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

Association between allergy and asthma from childhood to middle adulthood in an Australian cohort study

A cohort of 378 asthmatic children was studied from 7 to 35 yr of age at 7-yr intervals. On selection for inclusion in the study sample, the children had a wide range of severity of wheezing. At each 7-yr review, asthma severity, the presence of eczema or hay fever, and skin test reactivity to house dust mite or rye grass were recorded by questionnaire or clinical interview. We report on the course of asthma and these atopic conditions over the study period and discuss associations between the two phenomena. The presence of an atopic condition in childhood was found to increase the odds of more severe asthma in later life (odds ratio [OR] = 1.66, 95% confidence interval [CI]: 1.17 to 2.36 in the case of eczema; OR = 1. 39, 95% CI: 1.00 to 1.92 for hay fever; and OR = 2.25, 95% CI: 1.49 to 3.39 for skin test reactivity). Additionally, the odds of eczema and hay fever in later life increased with severity of asthma in childhood. The findings of this study provide substantially new quantitative information on the extent of association between asthma and atopic conditions from childhood into middle adulthood.

Pediatric origins of adult lung disease. 1. The contribution of airway development to paediatric and adult lung disease

In summary, factors that affect airway growth early in development appear to cause physiological effects that can be persistent. Reduced airway function early in life does not necessarily result in persistent symptoms, but the long term effects and impact on the development of chronic airflow limitation in adults are yet to be determined. Generally, long term sequelae seem to be related to the severity of the initial insult, but the development of persistent increased bronchial responsiveness is an independent risk factor for symptoms and abnormal lung function in later life. In addition, there appear to be separate genetic factors that influence atopy, airway development, and bronchial responsiveness.

Consequences of long-term inflammation. The natural history of asthma

Although asthma is classically defined as reversible airflow obstruction, and often remits in younger subjects with milder disease, the natural history of asthma is that various degrees of airflow obstruction may persist and, in the long-term, asthma may become moderately to fully irreversible. Severe, irreversible airflow obstruction may develop despite apparently appropriate therapy and in the absence of other risk factors, such as smoking and environmental insults. All studies of subjects with persisting asthma show increased decline in lung function compared with normal subjects. Persistent abnormal physiology is reflected both in reduced airflow rates and in increased airway responsiveness. The cellular and molecular mechanisms of airway remodeling are described elsewhere in this issue. Questions not yet clearly answered are the reasons for these persistent abnormalities in some asthmatics, and which subjects are most at risk. Factors that adversely impact the outcome as adults identified relatively consistently among many longitudinal studies of the natural history of asthma include: Female gender. Environmental tobacco smoke exposure in childhood. Personal tobacco smoking in adolescence and adulthood. Age of onset of symptoms. Severity of childhood asthma. Duration of asthma. Severity of lung function abnormality in childhood. Bronchodilator reversibility. Degree of airway hyperresponsiveness. Delay in initiating anti-inflammatory therapy. Remission among adult asthmatics is uncommon, but is associated with better initial lung function, young age, male gender, and lesser degrees of airway responsiveness. The role of atopy remains controversial. Conversely, risk factors for death from asthma include older age, smoking, atopy, impaired lung function, and moderate to high reversibility. Treatment can improve lung function, reduce airway responsiveness, and improve quality of life. The overall effect of treatment on the natural history of the disease is not yet clear, despite significant short-term improvements from effective anti-inflammatory therapy.

Asthma from childhood to adulthood: asthma severity, allergies, sensitization, living conditions, gender influence and social consequences

The course of asthma severity, clinical allergies, allergic sensitization, changes in living conditions and social outcome were studied prospectively over five follow-up visits from the mean age of 9 to 30 years in a cohort of 28 boys and 27 girls, selected randomly among asthmatic children attending a paediatric outpatient unit. Asthma severity improved from childhood to adulthood, judged by symptom and medication scores and by the number of hospital admissions, but only nine subjects (16%) had been free from symptoms and medication over the last year of follow-up. After adolescence, asthma continued to improve among the males but not among the females. This difference could not be explained by gender differences in the course of clinical allergies or sensitization (skin-prick-tests and RAST) to common inhaled allergens, or by differences in environmental or social conditions. Sensitization to relevant perennial inhaled allergens correlated with asthma severity during adulthood. In general, clinical allergies and sensitization to inhaled allergens adopted during childhood persisted into adulthood. Approximately 10% of the subjects never adopted a clinical allergy or a positive allergy test. The social outcome was good.

Prolonged episodes of persistent asthma: A distinct clinical pattern with characteristic clinical features

STUDY OBJECTIVES

To investigate a clinical pattern of unexplained persistent asthma that is episodic in nature and lasts for months to years. This pattern of prolonged episodes of unexplained, persistent asthma was not defined previously.

DESIGNS

Investigating the clinical features using a retrospective cohort design.

SETTING AND PATIENTS

Eighteen subjects (ages, 13 to 64 years) from an allergy practice in a large prepaid health maintenance organization who had two or more prolonged episodes of unexplained persistent asthma lasting >/= 2 months during a 12-year period.

RESULTS

These subjects accounted for 39 asthmatic episodes lasting from 2 to 74 months (median, 7 months). The duration of the episodes positively correlates with the severity of asthma (p = 0.02) at the initial part of the episodes. All episodes demonstrated a similar pattern, with symptom severity greatest at the onset and gradually diminishing until recovery. The relatively symptom-free intervals between the episodes ranged from 1.5 to 63 months (median, 13 months). Fifty-six percent of the episodes (95% confidence interval [CI], 40% to 72%) were associated with symptoms very suggestive or suggestive of an infection of the upper respiratory tract at the onset of the episodes; 33% of the episodes (95% CI, 19% to 50%) had possible symptoms suggestive of an infection; whereas only 10% of the episodes (95% CI, 3% to 24%) had questionable or no symptoms suggestive of an infection of the upper respiratory tract. Thirty-four episodes had the onset between September and March, whereas only 5 episodes occurred between April and August (p < 0. 001).

