The natural history of childhood asthma to adult life

Contemporary Concise Review 2023: Asthma

Asthma research and management needs to meet the priorities of the end user-patients, carers and clinicians. A better understanding of the natural history of asthma and the progression of disease has highlighted the importance of early identification of patients with asthma and the potential role of early intervention. Management of mild asthma requires a consistent approach with the same detail and consideration used when managing severe disease. Evidence around treatable traits approaches continues to evolve, supporting the role of a personalized medicine in asthma. Oral corticosteroid (OCS) stewardship continues to be an urgent issue in asthma management. Strategies to taper OCS doses and the implementation of biologic therapies for their steroid sparing benefits will be important steps to address this problem. The concept of remission in asthma provides an ambitious target and treatment outcome.

Barriers to clinical remission in severe asthma

Severe asthma is associated with an increased risk for exacerbations, reduced lung function, fixed airflow obstruction, and substantial morbidity and mortality. The concept of remission in severe asthma as a new treatment goal has recently gained attention due to the growing use of monoclonal antibody therapies, which target specific pathologic pathways of inflammation. This review evaluates the current definitions of asthma remission and unveils some of the barriers for achieving this state in the severe asthma population. Although there is no unified definition, the concept of clinical remission in asthma should be based on a sustained period of symptom control, elimination of oral corticosteroid exposure and exacerbations, and stabilization of pulmonary function. The conjugation of these criteria seems a realistic treatment target in a minority of asthmatic patients. Some unmet needs in severe asthma may affect the achievement of clinical remission. Late intervention with targeted therapies in the severe asthma population may increase the risk of corticosteroid exposure and the development of irreversible structural airway changes. Moreover, airway infection is an important component in persistent exacerbations in patients on biologic therapies. Phenotyping exacerbations may be useful to guide therapy decisions and to avoid the liberal use of oral corticosteroids. Another challenge associated with the aim of clinical remission in severe asthma is the multifaceted interaction between the disease and its associated comorbidities. Behavioural factors should be evaluated in case of persistent symptoms despite optimised treatment, and assessing biomarkers and targeting treatable traits may allow for a more objective way of reaching remission. The concept of clinical remission will benefit from an international consensus to establish unifying criteria for its assessment, and it should be addressed in the future management guidelines.

Respiratory symptoms, exacerbations and sleep disturbances are more common among participants with asthma and chronic airflow limitation: an epidemiological study in Estonia, Iceland and Sweden

BACKGROUND

Chronic airflow limitation (CAL) is a hallmark of chronic obstructive pulmonary disease but is also present in some patients with asthma. We investigated respiratory symptoms, sleep and health status of participants with and without CAL with particular emphasis on concurrent asthma using data from adult populations in Iceland, Estonia and Sweden investigated within the Burden of Obstructive Lung Disease study.

METHODS

All participants underwent spirometry with measurements of forced expiratory volume in 1 s (FEV1) and forced vital capacity (FVC) before and after bronchodilation. CAL was defined as postbronchodilator FEV1/FVC below the lower limit of normal. IgE-sensitisation and serum concentrations of eosinophil-derived neurotoxin (S-EDN) were assessed in a subsample. The participants were divided into four groups: no self-reported doctor's diagnosed asthma or CAL, asthma without CAL, CAL without asthma and asthma and CAL: χ2 test and analysis of variance were used in bivariable analyses and logistic and linear regression when analysing the independent association between respiratory symptoms, exacerbations, sleep-related symptoms and health status towards CAL, adjusting for centre, age, sex, body mass index, smoking history and educational level.

RESULTS

Among the 1918 participants, 190 (9.9%) had asthma without CAL, 127 (6.6%) had CAL without asthma and 50 (2.6%) had CAL with asthma. Having asthma with CAL was associated with symptoms such as wheeze (adjusted OR (aOR) 6.53 (95% CI 3.53 to 12.1), exacerbations (aOR 12.8 (95% CI 6.97 to 23.6), difficulties initiating sleep (aOR 2.82 (95% CI 1.45 to 5.48), nocturnal gastro-oesophageal reflux (aOR 3.98 (95% CI 1.79 to 8.82)) as well as lower physical health status. In these analyses, those with no asthma and no CAL were the reference group. The prevalence of IgE-sensitisation was highest in both asthma groups, which also had higher levels of S-EDN.

CONCLUSION

Individuals with self-reported asthma with CAL suffer from a higher burden of respiratory and sleep-related symptoms, higher exacerbation rates and lower health status when compared with participants with asthma alone or CAL alone.

The impact of asthma-exclusive nursing scheme on the treatment effect of asthma patients

OBJECTIVE

To investigate the impact of the asthma-exclusive nursing scheme on the treatment effect of asthma patients.

METHODS

A total of 120 asthma patients treated in our hospital from January 2019 to June 2019 were included for the research, with 60 patients in Group A from January 2019 to March 2019, and 60 patients in Group B from April 2019 to June 2019. Montelukast combined with formoterol lyophilized powder was employed as the treatment for all patients. An asthma-exclusive nursing scheme was given to Group A, and conventional nursing was applied to Group B. The analysis and comparison of symptom relief time (SRT), pulmonary function indicators (PFI), 6-minute walking distance (6MWD), adverse drug reactions (ADRs), levels of inflammatory factors (LIF), and overall efficacy between the two groups were conducted.

RESULTS

After the treatment, Group A yielded a more promising outcome of SRT than Group B (P<0.001). Moreover, a notable increase of PFI and LIF of both groups of patients was observed, in which Group A garnered more promising results than Group B (P<0.001), and similar results were also demonstrated with regard to 6MWD (P<0.001). Neither abnormal metabolism in patients nor significant difference of ADRs between the two groups was detected (P>0.05). The overall efficacy and compliance rate of Group A were higher than those of Group B, and the 6-month recurrence rate was lower than that of Group B (P<0.05).

