Asthma--time for a change of name?

The Asthma Predictive Index: a very useful tool for predicting asthma in young children

Recurrent wheezing is a common problem in young children: approximately 40% of children wheeze in their first year of life. However, only 30% of preschoolers with recurrent wheezing still have asthma at the age of 6 years. Nevertheless, asthma, the most prevalent chronic disease in children, is difficult to diagnose in infants and preschoolers. This article reviews the importance of determining at an early age which infants/preschoolers will have asthma later in life, analyzes the pros and cons of different predictive indices, and discusses the efficacy of the Asthma Predictive Index.

Phenotypes of childhood asthma: are they real?

It has been suggested that there are several distinct phenotypes of childhood asthma or childhood wheezing. Here, we review the research relating to these phenotypes, with a focus on the methods used to define and validate them. Childhood wheezing disorders manifest themselves in a range of observable (phenotypic) features such as lung function, bronchial responsiveness, atopy and a highly variable time course (prognosis). The underlying causes are not sufficiently understood to define disease entities based on aetiology. Nevertheless, there is a need for a classification that would (i) facilitate research into aetiology and pathophysiology, (ii) allow targeted treatment and preventive measures and (iii) improve the prediction of long-term outcome. Classical attempts to define phenotypes have been one-dimensional, relying on few or single features such as triggers (exclusive viral wheeze vs. multiple trigger wheeze) or time course (early transient wheeze, persistent and late onset wheeze). These definitions are simple but essentially subjective. Recently, a multi-dimensional approach has been adopted. This approach is based on a wide range of features and relies on multivariate methods such as cluster or latent class analysis. Phenotypes identified in this manner are more complex but arguably more objective. Although phenotypes have an undisputed standing in current research on childhood asthma and wheezing, there is confusion about the meaning of the term 'phenotype' causing much circular debate. If phenotypes are meant to represent 'real' underlying disease entities rather than superficial features, there is a need for validation and harmonization of definitions. The multi-dimensional approach allows validation by replication across different populations and may contribute to a more reliable classification of childhood wheezing disorders and to improved precision of research relying on phenotype recognition, particularly in genetics. Ultimately, the underlying pathophysiology and aetiology will need to be understood to properly characterize the diseases causing recurrent wheeze in children.

Use and safety of long-acting β2-agonists for pediatric asthma

Asthma guidelines recommend the use of long-acting β2-agonists (LABAs) as the preferred add-on therapy for adults and children over 5 years of age when asthma is inadequately controlled by inhaled corticosteroids alone. It has been suggested that LABA use may be associated with an increased risk of morbidity and mortality; however, this view is controversial since study findings have been inconsistent. While the safety profile of LABA monotherapy has been questioned, the value of concomitant inhaled corticosteroids to eliminate possible risks remains unproven. There is a paucity of efficacy and safety data for LABA use in children, and existing evidence is not sufficiently convincing to demonstrate a clear position for LABAs in the management of childhood asthma. The main aims of this article are to place LABAs in context in the management of childhood asthma and evaluate the current evidence for safety and efficacy.

Wheeze and asthma prevalence and related health-service use in white and south Asian pre-schoolchildren in the United Kingdom

BACKGROUND

Epidemiological data for south Asian children in the United Kingdom are contradictory, showing a lower prevalence of wheeze, but a higher rate of medical consultations and admissions for asthma compared with white children. These studies have not distinguished different asthma phenotypes or controlled for varying environmental exposures.

OBJECTIVE

To compare the prevalence of wheeze and related health-service use in south Asian and white pre-schoolchildren in the United Kingdom, taking into account wheeze phenotype (viral and multiple wheeze) and environmental exposures.

METHODS

A postal questionnaire was completed by parents of a population-based sample of 4366 white and 1714 south Asian children aged 1-4 years in Leicestershire, UK. Children were classified as having viral wheeze or multiple trigger wheeze.

RESULTS

The prevalence of current wheeze was 35.6% in white and 25.5% in south Asian 1-year-olds (P<0.001), and 21.9% and 20.9%, respectively, in children aged 2-4 years. Odds ratios (ORs) (95% confidence interval) for multiple wheeze and for viral wheeze, comparing south Asian with white children, were 2.21 (1.19-4.09) and 1.43 (0.77-2.65) in 2-4-year-olds after controlling for socio-economic conditions, environmental exposures and family history. In 1-year-olds, the respective ORs for multiple and viral wheeze were 0.66 (0.47-0.92) and 0.81 (0.64-1.03). Reported GP consultation rates for wheeze and hospital admissions were greater in south Asian children aged 2-4 years, even after adjustment for severity, but the use of inhaled corticosteroids was lower.