CONCLUSIONS

These observations indicate that prolonged episodes of unexplained, persistent asthma lasting for months to years constitute a distinct clinical pattern of asthma with characteristic clinical features.

Natural history of chronic asthma and its long-term effects on pulmonary function

Although asthma is a disease that has intrigued physicians since antiquity, its natural history has been incompletely determined. It has long been held that the presence of asthma, per se, does not carry with it any long-term deterioration in lung function, but recently this view has been challenged, and it has become fashionable to define asthma as being only partially reversible. At present, there are limited data to support such a view. All of the available information indicates that the vast majority of patients do not experience the development of a progressive decline in pulmonary mechanics or appear to be at risk for a diminution in life expectancy.

The epidemiology of childhood asthma

Variability is the hallmark of childhood asthma. Conceptually defined as variable airflow obstruction, asthma affects individual children through a variety of clinical manifestations. Particular controversy surrounds the nature of wheezing in early infancy and its relationship to atopic asthma of later onset. Asthma prognosis is also highly variable and only to a limited extent predictable by clinical indicators in early childhood. Long-term follow-up studies suggest a complex pattern of remission and relapse as wheezy children are followed through adolescence into adult life. Similarly, the population burden of asthma is highly variable, both over time and between countries. The balance of evidence worldwide suggests a modest but sustained increase in the prevalence of asthma symptoms over the past three decades. Superimposed on this have been larger changes in diagnostic fashion and use of health services for childhood asthma in many countries. There is substantial international variation in the prevalence of asthma symptoms, and marked urban-rural differences have been reported from several African countries. These contrast with the more uniform distribution of the disease within industrialized countries, reflecting its ubiquity in affluent societies.

Remission of asthma in the middle aged and elderly: report from the Obstructive Lung Disease in Northern Sweden study

BACKGROUND

Remission of asthma in adults has been considered to be low but is still not well documented. In children remission occurs with a rate estimated at approximately 50%. Remission of asthma in middle aged and elderly subjects was investigated as part of a population based study of respiratory diseases in Northern Sweden.

METHODS

In 1986 86% of 6610 subjects participated in a questionnaire survey. After a clinical validation study 300 subjects were diagnosed as having current asthma. In 1996 5935 subjects of the cohort could be traced for a third survey and 87% participated. Of the subjects with current asthma in 1986, 267 participated. In addition, 60 symptomatic subjects were classified as suspected asthma and 58 of them participated in 1996. Remission of asthma was defined as no recurrent wheeze, no attacks of shortness of breath, and no use of asthma medicines in 1996.

RESULTS

Remission of asthma during the 10 year period under study was 6%. In subjects with suspected asthma, remission occurred in 22%. The average annual remission rate was less than 1%. Remission was associated with previously mild disease and cessation of smoking.

CONCLUSION

Remission of asthma or the disappearance of its symptoms to an asymptomatic latent phase appeared to be rare in middle aged and elderly subjects.

Relationships between duration of asthma and asthma severity among children in the Childhood Asthma Management Program (CAMP)

BACKGROUND

Many factors, including heredity, atopic status, and environment, have been implicated in the determination of asthma severity. Relatively little is known about the degree to which asthma duration influences asthma severity.

OBJECTIVE

The Childhood Asthma Management Program (CAMP), consisting of 1041 children (age 8. 9 +/- 2.1 years at enrollment) with mild-to-moderate asthma, offers an opportunity to examine the relationship between asthma duration and asthma severity.

METHODS

By using the extensive CAMP baseline cross-sectional data on asthma duration, spirometry, bronchial responsiveness, symptomatology, and markers of atopy, univariate and multivariate regression models were used to evaluate whether asthma duration is associated with asthma severity.

RESULTS

Duration of asthma in the study cohort from time of diagnosis until randomization into CAMP ranged from 0.3 to 12.1 years (mean, 5.0; SD, 2.7; median, 4.8). Asthma duration is associated in univariate analyses both with lower levels of several lung functions (P <.001), including methacholine bronchial reactivity (natural log [ln] FEV1 PC20, mg/mL; r = -0.112), prebronchodilator and postbronchodilator percent predicted FEV1 (r = -0.176 and r = -0.130, respectively), and prebronchodilator and postbronchodilator FEV1 /forced vital capacity (FVC) (%) (r = -0.237 and r = -0.211, respectively), as well as higher levels of symptoms (symptom score: r = 0.147, P <. 001) and borderline greater use of albuterol for symptoms (r = 0.058, P =.064) during a 28-day screening period before randomization. Simple linear regression detected the following differences in lung functions per year of asthma duration: ln FEV1 PC20, -0.050 mg/mL/y; prebronchodilator FEV1, -0.907 percent predicted/y; and prebronchodilator FEV1 /FVC, -0.729 percent predicted/y. After controlling for potential explanatory variables (atopy, inflammatory markers, household Der p 1 levels, anti-inflammatory medication use, and clinical center), regression models revealed that the duration of asthma remained significantly and independently associated with ln FEV1 PC20 (P =.004), prebronchodilator percent predicted FEV1 (P =.043), and prebronchodilator and postbronchodilator FEV1 /FVC (%) (P <.001), as well as being positively associated with mean daily symptom score (P <.001) and albuterol use for symptoms (P =.003) during a 28-day screening period. Duration was also found to be significantly associated with physician/nurse assessment of asthma severity and other historical measures of medication use.