CONCLUSION

With the aid of an asthma-exclusive nursing scheme, montelukast combined with formoterol can safely and substantially optimize the PFI and LIF of asthma patients and enhance their exercise capacity, which is of application value in clinical practice.

A review on the pathophysiology of asthma remission

Asthma is a chronic respiratory condition, which is highly prevalent worldwide. Although no cure is currently available, it is well recognized that some asthma patients can spontaneously enter remission of the disease later in life. Asthma remission is characterized by absence of symptoms and lack of asthma-medication use. Subjects in asthma remission can be divided into two groups: those in clinical remission and those in complete remission. In clinical asthma remission, subjects still have a degree of lung functional impairment or bronchial hyperresponsiveness, while in complete asthma remission, these features are no longer present. Over longer periods, the latter group is less likely to relapse. This remission group is of great scientific interest due to the higher potential to find biomarkers or biological pathways that elicit or are associated with asthma remission. Despite the fact that the definition of asthma remission varies between studies, some factors are reproducibly observed to be associated with remitted asthma. Among these are lower levels of inflammatory markers, which are lowest in complete remission. Additionally, in both groups some degree of airway remodeling is present. Still, the pathological disease state of asthma remission has been poorly investigated. Future research should focus on at least two aspects: further characterisation of the small airways and airway walls in order to determine histologically true remission, and more thorough biological pathway analyses to explore triggers that elicit this phenomenon. Ultimately, this will result in pharmacological targets that provide the potential to steer the course of asthma towards remission.

Prevalence of bronchial asthma and its associated risk factors in school-going adolescents in Tier-III North Indian City

BACKGROUND

Asthma is one of the most common chronic diseases of childhood and a major health problem not only in India but globally. Despite multifold increase in prevalence, there is paucity of data on bronchial asthma from non-metro cities. The objectives were to find prevalence of bronchial asthma and various risk factors that are associated in this age group and determine the extent of under diagnosis.

MATERIALS AND METHODS

A cross-sectional study involving 927 students from four government and three private schools was conducted using International Study of Asthma and Allergies in Childhood questionnaire.

RESULTS

Prevalence of bronchial asthma in adolescents was 13.1% (n = 121) of which 10.3% had episodes in the past 1 year. Prevalence was higher among males (8.77%) compared to females (4.33%). About 77.7% of total asthmatics were newly diagnosed cases. Prevalence was significantly higher among those having pets at home (P < 0.001), belonging to higher socioeconomic status (P = 0.021), using smoke-producing fuel at home (firewood/cow dung/kerosene; P = 0.032), and with history of smoking among family members (P = 0.035). Among current asthmatics, 72.3% reported cold/rhinitis (54.6% in March-May duration), 63.6% nocturnal dry cough, 50.5% sleep disturbances, and 38.9% speech disturbances in the past 1 year.

CONCLUSION

The study shows higher prevalence of bronchial asthma in school-going population (11-16 years) compared to other parts of Northern India possibly attributable to rapid industrialization and post harvesting season when the study was carried out. Preventive interventions need to be taken to reduce disease burden at community level.

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.

Association between menarche and increased bronchial hyper-responsiveness during puberty in female children and adolescents

PURPOSE

Bronchial hyper-responsiveness (BHR) is a key feature of asthma. The degree of BHR in children may be altered by several factors. We evaluated the prevalence of BHR according to age and gender in pediatric and adolescent population and analyzed the associated factors for gender differences.

METHODS

Among the 2,067 subjects, methacholine challenge tests were performed in 1,820 children from one elementary and one middle school in Seoul, Korea. A total of 1,725 subjects between 6 and 14 years old were included in the analysis. The prevalence of BHR, defined as a provocative concentration that induced a 20% reduction of FEV₁ (PC₂₀ ) that was less than 8 mg/ml, was evaluated according to age and gender. Gender differences associated with BHR prevalence at each age were calculated and multiple logistic regression analyses were performed to identify factors associated with BHR by gender.

RESULTS

The prevalence of BHR (PC₂₀  ≤ 8 mg/ml) for each gender decreased with age (P < 0.001). Although the prevalence of BHR linearly decreased in males with age, females showed an increase after 11 years of age. BHR in males was associated with a younger age (aOR, 0.797; 95%CI, 0.678-0.925), a higher blood eosinophil counts (%) (aOR, 1.160; 95%CI, 1.047-1.284), atopy (aOR, 2.091; 95%CI, 1.003-4.359), and a lower FEV₁ /FVC ratio (aOR, 0.947; 95%CI, 0.901-0.995), and FEF_25-75% (aOR, 0.980; 95%CI, 0.961-0.999). In females, BHR was significantly associated with a younger age (aOR, 0.845; 95%CI, 0.747-0.957), lower FEV₁ (%) (aOR, 0.961; 95%CI, 0.938-0.984), and menarche (aOR, 3.674; 95%CI, 1.226-11.012).

CONCLUSION

BHR declined with age in the Korean pediatric population. A younger age and reduced lung function were common factors related to BHR in both genders. Additionally, atopy was related to BHR in males, whereas sexual maturation was related to BHR in females. These findings have important clinical implications for evaluating of childhood BHR and asthma related to gender. Pediatr Pulmonol. 2016;51:1040-1047. © 2016 Wiley Periodicals, Inc.