CONCLUSIONS

South Asian 2-4-year-olds are more likely than white children to have multiple wheeze (a condition with many features of chronic atopic asthma), after taking into account ethnic differences in exposure to some environmental agents. Undertreatment with inhaled corticosteroids might partly explain their greater use of health services.

Suggestions for a uniform terminology in allergology and pneumology

As authors tend to use different terms for the same entity or meaning, it may be the time for a uniformly use terminology in allergology and pneumology. The proposals reflect personal suggestions and are not authorized by any consensus conference, task force or specialized society. Presented are proposals for concepts- it was not intended to give definitions, which would open an even broader field of differing opinions. To avoid misunderstandings and to standardize scientific language, it seems sensible to agree on a single term - even if several alternatives are possible.

Atopic dysfunction and risk of central nervous system tumours in children

Risk factors for central nervous system (CNS) tumours in children remain largely unknown. Evidence of an inverse relationship between atopy and tumour development exists in adults but little is known about childhood tumours. This study aims to examine the risk of childhood CNS tumours given a history of eczema and asthma. Cases of children diagnosed with CNS tumours (n=575) and controls (n=6292) from the UK Childhood Cancer Study (UKCCS) were analysed using conditional logistic regression comparing reported histories of allergic disease. Asthma was statistically significantly and negatively associated with all CNS tumours (odds ratios, OR 0.75, confidence of interval, CI(95%): 0.58-0.97), though this was not observed for eczema (OR 0.94, CI(95%): 0.74-1.18). Individuals who had suffered both asthma and eczema showed the most significant reduction in risk (OR 0.48, CI(95%): 0.28-0.81). Analysis by tumour subtype showed the strongest effect for the medulloblastoma/PNET group. These results may have a biological explanation with raised immunosurveillance in atopic individuals protecting against the development of brain tumours. Alternative explanations might include bias, reverse causality or confounding.

A parent-completed respiratory questionnaire for 1-year-old children: repeatability

BACKGROUND AND AIMS

There are few standardised questionnaires for the assessment of respiratory symptoms in preschool children. We have developed and tested the short-term repeatability of a postal questionnaire on respiratory symptoms for 1-year-old children.

METHODS

A newly developed postal questionnaire for the assessment of wheeze and other respiratory symptoms was sent to parents of a population-based random sample of 4300 children aged 12-24 months. After an interval of 3 months, a random sample of 800 respondents received the questionnaire a second time. The responses were compared using Cohen's kappa (kappa) to assess agreement corrected for chance.

RESULTS

The first questionnaire was returned by 3194 (74%) families, the second one by 460/800 (58%). Repeatability was excellent (kappa 0.80-0.96) for questions on household characteristics, environmental exposures and family history, good (kappa 0.61-0.80) for questions on prevalence, severity and treatment of wheeze, and moderate (kappa 0.39-0.66) for chronic cough and upper respiratory symptoms.

CONCLUSIONS

This short postal questionnaire designed for use in population-based studies has excellent repeatability for family and household characteristics and good repeatability for questions on wheeze. Short-term changes in symptom status might be responsible for variable answers on recent chronic cough and upper respiratory symptoms. Overall, the questionnaire is a valuable instrument for community-based research on respiratory symptoms in 1 to 2-year-old children.

Nedocromil sodium for chronic asthma in children

BACKGROUND

Currently inhaled corticosteroids are the main stay in the maintenance treatment of chronic asthma in children. Although inhaled corticosteroids play a crucial role in the management of childhood asthma, the long-term side effects of inhaled corticosteroids used in the management of chronic asthma in children are not clearly known.

OBJECTIVES

The objective of this review is to compare the safety and efficacy of inhaled nedocromil sodium with placebo in the treatment of chronic asthma in children.

SEARCH STRATEGY

We searched the Cochrane airway group trials register, Cochrane controlled trials register, Current contents, review articles, reference lists of articles. We also contacted the drug manufacturer and primary authors for additional citations. We also searched abstracts of major respiratory society meetings. The last search was carried out in October 2004

SELECTION CRITERIA

Randomised placebo controlled trials comparing nedocromil sodium to placebo in the treatment of chronic asthma in children (0 to 18 years).