CONCLUSIONS

These data demonstrate that asthma duration is associated with lower lung function, greater methacholine responsiveness, more asthma symptomatology, and greater use of as-needed albuterol, which are all measures of asthma severity. As such, early diagnosis and intervention may be necessary to ameliorate these adverse effects of persistent asthma.

Asthma and reproductive medicine

Asthma is a common disease affecting approximately 5 percent of the population and is a major cause of disability. Research interest in the condition is high because of frequent reports that the incidence, prevalence, severity, and mortality rates have been rising in recent years. Although the etiology remains elusive, knowledge about its pathophysiology is extensive and detailed, which in turn has spawned an impressive array of effective and safe drugs to prevent and treat acute exacerbations. Pharmacotherapy is enhanced by appropriate environmental control measures and immunotherapy for the significant number of asthmatics with an allergic component to their disease. The pregnant asthmatic may pose special requirements for the small minority with severe corticosteroid-dependent disease or those subject to frequent attacks. However, the great majority of asthmatic women need not face much risk of adverse effects on the course of the pregnancy or significant fetal or perinatal abnormalities, as long as appropriate preventive measures and monitoring are taken.

Evolution of asthma through childhood

The greatest incidence of childhood asthma is among males under 5 years, with decreasing numbers of new cases with age. Many young children wheeze, but remission is common especially in non-atopic children without a family history of allergy or asthma, whose wheezing relates more to infections and environmental tobacco smoke exposure. The prognosis of childhood asthma is best established from population studies, in which some two-thirds of wheezy children become symptom-free as adults, whereas follow-up studies of wheezing children seen in office or specialty clinic practice, who generally have more severe asthma, show a much greater likelihood (60-80%) of persistence of asthma into adulthood. Factors predisposing to persistence of childhood asthma include a positive family history, development of atopy, environmental exposures to allergens and cigarette smoke, markers of severity of childhood asthma, and female gender.

Effects of inhaled corticosteroids on the consequences of asthma

Asthma is a chronic inflammatory disease of the airways involving a characteristic pattern of airway infiltration with lymphocytes, eosinophils, and mast cells, subepithelial deposition of collagen, and hypertrophy and hyperplasia of smooth muscle and of goblet cells and submucosal glands. The consequences of this chronic process include episodic or persistent symptoms, bronchial hyperreactivity, attacks of bronchoconstriction that may require emergency care or hospitalization and can lead to death, impairment in quality of life, and the development of irreversible airflow obstruction. Careful pathologic studies have shown that inhaled corticosteroid therapy can reverse or suppress airway inflammation, and prospective controlled clinical trials have proven that it can also improve symptoms, reduce bronchial hyperreactivity, and reduce the frequency and severity of attacks. It is also highly likely, although it is not yet proven, that inhaled corticosteroid therapy reduces the risk of asthma fatality and prevents or retards airway wall remodeling. These beneficial effects are easily shown in patients with moderate or severe asthma. Although inhaled corticosteroid therapy also benefits patients with mild asthma, it is less certain that the costs and risks of continuous therapy are justified. For these patients, the most important issues that remain to be resolved are the nature of the risk of development of permanent airflow obstruction and the effects of early, sustained treatment on the chances of sustained remission of asthma after all therapy has been stopped.

The natural history of asthma

Our understanding of the natural history of asthma is improving through the establishment of a more precise definition of asthma linked with information from large-scale longitudinal studies. Risk factors for the development of childhood asthma including sex, atopic status, genetic and familial factors, respiratory infections, and outdoor and indoor pollution are now more clearly understood. New information on the relation of viral wheezing episodes in infancy to later childhood asthma is evolving. We now know that children who start wheezing early in life and continue to wheeze at age 6 years are more likely to have a maternal history of asthma, elevated serum IgE levels, and normal lung function in the first year of life. However, at age 6 years they have both elevated serum IgE levels and diminished lung function. Approximately 50% of adults who report having had childhood asthma no longer have symptoms. Airway responsiveness in childhood tends to predict airway responsiveness in adulthood and to be greater in asthmatics with persistent symptoms. Studies of the natural history of asthma support the hypothesis that early therapeutic intervention in mild disease may lead to an improved clinical outcome. Adults exposed to specific occupational environments are at additional risk for the development of asthma. As we learn more about the natural history of asthma, we will have a better understanding of the effect of early diagnosis, environmental control, and therapy on the outcome of the disease.

The natural history of respiratory symptoms in a cohort of adolescents

A cohort of 2,289 children, previously studied at the age of 6-8 yr, were followed up by means of a postal questionnaire when aged 14 -16 yr to examine the association between potential risk factors and the natural history of respiratory symptoms. Children with current symptoms, persistent symptoms, and late-onset symptoms were identified and multivariate analyses were performed to determine the independent association between risk factors and these various symptom-based subgroups. Personal and family history of atopy was significantly associated with all symptom groups and with the presence of doctor-diagnosed asthma. Smoking, either active or passive, was shown to be significantly associated with current, persistent, and late-onset symptoms. Other factors shown to be significantly associated with certain symptom groups were gender (late-onset wheeze), single-parent households (current cough, persistent cough), social class (late-onset wheeze), number of children in the household (persistent wheeze, late-onset cough), number of furry pets in the household (current wheeze), birth weight (late-onset wheeze), and gas cookers (current wheeze, persistent wheeze). In a subgroup of children studied in more detail in 1987, bronchial hyperresponsiveness in 1987 was positively associated with persistent wheeze in 1995, whereas positive skin-prick testing in 1987 was not.