Risk Factors Associated with Irreversible Airway Obstruction in Asthma: A Systematic Review and Meta-Analysis

Irreversible airway obstruction (IAO) is a subtype of asthma and relates to poorer prognosis in some asthma patients. However, the prevalence and risk factors for IAO are unknown. A systematic review regarding controlled clinical studies (cohort, case-control studies) on IAO asthma in adult and/or children affected by asthma/early wheeze was performed. Eighteen papers were identified in this study. It was reported that the incidence of IAO at random effects or fixed effects in severe asthma and nonsevere asthma was 0.54 (95% CI: 0.45–0.62) and 0.16 (95% CI: 0.12–0.20), respectively. In IAO asthma, the pooled odds ratio (OR) related to smoking exposure was 2.22 (95% CI: 1.82–2.73), the OR for male, smoking, and fractional exhaled nitric oxide (FENO) was 2.22 (95% CI: 1.82–2.7), 1.79 (95% CI: 1.46–2.19), and 2.16 (95% CI: 1.05–4.43), respectively, suggesting these factors increase the risk of IAO. However, a decreased OR in IAO asthma was observed due to rhinitis (OR = 0.31, 95% CI: 0.24–0.40), atopy (OR = 0.584, 95% CI: 0.466–0.732), and atopic dermatitis (OR = 0.60, 95% CI: 0.42–0.85), indicating these factors are associated with reduced risk of IAO. IAO in asthma is associated with gender, smoking, FENO, rhinitis, atopy, and atopic dermatitis.

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.

Declines with age in childhood asthma symptoms and health care use: an adjustment for evaluations

RATIONALE

Asthma is a variable condition with an apparent tendency for a natural decline in asthma symptoms and health care use occurring as children age. As a result, asthma interventions using a pre-post design may overestimate the intervention effect when no proper control group is available.

OBJECTIVES

Investigate patterns of natural decline over time with increasing age in asthma symptoms and health care use of children. Develop a statistical procedure that enables adjustment that accounts for expected declines in these outcomes and is useable when intervention evaluations must rely solely on pre-post data.

METHODS

Mixed-effects models with mixture distributions were used to describe the pattern of symptoms and health care use in 3,021 children aged 2 to 15 years in a combined sample from three controlled trials. An adaptive least squares estimation was used to account for overestimation of intervention effects and make adjustments for pre-post only data. Termed "Adjustment for Natural Declines in Asthma Outcomes (ANDAO)," the adjustment method uses bootstrap sampling to create control cohorts comparable to subjects in the intervention study from existing control subjects. ANDAO accounts for expected declines in outcomes and is beneficial when intervention evaluations must rely solely on pre-post data.

MEASUREMENTS AND MAIN RESULTS

Children under 10 years of age experienced 18% (95% confidence interval, 15-21%) fewer symptom days and 28% (95% confidence interval, 24-32%) fewer symptom nights with each additional year of age. The decline was less than 10% after age 10 years, depending on baseline asthma severity. Emergency department visits declined regardless of baseline symptom frequency (P = 0.02). The adjustment method corrected estimates to within 2.4% of true effects through simulations using control cohorts.

CONCLUSIONS

Because of the declines in symptoms and health care use expected with increasing age of children with asthma, pre-post comparisons will greatly overestimate intervention effects. The ANDAO provides means to adequately estimate treatment effects when a control group design is not possible.

Declines with age in childhood asthma symptoms and health care use. An adjustment for evaluations

RATIONALE

Asthma is a variable condition with an apparent tendency for a natural decline in asthma symptoms and health care use occurring as children age. As a result, asthma interventions using a pre-post design may overestimate the intervention effect when no proper control group is available.

OBJECTIVES

Investigate patterns of natural decline over time with increasing age in asthma symptoms and health care use of children. Develop a statistical procedure that enables adjustment that accounts for expected declines in these outcomes and is useable when intervention evaluations must rely solely on pre-post data.

METHODS

Mixed-effects models with mixture distributions were used to describe the pattern of symptoms and health care use in 3,021 children aged 2 to 15 years in a combined sample from three controlled trials. An adaptive least squares estimation was used to account for overestimation of intervention effects and make adjustments for pre-post only data. Termed "Adjustment for Natural Declines in Asthma Outcomes (ANDAO)," the adjustment method uses bootstrap sampling to create control cohorts comparable to subjects in the intervention study from existing control subjects. ANDAO accounts for expected declines in outcomes and is beneficial when intervention evaluations must rely solely on pre-post data.

MEASUREMENTS AND MAIN RESULTS

Children under 10 years of age experienced 18% (95% confidence interval, 15-21%) fewer symptom days and 28% (95% confidence interval, 24-32%) fewer symptom nights with each additional year of age. The decline was less than 10% after age 10 years, depending on baseline asthma severity. Emergency department visits declined regardless of baseline symptom frequency (P = 0.02). The adjustment method corrected estimates to within 2.4% of true effects through simulations using control cohorts.

CONCLUSIONS

Because of the declines in symptoms and health care use expected with increasing age of children with asthma, pre-post comparisons will greatly overestimate intervention effects. The ANDAO provides means to adequately estimate treatment effects when a control group design is not possible.

Burden of asthma among children in a developing megacity: childhood asthma study, Pakistan

OBJECTIVES

Global burden of childhood asthma has increased in the past few decades, particularly in low-income countries. In Pakistan, there is a lack of community-based epidemiological studies estimating the burden of asthma among children. This study determined the prevalence and predictors of asthma among children 3-17 years of age in Karachi, Pakistan.

METHODS

A two-stage community-based representative cross-sectional survey was conducted in Karachi from March 2012 to April 2013 comprising 1046 children aged 3-17 years. Of 7500 clusters, 80 were randomly selected, and of these, 15 children per cluster were enrolled randomly. A translated and pre-tested version of International Study of Asthma and Allergies in Children questionnaire was administered.

RESULTS

The overall prevalence of asthma among study participants was 10.2% (95% CI: 8.4-12.0). Asthma was more likely to occur among boys (adj. OR: 2.5, 95% CI: 1.6-4.0), children in the younger age group (3-7 years) (adj. OR: 2.9, 95% CI: 1.7-4.8), those living in households with ill-ventilated kitchens (adj. OR: 1.8, 95% CI: 1.1-3.1), having family history of asthma (adj. OR: 2.3, 95% CI: 1.3-3.9) and those of the Sindhi ethnicity (adj. OR: 2.2, 95% CI: 1.1-4.4).

