Asthma from childhood to adulthood: course and outcome of lung function

Factors Associated with Persistence of Severe Asthma from Late Adolescence to Early Adulthood

RATIONALE

Asthma severity in children generally starts mild but may progress and stay severe for unknown reasons.

OBJECTIVES

Identify factors in childhood that predict persistence of severe asthma in late adolescence and early adulthood.

METHODS

The Childhood Asthma Management Program is the largest and longest asthma trial in 1041 children aged 5-12 years with mild to moderate asthma. We evaluated 682 participants from the program with analyzable data in late adolescence (age 17-19) and early adulthood (age 21-23).

MEASUREMENTS

Severe asthma was defined using criteria from the American Thoracic Society and the National Asthma Education and Prevention Program to best capture severe asthma. Logistic regression with stepwise elimination was used to analyze clinical features, biomarkers, and lung function predictive of persistence of severe asthma.

MAIN RESULTS

In late adolescence and early adulthood 12% and 19% of the patents had severe asthma, respectively; only 6% were severe at both time periods. For every 5% decrease in post bronchodilator FEV1/FVC in childhood, the odds of persistence of severe asthma increased 2.36-fold (95% CI: 1.70-3.28; p <0.0001), for participants with maternal smoking during pregnancy odds of persistence of severe asthma increased 3.17-fold (95% CI: 1.18-8.53, p=0.02). Reduced growth lung function trajectory was significantly associated with persistence of severe asthma compared to normal growth.

CONCLUSIONS

Lung function and maternal smoking during pregnancy were significant predictors of severe asthma from late adolescence to early adulthood. Interventions to preserve lung function early may prevent disease progression.

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.

Prevalence of asthma and other allergic conditions in adults in Khuzestan, southwest Iran, 2018

Background

Health information on the dimensions of asthma and allergic conditions in Khuzestan Province, as a major industrial and polluted area in Iran as and the Middle East, is inadequate. This study was performed to measure the prevalence of asthma and other allergic conditions in adults in Khuzestan Province.

Methods

This population-based cross-sectional study was carried out in 17 villages and 27 cities of Khuzestan Province during the years 2017–2018 on 20 to 65 year old respondents. Two-stage cluster sampling was used. The ECRHS (European Community Respiratory Health Survey) questionnaire was completed for individuals with additional questions regarding other allergic conditions.

Results

In the study, 5720 questionnaires were distributed of which 5708 were returned. The prevalence of current asthma was 8.5% and that of asthma-like symptoms was 19.0%. The most common symptoms of asthma were nocturnal cough (13.6%), chest tightness (12.3%) and wheezing (13.1%). The prevalence of allergic rhinitis (AR), eczema and airway hyperresponsiveness were 27.2, 10.7, and 38.7%, respectively. The prevalence of current asthma was strongly correlated with age, current location (city, village), and the smoking status of respondents (p < 0.05).

Conclusion

The prevalence of current asthma and asthma-like symptoms in Khuzestan Province is almost twice as high as in Iran. Given the high prevalence of symptoms of airway hyperresponsiveness in the entire province, it is necessary to take environmental measures to mitigate the emergence of new cases of asthma among the residents. In addition, surveillance studies are necessary to monitor the trends in the prevalence of asthma in this province.

Prevalence of airway hyperresponsiveness and its seasonal variation in children with asthma

BACKGROUND

Airway hyperresponsiveness (AHR) is a key feature of asthma and can be detected using various bronchoprovocation tests. In pediatric populations, the percentage of a positive methacholine challenge test (MCCTs) in children with asthma varies among studies, and some have reported seasonal variability. However, these studies have mostly been conducted in temperate regions. This study evaluated the prevalence of AHR to methacholine and its seasonal variation in asthmatic children in Taiwan, a subtropical country.

