to be an important period in the body's response to allergens whereby eczema decreases in prevalence, whereas rhinitis and rye grass sensitization increase in prevalence.

Development of rhinitis may be an indicator for the persistence of childhood asthma

OBJECTIVES

Results of previous studies have established several factors related with the natural course of childhood asthma. The aim of this study is to investigate the prognosis of childhood asthma and to determine possible risk factors for disease persistence.

METHODS

An outpatient cohort with a median (interquartile range) follow-up duration of 19.4 (17.7-21.8) years was re-evaluated. Current clinical remission (CR) was defined as no asthma symptoms and no use of controller medication within the past year.

RESULTS

Out of 115 patients, 78 could be surveyed with questionnaire and 46 patients with a median age of 25.3 (23.9-27.0) years were further investigated with clinical work-up. Nineteen (24.4%) patients were in CR in both visits (adolescence and young adulthood). A further 7 patients (9.0%) who were not in CR at adolescence were in CR at the young adulthood visit. However, 21 patients (26.9%) who were in CR at adolescence were not in CR at the young adulthood visit. Thirty-one patients (39.7%) with persistent symptoms at adolescence were not in CR at young adulthood, either. In multivariate logistic models, the presence of obstructive pattern (forced expiratory volume in 1s (FEV1)/forced vital capacity (FVC) <80% vs. ≥80%) in pulmonary function tests during the adolescence period (odds ratio; [95% confidence interval] (6.71 [1.65-27.29]; p=0.008) and later-onset rhinitis (10.27 [1.18-89.13]; p=0.035) predicted the absence of CR at young adulthood.

CONCLUSION

A substantial number of patients who were in CR during adolescence have re-emerging disease. The presence of obstructive pattern in adolescence and later-onset rhinitis were associated with the absence of CR in young adults with asthma. Awareness of risk factors along with early interventions may provide better results in childhood asthma.

Outcomes of childhood asthma to the age of 50 years

BACKGROUND

In 1964, The Melbourne Asthma Study was established to describe the spectrum and natural history of childhood asthma.

OBJECTIVE

To describe the clinical and lung function outcome of childhood asthma to the age of 50 years.

METHOD

Subjects were invited to complete an interviewer-administered questionnaire, skin prick testing, and measurement of lung function from the age of 7 years to the age of 50 years at 7-year intervals.

RESULTS

Of 458 survivors (from the original 484 subjects at recruitment), 346 subjects (76%) participated, of whom, 197 completed lung function measurement. Asthma remission at the age of 50 years was 64% in those with wheezy bronchitis, 47% for those with persistent asthma, and 15% for those with severe asthma in childhood. Multivariable analysis identified severe asthma in childhood (odds ratio [OR] 11.9 [95% CI, 3.4-41.8]), female sex (OR 2.0 [95% CI, 1.1-3.6]), and childhood hay fever (OR 2.0 [95% CI, 1.0-4.0]) as risk factors for "current asthma" at age 50 years. There was no evidence of a difference in the rate of decline in FEV1 (mL/y, 95% CI) between the severe asthma group (15 mL/y [95% CI, 9-22 mL/y]) and all the other recruitment groups: control (16 mL/y [95% CI, 12-20 mL/y]), mild wheezy bronchitis (14 mL/y [95% CI, 8-19 mL/y]), wheezy bronchitis (16 mL/y [95% CI, 11-20 mL/y]), and persistent asthma (19 mL/y [95% CI, 13-24 mL/y]).

CONCLUSION

The clinical and lung function outcome in adult life is strongly determined by asthma severity in childhood. The reduced lung function seen in adults is established in childhood and does not appear to decline more rapidly in adult years despite continuing symptoms.

Influence of asthma definition on the asthma-obesity relationship

Background

Epidemiological studies suggest an association between obesity and asthma in adults and children. Asthma diagnosis criteria are different among studies. The aim of this study was to test the influence of asthma definition on the asthma-obesity relationship.

Methods

In a cross-sectional analysis of 1922 men and women, subjects completed a translated questionnaire from the European Community Respiratory Health Survey and underwent spirometry and a bronchial challenge test. Weight, height and waist circumference were measured. Multiple logistic regression analysis was carried out to assess the association of variables related to obesity and asthma. Asthma was defined either by the presence of symptoms with bronchial hyperresponsiveness (BHR) or by a self-report of a physician-made diagnosis. The following variables were separately tested for associations with asthma: socioeconomic characteristics, schooling, physical activity, smoking status, anthropometry and spirometry.

Results

No association was detected between asthma confirmed by BHR and obesity indicators, odds ratio (OR) = 1.08 (95% confidence interval: 0.69 - 1.68) for obesity assessed by body mass index ≥ 30 kg/m²; OR = 1.02 (0.74 - 1.40) for obesity assessed by abnormal waist-to-height ratio; and, OR = 0.96 (0.69 - 1.33) for abnormal waist circumference. On the contrary, a previous diagnosis of asthma was associated with obesity, OR = 1.48 (1.01 - 2.16) for body mass index ≥ 30 kg/m²; OR = 1.48 (1.13 - 1.93) for abnormal waist-to-height ratio; and, OR = 1.32 (1.00 – 1.75) for abnormal waist circumference. Female gender, schooling ≥ 12 years and smoking were associated with BHR-confirmed asthma. Physically inactive subjects were associated with a previous diagnosis of asthma.

Conclusions

Our findings indicate that the relationship between asthma and obesity in epidemiological studies depends on the definition adopted. Certain components of asthma, for instance, symptoms may be more prone to the obesity influence than other ones, like bronchial hyperresponsiveness.

Asthma and other recurrent wheezing disorders in children (acute)

INTRODUCTION

Acute childhood asthma is a common clinical emergency presenting across a range of ages and with a range of severities.

METHODS AND OUTCOMES

We conducted a systematic review and aimed to answer the following clinical question: What are the effects of treatments for acute asthma in children? We searched: Medline, Embase, The Cochrane Library, and other important databases up to June 2010 (Clinical Evidence reviews are updated periodically, please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA).

RESULTS

We found 35 systematic reviews, RCTs, or observational studies that met our inclusion criteria. We performed a GRADE evaluation of the quality of evidence for interventions.