CONCLUSION

This study is the first robust evidence regarding asthma among children in Pakistan, reporting a high burden in this group. Family history, male gender, Sindhi ethnicity and ill-ventilated kitchen were identified as important predictors of asthma. Targeted preventive measures and intervention studies are required to better understand and reduce the burden of asthma among children in Pakistan.

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.

Adult-onset asthma becomes the dominant phenotype among women by age 40 years. the longitudinal CARDIA study

RATIONALE

Although asthma is usually considered to originate in childhood, adult-onset disease is being increasingly reported.

OBJECTIVES

To contrast the proportion and natural history of adult-onset versus pediatric-onset asthma in a community-based cohort. We hypothesized that asthma in women is predominantly of adult onset rather than of pediatric onset.

METHODS

This study used data from the Coronary Artery Risk Development in Young Adults (CARDIA) cohort in the United States over a 25-year period. Adult- and pediatric-onset asthma phenotypes were studied, as defined by age at onset of 18 years or older. Subjects with asthma were categorized by sex, obesity, atopy, smoking, and race by mean age/examination year, using a three-way analysis of covariance model. Natural history of disease was examined using probabilities derived from a Markov chain model.

MEASUREMENTS AND MAIN RESULTS

Asthma of adult onset became the dominant (i.e., exceeded 50%) phenotype in women by age 40 years. The age by which adult-onset asthma became the dominant phenotype was further lowered for obese, nonatopic, ever-smoking, or white women. The prevalence trend with increasing time for adult-onset disease was greater among subjects with nonatopic than atopic asthma among both sexes. Furthermore, adult-onset asthma had remarkable sex-related differences in risk factors. In both sexes, the quiescent state for adult-onset asthma was less frequent and also "less stable" over time than for pediatric-onset asthma.

CONCLUSIONS

Using a large national cohort, this study challenges the dictum that most asthma in adults originates in childhood. Studies of the differences between pediatric- and adult-onset asthma may provide greater insight into the phenotypic heterogeneity of 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.

Characteristics of children with asthma who achieved remission of asthma

OBJECTIVE

To characterize two groups of asthmatics who had achieved remission and those who had not achieved remission of asthma.

METHODS

The study was a retrospective cohort study based on 117 asthmatic children who participated in a previous study. We categorized the children into two groups: asthmatics with remission versus asthmatics without remission. We defined remission of asthma as lack of symptoms/signs of asthma or asthma-related medications or health care services for at least three consecutive years. Long-term remission was defined by no relapse of asthma after achieving remission. We characterized these groups.

RESULTS

Of the 117 subjects, 70 (60%) were male, 91 (78%) were Caucasians, and the mean age at index date of asthma was 8.1 years. A total of 59 asthmatic children (50%) achieved remission and 28 asthmatics (24%) achieved long-term remission. Asthmatics with remission were more likely to be Caucasian (87%) compared to those without (69%) (p = .039) There were no differences in the frequency of visits for viral (0.3 vs. 0.4 per person-years, p = .29) or bacterial infections (0.7 vs. 0.5 per person-years, p = .49) between asthmatics with and without remission. Gender, socioeconomic status, smoking exposure, family history of asthma or atopy, breastfeeding history, peak flow meter availability, asthma action plan, and influenza vaccinations were not associated with remission.

CONCLUSIONS

Only half of asthmatic children accomplished remission of asthma ever and 24% of asthmatic children had long-term remission. Ethnicity may affect remission of asthma but microbial infections may not influence the likelihood of remission of asthma and vice versa.

High use of health services in patients with suboptimal asthma drug regimens: a population-based assessment in British Columbia, Canada

BACKGROUND

Despite numerous clinical guidelines on asthma management, patients often receive suboptimal drug therapy. This study identified patients who received suboptimal regimens according to the National Heart, Lung and Blood Institute (NHLBI) Guidelines for the Diagnosis and Management of Asthma in a complete population (residents of British Columbia, Canada) and determined the association between patients' regimens and utilization of healthcare services.

METHODS

A total of 65,345 asthma patients were identified using provincial health service utilization data (including all respiratory-related prescription medication dispensings, physician and hospital visits) for the 2009 fiscal year. Patient-specific regimens of inhaled short-acting bronchodilators (SABA) with or without inhaled corticosteroids (ICS) were categorized as optimal or suboptimal. Logistic regression models were used to determine the association between regimen optimality and health service utilization, adjusted for socioeconomic status, prior year hospital and emergency department (ED) visits for asthma.

RESULTS

Patients with suboptimal regimens had significantly greater risk of using health services than patients with optimal regimens of SABA and/or ICS. In particular, adolescents with suboptimal regimens were the most likely to have hospital admissions (odds ratio (OR) 3.8; 95% confidence interval (CI) 1.8-7.8), visit the ED (OR 2.2; 95% CI 1.6-3.1) and be high users of family physician services (OR 5.7; 95% CI 4.0-8.1) compared with patients in other age groups.

CONCLUSIONS

Suboptimal regimens are associated with significantly high usage of health services. Identifying patients with suboptimal regimens and improving their medication management in accordance with asthma clinical guidelines are likely to result in lower health service utilization.

Airway function, inflammation and regulatory T cell function in subjects in asthma remission

BACKGROUND

Factors associated with asthma remission need to be determined, particularly when remission occurs in adulthood.

OBJECTIVE

To evaluate airway responsiveness and inflammation in adult patients in asthma remission compared with adults with mild, persistent symptomatic asthma.

METHODS

Adenosine monophosphate and methacholine responsiveness were evaluated in 26 patients in complete remission of asthma, 16 patients in symptomatic remission of asthma, 29 mild asthmatic patients and 15 healthy controls. Blood sampling and induced sputum were also obtained to measure inflammatory parameters.