METHODS

A total of 276 children with asthma and their MCCT results were retrospectively reviewed. All were diagnosed with asthma and received asthma controllers regularly. They were assigned to four season groups depending in which season MCCTs were administered, with seasons categorized by the Central Weather Bureau of Taiwan. Subgroup analyses, including for sex, age, and atopy level, were compared for seasonal difference.

RESULTS

The prevalence of methacholine hyperresponsiveness was 70.7% (n = 195), and the children who were younger and had higher total serum IgE were more sensitive to methacholine (p = 0.019 and p < 0.005, respectively). No significant difference in AHR prevalence among seasons was observed (p = 0.480). The percentage of borderline, mild, and moderate severity of MCCT results was almost equally distributed among the seasons. In subgroup analysis, the children with a higher IgE level (≥75th percentile of all data) had a higher proportion of positive MCCTs in summer (88.6%, p = 0.016).

CONCLUSION

In total, 70% of the children with asthma in Taiwan had AHR to methacholine, which varied among seasons. Children with a higher total serum IgE level may be more seasonally dependent, particularly in summer.

Prevalence and associated factors for self-reported asthma in a Canadian population: The Canadian Community Health Survey, 2014

BACKGROUND

Asthma prevalence is increasing among adults, yet limited information regarding the association between adult asthma and environmental and personal exposures is available using large nationally representative population-based survey.

OBJECTIVE

To determine the prevalence of asthma and associated factors for self-reported asthma in a Canadian population aged 12 years and older by using the Canadian Community Health Survey (CCHS) 2014 cross-sectional cohort.

METHODS

We used data from the 2014 CCHS. Asthma was determined through self-reported health professional diagnosis. Information regarding covariates of importance, such as socio-economic status, life style variables, was obtained. A weighted logistic regression analysis was performed with appropriate technique for clustering effects.

RESULTS

Estimated self-reported asthma prevalence of 8.1% in the greater than 12 years old Canadian population was observed. We found that a substantial proportion of Canadians (aged 12 and older) reported having asthma and geographical differences and differences between specific provinces in asthma prevalence. Women had higher prevalence of asthma than men, but the relationship depended on age and body mass index (BMI). Interactions between household income and smoking status were observed to predict the probability of asthma.

CONCLUSIONS

Additional studies are needed to determine which factors influence the asthma prevalence between sex, BMI as well as smoking status and household income and its interactions with each other.

Relationships between total and allergen-specific serum IgE concentrations and lung function in young adults

BACKGROUND

Prior studies have shown relationships between serum immunoglobulin E (IgE) and asthma.

OBJECTIVE

To investigate relationships between total and allergen-specific IgE concentrations and lung function in young adults.

METHODS

Measurements of total IgE, allergen-specific IgE to 6 common allergens, and spirometry (forced expiratory volume in one second [FEV(1)], forced vital capacity [FVC], FEV(1)/FVC, and percent change in FEV(1) after bronchodilation) were used to calculate correlations between the logarithmically transformed IgE values and measures of lung function among participants in a birth cohort not selected for risk of allergic disease stratified by current asthma, prior asthma, or no asthma.

RESULTS

The 428 participants were 51.6% female, 93% white, and 18.4 (standard deviation = 0.6) years old. Forty-eight (11.2%) had current asthma, 55 (12.9%) had a history of asthma, and 325 (75.9%) never had asthma. For males with current asthma, correlations between total IgE and FEV(1)% and FVC% were -0.51 (P = .06) and -0.70 (P = .005), respectively. For females with current asthma, the only significant correlation was between total IgE and the FEV(1)/FVC ratio (-0.55, P = .001). After excluding smokers and individuals without detectable allergen-specific IgE, the negative correlations for both males and females remained statistically significant. The correlations among males or females with prior asthma or no history of asthma were minimal and not statistically significant. The sum of the allergen-specific IgEs showed the same pattern of relationships to lung function as did total IgE.

CONCLUSION

Our results show significant negative correlations that vary by gender between both total and allergen-specific IgE and measurements of lung function in young adults with current asthma.