Effects of inhaled corticosteroids on growth

Inhaled corticosteroids are an established treatment for asthma in childhood. The risk of adverse events associated with conventional doses of inhaled corticosteroids is low, but in children with asthma concern remains about the potential effects of these compounds on growth. Short-term growth in children can be measured with knemometry. This technique measures changes in lower leg length that can be detected over periods as short as days or even intradaily. However, nonlinearity of lower leg growth and the complexity of statural growth confound any attempts to derive a predicted height from short-term measurements of the lower leg. Knemometry is better at detecting growth suppression than growth promotion. With knemometry, inhaled fluticasone propionate 200 microg/day had no effect on lower leg growth, but beclomethasone propionate 400 microg/day significantly reduced lower leg growth. Inhaled budesonide also caused a dose-dependent reduction in lower leg growth, but this only reached significance at the 800 microg/day dose. Long-term growth in children is measured with stadiometry. Growth velocity can only be determined from measurements of height taken over a period of at least 1 year. There is no evidence that inhaled corticosteroids at conventional doses have an adverse effect on the final height of children, but it is important to be aware of the growth-impairing effect of poorly controlled asthma. All children with asthma receiving inhaled corticosteroids should have their growth monitored, and any deviation from the expected pattern should be investigated. The effect of early intervention with inhaled steroids in childhood warrants further investigation.

Epidemiology of Asthma

Epidemiology of asthma is discussed in terms of the prevalence, risk factors associated with increasing morbidity and mortality, impact on life-style, long-term prognosis, and economic impact. Those most at risk for development of asthma are young children, African Americans, and those in lower economic status and inner-city communities. The primary contributing factor to increasing morbidity and mortality is undertreatment. Contributing factors may be restricted access to continuing medical care, unstable family situations, cultural and language barriers, failure to recognize severity of the disease, and inability to afford care.

Care of asthma: allergy clinic versus emergency room

BACKGROUND

Demographic and socioeconomic factors have an impact upon the morbidity and mortality rates of asthma in inner-city pediatric populations. Many pediatric patients with asthma use the emergency room as their primary care physician, while a smaller number of children with asthma use the allergy-immunology clinic.

OBJECTIVE

We examined the demographic and socioeconomic characteristics of asthmatic patients using the emergency room as their primary care physician and of those attending the allergy-immunology clinic in the same inner-city hospital. We compared the morbidity and cost of care of asthmatic patients who received their medical care in the emergency room to that of those who received their care in the allergy-immunology clinic.

METHODS

Fifty consecutive emergency room patients and 25 clinic patients were studied using an identical questionnaire.

RESULTS

There was no difference between the two groups in the total number of individuals per household, children per family, monthly income, type or size of dwelling, financial problems purchasing medications, health insurance type, distance to the medical center, or education of the caretaker. Severity of asthma was not different in the two groups before the start of the study. The only significant demographic difference was in age: 10.6 years for the clinic group and 7.8 years for the emergency room group (P < .002). Clinically, in the year preceding the interview, the clinic group had significantly less nocturnal cough (P < .025), sleep interruption (P < .001), weekly asthma (P < .05), and emergency room visits (P < .09). The allergy clinic group had an approximate average savings of $137 per patient per year. Hospital admissions and emergency room costs were increased by a small group of three allergy clinic patients, decreasing the difference in the cost of care between the two groups.

CONCLUSION

The data showed that patients who attended the emergency room and those who attended the allergy-immunology clinic were not demographically or socioeconomically different. The decreased morbidity of asthma and cost of care for the allergy clinic patients, as opposed to the emergency room patients, are likely due to the care given in the allergy-immunology clinic.

Childhood antecedents of adult respiratory disease

This review examines the relations between early childhood lower respiratory symptoms and adult respiratory disease. The problems associated with investigating potential associations between respiratory disease in children and adults are discussed. Some studies have limitations because they are retrospective and early childhood respiratory symptoms have not been accurately diagnosed. Therefore, in this review, particular attention is paid to longitudinal studies (some from birth) that have used strict diagnostic criteria for respiratory episodes. These studies provide unique insights into the risk factors for the development of childhood respiratory problems and for persistence of symptoms into adulthood. Although cross-sectional studies have indicated that early childhood respiratory disease is more frequent in adults with respiratory disease, evidence from longitudinal studies suggests that respiratory symptoms such as wheezing, are transient in the majority of infants and result from developmentally small airways. These longitudinal investigations have also indicated that persistence of symptoms into later childhood is associated with atopy. The important role of cigarette-smoke exposure as a risk factor for abnormal pulmonary development, persistence of respiratory disease and reduction in lung function is discussed. The discovery of genetic markers associated with respiratory syndromes such as asthma, should facilitate studies that investigate the childhood antecedents of adult respiratory disease. Future longitudinal studies using genetic markers, will allow relations between specific genotypes and phenotypic outcomes to be examined.

Stability of respiratory symptoms in unlabelled wheezy illness and nocturnal cough

OBJECTIVE

To assess the natural history of respiratory symptoms not labelled as asthma in primary schoolchildren.

DESIGN

Repeat questionnaire survey of subgroups identified from a previous questionnaire survey after a two year delay.