RESULTS

Perception of breathlessness at 20% fall in forced expiratory volume in 1 s was similar among groups. In subjects with symptomatic remission of asthma, responsiveness to adenosine monophosphate and methacholine was intermediate between mild asthma and complete asthma remission, with the latter group similar to controls. Asthma remission was associated with a shorter duration of disease. Blood immunoglobulin E levels were significantly increased in the asthma group, and blood eosinophils were significantly elevated in the complete asthma remission, symptomatic remission and asthma groups compared with controls. The suppressive function of regulatory T cells was lower in asthma and remission groups compared with controls.

CONCLUSION

A continuum of asthma remission was observed, with patients in complete asthma remission presenting features similar to controls, while patients in symptomatic asthma remission appeared to be in an intermediate state between complete asthma remission and symptomatic asthma. Remission was associated with a shorter disease duration. Despite remission of asthma, a decreased suppressor function of regulatory T cells was observed, which may predispose patients to future recurrence of the disease.

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.

Characteristics of young atopic adults with self-reported past wheeze and airway hyperresponsiveness

BACKGROUND

The present study aimed to illustrate clinical characteristics of spirometric measures and allergy sensitisation among young atopic adults who reported wheezing episodes before adulthood but were not diagnosed with asthma by physicians and have no current wheeze symptoms (self-reported past-wheezers), especially those who exhibited airway hyperresponsiveness (AHR).

METHODS

Fifty self-reported past-wheezers were divided into two groups according to AHR to methacholine. Spirometric functions and blood atopic parameters were compared in these groups with those in 25 age-matched atopic adults with a history of childhood asthma diagnosed by specialists but have no current wheeze symptoms (past-asthmatics) and in 60 counterparts without a previous and current wheezing episode (never-wheezers).

RESULTS

Twenty-one of the 50 past-wheezers exhibited AHR (PC(20) < 8 mg/ml). Levels of spirometric function and allergic sensitization in both past-wheezer groups were intermediate between those in never-wheezers and past-asthmatics. Lower FEV(1) and FEF(25-75) values (% predicted) were observed in self-reported past-wheezers with AHR relative to those without AHR. More blood eosinophils and higher serum levels of total IgE and IgE specific to house dust mites were observed in self-reported past-wheezers with AHR relative to those without AHR.

CONCLUSIONS

Our findings raise the possibility that self-reported past-wheezers with AHR might form a distinct subgroup with features similar to past-asthmatics, which is one of the risk groups for adult asthma.

Hormonal link to autoimmune allergies

IgE recognition of autoantigens might augment allergic inflammation in the absence of exogenous allergen exposure. Among allergy and autoimmunity, there is disproportionate representation of males before puberty and females after puberty, suggesting a role for sex hormones. Hormone allergy is an allergic reaction where the offending allergens are one's own hormones. It is an immune reaction to the hormones, which can interfere with the normal function of the hormones. It can occur perimenstrually in women along with the variation in menstrual cycle. The perimenstrual allergies are about the cyclic abundance of the hormone causing a cyclic expression of allergic symptoms. The inflammatory mechanisms of allergic reactions to hormone allergens, which are intrinsic to the body, are the same as the mechanisms of allergic reactions to external allergens.

A GIS-based assessment of environmental influences on allergy development in children

This study aims to assess potential environmental influences on allergy development in children. Based on a parent-completed questionnaire survey administered in Hong Kong in 2003 in accordance with the International Study of Asthma and Allergies in Childhood protocol, the prevalence and incidence of asthma and rhinoconjunctivitis of 508 preschool children aged 4 to 6 years in Yuen Long District were determined and a range of indoor and outdoor environmental factors were assessed. Exposure to moisture and mold in the first year of life increased the risk of asthma (adjusted odds ratio [aOR] = 2.56; 95% confidence interval [CI] = 1.40-4.68) and rhinoconjunctivitis (aOR = 2.09; 95% CI = 1.15-3.80). Current maternal smoking was also associated with a higher prevalence of asthma (aOR = 2.00; 95% CI = 1.04-3.84). No association was observed between outdoor traffic-related air pollutants and the prevalence of the allergic conditions. Indoor home environments had a stronger influence on allergy development, whereas exposure to traffic-related external environment gave a variable effect, the significance of which would be difficult to be substantiated.

Gender differences in S-nitrosoglutathione reductase activity in the lung

S-nitrosothiols have been implicated in the etiology of various pulmonary diseases. Many of these diseases display gender preferences in presentation or altered severity that occurs with puberty, the mechanism by which is unknown. Estrogen has been shown to influence the expression and activity of endothelial nitric oxide synthase (eNOS) which is associated with increased S-nitrosothiol production. The effects of gender hormones on the expression and activity of the de-nitrosylating enzyme S-nitrosoglutathione reductase (GSNO-R) are undefined. This report evaluates the effects of gender hormones on the activity and expression of GSNO-R and its relationship to N-acetyl cysteine (NAC)-induced pulmonary hypertension (PH). GSNO-R activity was elevated in lung homogenates from female compared to male mice. Increased activity was not due to changes in GSNO-R expression, but correlated with GSNO-R S-nitrosylation: females were greater than males. The ability of GSNO-R to be activated by S-nitrosylation was confirmed by: 1) the ability of S-nitrosoglutathione (GSNO) to increase the activity of GSNO-R in murine pulmonary endothelial cells and 2) reduced activity of GSNO-R in lung homogenates from eNOS^−/− mice. Gender differences in GSNO-R activity appear to explain the difference in the ability of NAC to induce PH: female and castrated male animals are protected from NAC-induced PH. Castration results in elevated GSNO-R activity that is similar to that seen in female animals. The data suggest that GSNO-R activity is modulated by both estrogens and androgens in conjunction with hormonal regulation of eNOS to maintain S-nitrosothiol homeostasis. Moreover, disruption of this eNOS-GSNO-R axis contributes to the development of PH.

Phenotypic differences between asymptomatic airway hyperresponsiveness and remission of asthma

BACKGROUND

The present study aimed to illustrate differences in characteristics and perception of dyspnea between young atopic adults who have no history of asthma (never-asthmatics) with or without asymptomatic airway hyperresponsiveness (AHR) and those who had childhood asthma and consider themselves to be grown out of the disease (past-asthmatics).