Epicutaneous exposure to staphylococcal superantigen enterotoxin B enhances allergic lung inflammation via an IL-17A dependent mechanism

Atopic dermatitis (AD) is the initial step of the atopic march: the progression from AD to allergic rhinitis and asthma. There is a close association between skin barrier abnormalities and the development of AD and the atopic march. One of cardinal features of AD is that the lesional skin of the majority of AD patients is chronically colonized with Staphylococcus aureus with half isolates producing superantigen enterotoxin B (SEB). Although diverse roles of SEB in the pathogenesis and severity of AD have been recognized, whether SEB contributes to the dermal inflammation that drives lung inflammation and airway hyperresponsiveness (AHR) has not been examined. Here we show a novel role of S. aureus superantigen SEB in augmenting allergen ovalbumin (Ova) induced atopic march through an IL-17A dependent mechanism. When mice epicutaneously (EC) sensitized with allergen Ova, addition of topical SEB led to not only augmented systemic Th2 responses but also a markedly exaggerated systemic Th17/IL-17 immune environment. The ability of SEB in enhancing Th17/IL-17 was mediated through stimulating lymphocytes in spleen and draining lymph nodes to promote IL-6 production. Epicutaneous sensitization of mice with a combination of Ova and SEB significantly enhanced Ova-induced AHR and granulocytic lung inflammation than Ova allergen alone. When IL-17A was deleted genetically, the effects of SEB on augmenting lung inflammation and AHR were markedly diminished. These findings suggest that chronic heavy colonization of enterotoxin producing S. aureus in the skin of patients with atopic dermatitis may have an important role in the development of atopic march via an IL-17A dependent mechanism.

Age and sex influences on airway hyperresponsiveness

OBJECTIVE

The precise relationship between age and gender and their influence on airway reactivity has not been clearly defined. Previous studies of age and gender influences on airway reactivity have been confounded by environmental influences such as cigarette smoking. The objective of this study was to examine the effect of age and gender on airway reactivity in C57BL/6 mice housed under controlled conditions, independent of confounding environmental factors.

METHODS

Mice were separated into four experimental groups based on age and gender: males at 6 and 12 weeks of age and females at 6 and 12 weeks of age. Airway reactivity to inhaled methacholine was examined in each group.

RESULTS

Significant differences in methacholine-induced airway reactivity were observed between the sexes at both age groups. At 6 weeks of age, the males demonstrated a significantly increased airway reactivity to methacholine as compared to females (p <.001). Paradoxically, at 12 weeks of age, the males demonstrated a significantly lower response to methacholine as compared to females (p <.001). Hence the relationship between age and airway reactivity is markedly different in males as compared to females. Examination of intragender differences revealed that in female mice, airway reactivity increased significantly with age (p <.001). In contrast, males demonstrated a significant reduction in airway reactivity with age (p <.001).

CONCLUSION

These findings demonstrate important differences in airway reactivity related to age and gender that are observed independent of any environmental influences. Furthermore, these findings highlight the importance of careful age and sex matching in studies of airway reactivity.

Factors influencing the incidence and prevalence of food allergy

Food allergy is an increasing problem in Europe and elsewhere and severe reactions to food are also becoming more common. As food allergy is usually associated with other forms of allergic sensitisation it is likely that many risk factors are common to all forms of allergy. However the potential severity of the disease and the specific public heath measures required for food allergy make it important to identify the specific risk factors for this condition. Food allergy is unusual in that it often manifests itself very early in life and commonly remits with the development of tolerance. Hypotheses that explain the distribution of food allergy include specific genetic polymorphisms, the nature of the allergens involved and the unique exposure to large quantities of allergen through the gut. Progress has been made in developing more specific and testable hypotheses but the evidence for any of these is still only preliminary. Further collaborative research is required to develop an appropriate public health response to this growing problem.