SUBJECTS

The original population of 5321 Sheffield children aged 8-9 years yielded 4406 completed questionnaires in 1991(82.8%). After excluding children with a label of asthma, there were 370 children with current wheeze, 129 children with frequent nocturnal cough, and a random sample of 222 children with minor cough symptoms and 124 asymptomatic children.

RESULTS

Response rates in the four groups were 233 (63.0%), 77 (59.7%), 160 (72.1%), and 90 (72.6%) respectively. Of those who initially wheezed, 114 (48.9%) had stopped wheezing and 42 (18.0%) had been labelled as having asthma. Those with more frequent wheezing episodes (p < 0.02) and a personal history of hay fever (p < 0.01) in 1991 were more likely to retain their wheezy symptoms. In the children with frequent nocturnal cough in 1991, 20.1% had developed wheezing, 42.9% had a reduced frequency of nocturnal coughing, and 14.2% had stopped coughing altogether two years later. One sixth had been labelled as having asthma. Children with nocturnal cough were more likely to develop wheezing if they had a family history of atopy (p = 0.02). Only 3.8% and 3.3% of those with minimal cough and no symptoms respectively in 1991 had developed wheeze by 1993 (1.9% and 1.0% labelled as asthma).

CONCLUSIONS

Most unlabelled recurrent respiratory symptoms in 8-10 year olds tend to improve. Unlabelled children who have persistent symptoms have other features such as frequent wheezing attacks and a family or personal history of atopy. If a screening questionnaire were to be used to identify such children, a combination of questions should be employed.

Spirometry, bronchodilator test or symptom scoring for the assessment of childhood asthma

The value of spirometry, the bronchodilator test and 2 weeks' symptom scoring for the assessment of the severity of childhood asthma was studied in a series of 65 consecutively referred school-aged asthmatic children, with the diurnal peak expiratory flow (PEF) variability in home recordings serving as a golden standard. The amplitude of the peak expiratory flow rate (PEFR) variation could be best predicted by the baseline forced expiratory volume in 1 s (FEV1) and the past history of the symptom rate, the correlation with FEV1 being -0.48, p < 0.001. Although the baseline forced expiratory flow between 25 and 75% of the forced vital capacity (FEF25-75%) and the responses of FEV1 and FEF25-75% to salbutamol also showed significant correlations with the diurnal PEFR variability (r = -0.43, r = 0.47 and 0.41, p < 0.001, respectively), these variants did not improve the regression model. The baseline FEV1. FEF25-75% and PEFR and their responses to salbutamol also had a slight but statistically significant correlation with the methacholine threshold, but the symptom score on the diary card did not show comparable correlations with either the diurnal PEFR variability or the methacholine threshold (r = 0.09, NS, and r = 0.05, NS, respectively). These results indicate that both baseline lung function and the response to the bronchodilator test correlate with the severity of childhood asthma more appropriately than does the symptom score on a diary card. Since many of these correlations were rather weak, however, the assessment of the severity of childhood asthma cannot be reliably based solely on spirometry in all patients.

Prognostic factors for the outcome of childhood asthma in adolescence

By the second decade of life asthma symptoms often abate and it may seem that patients with mild asthma have "outgrown" the disease. Unfortunately this is likely to be the exception rather than the rule. Although the severity of asthma symptoms fluctuates with time, the inherited tendency towards respiratory symptoms never disappears and many teenagers who seem to be free of symptoms do, in fact, have persistent asthma. During symptom-free periods subclinical, but nevertheless significant, airways obstruction and/or bronchial hyperresponsiveness may be present. It is not unusual for adults who have been asymptomatic for a number of years to redevelope asthma symptoms. Indeed, much of the so-called adult onset asthma has its roots in childhood. Levison concluded that, in these subjects, it is often not the asthma that is outgrown but the paediatrician. The more severe asthma is in childhood the more likely it is that the disease will persist in adulthood. A complete list of the characteristics of the disease in childhood, and the potential risk factors associated with an unfavourable prognosis, such as pulmonary function and bronchial responsiveness and markers of airway inflammation, is therefore needed. As properly matched and controlled prospective long term studies have not been published it has not been possible to evaluate the effects on prognosis of any single class of antiasthma agent. Such studies are needed to find out if it is possible to alter the natural history of the disease. In theory modern asthma treatments, because they are able to improve symptoms and underlying disease phenomena, are also beneficial in the long term prognosis of childhood asthma. The majority of patients with persistent asthma included in the currently available studies were not receiving adequate treatment. Since compliance with therapeutic regimens in asthma, especially in adolescence, is low, a monitoring system is needed to guarantee adequate follow up and treatment during and beyond puberty.

Long-term survival of a cohort of community residents with asthma

BACKGROUND

Reports of an increase in asthma-related mortality have been based on studies of death certificates from the general U.S. population on which asthma was listed as an underlying cause of death. We addressed the issue in a different way by analyzing long-term survival in a defined, population-based cohort of patients with asthma.

METHODS

We identified all residents of Rochester, Minnesota, in whom asthma was diagnosed from January 1, 1964, through December 31, 1983, by reviewing the medical records of all patients with asthma and associated diagnoses, using explicit predefined criteria. The patients' vital status at last follow-up was ascertained. Medical records, death certificates, and autopsy reports were reviewed to classify deaths as due either to asthma or to other conditions.

RESULTS

We identified 2499 patients with definite or probable asthma. The mean duration of follow-up was 14 years (range, 0 to 29). There were 140 deaths during 32,605 person-years of follow-up. Overall survival was not significantly different from the survival that was expected for residents of Rochester. Survival was less than expected in patients who were 35 years of age or older when their asthma was diagnosed and who also had another lung disease (predominantly chronic obstructive pulmonary disease). Four percent of all deaths in the study cohort were due to asthma, and all were among adults. Survival was not related to the year of onset of asthma.