CONCLUSIONS

In this systematic review we present information relating to the effectiveness and safety of the following interventions: beta2 agonists (high-dose nebulised, metered-dose inhaler plus spacer device versus nebuliser, intravenous), corticosteroids (systemic, high-dose inhaled), ipratropium bromide (single- or multiple-dose inhaled), magnesium sulphate, oxygen, and theophylline or aminophylline.

Asthma and other recurrent wheezing disorders in children (chronic)

INTRODUCTION

Childhood asthma is the most common chronic paediatric illness. There is no cure for asthma but good treatment to palliate symptoms is available. Asthma is more common in children with a personal or family history of atopy, increased severity and frequency of wheezing episodes, and presence of variable airway obstruction or bronchial hyperresponsiveness. Precipitating factors for symptoms and acute episodes include infection, house dust mites, allergens from pet animals, exposure to tobacco smoke, and exercise.

METHODS AND OUTCOMES

We conducted a systematic review and aimed to answer the following clinical questions: What are the effects of single-agent prophylaxis in children taking as-needed inhaled beta(2) agonists for asthma? What are the effects of additional prophylactic treatments in childhood asthma inadequately controlled by standard-dose inhaled corticosteroids? We searched: Medline, Embase, The Cochrane Library, and other important databases up to June 2010 (Clinical Evidence reviews are updated periodically, please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA).

RESULTS

We found 48 systematic reviews, RCTs, or observational studies that met our inclusion criteria. We performed a GRADE evaluation of the quality of evidence for interventions.

CONCLUSIONS

In this systematic review we present information relating to the effectiveness and safety of the following interventions: beta(2) agonists (long-acting), corticosteroids (inhaled standard or higher doses), leukotriene receptor antagonists (oral), omalizumab, and theophylline (oral).

An official American Thoracic Society public policy statement: Novel risk factors and the global burden of chronic obstructive pulmonary disease

RATIONALE

Although cigarette smoking is the most important cause of chronic obstructive pulmonary disease (COPD), a substantial proportion of COPD cases cannot be explained by smoking alone.

OBJECTIVES

To evaluate the risk factors for COPD besides personal cigarette smoking.

METHODS

We constituted an ad hoc subcommittee of the American Thoracic Society Environmental and Occupational Health Assembly. An international group of members was invited, based on their scientific expertise in a specific risk factor for COPD. For each risk factor area, the committee reviewed the literature, summarized the evidence, and developed conclusions about the likelihood of it causing COPD. All conclusions were based on unanimous consensus.

MEASUREMENTS AND MAIN RESULTS

The population-attributable fraction for smoking as a cause of COPD ranged from 9.7 to 97.9%, but was less than 80% in most studies, indicating a substantial burden of disease attributable to nonsmoking risk factors. On the basis of our review, we concluded that specific genetic syndromes and occupational exposures were causally related to the development of COPD. Traffic and other outdoor pollution, secondhand smoke, biomass smoke, and dietary factors are associated with COPD, but sufficient criteria for causation were not met. Chronic asthma and tuberculosis are associated with irreversible loss of lung function, but there remains uncertainty about whether there are important phenotypic differences compared with COPD as it is typically encountered in clinical settings.

CONCLUSIONS

In public health terms, a substantive burden of COPD is attributable to risk factors other than smoking. To prevent COPD-related disability and mortality, efforts must focus on prevention and cessation of exposure to smoking and these other, less well-recognized risk factors.

Trends in prevalence of childhood and parental asthma in Merseyside, 1991-2006

BACKGROUND

To determine changes in prevalence of parental and childhood asthma in Merseyside between 1991 and 2006.

METHODS

Four standardized cross-sectional respiratory surveys using a parent-completed questionnaire were completed in 1991 (n = 1171), 1993 (n = 2368) 1998 (n = 1964) and in 2006 (n = 1074) among primary school children attending the same schools in lower socio-economic areas of Merseyside. Main outcome measures were prevalence of doctor diagnosed asthma (DDA) and the symptom triad of cough, wheeze and breathlessness (C+W+B+).

RESULTS

Between 1991 and 1998 prevalence of DDA increased (P < 0.001), but in 2006 this decreased from 29.8 to 19.4% (P < 0.001). Prevalence of C+W+B+ increased from 7.8 to 8.0% by 1998, then decreased to 6.7% in 2006 (P = 0.39). Between 1998 and 2006, childhood hospital admissions for respiratory illness decreased from 11.3 to 9.7% (P = 0.23). During this period paternal asthma prevalence increased from 8.6 to 10.7% (P = 0.001) and maternal asthma from 11.2 to 13.4% (P = 0.09).

CONCLUSIONS

An increase in the prevalence of DDA and asthmatic respiratory symptoms occurred in children prior to 1998, but this had decreased by 2006. Prevalence of parental asthma increased during the same period.

Relationship between bronchial hyperreactivity and asthma remission during adolescence

BACKGROUND

Many children with asthma outgrow this disease after the onset of puberty. However, the precise mechanism of outgrowing asthma in children is still unclear.

OBJECTIVE

To evaluate the characteristics of respiratory physiology during adolescence.

METHODS

The results of the lung function test and methacholine inhalation challenge were prospectively evaluated in adolescent patients with asthma with and without symptoms. One hundred sixty children with asthma participated. Twenty-eight children had symptom-free adolescent asthma (i.e., remission asthma) (boy to girl ratio, 16:12; mean age, 14.6 years), 25 had intermittent adolescent asthma (boy to girl ratio, 16:9; mean age, 14.9 years), and 47 had symptomatic adolescent asthma (boy to girl ratio, 27:20; mean age, 12.7 years). For comparison purposes, 60 younger children with symptomatic asthma participated. The parameters of bronchial hyperresponsiveness, baseline respiratory resistance, threshold of methacholine (Dmin) (bronchial sensitivity), and speed of bronchial constriction (Sm) (bronchial reactivity) were measured by methacholine inhalation challenge using the continuous oscillation method.

RESULTS

There was no significant difference in lung function results, such as forced vital capacity and forced expiratory volume in 1 second, between the intermittent asthma and the remission asthma groups. Also, there was no significant difference in baseline respiratory resistance and Dmin between the 2 groups. However, the value of Sm of the remission asthma group was significantly lower than that of the intermittent asthma group (P = .02) and the symptomatic asthma group (P = .02).