Factors affecting bronchial hyperreactivity in asthmatic children

Bronchial hyperresponsiveness (BHR), the exaggerated airway narrowing in response to nonspesific stimuli, is a common characteristic of asthma. One hundred thirty-five children who were diagnosed asthma in the outpatient clinic of Gazi University Hospital, Pediatric Allergy and Asthma Department between January 2007 and January 2008 were retrospectively analysed from the asthma database of the division. BHR was not found to be different according to sex. Younger the age of the patient, more severe was BHR (p = 0.096, r = 0.164). Younger the age at onset of the symptoms, the more severe was the BHR (p < 0.001, r = 0.307). Patients who had an asthmatic first degree relative and who were exposed to passive smoking at home, had more severe BHR (p = 0.006 and p = 0.032, respectively). There were more hospitalizations among the asthmatic children with moderate-severe BHR (p = 0.027) however no correlation was found between chronic asthma severity and the degree of BHR). In this study we found that age, age at onset of symptoms, having a parent with asthma, exposure to tobacco smoke and baseline lung function are related to BHR measured at referral. Serum levels of Ig E or skin prick test positivity were not found to have any effect on BHR severity. Considering BHR severity, we could not reveal any relation between atopic and nonatopic children. However among atopic subjects, the ones with indoor allergen sensitization had more severe BHR.

Clinical assessment of asthma progression in children and adults

Asthma is a heterogeneous disorder with a variable course, characterized by episodes of cough, wheezing and shortness of breath, reversible airflow limitation, and bronchial hyperresponsiveness. It begins early in life in many subjects with intermittent symptoms occurring with viral respiratory tract infections. Over time, and in genetically susceptible children (those with an atopic predisposition), the disease becomes more persistent with symptoms occurring in the absence of respiratory tract infections. Children with persistent wheezing are eventually diagnosed with asthma, with those at greatest risk having developed allergic sensitization early in life. Among children with asthma, some will have lifelong asthma with active symptoms and progressive loss of lung function over time, whereas other children will undergo asthma remission in adolescence. Once in remission, the disease may remain quiescent, or it may relapse in midadult life. This review focuses on studies that have enhanced our understanding of the progression of asthma from infancy to adulthood. Studies evaluating progressive loss of lung function, the best-studied measure of asthma progression, are also reviewed, followed by a brief discussion of whether asthma progression can be modified by inhaled glucocorticoid therapy.

Reduced airway function in early adulthood among subjects with wheezing disorder before two years of age

AIM

To compare airway function in early adulthood in subjects with wheezing in infancy with age-matched controls and to analyze what accounts for a possible difference.

METHODS

Asthma development has been prospectively studied in 101 children hospitalized due to wheezing before the age of two. The cohort was re-investigated at age 17-20 years and tested with spirometry and for bronchial hyper-responsiveness and allergic sensitization. An age-matched population (n = 294) was used for comparison.

RESULTS

The cohort had a significantly lower FEV(1)/FVC ratio and MEF(50), both pre- and post-bronchodilation, compared with the controls, P < 0.01. The reduction in airway function was most evident in current asthmatic female subjects, but a reduced pre-bronchodilation FEV(1)/FVC ratio was also seen in symptom-free cohort subjects, P = 0.03. In the multivariate analysis, female gender was the most prominent independent risk factor for reduced airway function in early adulthood, pre-bronchodilation OR 4.0 (1.4-11.3) and post-bronchodilation OR 8.8 (1.8-42.0). In addition, a history of early wheezing, that is, belonging to the cohort, was an independent risk factor for reduced airway function pre-bronchodilation, OR 3.3 (1.3-8.7). Furthermore, there was an association between current bronchial hyper-responsiveness and an increased risk of reduced airway function post-bronchodilation, OR 7.3 (2.0-26.6).

CONCLUSION

Reduced airway function in early adulthood was found in subjects with wheezing early in life, compared with age-matched controls. The reduction was most prominent in females with current asthma.