DATA COLLECTION AND ANALYSIS

Both authors independently assessed trial quality and extracted data. Study authors were contacted for additional information.

MAIN RESULTS

Fifteen trials (twelve parallel group studies; three crossover trials recruiting 1422 children (837 males and 585 females)) were included. The studies were generally of good methodological quality. Two large long term studies used nedocromil for six months and four to six years and showed conflicting results in symptom free days. Short term studies (duration between 4 weeks to 12 weeks) showed that nedocromil sodium produced some improvement in a number of efficacy measures compared to placebo including FEV(1), FVC, FEV(1) % predicted, PC20 FEV(1), evening PEF and symptom scores. The parent's assessment of efficacy was in favour of nedocromil (odds ratio (OR) 0.5 (95% CI 0.3 to 0.8). Nedocromil sodium has a good safety profile. The only significant side effect observed was unpleasant taste. There was little evidence for a clinically dose response effect and only a few studies recruited participants with severe asthma.

AUTHORS' CONCLUSIONS

A limited number of small studies have shown that nedocromil is of benefit in improving lung function and some measures of symptoms, but the evidence with regard to the primary outcome of the review was conflicting. Two long-term trials did not show consistent effects on lung function outcomes, whereas several small short-term trials have shown benefit in these outcomes. Differing severities at baseline may explain this difference with milder participants experiencing less benefit, although the discrepancy between study findings may also reflect publication bias. Nedocromil sodium is associated with a very good safety profile with no significant short term or long- term adverse side effects. Although nedocromil may have advantages over inhaled corticosteroids in terms of side effects, there is a need for head to head trials of nedocromil and inhaled corticosteroids to establish whether asthma control is similar, especially in mild asthma. It is not yet clear where nedocromil should sit in relation to other therapies in the treatment of asthma in children.

Race disparities in childhood asthma: does where you live matter?

OBJECTIVE

This study investigates whether racial/ethnic disparities in childhood asthma prevalence can be explained by differences in family and neighborhood socioeconomic position (SEP).

METHODS

Data were from the 2001 Rhode Island Health Interview Survey (RI HIS), a statewide representative sample of 2,600 Rhode Island households, and the 2000 U.S. Census. A series of weighted multivariate models were fitted using generalized estimating equations (GEE) for the logistic case to analyze the independent and joint effects of race/ethnicity and SEP on doctor-diagnosed asthma among 1,769 white, black and Hispanic children <18 years old.

RESULTS

Compared with white children, black children were at increased odds for asthma and this effect persisted when measures of family and neighborhood SEP were included in multivariate models (AOR: 2.49; 95% Cl: 1.30-4.77). Black children living in poverty neighborhoods had substantially higher odds of asthma than Hispanic and white children in poverty areas and children in moderate- and high-income neighborhoods (AOR: 3.20: 95% Cl: 1.62-6.29).

CONCLUSION

The high prevalence of asthma among black children in poor neighborhoods is consistent with previous research on higher-than-average prevalence of childhood asthma in poor urban minority communities. Changing neighborhood social structures that contribute to racial disparities in asthma prevalence remains a challenge.

Bronchial responsiveness and serum eosinophil cationic protein levels in preschool children with recurrent wheezing

BACKGROUND

Bronchial hyperresponsiveness is a universally recognized phenomenon of asthma, and increased levels of eosinophil cationic protein (ECP) have been identified in the serum of patients with asthma.

OBJECTIVES

To investigate whether enhanced bronchial responsiveness and elevated serum ECP levels are associated with recurrent wheezing in preschool children and to examine the possible relationship between these 2 variables.

METHODS

We recruited 130 children aged 4 to 6 years: 59 with at least 3 episodes of wheezing in the previous year (current wheezers), 38 with a documented history of wheezing before 3 years of age but no subsequent wheezing episodes (past wheezers), and 33 who had never experienced wheezing (nonwheezers). The children underwent methacholine bronchial provocation tests using a modified auscultation method and blood sampling for the measurement of ECP levels.

RESULTS

Current wheezers showed greater bronchial responsiveness than past wheezers and nonwheezers, as demonstrated by lower provocation concentrations that caused audible wheeze and lower provocation concentrations that caused a decline in oxygen saturation of at least 5% from baseline. Likewise, current wheezers had higher serum ECP levels than the other 2 groups. Among current wheezers, ECP levels showed a significant negative correlation with provocation concentrations that caused oxygen desaturation and a marginally significant correlation with provocation concentrations that caused audible wheeze.