CONCLUSIONS

Survival among patients with asthma but no other lung disease was not significantly different from expected survival. However, patients 35 or older who had asthma associated with chronic obstructive pulmonary disease did have worse than expected survival. Asthma was classified as the cause of death in only 4 percent of the patients, and there was no evidence of an increased risk of death among patients with a more recent diagnosis of asthma. These results provide assurance that community-based patients with asthma usually have a good prognosis.

Cow milk allergy within the spectrum of atopic disorders

In order to examine the relationship between cow milk allergy (CMA) and atopic disorders in childhood, a consecutive group of 42 infants with IgE mediated CMA was followed for at least 2 years. The incidence of sensitization to common food and inhalant antigens and the development of eczema, asthma, and food allergies was examined for the cohort and compared between patients whose CMA remitted and those with persistent disease. In this cohort the prevalence of eczema was 57%, asthma 69%, egg allergy 67%, peanut allergy 55%, and 83% of infants demonstrated positive skin-prick tests to three or more allergens. At the end of the study CMA had remitted in 13 patients (median age 44 months) whereas in 29 patients it persisted (median age 44 months). Although there was no significant difference in the incidence of eczema or asthma during the study between these two patient groups, the incidence of allergy to egg and peanut butter was significantly greater for children with persistent CMA. Consistent with our hypothesis that children with persistent CMA have a more severe dysregulation of IgE synthesis than those whose disease remits, patients with persistent CMA had a significantly higher incidence of and level of skin sensitivity to inhalant and other dietary allergens. Sensitization to the inhalant allergens Dermatophagoides pteronyssinus, cat dander and rye grass was frequently seen in early infancy and increased during the study period. Thus, children with IgE mediated CMA frequently generate IgE responses to multiple dietary and inhalant allergens in infancy and early childhood and develop immediate hypersensitivity to other foods as well as clinical eczema, and asthma.

Prognosis of asthma in children: a cohort study into adulthood

Fifty-six children with asthma, randomly selected from a hospital clinic, were followed prospectively for 15 years from a median age of 9-24 years of age. Four follow-ups were performed and included scoring of the frequency of wheezing, the need for medication, admissions to hospital, spirometry, skin prick tests and RAST to common inhaled allergens, and evaluation of living conditions. One patient died of asthma. The remaining 55 reported for all follow-ups. After the second follow-up at a median age of 13 years, all parameters of severity of asthma showed improvement, which was significant at the last follow-up when all subjects were more than 20 years of age. Only 16% of the subjects had been free from wheezing and medication the year prior to the last follow-up. Approximately 90% of the children had clinical allergies and positive allergy tests to pollens and danders and the majority of children retained both the allergies and the reactivity into adulthood. Reactivity to moulds and mites was less frequent (40% and 31%, respectively) and seemed to decrease in adulthood. Approximately 10% of the subjects developed neither clinical allergies nor reactivity in allergy tests. Children with atopic eczema usually retained their eczema as adults. Frequent wheezing and abnormal spirometry in childhood and early onset of asthma were associated with poorer outcome. The social prognosis was excellent.

Factors in childhood as predictors of asthma in adult life

OBJECTIVE

To determine which factors measured in childhood predict asthma in adult life.

DESIGN

Prospective study over 25 years of a birth cohort initially studied at the age of 7.

SETTING

Tasmania, Australia.

SUBJECTS

1494 men and women surveyed in 1991-3 when aged 29 to 32 (75% of a random stratified sample from the 1968 Tasmanian asthma survey of children born in 1961 and at school in Tasmania).

MAIN OUTCOME MEASURES

Self reported asthma or wheezy breathing in the previous 12 months (current asthma).

RESULTS

Of the subjects with asthma or wheezy breathing by the age of 7, as reported by their parents 25.6% (190/741) reported current asthma as an adult compared with 10.8% (81/753) of subjects without parent reported childhood asthma (P < 0.001). Factors measured at the age of 7 that independently predicted current asthma as an adult were being female (odds ratio 1.57; 95% confidence interval 1.19 to 2.08); having a history of eczema (1.45; 1.04 to 2.03); having a low mild forced expiratory flow rate (interquartile odds ratio 1.40; 1.15 to 1.71); having a mother or father with a history of asthma (1.74 (1.23 to 2.47) and 1.68 (1.18 to 2.38) respectively); and having childhood asthma (1.59; 1.10 to 2.29) and, if so, having the first attack after the age of 2 (1.66; 1.17 to 2.36) or having had more than 10 attacks (1.70; 1.17 to 2.48).

CONCLUSION

Children with asthma reported by their parents in 1968 were more likely than not to be free of symptoms as adults. The subjects who had more severe asthma (especially if it developed after the age of 2 and was associated with reduced expiratory flow), were female, or had parents who had asthma were at an increased risk of having asthma as an adult. These findings have implications for the treatment and prognosis of childhood asthma, targeting preventive and educational strategies and understanding the onset of asthma in adult life.