Factor analysis in the Genetics of Asthma International Network family study identifies five major quantitative asthma phenotypes

BACKGROUND

Asthma is a clinically heterogeneous disease caused by a complex interaction between genetic susceptibility and diverse environmental factors. In common with other complex diseases the lack of a standardized scheme to evaluate the phenotypic variability poses challenges in identifying the contribution of genes and environments to disease expression.

OBJECTIVE

To determine the minimum number of sets of features required to characterize subjects with asthma which will be useful in identifying important genetic and environmental contributors. Methods Probands aged 7-35 years with physician diagnosed asthma and symptomatic siblings were identified in 1022 nuclear families from 11 centres in six countries forming the Genetics of Asthma International Network. Factor analysis was used to identify distinct phenotypes from questionnaire, clinical, and laboratory data, including baseline pulmonary function, allergen skin prick test (SPT).

RESULTS

Five distinct factors were identified:(1) baseline pulmonary function measures [forced expiratory volume in 1 s (FEV(1)) and forced vital capacity (FVC)], (2) specific allergen sensitization by SPT, (3) self-reported allergies, (4) symptoms characteristic of rhinitis and (5) symptoms characteristic of asthma. Replication in symptomatic siblings was consistent with shared genetic and/or environmental effects, and was robust across age groups, gender, and centres. Cronbach's alpha ranged from 0.719 to 0.983 suggesting acceptable internal scale consistencies. Derived scales were correlated with serum IgE, methacholine PC(20), age and asthma severity (interrupted sleep). IgE correlated with all three atopy-related factors, the strongest with the SPT factor whereas severity only correlated with baseline lung function, and with symptoms characteristic of rhinitis and of asthma.

CONCLUSION

In children and adolescents with established asthma, five distinct sets of correlated patient characteristics appear to represent important aspects of the disease. Factor scores as quantitative traits may be better phenotypes in epidemiological and genetic analyses than those categories derived from the presence or absence of combinations of +ve SPTs and/or elevated IgE.

Association between Gm allotypes and asthma severity from childhood to young middle age

Immunoglobulin constant heavy G chain (IGHG) gene polymorphisms are associated with atopy and can be determined by the serum Gm allotypes. We studied whether certain polymorphisms are related to asthma severity and to the extent or intensity of allergic sensitization in asthmatic subjects followed from childhood to young middle age. Fifty-five subjects (28 males) with childhood asthma were all followed-up prospectively on six occasions from a mean age of 9 to 35 years in a study including asthma severity scoring, spirometry, skin prick, and specific serum IgE antibody testing. At the last visit, extended lung function tests and a cold air challenge were performed, and IGHG gene polymorphisms were identified by the alternative serum IgG subclass allotypes, employing ELISA and double immunodiffusion. The 19 subjects with the homozygous IGHG*bf/*bf genotype (originating from the IGHG3*b and the IGHG1*f alleles, which are in strong linkage disequilibrium), showed significantly higher asthma scores, lower airway function, and greater bronchodilator responses from childhood to adulthood, and in middle age greater airway hyperresponsiveness, compared to the subjects with the IGHG*bf/*ga or IGHG*ga/*ga genotypes. Among the subjects sensitized to animal danders, those with the IGHG*bf/*bf genotype showed the highest specific IgE levels. In conclusion, IGHG gene polymorphisms were associated with the severity and outcome of childhood asthma, and with the intensity of allergic sensitization.

The impact of pre- and post-natal smoke exposure on future asthma and bronchial hyper-responsiveness

AIM

To analyse the impact of pre- and post-natal smoke exposure on asthma presence, bronchial hyper-responsiveness, airway function and active smoking in early adulthood.

METHODS

We have prospectively studied 101 children hospitalized due to wheezing before the age of 2 years. The cohort was re-investigated at age 17-20 years and tested for airway function and bronchial hyper-responsiveness. Data on maternal smoking during pregnancy were obtained from the Swedish Medical Birth Register.