CONCLUSIONS

Enhanced bronchial responsiveness and elevated serum ECP levels are associated with recurrent wheezing in 4- to 6-year-old children. These results suggest that wheezing during preschool years may be phenotypically similar to wheezing in older children.

The social and economic consequences of childhood asthma across the lifecourse: a systematic review

BACKGROUND

Asthma prevalence rates are high, and may be increasing in the Western world, particularly among children. The aim of this study was to evaluate the longer-term social and economic consequences of having asthma as a child and to determine whether adverse consequences are more severe for poorer children.

METHODS

Results from published and unpublished, quantitative and qualitative studies were synthesized narratively to examine the impact of childhood-onset asthma on school attendance, academic achievement and employment in adulthood. The question of whether the impact differed for different social groups was also examined.

FINDINGS

Twenty-nine good quality studies were identified, including in total 12 183 children with asthma or wheeze. Compared with asymptomatic children, those with asthma missed more days of school (additional absence as a result of asthma ranged from 2.1 to 14.8 days). Studies of academic achievement found that children with asthma performed as well as their healthy peers. The existing evidence on labour market performance is sparse, but there is an indication that people with asthma during childhood experience disadvantage in later employment. In an examination of consequences by social position, children with asthma from deprived areas were more likely to miss school than their more affluent peers, and minority ethnic children were also more likely to have poor school attendance. The only qualitative study suggested that children with asthma strove to participate fully in every aspect of their daily lives.

INTERPRETATION

Although asthma limits children's daily activities and affects their social activities, this research synthesis found little evidence of major, adverse long-term social and economic consequences in studies reviewed. Further longitudinal research using comparison groups is needed to fill key gaps in the existing evidence base.

Anticholinergic therapy for chronic asthma in children over two years of age

BACKGROUND

In the intrinsic system of controlling airway calibre, the cholinergic (muscarinic) sympathetic nervous system has an important role. Anticholinergic, anti muscarinic bronchodilators such as ipratropium bromide are frequently used in the management of childhood airway disease. In asthma, ipratropium is a less potent bronchodilator than beta-2 adrenergic agents but it is known to be a useful adjunct to other therapies, particularly in status asthmaticus. What remains unclear is the role of anticholinergic drugs in the maintenance treatment of chronic asthma.

OBJECTIVES

To determine the effectiveness of anticholinergic drugs in chronic asthma in children over the age of 2 years.

SEARCH STRATEGY

The Cochrane Airways Group trials register and reference lists of articles were searched in January 2002.

SELECTION CRITERIA

Randomised controlled trials in which anticholinergic drugs were given for chronic asthma in children over 2 years of age were included. Studies including comparison of: anticholinergics with placebo, and anticholinergics with any other drug were included.

DATA COLLECTION AND ANALYSIS

Eligibility for inclusion and quality of trials were assessed independently by two reviewers.

MAIN RESULTS

Eight studies met the inclusion criteria.Three papers compared the effects of anticholinergic drugs with placebo, and a meta-analysis of these results demonstrated no statistically significant benefit of the use of anticholinergic drugs over placebo in any of the outcome measures used. The results of one of these trials could not be included in the meta-analysis but the authors did report significantly lower symptom scores with inhaled anticholinergics compared with placebo. However, there was no significant difference between ipratropium bromide and placebo in the percentage of symptom-free nights or days. Two trials studied the effects of anticholinergics on bronchial hyper responsiveness to histamine, by measuring the provocation dose of histamine needed to cause a fall of 20 % in FEV1 (PD 20). One study (comparing anticholinergics with placebo) reported a statistically significant increase in PD 20 but this was not found in another study (comparing anticholinergics with a beta-2 agonist). Both trials also examined the effect of anticholinergic drugs on diurnal variation in peak expiratory flow rate (PEFR) and reported no significant effect. Two studies compared the addition of an anticholinergic drug to a beta-2 agonist with the beta-2 agonist alone. Both trials failed to show any significant benefit from the long term use of combined anticholinergics with beta-2 agonists compared with beta-2 agonists alone. One trial compared the effects of oral and inhaled anticholinergic drugs with placebo. No statistically significant differences were found in any of the outcome measures except for a higher FEV1 / VC ratio and RV / TLC ratio with oral anticholinergic therapy when compared with placebo.