Persistence of airway obstruction and hyperresponsiveness in subjects with asthma remission

This study was designed to determine if there is residual airflow obstruction and/or airway hyperresponsiveness in adults with symptomatic asthma remission, and if age at remission or its duration influence these parameters. We studied 30 subjects, (20 men, 10 women, 28 atopics, aged 18 to 61 years; mean, 32 years) with a history of asthma (mean duration, 2 to 33 years) but who reported no symptoms or medication requirement for > or 2 years. They were individually matched for age, sex, and atopy, to a control group of 30 subjects without history of asthma. Each subject had a respiratory questionnaire and measurements of expiratory flows, lung volumes, and bronchodilator response. Morning/evening peak expiratory flow rates (PEFRs) were recorded for a 2-week period and two methacholine inhalation tests were obtained on separate days. Initial FEV1 and FVC for ex-asthmatics (controls) were, respectively, 91.0 +/- 2.5 percent and 97.8 +/- 2.3 percent (104.1 +/- 1.9 and 104.0 +/- 1.8 percent) of predicted values. Twenty nine ex-asthmatics (15 controls) had occasional respiratory symptoms, not attributed to asthma. Most subjects with asthma remission had evidences of mild airflow obstruction, associated to a methacholine response either increased in 11 (PC20 methacholine, 0.18 to 5.6 mg/ml) or "borderline" in 10 others (PC20 between 8 and 20 mg/ml). Airway responsiveness was normal (PC20 > 20 mg/ml) in 8 ex-asthmatics and in 21 controls (PC20 was under 8 mg/ml and between 10 and 20 mg/ml in, respectively, 5 and 4 controls). Mean reversibility of FEV1 after 200 micrograms of albuterol was 5.7 (range, -1.1 to 14.1 percent) compared with 2.5 (-4.4 to 10.5) in controls. Mean and maximal diurnal variation of PEFR were, respectively, 4.6 +/- 0.4 percent and 12.3 +/- 1.3 percent (controls, 2.9 +/- 0.3 and 7.0 +/- 0.8 percent). There was a significant correlation between PC20 and age at the diagnosis of asthma or at the onset of remission. Airway responsiveness was significantly less when asthma or remission of asthma occurred at a younger age, although there was no difference for baseline FEV1 and no significant correlation between PC20 and duration of asthma or of remission. Perception of bronchoconstriction was similar in both controls and ex-asthmatics. In conclusion, most ex-asthmatics who considered to be in asthma remission showed a persistent increase in airway responsiveness with or without mild airflow obstruction, suggesting that symptom report may be insufficient to determine that asthma is in true remission.

Bronchial responsiveness in children and adolescents: a comparison between previously asthmatic, currently asthmatic, and normal subjects

The aim of this study was to examine the degree of bronchial responsiveness in previously asthmatic subjects. Of 253 patients, born within 1964-1974, followed in the pediatric department at the University hospital in Copenhagen, 224 subjects (89%) were successfully contacted by telephone; of these 195 complained of persistent asthma and 29 (13%) had had no asthmatic symptoms for at least 2 years. On the basis of the degree of respiratory symptoms, 58 individuals were examined at the outpatient clinic. Of these, (1) 19 were previously asthmatics, (2) 20 had current mild asthma, and (3) 19 had current severe asthma. Furthermore, 19 healthy individuals, age-matched with the preceding asthmatic subjects, were selected as controls. In all subjects, skin prick tests, lung function tests, and bronchial challenge tests with inhaled histamine and bronchodilator were performed. Furthermore, the subjects measured their peak expiratory flow (PEF) twice daily during a period of 4 weeks. Of the 39 current asthmatic subjects, 82% had a PC20 < or = 8 mg/ml, whereas all previously asthmatic subjects and the controls had a PC20 > 8 mg/ml. The degree of bronchial responsiveness as indicated by the dose-response slope (DRS), the percentage change in forced expiratory volume in 1 sec (FEV1) per inhaled mumol of histamine, was found to be significantly higher in previously asthmatic patients (median logDRS 0.1 delta %FEV1/mumol) than in controls (median logDRS-0.4 delta %FEV1/mumol) (p < 0.001). Furthermore previously asthmatic subjects had significantly increased change in FEV1 after inhalation of bronchodilator and peak expiratory flow variability compared to controls. These findings suggest that apparently asymptomatic previously asthmatic subjects have increased airway variability.

Clinical features of adult-relapse asthma in comparison with those of child-onset asthma and adult-onset asthma

Clinical features of adult-relapse asthma (group B, n = 15) were compared with those of child-onset asthma (group A, n = 18) and adult-onset asthma (group C, n = 34) in terms of allergic component and bronchial hypersensitivity. The percentage of patients with high levels of serum IgE (> 300 U/ml) in groups A, B, and C was 83%, 73%, and 50%, respectively, and the percentage of patients with positive IgE RAST for house dust was 87.5%, 78.6%, and 46.7%, and that for mite was 93.3%, 92.9%, and 58.6% in groups A, B, and C, respectively. The histamine concentration of PC20 for the bronchial hypersensitivity test in groups A, B, and C was 196 micrograms/ml, 500 micrograms/ml, and 724 micrograms/ml, respectively. Thus, the adult-relapse asthma was closer to the child-onset asthma type in allergic state and closer to the adult-onset asthma type in bronchial hypersensitivity state. The classification employed here seemed to provide some merits in delineating the features of adulthood asthma.

Risk factors for the persistence of respiratory symptoms in childhood asthma

We studied the prognosis of childhood asthma in a cohort of 406 children 8 to 12 yr of age when enrolled. Subjects were followed for a mean of 14.8 yr after their initial evaluation, with a follow-up rate of 86%. The mean age at follow-up was 24.7 yr. We assessed the predictive value of sex and various childhood variables on the outcome of symptoms and medication use in adulthood. Although only 19% of subjects were still under a physician's supervision at the time of follow-up, 76% had respiratory symptoms, 32% used maintenance medication, and 22% used medication intermittently. The incidence of cigarette smoking was disturbingly high (33%). In adulthood, women were more likely than men to have symptoms (85 versus 72%, respectively). The childhood symptom severity and the childhood degree of bronchial responsiveness in combination with a low %FEV1 were also related to the outcome of asthma in adulthood. The high prevalence of symptoms in adults at follow-up coupled with the low rate of physician supervision and medication usage suggest that more aggressive treatment may be indicated in asthmatic children.