RESULTS

There was a significant, independent correlation between both pre- and post-natal smoke exposure and asthma at age 17-20 years, OR 3.5 (1.1-11.3) and 3.4 (1.2-10.1), respectively. Maternal smoking during pregnancy was an independent risk factor for current bronchial hyper-responsiveness, OR 6.6 (1.2-35.5). Pre-natal smoke exposure seemed to negatively affect small airway function in early adulthood due to structural changes. Post-natal smoke exposure was independently associated with an increased risk of current smoking, OR 7.4 (1.6-35.2).

CONCLUSION

In subjects hospitalized due to early wheezing, pre- and post-natal smoke exposure increase the risk of asthma in early adulthood. The connection between pre-natal smoke exposure and asthma appears to be mediated via the development of bronchial hyper-responsiveness. Smoke exposure in infancy is associated with an increased risk of active smoking in early adult age, which is in turn linked to current asthma.

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.

Obtaining optimal control in mild asthma: theory and practice

BACKGROUND

Studies have shown that asthma severity is easily under-estimated and as a result, patients may be under-treated with reduced asthma control.

OBJECTIVE

This study, performed in the General Practice Research Database (GPRD), investigates asthma control in patients treated as intermittent asthmatics (short-acting beta agonist (SABA) alone), or persistent asthmatics (additional inhaled cortico-steroid (ICS), no other medication).

METHODS

Patients (0-45 years) diagnosed with asthma between 1 January 1995 and 31 December 2001 taking > or =2 scripts for SABA (SABA only group) or > or =3 scripts for ICS (ICS group) in the first six months following diagnosis were selected. Factors associated with drug prescriptions were assessed.

RESULTS

SABA script rates were 3.6 and 5.1 per year in the SABA and ICS group respectively, i.e. >1 dose/day. 10.5% of SABA group and 13.4% of ICS group used oral steroids. Within the SABA group, 37% were stepped up to ICS, the time to first ICS script being significantly associated with prior hospitalization (RR 2.26, CI 1.65-3.10) and atopy (RR 1.47, CI 1.33-1.63). A higher rate of oral steroid use was significantly associated with using ICS, being female, adult and smoking. Smokers and atopic individuals had increased risk of obtaining an earlier script for oral steroid (RR 1.32, CI 1.10-1.59 and RR 1.28, CI 1.10-1.49, respectively).

CONCLUSIONS

Asthma control was sub-optimal in a substantial proportion of patients using relatively high doses of SABA, or SABA and ICS from the outset of asthma treatment in general practice. Being female, atopic, a smoker and prior hospitalization were all associated with lack of asthma control and could guide physicians in treatment prescribing.

Hormone replacement therapy and obstructive airway diseases

Controversy exists as to the role of female reproductive hormones in asthma and COPD and, specifically, the effect of hormone replacement therapy (HRT) on these disorders. The differential incidence of asthma over the menstrual life cycle suggests an effect of female reproductive hormones on asthma; less data are available for COPD. Estrogen and progesterone have protean effects at the cellular level, consistent with potentially harmful and beneficial effects in lung disease. Large epidemiologic studies show an increased risk of development of asthma with the use of HRT but no consistent effects on COPD. Clinical and epidemiologic studies of exacerbations are limited, but suggest either a harmful effect or no effect of HRT on exacerbations of asthma and COPD. HRT appears to increase the risk of development of asthma but is not associated with the loss of lung function characteristic of COPD. Because the development of asthma is rare in postmenopausal women, the absolute increase in risk among women without asthma is modest. Physicians may wish to avoid HRT therapy in patients with difficult to control asthma and COPD. Clinical decisions to start or continue HRT among women without asthma or COPD should be based on the effects of HRT on more common diseases such as cardiovascular disease, breast cancer and osteoporosis, non-vertebral fractures and colon cancer.

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.

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.