CONCLUSIONS

These data show that the adolescents with asthma remission showed a significant decrease of Sm, whereas Dmin was not changed. These results suggest one of the mechanisms by which asthma is outgrown in children and explain the common clinical aspects of adolescent asthma, such as symptom-free but bronchial hyperresponsive asthma.

Health-related quality of life in young adults with asthma

BACKGROUND

The aim was to study health-related quality of life, five years after an intervention study among young adults with asthma.

METHOD

The design was a follow-up study of a cohort of young adults with asthma (n=64) and 248 general population controls. Both groups were investigated at follow-up with a respiratory questionnaire and one generic quality-of-life instrument, and the asthma cohort also completed one-asthma-specific questionnaire. The material was analyzed with multivariate models.

RESULTS

Female gender and low FEV1 at baseline predicted both a decline during follow-up and a low quality of life at follow-up. The asthma cohort and controls scored similarly regarding generic quality of life. However, in the asthma cohort, females scored significantly lower in the physical dimension of the generic instrument, especially in the domain of general health.

CONCLUSIONS

There is an association between low FEV1 and a decline in quality of life among young adults with asthma, i.e. low FEV1 predicts a decline in quality of life during a five-year period. Young females with asthma seem to have lower quality of life compared with young males with asthma.

Tobacco smoke exposure and tracking of lung function into adult life

Maternal smoking during pregnancy leads to abnormal lung function in infancy that tracks through to later childhood and continues into adult life. This is associated with transient wheezing illnesses through early childhood. Both social and physiological factors are likely to predispose those exposed to passive smoke to become active smokers. Adult smokers demonstrate an increased decline of lung function with age. The effects of passive smoke exposure vary with genetic factors, gender, race and exposure to other pollutants. Exposure to environmental tobacco smoke and subsequent active smoking both aggravate symptoms and have a negative effect on lung function in those with asthma.

Risk factors related to fixed airway obstruction in patients with asthma after antiasthma treatment

BACKGROUND

There are many unanswered questions about the role of airway remodeling in asthma.

OBJECTIVE

To evaluate the physiologic factors related to airway remodeling after antiasthma drug treatment for 1 year.

METHODS

We gave 582 patients with asthma long-term control medication for 1 year according to the severity of their asthma. Airway remodeling was defined using forced expiratory volume in 1 second/forced vital capacity and a predicted forced expiratory volume in 1 second of less than 75% after antiasthma treatment.

RESULTS

Of the 582 patients, 49 (8.4%) had airway remodeling. Severe asthma resulted in more airway remodeling than mild-to-moderate asthma. Asthmatic patients with airway remodeling were significantly older and had a longer duration of asthma. Asthmatic patients with airway remodeling had more emphysema on high-resolution computed tomography, a higher rate of near-fatal asthma attacks, a lower percentage of sputum eosinophils, a lower atopy frequency, a greater response to short-acting bronchodilators, and a lower body mass index (BMI) than those without airway remodeling. Age, asthma duration, and BMI were important discriminators of airway remodeling.

CONCLUSION

Nonatopy, asthma duration, emphysema on high-resolution computed tomography, sputum eosinophils, age, and BMI before antiasthma treatment are important factors related to airway remodeling in patients with asthma.

Determinants of lung function and airway hyperresponsiveness in asthmatic children

BACKGROUND

Asthma patients exhibit an increased rate of loss of lung function. Determinants to such decline are largely unknown and the modifying effect of steroid therapy is disputed. This cross-sectional study aimed to elucidate factors contributing to such decline and the possible modifying effect of steroid treatment.

METHODS

We analyzed determinants of lung function and airway hyperresponsiveness (AHR) in a Scandinavian study of 2390 subjects from 550 families. Families were selected for the presence of two or more asthmatic children as part of a genetic study, Scandinavian Asthma Genetic Study (SAGA).

RESULTS

The primary analysis studied the association between the lung function and delay of inhaled corticosteroids (ICS) after asthma diagnosis among asthmatic children and young adults with a history of regular ICS treatment (N=919). FEV(1) percent predicted (FEV(1)% pred) was 0.25% lower per year of delay from diagnosis until treatment (p=0.039). This association was significantly greater in allergy skin prick test negative children. There was no significant influence of gender, age at asthma onset, or smoking. In the secondary analysis of the whole population of 2390 asthmatics and non-asthmatics, FEV(1)% pred was inversely related to having asthmatic siblings (-7.9%; p<0.0001), asthma diagnosis (-2.7%; p=0.0007), smoking (-3.5%; p=0.0027), and positive allergy skin prick test (-0.47% per test; p=0.012), while positively related to being of female gender (1.8%; p=0.0029). Risk of AHR was higher by having asthmatic siblings (OR 2.7; p<0.0001), being of female gender (OR 2.0; p<0.0001), and having asthma (OR 2.0; p<0.0001).

CONCLUSIONS

These data suggest that lung function is lower in asthmatics with delayed introduction of ICS therapy, smoking, and positive allergy skin prick test. Lung function is lower and AHR higher in female asthmatics and subjects with asthmatic siblings or established asthma.

Effect of aging on the relationship between asthma severity and bronchial hyperresponsiveness in children with asthma

An association between asthma and bronchial hyperresponsiveness (BHR) has been demonstrated. It is possible that the relationship between asthma severity and BHR in children with asthma is different in infants and in adolescents. The aim of this study is therefore to evaluate the effect of aging on the relationship between the severity of asthma and BHR in children with asthma. We measured BHR in 386 subjects ranging from 2 to 20 years of age. The subjects consisted of 323 children with asthma (boys:girls = 193:130, mean age 9.7 years) and 63 age-matched controls (boys:girls = 25:38, mean age 8.2 years). BHR was measured using the methacholine inhalation challenge by measuring the transcutaneous oxygen pressure (tcPO2) in children less than 6 years of age (Dmin-PO2) and by measuring the respiratory resistance (Rrs) in children 6 years of age and older (Dmin-Rrs). Throughout the whole age range, both the Dmin-PO2 and Dmin-Rrs in each asthma severity group were higher than those in the controls. In the asthmatics aged 2-5 years, the Dmin-PO2 levels in the mild asthma group were higher than those in the moderate and severe asthma groups (p < 0.001, p < 0.001, respectively), and the Dmin-PO2 levels in the moderate asthma group were also higher than those in the severe asthma group. This tendency was also found in the age ranges of 6-9 years and 10-13 years. In the asthmatics aged 14-20 years, the Dmin-Rrs levels were not significantly different among the three groups. Taken together, these data show that aging has an effect on the relationship between the severity of asthma and BHR during childhood and that BHR may not be the sole determinant for the severity of asthma in adolescence.