METHODS

Blood parameters, lung function and methacholine PC(20) were measured in 88 never-asthmatics and 24 past-asthmatics. A perception score of dyspnea at 20% fall in FEV(1) (PS(20)) was obtained by interpolation of the two last points on the perception (modified Borg scale)/fall in FEV(1) curve during methacholine challenge.

RESULTS

Thirty-one of 88 never-asthmatics and eighteen of 24 past-asthmatics exhibited AHR (PC(20) was <8 mg/ml). Higher levels of specific IgE to house dust mite in past-asthmatics were observed than never-asthmatics with and without AHR. Mean values of FEV(1) and FEF(25-75) (%predicted) were significantly lower in past-asthmatics than never-asthmatics without AHR, and the values in never-asthmatics with AHR were intermediate between never-asthmatics without AHR and past-asthmatics. PC(20) was not significantly different between past-asthmatics and never-asthmatics with AHR. Of particular interest was that PS(20) was significantly lower in never-asthmatics with AHR compared with past-asthmatics.

CONCLUSION

The present findings suggest the possibilities that presence or absence of past history of outgrow of childhood asthma might be associated with airway narrowing, sensitization to house dust mite and perception of dyspnea in young asymptomatic adults with atopy and AHR.

The irreversible component of persistent asthma

Irreversible airflow obstruction or limitation occurs in some patients with asthma, can develop early in life, and becomes more common as asthma becomes more severe. Efforts to understand irreversible airflow obstruction or limitation have been hampered by the lack of a standardized definition of the phenotype and by the lack of appropriate research models. Unfortunately, it appears that currently available asthma treatments do not prevent this important asthma complication. Herein, the evidence of an irreversible component of asthma, its underlying pathology, and the limitations of current asthma treatments are reviewed.

Asthma and sickle cell disease: two distinct diseases or part of the same process?

A physician diagnosis of asthma in children and adults with sickle cell disease (SCD) has been associated with increased rates of pain and acute chest syndrome (ACS) episodes and premature death. Despite the clinical significance of a doctor’s diagnosis of asthma in individuals with SCD, the criteria for a physician diagnosis of asthma are not well defined. Many features of asthma are common in individuals with SCD, including symptoms of wheezing, obstructive lung disease and airway hyper-responsiveness. However, it is not clear if these signs and symptoms of asthma reflect a physician diagnosis of asthma, or if these asthma features are related to SCD. Further complicating the diagnosis of asthma in children with SCD is the significant overlap in clinical manifestations between an asthma exacerbation and an ACS episode. Evidence supporting the concept that asthma and SCD are separate co-morbid conditions includes a similar prevalence of asthma between children with SCD and those in the general population and the observation that asthma is inherited in a familial pattern in the families of children with SCD. In contrast, there is significant evidence that asthma-like features may be associated with SCD without a diagnosis of asthma, including a higher than expected prevalence of airway hyper-responsiveness and obstructive lung disease. Regardless of whether SCD and asthma are distinct or overlapping co-morbid conditions, we recommend a systematic and complete evaluation of asthma when the diagnosis is suspected or when patients have multiple episodes of pain or ACS.

Asthma and sickle cell disease: two distinct diseases or part of the same process?

A physician diagnosis of asthma in children and adults with sickle cell disease (SCD) has been associated with increased rates of pain and acute chest syndrome (ACS) episodes and premature death. Despite the clinical significance of a doctor's diagnosis of asthma in individuals with SCD, the criteria for a physician diagnosis of asthma are not well defined. Many features of asthma are common in individuals with SCD, including symptoms of wheezing, obstructive lung disease and airway hyper-responsiveness. However, it is not clear if these signs and symptoms of asthma reflect a physician diagnosis of asthma, or if these asthma features are related to SCD. Further complicating the diagnosis of asthma in children with SCD is the significant overlap in clinical manifestations between an asthma exacerbation and an ACS episode. Evidence supporting the concept that asthma and SCD are separate co-morbid conditions includes a similar prevalence of asthma between children with SCD and those in the general population and the observation that asthma is inherited in a familial pattern in the families of children with SCD. In contrast, there is significant evidence that asthma-like features may be associated with SCD without a diagnosis of asthma, including a higher than expected prevalence of airway hyper-responsiveness and obstructive lung disease. Regardless of whether SCD and asthma are distinct or overlapping co-morbid conditions, we recommend a systematic and complete evaluation of asthma when the diagnosis is suspected or when patients have multiple episodes of pain or ACS.

Pediatric asthma and related allergic and nonallergic diseases: patient-oriented evidence-based essentials that matter

Asthma is the most common medical diagnosis among hospitalized children. In the USA, asthma has accounted for approximately 15% of nonsurgical admissions to hospital in the pediatric age group. Asthma is also one of the leading causes for emergency care requirements, one of the leading causes for missed school, and a cause for considerable morbidity, disability and occasional mortality at all ages. Despite these discouraging statistics, convincing data indicate that this failure of asthma management is not the result of inadequate therapeutic potential, but instead represents ineffective delivery of medical care. Management of asthma and its major co-morbidities, allergic and nonallergic rhinitis, and atopic dermatitis requires a knowledge of the alternative therapies, natural history, and educational techniques for providing patients and families with the ability to manage these troublesome chronic disorders.

Characterization of the duration from onset of asthma symptoms to asthma disease

BACKGROUND

Little is known about factors associated with progression of childhood asthma from onset of symptoms to index date determined by medical records.

OBJECTIVE

To determine the duration between the onset of asthma symptoms to index date of asthma (ie, time when one met the criteria for asthma) and associated factors.

METHODS

Study participants came from a sample of 839 healthy children, aged 5 to 12 years, who had participated in a previous study. Comprehensive medical record reviews were conducted to determine first documentation of asthma symptoms and index date of asthma. Factors were evaluated for an association with the duration from onset of asthma symptoms to index date of asthma.