Spontaneous improvement in bronchial responsiveness and its limit during preadolescence and early adolescence in children with controlled asthma

To study whether improvement in bronchial responsiveness contributes to outgrowing of asthma, PC20-histamine was measured longitudinally in nine nonsteroid-dependent asthmatic children (six boys, three girls), aged 8.1 to 9.8 years (mean, 9.2 years) at the beginning of the study. The measurement was discontinued when final inhaled histamine concentration in at least two consecutive measurements did not exceed the previous highest one. Two or more doubling concentration differences in inhaled histamine is regarded as significant in our center. Mean (SD) study period was 3.6 (0.8) years, interval of the measurements was 10.6 (2.3) months. Geometric mean of PC20-histamine at the beginning was 0.39 mg/ml. PC20-histamine improved significantly in seven of nine patients during the study period, though best values were less than 8 mg/ml in all. Mean (SD) age reaching the highest final concentration was 11.0 (0.8) years. These data suggest that the improvement in bronchial responsiveness may be one of mechanisms in the outgrowing of asthma around adolescence.

Childhood asthma: diagnosis and treatment

This discussion of asthma management should be regarded as providing guidelines, not dogma. The underlying principles of asthma management include recognition of the variability of the disease and the importance of the underlying inflammatory condition. Clinical assessment is not enough and objective monitoring with PEFR or spirometry provides important data. The treatment protocols require individualization. It is important that the patient and family are team members working together with the medical staff toward a goal of good asthma management. In the discussion of the management of asthma, much emphasis was placed on spirometry and home measurement of PEFR. Office use of spirometry is now the norm for asthma management. Providing asthmatic patients with peak flow meters and instructions in their use is part of the routine care of asthma. Instruction of the patient and family in the proper use of medications is paramount. The MDI devices need to be prescribed with careful instructions regarding their use. When the patient comes in for follow-up, part of the examination should include the patient's demonstration of how he uses this device. Discussion of the proper and safe use of bronchodilators is important. Overuse of inhaled bronchodilators may be a reflection of increasing asthma or, at the very least, evidence that the patient does not understand appropriate treatment of asthma. If a patient is dependent on regular use of an inhaled beta agent, it is likely that he would benefit from therapy directed at the underlying inflammation of asthma. The patient and the family should understand the purpose of each medication, the side effects, and the risks and benefits of their use. In particular, if steroid medications are necessary, the reasons for their use should be explained. Carefully matching the severity of the asthma with the therapeutic protocols provides an organized approach to asthma treatment. Avoiding triggers of asthma and controlling the environmental exposure to potential triggers leads to lower medication requirements and less lability. Offering the family written instructions to cope with changes in the child's condition, based on assessment of clinical and PEFR observations, allows them more autonomy and comfort in the day-to-day care of the asthmatic child.

Asthma-related hospital use among Finnish asthmatics of working age

The aim was to examine asthma-related use of hospital services among persons of working age (15-64 years) in Finland on the basis of hospital discharge registers over a period of 15 years. A total of 155,080 asthma-induced treatment periods and 1,270,453 hospitalisation days were observed in the working-age population during the period concerned. Although the use of hospital services was found to be smallest in the second youngest male age-group (25-34 years), the numbers of treatment periods and hospitalisation days observed among men relative to population were found to increase by age. Middle-aged (35-44) female asthmatics tend to use hospital services more often than men of the same age, but no difference was observed between the sexes in the oldest age-group (55-64 years). The long-term monitoring and guidance of asthmatics and the specialist services required should be coordinated within the basic health care system as in the case of other chronic diseases. The long-term monitoring of asthmatics should be performed by general practitioners, and in the light of the present findings special emphasis should be placed on subjects aged 35 years and older.

Pubertal growth curves of ventilatory function: relationship with childhood respiratory symptoms

This study describes longitudinal growth patterns of ventilatory function in relation to the growth of standing height and weight of boys and girls aged 12.5 to 18 yr with or without a positive history of prepubertal respiratory symptoms. Ventilatory function was characterized by FVC, FEV1, peak expiratory flow (PEF) and maximal expiratory flow at 50% of the FVC (MEF50), derived from maximum expiratory flow volume (MEFV) curves. Data on respiratory symptoms and MEFV curves were obtained in a longitudinal survey of 404 children from a Dutch secondary school. Measurements were made at 6-month intervals between 1978 and 1985. The subjects selected for analysis comprised 151 boys and 118 girls for whom between nine and 14 measurements were available. In asymptomatic boys, the average peak growth rate of standing height occurred at about 14 yr, whereas the growth rates of the ventilatory function indices peaked about 0.8 (FVC) to 1.5 (MEF50) yr later. Weight growth paralleled that of FVC and FEV1. In girls, growth rates of all indices decreased over the whole age range. Adolescents with a positive history of prepubertal respiratory symptoms exhibited lung growth parallel to asymptomatic subjects, but at a lower level. In symptomatic boys, and to a lesser extent in girls, we found consistently lower levels of FVC, FEV1, and MEF50. We conclude that adolescents with a positive history of prepubertal respiratory symptoms, even if they lose their symptoms, remain at a disadvantage with respect to their ventilatory function when they reach adulthood.