Are risk factors of childhood asthma predicting disease persistence in early adulthood different in the developing world?

BACKGROUND

Predictive factors of childhood asthma for favorable prognosis may differ between populations where a variety of genetic and environmental factors are present.

OBJECTIVES

To document the factors predicting disease persistence in early adulthood in Turkey.

METHODS

An outpatient cohort (n = 115) with a mean follow-up duration of 11.4 +/- 0.2 years was evaluated. Complete remission was defined as no asthma symptoms, no use of controller medication, no airflow limitation and no airway hyper-responsiveness, and clinical remission as no symptoms and no use of controller medication, within the past year.

RESULTS

The mean ages during referral and at the final visit were 5.8 +/- 0.2 and 17.1 +/- 0.2 years, respectively. Thirty-one (27%) were in complete remission, and a further 30 (26%) in clinical remission. In multivariate logistic models, diminished airflow [forced expiratory volume in 1 s (FEV1) < 80% vs > or = 80%] at the initial lung function test predicted current diminished airflow (8.422; 2.202-32.206) (odds ratio; 95% confidence interval), and presence of obstructive pattern (FEV1/forced vital capacity (FVC) < 80% vs > or = 80%) predicted current obstructive pattern (29.333; 3.022-284.724). Furthermore, female gender appeared to predict persistence of asthma symptoms (3.330; 1.250-8.333) and absence of clinical remission (2.398; 1.038-5.254); eosinophilia predicted persistence of symptoms (4.271; 1.080-16.889) and presence of airway hyper-responsiveness (3.723; 1.129-12.278).

CONCLUSIONS

Diminished airflow, female gender and eosinophilia appear to predict an adverse outcome of childhood asthma, supporting the concept that variability may exist between populations.

Asthma symptoms in early childhood--what happens then?

AIM

To study the outcome in early adulthood for children with early asthma symptoms and to analyse the factors associated with current asthma.

METHODS

In a prospective study, we have re-investigated 89/101 children who were hospitalized before the age of two years due to wheezing. The children were investigated using a questionnaire and allergy and bronchial hyper-responsiveness tests at the age of 17-20 years and compared with age-matched controls.

RESULTS

In the cohort, 43% had had asthma symptoms in the preceding 12 months compared with 15% in the control group. The strongest risk factors for asthma were current allergy, bronchial hyper-responsiveness and female gender. Female gender and passive smoking in infancy were independent infantile risk factors. In addition to female gender, two pathways led to current asthma: an allergic pathway from family atopy via the development of allergy and another pathway from early passive smoking via hyper-responsiveness and active smoking.

CONCLUSION

In children with early wheezing disorder, current allergy, bronchial hyper-responsiveness and female gender were the strongest risk factors for asthma in early adulthood, while female gender and passive smoking in infancy were independent infantile risk factors. The effects of early passive smoking persist longer than previously reported.

A doctor's ability to assess the severity of childhood asthma by simple clinical features

AIMS

To ascertain whether the severity of childhood asthma can be reliably assessed by simple clinical features, 94 newly diagnosed, school-aged asthmatic children were investigated.

METHODS

The study included parental interviews, physical examination, skin prick tests, lung function studies, including a brief visual interpretation of the flow-volume curve, and a 6-min exercise challenge test on a treadmill, which was used as a reference.

RESULTS

Baseline lung function studies showed a concave-shaped flow-volume curve in 40 (43%) patients, reduced maximal mid-expiratory flow (MMEF) in 25 (27%) and a reduced ratio of forced expiratory volume in 1 s to forced vital capacity (FEV(1)/FVC) in 14 (15%). The drop in peak expiratory flow (PEF) after exercise ranged from 0 to 79% of the baseline (mean 21.3%) and exceeded 12.5% in 52 (55%) patients. There was a small but significant correlation between the baseline FEV(1)/FVC and MMEF values and the response to exercise (r=-0.39 and -0.35; p=0.000, respectively), but when studied by linear regression analysis, the response to exercise was best predicted by the past symptom rate and a concave pattern in the pre-test maximal expiratory flow-volume curve. The values of traditional lung function tests or age, atopy, duration of symptoms or history of exercise-induced wheezing did not remain in the model.

CONCLUSIONS

These results show that the severity of asthma in school-aged children can be predicted at the first visit based on the past rate of symptoms and a visual interpretation of the maximal expiratory flow-volume curve.

Validation of a Dutch language screening instrument for 5-year-old preterm infants

AIM

The validation of the Dutch Taal Screenings Test (TST), a language-screening test, which is included in a follow-up instrument developed to enable paediatricians to assess 5-y-old preterm infants for their motor, cognitive and speech and language development.

METHODS

The speech and language development of 145 5-y-old infants born before 32 wk of gestation and/or with a birth weight of less than 1500 g was assessed by a paediatrician using the TST and by a speech therapist using standardized language tests.

RESULTS

All correlations between the instruments were significant. Using the original cut-off point of the TST for abnormal speech and language development (18 points), the paediatrician will only identify 62% of the children who need speech therapy. For this group of children, a cut-off point of 17 is more effective. The positive predictive value of the TST improved from 77% to 82% by using a parent and school questionnaire to evaluate in a more subjective way the speech and language development.

CONCLUSION

Using the TST, paediatricians will be able to identify speech or language problems in 5-y-old preterm infants.

The relationship between infant airway function, childhood airway responsiveness, and asthma

The relationship between reduced pulmonary function in early life and persistent wheeze (PW) in school-aged children remains uncertain. In this study, VmaxFRC was assessed at 1 month of age, and the presence of wheeze up to 11 years of age was prospectively identified. At 11 years of age, airway responsiveness (AR) to inhaled histamine and atopy were assessed. Recent wheeze at 11 years of age was associated with a reduced mean z score for VmaxFRC at 1 month of age (-0.41 [SD 0.91], n = 31) compared with no recent wheeze (0.04 [SD 1.00], n = 153, p = 0.03). Wheeze between 4 and 6 years that persisted at 11 years (PW) was most prevalent among those with reduced VmaxFRC at 1 month and atopy aged 11 years (p = 0.002) or reduced VmaxFRC and increased AR aged 11 years (p = 0.015). When all factors were considered, reduced VmaxFRC at 1 month (p = 0.03) and increased AR aged 11 years (p < 0.001) were independently associated with PW (n = 17) compared with other outcomes (n = 129). Reduced airway function present in early infancy is associated with PW at 11 years of age, and this relationship is independent of the effect of increased AR and atopy in childhood.