REVIEWER'S CONCLUSIONS

The present review summarises the best evidence available to date. Although there were some small beneficial findings in favour of anticholinergic therapy, there is insufficient data to support the use of anticholinergic drugs in the maintenance treatment of chronic asthma in children.

A parent completed questionnaire to describe the patterns of wheezing and other respiratory symptoms in infants and preschool children

AIM

To develop a standardised and validated respiratory symptom questionnaire for use in epidemiological or follow up studies in infants and preschool children.

METHODOLOGY

After initial design and development, the questionnaire was administered to two cohorts of subjects, one recruited from a respiratory clinic and the other from a postnatal ward. The two cohorts then repeated the questionnaire, two weeks apart. The qualities of the questionnaire were assessed.

RESULTS

Response rate to the initial questionnaire was 100% for the clinic based cohort and 64% for postnatally recruited families (total number of subjects 114). Questions showed good to moderate short term reliability (weighted kappa scores 0.47-0.7; average correct classification rates 0.74-0.91). Four domain concept scores showed excellent internal consistency (Cronbach alpha scores 0.87-0.95). Using principal component factor analysis, four new domains were devised showing acceptable construct validity and internal consistency. Criterion validity was assessed using a respiratory physician based diagnosis of asthma (RPBDA) as the gold standard for comparison. All eight scales in the questionnaire could significantly distinguish between infants with RPBDA and well or mildly symptomatic subjects.

CONCLUSION

We have developed a practical, acceptable questionnaire with eight concept domains for use in infants and preschool children. The questionnaire has strong construct validity and internal consistency with good short term reliability of questions. More detailed study of criterion validity and the responsiveness of the questionnaire is required using a larger population and including children with the different phenotypes of wheezy illness.

Patients with a longer duration of symptoms of acute asthma are more likely to require admission to hospital

OBJECTIVE

To determine whether, for patients with moderate or severe asthma presenting to emergency departments, there is a difference in need for hospitalization between those with a duration of symptoms less than 6 h and those with a longer duration of symptoms.

METHODS

This prospective, observational study investigated a sample of patients presenting with acute asthma between 21 August and the 3 September 2000, attending study emergency departments and classified as having moderate or severe asthma according to the National Asthma Guidelines. Data collected included duration of symptoms (less than 6 h or greater than 6 h) and disposition following emergency department treatment (home, ward, intensive care unit, high dependency unit, transfer). Data analysis was by Chi square analysis.

RESULTS

Of 381 eligible patients, 348 had sufficient data for entry into this study (33 had missing data). Patients with duration of symptoms more than 6 h were more likely to require hospital admission (P < 0.0001). The relative risk for hospital admission or transfer as opposed to discharge from the emergency department for the group with a duration of symptoms of more than 6 h was 2.2.

CONCLUSION

Patients presenting with moderate or severe asthma and a duration of symptoms of more than 6 h are more likely to require hospital admission or transfer for further treatment than patients with a shorter duration of symptoms. This has implications for decision making regarding asthma management and disposition in the emergency department.

Persistent wheezing in infants with an atopic tendency responds to inhaled fluticasone

BACKGROUND

The role of inhaled corticosteroids for the treatment of wheeze in infancy remains unclear.

AIM

To investigate the effect of inhaled fluticasone on symptoms in a group of wheezy infants who had a high risk of progressing to childhood asthma.

METHODS

A total of 52 infants, under 1 year of age, with a history of wheeze or cough and a history (personal or first degree relative) of atopy were prescribed either 150 microg fluticasone twice daily (group F) or placebo (group P), via metered dose inhaler, for 12 weeks following a two week run in period. Symptoms were scored in a parent held diary and the mean daily symptom score (MDS) and symptom free days (SFD) calculated for each two week period.

RESULTS

Thirty seven infants completed the study. Both MDS and SFD improved significantly between the run in and final two week period in group F, but not group P, with a mean difference in change (95% CI) between groups of 1.12 (0.05 to 2.18) for MDS and median difference of 3.0 (0.002 to 8.0) for SFD.

CONCLUSION

Improvement of clinical symptoms in response to fluticasone can be shown in this high risk group of infants. In the absence of effective alternatives inhaled corticosteroids should be considered in this patient group.