RESULTS

Of the study sample, 222 children met the criteria for asthma and had an available onset date of asthma symptoms. The median ages at onset of asthma symptoms and the index date were 5.6 and 7.6 years, respectively. The median duration between onset of asthma symptoms and index date was 2.9 months, and the mean was 17.2 months. There was a tendency for patients with a pet at home (P = .047), exercise-induced symptoms (P = .04), younger age at symptom onset (P = .05), and more severe asthma (P = .05) to have a shorter duration from onset of symptoms to index date.

CONCLUSIONS

The duration from onset of asthma symptoms to index date of asthma varies significantly depending on host and environmental factors. It does not necessarily correlate with commonly recognized risk factors for incidence or severity of asthma.

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.

Diagnosing asthma in children: what is the role for methacholine bronchoprovocation testing?

OBJECTIVE

To determine whether measurement of airways responsiveness to methacholine can help physicians diagnose asthma in children.

METHODS

Children from the 1995 Manitoba birth cohort were assessed by asthma specialists, had skin testing and measurement of airways responsiveness to methacholine (PC20). We selected children with doctor-diagnosed asthma and healthy children as controls (no asthma, no allergic rhinitis, negative skin tests). Sensitivities and specificities for asthma were calculated. Receiver operating curves were calculated to determine the best fit of the methacholine challenge as a diagnostic test.

RESULTS

640 children were assessed. Two hundred fifteen children with doctor diagnosed asthma and 197 healthy controls successfully completed a methacholine challenge. Airways hyperresponsiveness was a moderately sensitive and specific measure for the diagnosis of asthma in girls, whether atopic (sensitivity of 71% and specificity of 69% at PC20 < or = 4.0 mg/ml) or not (sensitivity of 77% and specificity of 53% at PC20 < or =8.0 mg/ml). Airways hyperresponsiveness was also helpful for the diagnosis of asthma in atopic boys (sensitivity of 67% and specificity of 75% at PC20 < or =2.0 mg/ml), but of absolutely no help in the diagnosis of asthma in nonatopic boys.

CONCLUSION

Measurement of airways hyperresponsiveness to methacholine can be useful in children who are atopic and of some value in nonatopic girls. The presence or absence of airways hyperresponsiveness to methacholine is of no help for the diagnosis of asthma in nonatopic boys. Laboratory tests must be placed in context of the clinical assessment of children for asthma.

Impact of gender on asthma in childhood and adolescence: a GA2LEN review

A number of studies have shown gender differences in the prevalence of wheeze and asthma. The aim of this review was to examine published results on gender differences in childhood and adolescent asthma incidence and prevalence, define current concepts and to identify new research needs. A Medline search was performed with the search words (gender OR sex) AND (child OR childhood OR adolescence) AND (asthma). Articles that reported on absence or presence of gender differences in asthma were included and reviewed, and cross-references were checked. Boys are consistently reported to have more prevalent wheeze and asthma than girls. In adolescence, the pattern changes and onset of wheeze is more prevalent in females than males. Asthma, after childhood, is more severe in females than in males, and is underdiagnosed and undertreated in female adolescents. Possible explanations for this switch around puberty in the gender susceptibility to develop asthma include hormonal changes and gender-specific differences in environmental exposures. This aspect needs consideration of the doctors and allergists who diagnose and treat asthmatic individuals. In conclusion, sex hormones are likely to play an important role in the development and outcome of the allergic immune response and asthma in particular. By obtaining functional data from appropriate models, the exact underlying mechanisms can be unravelled. To examine the effect of gender-specific differences in environmental exposures and changes of asthma prevalence and severity in puberty, larger populations may need to be investigated.

Age-related changes in the asthmatic phenotype in children

PURPOSE OF REVIEW

To review the changes in the asthma phenotype as children progress from childhood into young adulthood.

RECENT FINDINGS

Some children with asthma in the early school years improve symptomatically during adolescence and young adulthood, with less frequent remissions and increased relapse rates in those with severe symptoms. During remission of symptoms, lung function abnormalities, airway hyper-responsiveness, and airway inflammation often persist. New data from the Childhood Asthma Management Program cohort show progression of lung function abnormalities during adolescence.

SUMMARY

Most children with persistent asthma have persistent disease as adults, and lung function abnormalities continue to progress as these children age.

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.

Study of growth in prepubertal asthmatics

OBJECTIVE

The aim of this pilot study was to assess whether long standing asthma affects growth in prepubertal Egyptian children before initiation of long-term corticosteroid therapy.

METHODS

Children with asthma were divided into two groups according to asthma severity, moderate (n=24) and severe (n=14) and were compared for their physical and skeletal growth with a control group (n=15) using standard deviation score (SDS) and one-way ANOVA (analysis of variance) test.

RESULTS

No statistically significant differences were found between various growth parameters (weight, height, BMI, upper segment lower segment ratio, and skin fold thickness in asthmatic and normal children, although a positive correlation was found between the age at which the asthma presented and the height in all asthmatic children, r= 0.288, p= 0.036. The bone age standard deviation scores (SDS) were 0.97 mean, -0.165 and -0.572 for controls, moderate and severe asthmatics respectively (P< 0.05), and significant inter group difference between the 2 asthmatic groups (moderate and severe) and the controls was found.

CONCLUSION

The authors conclude that there was no significant major effect of asthma per se on growth parameters in children, but that skeletal maturation was influenced by long standing asthma.