Natural history of asthma

For some children, asthma is a disease whose symptoms seem to remit with time. Numerous children, however, develop disease that is persistent throughout their lifetimes and is associated with more severe symptoms, increased airway reactivity, and loss of lung function. These children typically have a family history of asthma and demonstrate increased airways reactivity and atopy in childhood. A clearer picture of the natural history of asthma in the developing child has been derived from the results of several longitudinal studies. Although some questions have been clarified, several questions still remain. Now that the incidence and severity of asthma seem to be increasing, children born in the last 10 years may experience more severe disease or a different pathophysiology than those born 30 to 40 years ago. New cohort studies are needed to assess this possibility. Additional investigations into the genetics of asthma causation will help elucidate the different phenotypic expressions of this complex disease. Once these different phenotypic groups can be identified early in life, further studies can be performed to explore the impact of therapeutic intervention on the severity of asthma symptoms and loss of lung function.

Long-term outcomes in paediatric asthma

Over the years the aims of asthma management have changed markedly from effective prednisolone treatment of symptoms and exacerbations towards more use of continuous prophylactic treatment. With our new understanding of the disease and its management definition of the aims of treatment and assessment of optimal asthma control have become much more complex. Even in times of evidence-based medicine our asthma management is based upon findings of effects on various outcomes in somewhat short-term (<1 year) controlled studies. However, assumptions about long-term effects upon the basis of findings in such studies should be made with great caution. Good examples of this are studies which assess the risk of systemic effects and clinical adverse effects of inhaled corticosteroids. From such studies it has become clear that systemic effects detected in short-term trials may have no predictive value of long-term adverse effects. Thus steroid-induced changes in lower leg growth rates assessed by knemometry do not predict long-term statural growth. Moreover, steroid-induced changes in statural growth over 1 year are not predictive of effects upon attained adult height. In contrast, reduced growth caused by uncontrolled asthma disease also seems to affect attained adult height adversely. These findings suggest that long-term outcomes should play a larger role when future asthma management strategies are decided. Some important long-term outcomes of asthma management in children include cure or remission of the disease, prevention of complications of the disease (airway remodelling, adverse effects upon growth/adult height, peak bone mineral density, physical impairment and psychosocial development) or its pharmacological management (adverse effects upon adult height, peak bone mineral density). More controlled long-term studies (several years) are needed to provide a better understanding of how these outcomes are best achieved.

Asthma severity, allergy and lung function during young middle life in subjects with asthma in childhood

The further course of asthma severity lung function, bronchial hyperresponsiveness (BHR) to cold air challenge (CACh), clinical allergies and allergic sensitization in young middle adulthood was studied in a cohort of 55 subjects with childhood asthma. All subjects (27 females) have attended all five previous and the current follow-up visit, undertaken at a mean age of 35 years. Twelve subjects (22%) reported no current asthma, 28 (51%) mild/intermittent, and 15 (27%) moderate/severe asthma. Asthma severity changed little in the individual subjects over the last 5-year period. Females continued to have higher asthma severity scores than the males, but the previously noted lower resting and post-bronchodilator % predicted FEV1 in females was not confirmed now. Pathological BHR to CACh tended to be more common among the males. Forty-four subjects were still allergic to animal danders and 35 to pollens. Sensitization rates (skin prick test or RAST) were similar to those recorded 5 years earlier and there was no clear evidence of tolerance developing. Five subjects have never shown evidence of allergy or sensitization. The extent of sensitization to animal danders showed statistically significant relationships to asthma severity and BHR to CACh. Social development and professional careers continued to be good.

Incidence rates and risk factors for asthma among school children: a 2-year follow-up report from the obstructive lung disease in Northern Sweden (OLIN) studies

Studies of incidence of asthma are still limited. A longitudinal study of asthma in school children was started in 1996 in Northern Sweden. The incidence of asthma and the associated risk factors have been studied over a 2 years period. The study started with a parental questionnaire, the ISAAC questionnaire with additional questions, and a skin-prick test. The cohort, 3,525 children, 7 and 8 years old at start, was followed after 1 and 2 years by using the same questions, Each year responded 97%. The cumulative incidence of physician-diagnosed asthma was 1.7%, 0.9/1,000/year the first year, and 0.8/1,000/year the second year. The cumulative incidence of wheezing was 6.3%, and of frequent or daily users of asthma medicines 2.1%. Significant risk factors for incident asthma were a positive skin test, OR 5.64 (3.10-10.25); rhinitis,OR 3.53 (1.80-6.90); eczema, OR 2.19 (1.26-3.82); a family history of asthma, OR 2.83 (1.75-4.56); low birth weight, OR 3.38 (1.61-754); respiratory infections, OR 2.12 (1.24-3.63); male gender, OR 1.71 (1.06-2.81); and a smoking mother OR 2.00 (1.07-3.73). In summary the incidence of asthma during 2 years after age 7 was high, almost 1/100/year. Allergy was the most important risk factor, but other factors were influential.

What determines knowledge of asthma among young people and their families?

In this analysis, we sought to determine factors that predicted the level of asthma knowledge in a sample of adolescents with asthma and their parents. Eighty-five young people aged 10-24 years attending tertiary care asthma clinics and 46 of their parents answered validated respiratory and asthma knowledge questionnaires. Older adolescents were more knowledgeable about asthma than were younger adolescents (r=0.36, p=0.001). Young people with severe asthma (p=0.015) scored higher on the asthma knowledge questionnaire than those with mild/moderate asthma. Asthma knowledge among young people was related to that of their mothers (r=0.47, p=0.014), however, only age and the asthma knowledge of fathers significantly predicted adolescent asthma knowledge. Adolescents develop increasing autonomy for asthma self-management as they mature, but parents remain an important source of information about asthma for young people.