Total serum IgE and outcome in infants with recurrent wheezing

OBJECTIVE

To investigate the relation between total serum IgE at 0.5-3 and 3-6 years, and the risk of allergic sensitisation and persistent wheezing up to 8 years of age.

METHODS

Prospective follow up study of 45 infants with highly recurrent wheezing, no allergic symptoms, and negative skin tests.

RESULTS

In the last follow up year, 15 children still suffered from wheezing. Five wheeze-free and four episodically wheezing children had become sensitised. No association was found between early (0.5-3 years) IgE z scores and the recurrence of wheezing during follow up, or atopic sensitisation. IgE z scores at 3-6 years were significantly higher in children with positive skin tests (p = 0.013), but were still not associated with recurrence of wheezing.

CONCLUSIONS

In subjects with frequent early wheezing and no signs of atopy, early total serum IgE measurements are not predictive of outcome.

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

BACKGROUND

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

METHODS

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

FINDINGS

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

INTERPRETATION

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

Risk factors for pediatric asthma. Contributions of poverty, race, and urban residence

The Child Health Supplement to the 1988 National Health Interview Survey was used to examine parent-reported current asthma among a nationally representative sample of 17,110 children zero to 17 yr of age. Numerous demographic variables were analyzed for independent associations with asthma using modified stepwise logistic regression, with models including specific combinations of risk factors. Black children had higher rates of asthma than did white children in unadjusted analyses, but after controlling for multiple factors, black race was not a significant correlate of asthma (adjusted odds ratio = 0.87, 95% CI = 0.63 to 1.21). Compared with nonurban white children, urban children, both black and white, were at significantly increased risk of asthma: urban and black (adjusted OR = 1.45, 95% CI = 1.14 to 1.86), urban and white (adjusted OR = 1.22, 95% CI = 1.01 to 1.48), whereas nonurban black children were not: nonurban and black (adjusted OR = 1.15, 95% CI = 0.83 to 1.61). Similarly, compared with nonurban, nonpoor children, urban and poor (adjusted OR = 1.44, 95% CI = 1.05 to 1.95), urban and nonpoor (adjusted OR = 1.22, 95% CI = 1.004 to 1.48), urban children, both poor and nonpoor, were at significantly increased risk of asthma, whereas nonurban poor children were not: nonurban and poor (adjusted OR = 1.03, 95% CI = 0.72 to 1.48). These results suggest that the higher prevalence of asthma among black children is not due to race or to low income per se, and that all children living in an urban setting are at increased risk for asthma.

Comparison of the seasonal patterns of asthma identified in general practitioner episodes, hospital admissions, and deaths

BACKGROUND

Seasonal variations in asthma are widely recognised. This study was undertaken to investigate the relative differences in seasonal patterns by age as they impact on episodes of care in general practice, hospital admissions, and deaths.

METHODS

General practice episode data from the Weekly Returns Service of the Royal College of General Practitioners, hospital admissions for asthma in England, and deaths registered as due to asthma in England and Wales over the years 1990-7 were examined. Age specific weekly rates of new episodes of asthma presenting to general practitioners, numbers of hospital admissions and deaths were analysed by the multiplicative decomposition method to separate secular from seasonal trends. The seasonal indices thereby obtained were plotted as three week moving averages.

RESULTS

In children aged 0-4 and 5-14 years general practice episodes and admissions to hospital were strikingly congruent in timing and in magnitude, except in September when particularly high rates of admission (absolute and relative to general practice episodes) occurred. In the 15-44 age group there were marked mid summer peaks of general practice episodes and deaths but admissions to hospital were at about the annual average; in September/October there were peaks of episodes and admissions whereas deaths peaked in November. In the 45-64 age group a peak in general practice episodes of asthma was evident in mid summer when admissions were about average and deaths were at a minimum; all three measures tended to increase gradually with the approach of winter. Finally, in those age over 65 years, general practice episodes of asthma, admissions to hospital, and deaths followed similar 'U' shaped patterns with substantial peaks in mid winter.

CONCLUSIONS

The seasonal pattern of asthma evolves with age. There are important differences in the seasonal pattern of general practice episodes, admissions to hospital, and deaths. Individual seasonal histories are important for the management of asthma. The combined analysis of these three data sets provides a new perspective on the epidemiology of asthma.