Relationship among pulmonary function, bronchial hyperresponsiveness, and atopy in children with clinically stable asthma

Pulmonary function testing plays a key role in the diagnosis and management of asthma in children. However, the literature does not clearly show whether children with clinically stable asthma have significantly reduced lung function when compared with normal children. We compared the lung function of 242 clinically stable asthmatic children who were initially diagnosed with mild intermittent or mild persistent asthma with the lung function of 100 nonasthmatic controls. The lung function was assessed using FEV1, FEV1/FVC, FEF25-75 and PEF. In addition, we measured bronchial hyperresponsiveness (BHR) using the provocation concentration of methacholine needed to produce a 20% fall in FEV1. All measures of pulmonary function were significantly decreased in the children with asthma. Pulmonary function was not influenced by atopy, serum IgE, or total eosinophil count (TEC). However, the likelihood ratio for trends revealed a significant association between our pulmonary parameters and the degree of BHR. Children with mild-to-severe BHR had greatly decreased lung function compared with those with normal BHR, the control group. In addition, a direct correlation was found between PC20 and our pulmonary parameters in asthmatic children. However, only atopic children with asthma had a significant correlation between PC20 and TEC. We found children with clinically stable asthma to have pulmonary obstruction, which associated strongly with their degree of BHR.

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.

Most difficult asthma originates primarily in adult life

Epidemiological studies indicate that most asthma starts in childhood. However, the characteristics of adults with difficult asthma differ from the general asthma population. Difficult asthma as defined by poor control despite high dose inhaled steroids and long acting beta 2 agonists disproportionately affects women, more often has onset in adult life and is less frequently associated with atopy, and therefore appears to be a distinct phenotype. If an alternative definition of difficult asthma that is life threatening asthma is used then many of the behavioural traits may have their origin in childhood. Patients with severe and difficult asthma form a specific subgroup of asthmatic patients with high medical need and research specifically into this group of patients is now needed.

Phenotype definition, age, and gender in the genetics of asthma and atopy

When studying genetics of complex diseases it is important to have a clearly described and objective phenotype. When drawing conclusions in association studies, age and gender of the population should be considered. Until we know what causes phenotypic differences between males and females and between children and adults, we should try to study longitudinal cohorts with phenotype assessment at different time points and stratify our analyses for gender. To acquire sufficient power for these types of analyses, international collaboration may be the only way to elucidate the intricate, gene-environmental interactions in atopy and asthma in an age- and gender-dependent manor.

Risk factors associated with occurrence of clinical deterioration after cessation of beclomethasone in asthmatic children and adolescents

Despite recent advances in the treatment of asthma using inhaled corticosteroids, the outcome for children after its discontinuation is not well known. This study aims to analyze the rate of clinical deterioration and related risk factors after beclomethasone withdrawal in asthmatic children and adolescents. One hundred two subjects with moderate or severe persistent asthma, who had started treatment with beclomethasone at the age of 2-11 years, were followed for 1 year after drug cessation. Depending on the occurrence of clinical deterioration, they were allocated to two groups, and then comparisons were made with respect to clinical criteria and skin prick test results. Statistical analysis was undertaken by using descriptive statistics and Cox's regression model. Treatment with beclomethasone had to be restarted in 28 patients (27.5%) because of relapse. There was a significant association with the risk of clinical deterioration with mother's history of asthma [hazard ratio (HR) = 2.19, 95% CI = 1.01-4.76, p = 0.04] and father's history of asthma and/or allergic rhinitis (HR = 2.34, 95% CI = 1.06-5.26, p = 0.03). A period shorter than 6 months without symptoms before prophylaxis cessation (HR = 2.26, 95% CI = 0.98-5.26, p = 0.05) and atopy (RH = 2.75, 95% CI = 0.94-7.69, p = 0.06) were also associated with risk of relapse but with marginal statistical significance. Results suggest that clinical benefits were maintained for at least 1 year in the majority of the children after the cessation of prophylaxis. Special attention must be given to those with atopy and a parental history of asthma and rhinitis because of the risk of clinical deterioration.

Successful withdrawal of inhaled corticosteroids in childhood asthma

OBJECTIVE

Although inhaled corticosteroids are useful and effective in the prophylaxis of childhood asthma, there is a dearth of information regarding the duration of treatment. The present study was undertaken to assess the possibility of successful withdrawal of inhaled corticosteroids in childhood asthma following good control of the disease.

METHODOLOGY

The study was carried out at the Asiri Hospital, Colombo, Sri Lanka and was a prospective observational clinical study. The participants were consecutive children with documented moderately severe and severe asthma seen over a period of 4 years from January 1990 and followed up to December 2003. Patients were allocated randomly to receive either beclomethasone dipropionate or budesonide. Initial dose of the selected drug was 300, 400 or 600 microg/day, depending on the child's age. After a period of stabilization, the dose was reduced from the starting dose to a maintenance level of 200, 300 or 400 microg/day, respectively. Once sustained control had been maintained for a period ranging from 9 to 18 months, gradual withdrawal was attempted. The dosage was reduced by 50-100 microg each time, at intervals of 3 months. Long-term follow up was maintained following withdrawal of inhaled corticosteroids. Breakthrough wheezing, acute severe attacks, hospitalization for wheezing and absence from school were used to assess the response.

RESULTS

Eighty-six children were recruited into the study. Eighty children responded well. The initial period on a high dose of corticosteroid was 8.4 months (range 4-12 months) and the average period of maintenance dosing was 11.7 months (range 9-18 months). The average time taken for withdrawal was 12.6 months (range 9-18 months). Successful withdrawal was achieved in 73 children. In this group, the mean total duration of treatment was 27.4 months (range 20-44 months). Up to December 2003, the subjects had been observed for an average period of 97.1 months (range 86-121 months) following withdrawal of inhaled corticosteroids. Of the 73 children in whom corticosteroids were withdrawn, 57 (78%) have remained well without any episodes of wheezing, and 14 (19%) have had mild episodes of wheezing that were easily controlled by bronchodilators. No patient needed hospitalization, long-term treatment or systemic corticosteroids. In two (3%) patients, it was necessary to restart inhaled corticosteroids because of troublesome recurrences.

CONCLUSION

It is possible to gradually withdraw inhaled corticosteroids in a significant proportion of asthmatic children once good control has been sustained on a maintenance dose for a considerable period.