Skin-prick test findings in atopic asthmatic children: a follow-up study from childhood to puberty

In a prospective cohort study we investigated the course of allergic sensitization from childhood to puberty in a group of children with atopic asthma. An attempt was made to correlate the findings with the persistence of asthma. A total of 150 children with atopic asthma established at 7 years of age were evaluated when 8-10 years of age. A battery of skin-prick tests (SPTs) to common environmental allergens, a detailed clinical history for asthma severity classification, and spirometric analyses, were performed. In 127 of these children a re-evaluation was performed at puberty. A variety of statistical methods were used to analyze the results regarding changes in skin test reactivity to individual aeroallergens and atopic index (degree of atopy), as well as to determine any correlation between these changes and the persistence of asthma in puberty. A wide spectrum of modification in skin reactivity to common environmental allergens was observed, including the complete loss of sensitization to some allergens or the development of a new one to others. Specifically, 34% of asthmatic children sensitive to Dermatophagoides pteronyssinus and 52.7% sensitive to cat lost their sensitivity in puberty, while only 7.5% and 11.1%, respectively, became sensitized (p = 0.03 and p = 0.001, respectively). In contrast, regarding pollen sensitivity, 30.2% and 24% of asthmatic children became sensitive in puberty to olive pollen and grasses mix, respectively, and only 11.7% and 12.5%, respectively, lost their sensitivity to these allergens (p = 0.04). No correlation was shown between the skin test reactivity changes to individual allergens and the persistence of asthma, but a significant correlation was found between atopic index to indoor allergens in childhood and the persistence of asthma at puberty (p = 0.04). Interestingly, multi-sensitivity to allergens (>/= 4 allergens) in childhood was also found to correlate with the persistence of asthma at puberty [p = 0.05, odds ratio (OR) = 2.65, 95% confidence interval (CI) 1.2-7.2]. Our findings indicate that significant modification of skin reactivity to common environmental allergens in atopic children with asthma in puberty can occur. However, no association between these changes and the persistence of asthma could be demonstrated, although children with indoor allergic sensitization and multi-reactivity were found to have a higher probability of maintaining their asthma in puberty.

The role of antileukotrienes in the treatment of asthma

Cysteinyl leukotrienes (Cys-LTs) are mediators released in asthma and are both direct bronchoconstrictors and proinflammatory substances that mediated several steps in the pathophysiology of chronic asthma, including inflammatory cells recruitment, vascular leakage, and possibly airway remodelling. Available evidence from clinical trials and real world experience derived from managing patients with asthma justifies a broader role for antiLTRAs in asthma management than that recommended in the National Asthma Education and Prevention Programm (NAEPP) and National Health Lung and Blood Institute (NHLBI) treatment guidelines. Leukotriene-receptor antagonist drugs (LTRAs) seem to be effective alternatives to inhaled corticosteroids (ICS) either as monotherapy or as adjunctive therapy that reduces the need for higher doses of ICS in patients with mild-to-moderate persistent asthma. LTRAs may be used as adjunctive therapy for al levels of disease severity because they are effective in combination with ICS during long-term maintenance therapy. The agents seem especially effective in preventing aspirin-induced asthma, exercise-induced asthma (EIA) and they may provide an additional advantage of reducing nasal congestion in patients with both asthma and rhinitis.

Incidence and remission of asthma: a retrospective study on the natural history of asthma in Italy

BACKGROUND

The knowledge of the natural history of asthma from birth to adulthood could provide important clues for its cause and for the understanding of epidemiologic findings.

OBJECTIVE

This study is aimed at assessing the incidence and remission of asthma from birth to the age of 44 years by using data from 18,873 subjects involved in a large, nationally representative, cross-sectional study carried out in Italy from 1998 through 2000.

METHODS

The onset of asthma was defined as the age at the first attack, and remission was considered present when a subject was neither under treatment nor had experienced an asthma attack in the last 24 months. Person-years and survival techniques were used for the analysis.

RESULTS

The average annual incidence rate for the 1953 to 2000 period was 2.56/1000 persons per year. Incidence peaked in boys less than 10 years of age (4.38/1000 persons per year) and in women 30 years of age or older (3.1/1000 persons per year) and showed a generational increase (incident rate ratio = 2.63 and 95% CI = 2.20-3.12 for 1974-1979 vs 1953-1958 birth cohort). The overall remission rate was 45.8% (41.6% in women and 49.5% in men, P <.001). Asthmatic patients in remission had an earlier age at onset (7.8 vs 15.9 years, P <.001) and a shorter duration of the disease (5.6 vs 16.1 years, P <.001) than patients with current asthma. The probability of remission was strongly (P <.001) and inversely related to the age at onset (62.8% and 15.0% in the <10- and > or =20-years age-at-onset groups, respectively).

CONCLUSION

With respect to its natural history, asthma presents 2 different forms: early-onset asthma, which occurs early in childhood, affects mainly boys, and has a good prognosis, and late-onset asthma, which generally occurs during or after puberty, mainly affects women, and has a poor prognosis. The minority of patients with early-onset asthma who do not remit represents more than 35% of patients with current asthma in the general young adult population.

Risk factors for airway remodeling in asthma manifested by a low postbronchodilator FEV1/vital capacity ratio: a longitudinal population study from childhood to adulthood

Airway remodeling may lead to irreversible loss of lung function in asthma. The impact of childhood asthma, airway responsiveness, atopy, and smoking on airway remodeling was investigated in a birth cohort studied longitudinally to age 26. A low postbronchodilator ratio of forced exhaled volume in 1 second (FEV1) to vital capacity (VC) at age 18 or 26 was used as a marker of airway remodeling. "Normal" study members with no history of asthma ever, no wheezing in the last year, and no smoking ever were used to determine sex- and age-specific reference values for this ratio. The lower limit of normal was defined as the mean ratio minus 1.96 standard deviation, delimiting the 2.5% of the normal population with the lowest FEV1/VC ratio. A low postbronchodilator FEV1/VC ratio was found in 7.4% and 6.4% of study members at ages 18 and age 26 and 4.6% at both assessments. Lung function was low throughout childhood in those with a consistently low postbronchodilator FEV1/VC ratio at both ages. Those with consistently low postbronchodilator ratios also showed a greater decline in the prebronchodilator FEV1/VC ratio from ages 9 to 26 compared with those with normal postbronchodilator ratios at both ages (males, -12% versus -6%, p < 0.0001; females, -10.5% versus -5.5%, p < 0.01). Asthma, male sex, airway hyperresponsiveness, and low lung function in childhood were each independently associated with a low postbronchodilator FEV1/VC ratio, which in turn was associated with an accelerated decline in lung function and decreased reversibility. These data suggest that airway remodeling in asthma, as manifested by impaired lung function, begins in childhood and continues into adult life.