Corticosteroid-sparing options in the treatment of childhood asthma

During the last 30 years, a significant rise in wheezing illness has occurred in the child population. Despite its high prevalence there is no clear definition of the disease, which includes a heterogeneous group of syndromes ranging from transient wheezing in infancy to atopic asthma with persistence into adult life. Molecular advances and further epidemiological information from well characterised individuals and their families are likely to clarify the different subtypes of wheezing illness and inform therapeutic options. With the recognition that chronic airway inflammation is a feature of persistent disease, at least in adults, there has been a trend towards the early introduction of anti-inflammatory treatment and particularly inhaled corticosteroids (ICS). However, the natural resolution of much wheezing illness, particularly in young children and in children with viral-induced episodes, suggests that newly presenting children should remain on symptomatic therapy alone while the severity of the disease is being assessed. Although ICS have become a cornerstone of management of chronic persistent disease, their ability to protect against exacerbations in young and mildly affected children is questionable. Alongside concerns about long term use of ICS and possible systemic adverse effects, there remains a need for alternative approaches to the control of the disease in children. Extrapolation of the findings of large multicentre adult studies into childhood, particularly for doubling the doses of ICS and long-acting beta2-agonists, may be unsound. Other approaches include the early introduction of inhaled cromones, use of second generation antihistamines, low dose theophyllines and, more recently, leukotriene modifiers. As the majority of preschool children will become asymptomatic by mid-childhood, there is an urgent need to identify those in whom chronic airway inflammation is developing, as it is in this group that early introduction of ICS may be of maximum benefit. In the remainder, other approaches, including use of corticosteroid-sparing longacting P2-agonists and leukotriene modifying drugs, may be more appropriate. Safe and effective oral preparations such as leukotriene modifying drugs are likely to establish a significant role in the management of symptoms in children of all ages and with all types of asthma and wheezing illness.

Bronchial asthma: recent advances

Asthma is one of the oldest diseases about which there are lots of myths in most parts of the world. The exact cause of this global disease still eludes scientists. The recent knowledge about the pathogenesis of the disease, led to rationalise the medications into different groups. Parallel to the increasing incidence of this disease, is the knowledge about the trigger factors and steps to reduce their exposure. Childhood asthma is a lot different from asthma in adults, as many children won't be able to use the inhalers like adults and most children will not be able to do lung function tests until they are about 6 years of age. Unlike for any other diseases, research has helped year after year in developing new strategies for management of asthma. Starting from definition of the disease to inventing newer medications, management of asthma has revolutionised in the last few years and has also accounted for the decreasing mortality in many countries. This article tries to give an overview of bronchial asthma in children including recent advances and possible future developments.

Beliefs about diagnosing asthma in young children

OBJECTIVES

To determine what factors primary care pediatricians believe are important in establishing the initial diagnosis of childhood asthma and to identify variations in physicians' beliefs concerning this clinical decision.

STUDY DESIGN

Massachusetts American Academy of Pediatrics Fellows were surveyed about their beliefs concerning the importance of 20 clinical factors associated with establishing the initial diagnosis of asthma.

RESULTS

Most clinicians considered recurrent wheeze (96%), symptomatic improvement with a bronchodilator (90%), recurrent cough (89%), exclusion of alternative diagnoses (87%), and suggestive peak flow findings (82%) as important in diagnosing asthma. However, there was substantial heterogeneity among clinicians as to which combinations of factors they each considered relevant; for example, only 60% identified all 5 of the above factors to be necessary or important. Further, <50% identified presence of any of the 20 factors as necessary. Although national guidelines cite objective assessment of pulmonary function as essential, spirometry and peak expiratory flow testing were identified as necessary by only 8% and 10%, respectively. Two factors believed to contribute to establishing the asthma diagnosis contradicted the National Asthma Education and Prevention Program guidelines and expert opinion (age >2 years and absence of fever during episodes) and these beliefs were more likely held by those clinicians in practice for >5 years.

CONCLUSIONS

The majority of pediatricians believe several common clinical factors establish a diagnosis of childhood asthma, but disagree over what combinations of these factors are important. Some misconceptions persist despite wide dissemination of clinical practice guidelines. We believe that future asthma guidelines will need to organize diagnostic criteria in an easily understood format, like a decision tree, to facilitate early recognition of asthma in young children.