Infants with flow limitation at 4 weeks: outcome at 6 and 11 years

Within a longitudinal study of lung function in 243 infants, we identified a group of 23 individuals with flow limitation in tidal expiration. In infancy, flow-limited children have reduced lung function and increased airway responsiveness (AR), and at 2 years of age they are diagnosed with asthma more frequently. We hypothesized that these observations would persist throughout childhood. Data from ages 3 to 11 years were analyzed. Only at 4 years of age did the flow-limited group have increased wheeze compared with other cohort members (odds ratio, 4.25; 95% confidence interval [CI], 1.11 to 16.2; p = 0.04; n = 114). At 6 years of age, 117 cohort members were seen. The flow-limited group (n = 14) had greater AR (p = 0.009) and reduced mean FEV(1) (131 ml; 95% CI, 16 to 246; p = 0.03) and FEF(25-75) (0.28 L/second; 95% CI, 0.05 to 0.52; p = 0.02). At 11 years of age, 183 children were seen and the flow-limited group (n = 18) had greater AR (p = 0.02) and a trend toward reduced mean FEF(25-75) (0.24 L/second; 95% CI, -0.02 to 0.49; p = 0.08). Atopy and parental asthma were not increased in the flow-limited group. We suggest that the physiologic abnormality that causes flow limitation in early infancy may identify an at-risk group, different from asthma, who have reduced lung function and increased airway responsiveness in later life.

Epidemiology of asthma and recurrent wheeze in childhood

To summarize, wheeze is common throughout childhood, although it decreases as children age. However, the characteristics of wheeze, its relations with asthma, and its risk factors all change with age. Longitudinal studies have shown that "transient early wheezing" predominates during the first years of life. The principal risks for this type of wheezing are largely mechanical, relating to small airways, and infectious, relating to the risk of becoming infected with respiratory viruses. Associated with passive exposure to cigarette smoke, exposure to other children, and not being breastfed, this form of wheezing was unrelated to increased airway liability or atopy in the child. For the majority of children, particularly those with low lung function at birth, wheezing with early LRIs is a benign condition, not associated with subsequent wheeze or risk for asthma. During the middle part of the first decade of life, wheezing appears to reflect a mix of infectious and allergic wheezing. By 6 yr of age, some children have already wheezed persistently. This group is more likely to have high total IgE levels, to be skin-test positive, and to be given a diagnosis of asthma. Further, their immunologic response to their early LRIs was consistent with a Th2 bias: persistent wheezers produced high levels of IgE, and did not demonstrate the normal pattern of decreased eosinophils. Nevertheless, the children who wheeze in middle childhood are a mixed group, with some being less allergic. Thus, although markers of allergy become increasingly important predictors of wheezing for the group as a whole, wheezing in middle childhood is not associated with later methacholine hyperresponsiveness (42). Finally, persistent allergic wheezing, usually associated with a diagnosis of asthma, predominates by the end of the first decade of life. Wheezing at this age is associated with methacholine responsiveness, peak-flow variability, and markers of atopy, such as total IgE and allergy skin-test response. Although children who wheezed early in life are more likely to wheeze later, early wheeze does not increase the risk of atopy, suggesting that early LRIs are markers of increased risk rather than causes. The gender differences in wheeze disappear, with boys becoming less likely to wheeze and to have asthma, whereas both conditions appear to increase in girls. Finally, some of the risk factors for early LRIs, such as exposure to other children in infancy, appear to be associated with protection from later allergic wheezing. Clearly, asthma and wheeze during childhood are complex entities, presenting with different characteristics at different ages, and implicating varied and changing causes. Genetic factors are important determinants of the intermediate phenotypes. However, environmental factors operating at different developmental stages also appear to influence the development of asthma. Additional research regarding these relationships is essential, both to elucidate possible causal mechanisms and to provide insight into the primary prevention of asthma.

The Melbourne Asthma Study: 1964-1999

A group of children with a past history of wheezing was randomly selected from the Melbourne community at the age of 7 years in 1964, and a further group of children with severe wheezing was selected from the same birth cohort at the age of 10 years. These subjects have been followed prospectively at 7-year intervals, with the last review in 1999, when their average age was 42 years. Eighty-seven percent of the original cohort who were still alive participated in the 1999 review. This study showed that the majority of children who had only a few episodes of wheezing associated with symptoms of a respiratory infection had a benign course, with many ceasing to wheeze by adult life. Most who continued with symptoms into adult life were little troubled by them. Conversely, those children with asthma mostly continued with significant wheezing into adult life, and the more troubled they were in childhood, the more likely symptoms continued. There was a loss in lung function by the age of 14 years in those with severe asthma, but the loss did not progress in adult life. The childhood asthma had been treated before the availability of inhaled steroids. There was no significant loss of lung function in those with milder symptoms.

The early course of newly diagnosed asthma

PURPOSE

We describe the intensity of therapy for patients with newly diagnosed asthma and how it changed during subsequent years in relation to age, sex, and initial level of therapy.

METHODS

We examined a cohort of 13,671 patients in Saskatchewan, Canada, who were initially between the ages of 5 and 44 years. Patients were followed prospectively, and the intensity of asthma therapy was measured during successive 12-month periods.

RESULTS

Based on the intensity of asthma drug therapy during the first year after entry into the cohort, 6661 patients (48.7%) were initially prescribed therapy judged to be appropriate for mild asthma, and 977 (7.1%) were dispensed medications in a manner suggesting their asthma was severe; the remaining 6033 (44.1%) were classified as receiving treatment of intermediate intensity. Among patients initially classified as receiving treatment appropriate for mild disease, only about 3% were dispensed medications that suggested that their asthma had become severe during up to 5 years of follow-up. Intensity of therapy waned in a substantial proportion of patients who were initially classified as having severe asthma, especially if they were initially younger than 15 years of age. Thirty-four per 100 patients initially younger than 15 years old were receiving medications appropriate for mild asthma, and 23 per 100 such patients received no medication for asthma during a 12-month period when followed up to 5 years.