Risk factors for early, persistent, and late-onset wheezing in young children. SIDRIA Collaborative Group

Wheezing in childhood is not a single disorder and different wheezing-associated respiratory illnesses have been recently described. We investigated the association between wheezing conditions and familial, pre-, peri-, and postnatal risk factors. We studied 16,333 children, 6 to 7 yr old, enrolled in a population-based study. Standardized questionnaires were filled in by parents. A total of 1,221 children had transient early wheezing, 671 had persistent wheezing, 918 had late-onset wheezing, and 13,523 never had wheezing or asthma (control group). Maternal asthma or chronic obstructive airway disease were significantly (p < 0.0001) more associated with persistent wheezing than with transient early and late-onset wheezing. The same pattern was observed for exposure to maternal smoke during pregnancy. Having a mother > 35 yr old was protective against transient early wheezing (odds ratio [OR]: 0.68, 95% confidence intervals [95% CI]: 0.53 to 0.86). Breast feeding >/= 6 mo was slightly protective against transient early wheezing (OR: 0.82, 95% CI: 0.68 to 0.97), whereas it was a moderate risk factor for late-onset wheezing (OR: 1.22, 95% CI: 0.99 to 1.50). On the contrary, having siblings and attending a day care center were both risk factors for transient early wheezing (OR: 1.41 [95% CI: 1.21 to 1.64] and 1.70 [95% CI: 1.48 to 1.96], respectively) and protective factors against wheezing of late onset (OR: 0.83 [95% CI: 0.70 to 0.97] and 0.72 [95% CI: 0.59 to 0.88]). There was a stronger (p < 0.0001) positive association between personal history of eczema or allergic rhinitis and persistent and late-onset wheezing than transient early wheezing. Our findings suggest a different contribution of risk factors to wheezing conditions in childhood.

Exhaled nitric oxide concentrations during treatment of wheezing exacerbation in infants and young children

While it is known that exhaled nitric oxide (ENO) is increased in adults and school children with asthma exacerbation probably as an expression of disease activity, no studies have investigated whether this phenomenon also occurs in infants and young children with recurrent wheeze exacerbation. We measured ENO in 13 young children (mean age 20.2 mo) with recurrent wheeze (Group 1) during an acute episode and after 5 d of oral prednisone therapy. ENO was measured also in nine healthy control subjects (Group 2) (mean age 16.9 mo) and in six children with a first-time viral wheezy episode (Group 3) (mean age 11 mo). To measure ENO, infants inhaled NO-free air via a face mask from a reservoir and, through a nonrebreathing valve, exhaled in a collecting bag that was analyzed by chemiluminescence. To address the question of whether the levels of ENO collected in the bag are a reflection of the pulmonary airway, ENO determinations were performed in two healthy infants before and after tracheal intubation for elective surgery. During the acute episode of wheezing the mean (+/- SEM) value of ENO in children with recurrent wheeze (Group 1) was 14.1 +/- 1.8 ppb, almost threefold higher than in healthy control subjects (5.6 +/- 0.5 ppb, p < 0.001). After steroid therapy we found a mean fall of 52% in ENO (5.9 +/- 0.7 ppb, p < 0.01) compared with baseline values. ENO values measured before and after intubation in two infants were 6 ppb and 5 ppb in one child and 7 ppb and 6 ppb in the other one. The mean value of ENO of children with first-time wheeze (Group 3) was 8.3 +/- 1.3 ppb, significantly lower (p < 0.05) than the value of children with recurrent wheeze (Group 1). In conclusion, we describe a method to measure ENO in young children and show that infants with recurrent wheeze have elevated levels of ENO during exacerbation that rapidly decrease after steroid therapy. This suggests that, in these children, airway inflammation could be present at a very early stage.

Phenotype stability in asthma and atopy in childhood

The asthma phenotype can be described using a combination of the following: symptom type, pattern and severity; markers of atopy; and measurement of bronchial responsiveness. Because of the very nature of the disease, symptoms of asthma are variable in both the short-and the long-term, and the natural history of the disease is such that symptoms in an individual may evolve over time through different patterns. Although atopy appears to be a life-long attribute resulting from an early life switching to a TH2 immune response, the surrogate markers of atopy each are subject to their own time-related determinants and patterns of change with age. Bronchial responsiveness in childhood is neither specific nor sensitive for asthma, and although showing good short-term repeatability, can vary widely when measured over a period of months or years. Stimuli for responsiveness testing should be chosen which can be inhaled safely in high doses so as to allow an end point to be reached by as many subjects within a population as possible, and individuals may have to be tested repeatedly over time so as to avoid misclassification.