CONCLUSION

Patients with asthma who are initially treated with therapy appropriate for mild asthma are rarely treated later with therapy suggesting the advent of severe disease. Patients initially dispensed medications suggesting the presence of severe asthma often see the intensity of treatment wane over time.

Assessing the evidence for remodelling of the airway in asthma

Asthma is now described as being characterized by reversible airflow obstruction, with bronchial inflammation and tissue remodelling of the airway wall. The description of remodelling has been usefully invoked to account for a component of airflow obstruction that is unresponsive to usual bronchodilator therapy. It is crucial to examine critically the evidence for this view, particularly the quantitation of specific changes in the epithelium, mucus glands, cell infiltrate, collagen, vessels and smooth muscle of the bronchial wall. The useful tools of immunohistochemistry and molecular biology combined with airway biopsy and well-designed clinical trials will be essential to determine the specific roles of cells and cytokines in airway remodelling in asthma.

Are all wheezing disorders in very young (preschool) children increasing in prevalence?

BACKGROUND

Distinct wheezing disorders co-exist in young (preschool) children, some of which (early transient wheeze and viral wheeze) are thought to be unrelated to atopy. Investigation of changes in prevalence of wheezing disorders in preschool children could provide important clues about underlying mechanisms responsible for increasing prevalence of asthma in schoolchildren.

METHODS

Repeated population surveys of the prevalence of respiratory symptoms were done by parent-completed postal questionnaires in random samples of 1650 (1990) and 2600 (1998) caucasian children aged 1-5 years living in the county of Leicestershire, UK.

FINDINGS

The response rates were 86% (1422 of 1650) in 1990 and 84% (2127 of 2522) in 1998. Between 1990 and 1998, there was a significant increase in the prevalance of reported wheeze ever (16% to 29%, p<0.0001), current wheeze (12% to 26%, p<0.0001), diagnosis of asthma (11% to 19%, p<0.0001), treatment for wheeze (15% to 26%, p<0.0001), and admission for wheeze or other chest trouble (6% to 10%, p<0.0001). The increase occurred both in children with viral wheeze (9% to 19%) and in those with the classic asthma pattern of wheezing with multiple triggers (6% to 10%). There was also an increase in transient early wheezers (3% to 5%), persistent wheezers (5% to 13%), and late-onset wheezers (6% to 8%), and in all severity groups. The increase could not be accounted for by putative household risk factors because these declined between the 2 years.

INTERPRETATION

The fact that all preschool wheezing disorders increased (including viral wheeze) makes it probable that factors unrelated to atopy are implicated in the changing epidemiology of wheeze in childhood.

Risk factors for the persistence of respiratory symptoms in childhood asthma

OBJECTIVE

To evaluate the parameters which could predict the persistence of respiratory symptoms in asthmatic children who have been treated with a considerably uniform therapy.

METHODS

A retrospective review was performed on the records of 279 children with asthma. An end of study visit, results of spirometry and prick tests completed the data. The mean age at referral and at final visit was 6.2 +/- 3.7 years and 8.9 +/- 4.1 years, respectively; and the children were followed up for a mean of 3 +/- 1.2 years.

RESULTS

Eighty-five of the 279 patients (30%) experienced no respiratory symptoms in the previous 12 months. There was no significant difference between those with and without current respiratory symptoms with respect to age, sex, age at onset of symptoms, duration of followup, age at referral, therapeutic choice, severity of asthma and duration of symptoms at referral. For subjects with current respiratory symptoms the initial serum total IgE level, and the percentage of RAST/prick test positivity was significantly higher than those without current respiratory symptoms (P = 0.0027, P = 0.011, respectively). Although the initial FEF 25%-75%, FEV1, and FEV1/FVC was significantly lower in those with current respiratory symptoms (P = 0.003; P = 0.005; and P = 0.04, respectively), there was no statistically significant difference between lung functions of the two groups at the end of followup. The persistence of respiratory symptoms was significantly predicted by initial FEF25%-75% and sensitivity to allergens (P = 0.03 and P = 0.04, respectively).

CONCLUSIONS

We concluded that the risk factors for the persistence of respiratory symptoms in our patient population have been low FEF25%-75% value and sensitivity to allergens at referral.

Incidence and remission of asthma in schoolchildren: report from the obstructive lung disease in northern Sweden studies

OBJECTIVE

An increasing prevalence of asthma has been reported worldwide as well as in Sweden. In 1996, the prevalence of asthma and type 1 allergy was investigated in a cohort of 3525 children 7 and 8 years old in 3 areas of northern Sweden. The aim of the present study was to estimate the incidence of asthma and to identify risk factors for incident cases over 1 year.

METHODS

The study started with a parental questionnaire, the International Study of Asthma and Allergies in Childhood questionnaire with additional questions, a skin prick test, and a validation study. The cohort was followed up after 1 year with the same questions. The response rate to the questionnaire was 97% in 1996, and 3339 children (97%) participated both in 1996 and 1997.

RESULTS

The incidence of physician-diagnosed asthma was 0.9/100/year; of wheezing, 3.8/100/year; and of new frequent or daily users of asthma medicines, 1.1/100/year. There was no difference by sex. The risk factor pattern based on incident cases of asthma was different from that based on prevalent cases. Significant risk factors for incident asthma were a positive skin test (odds ratio [OR]: 9.3; 95% confidence interval [CI]: 3.8-22.7); low birth weight (OR: 7.4; 95% CI: 2.2-24.5); and family history of asthma (OR: 2.6; 95% CI: 1.1-6.3). Having or having had pets at home was associated with a decreased risk for asthma and wheezing based on prevalent cases, although it was associated with an increased risk for incidence of wheezing (OR: 2.9; 95% CI: 1.3-6.2). Remission of asthma, which was reported by 10% of the children with current asthma during 1 year, was associated with a negative skin test.

CONCLUSION

The incidence of asthma at the age of 8 years was high, but remission was also common. Important risk factors for the development of asthma at this age were type 1 allergy, low birth weight, and family history of asthma. Furthermore, the results suggest that in a region where sensitivity to domestic animals is a strong risk factor for asthma, the presence of pets in the home may have different effects in early childhood compared with later in childhood.

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.