Changing prevalence of asthma in Australian children

Primary prevention of asthma

There has been a dramatic increase in the prevalence of asthma over the last quarter century, particularly in the industrialized world. Although our understanding of asthma continues to improve, there is no cure for the disease. Primary prevention of asthma is the focus of this review. Asthma is a disease with multiple gene-environment interactions. Candidate genes for asthma are considered, and potential interaction between one of those genes, CD14, and an environmental factor, endotoxin, is reviewed as it relates to the hygiene hypothesis. Environmental risk factors for asthma including allergens, pollutants, infectious factors, and dietary modifications are considered, particularly their potential for primary prevention of asthma. Ongoing cohort studies including the Canadian Allergy and Asthma Prevention Study, the Manchester Allergy and Asthma Study, the Children's Asthma Prevention Study from Australia, and the Prevention and Incidence of Asthma and Mite Allergy Study from the Netherlands are briefly reviewed. A more definitive understanding of genetic background and environmental triggers and their interactions is required before any specific approach to the primary prevention of asthma can be championed aggressively.

Prevalence of asthma, allergic rhinitis and eczema among university students in Bangkok

Prevalence of childhood asthma is increasing worldwide including in developing countries such as Thailand. Despite a wide availability of epidemiological data on childhood asthma in Thailand, prevalence of asthma in adults has not been well studied within this community. Objectives of this study were to study prevalence of asthma, allergic rhinitis and eczema in a random group of university students in Bangkok using the standardized written and video questionnaires from the ISAAC phase I protocol. The ISAAC phase I, written and video (International version, AVQ 3.0) questionnaires were administered to 3631 randomly selected university students from six universities in Bangkok. The age range of subjects were between 16-31 years (mean +/- SD= 19.1 +/- 1.7 years). There were 1197 males and 2434 females (ratio = 1:2.03). Data were entered into and analysed by the EpiInfo 4 program. Prevalence of wheeze within the past 12 months and of diagnosed asthma for this group of subjects was 10.1% and 8.8%. Prevalence of allergic rhinitis (nasal with eye symptoms within the past 12 months) was 26.3% and of eczema (rash at typical sites of atopic dermatitis, within the past 12 months) was 9.4%. Presence of rhinoconjunctivitis, gender and age were significant risk factors for asthma with male, younger subjects and those with rhinoconjunctivitis reported more frequent asthma-related symptoms (P < 0.01). As in previous studies which found an increase in asthma among Thai children, this survey indicates that the prevalence of asthma among Thai university students has increased to the same level as in several European countries. A large number of adults residing in Bangkok are suffering from rhinitis-related symptoms, the majority of which probably represents allergic rhinitis.

Increased occurrence of asthma and allergy: critical appraisal of studies using allergic sensitization, bronchial hyper-responsiveness and lung function measurements

BACKGROUND

Many studies have reported an increase in the occurrence of asthma and respiratory allergies in recent decades, but this increase is mostly based on studies using rather subjective measurements of asthma and allergies, such as questionnaires and doctor's diagnosis. None of the reviews specifically focused on studies using more 'objective' measurements, such as sensitization (specific IgE or skin prick testing (SPT)), bronchial hyper-responsiveness (BHR) or lung function (LF).

OBJECTIVE

To review articles studying a time trend of occurrence of these 'more objective' measurements.

METHODS

A MEDLINE-search (1966-February 2000) was performed. The following criteria were used: population-based, using IgE, SPT, BHR or LF measurements in the same age-group at least twice, with at least 2 years between and using similar methods.

RESULTS

The MEDLINE-search resulted in only 16 articles, performed in 13 populations in seven different countries. Nine articles used the same objective measurements twice in the whole population. Three of these reported a non-significant increase or decrease. The other six articles found a significant increase in at least one objective measurement and of these only three reported a consistent significant increase.

CONCLUSIONS

The increase in the occurrence of reported asthma and allergy is supported by only a few articles confirming these results with 'more objective measurements'.

A prospective study of the association between home gas appliance use during infancy and subsequent dust mite sensitization and lung function in childhood

BACKGROUND

Home gas appliance use has been associated with child respiratory illness but prospective data on the relationship between infant exposure and the development of child allergic disease has not been readily available.

OBJECTIVES

(a) To determine if home gas appliance use is associated with increased risk of house dust mite (HDM) sensitization. (b) To examine whether any association between current home gas use and airway obstruction is influenced by HDM sensitization.

METHODS

DESIGN

an 8-year follow-up birth cohort study of children born during 1988 and 1989.

PARTICIPANTS

a population-based sample (n = 498) of children who participated in the Tasmanian Infant Health Survey (TIHS) and resided in Northern Tasmania in 1997 (84% of eligible children).

MAIN OUTCOME MEASURES

(a) Skin prick test reaction to nine allergens, including Dermatophagoides pteronyssinus (Der p 1) and Dermatophagoides farinae (Der f 1). (b) Spirometric lung function indices, including forced expiratory volume in one second (FEV(1)) and forced vital capacity (FVC).

RESULTS

The relative risk for home gas appliance use at 1 month of age and HDM sensitization was 1.98 (1.04, 3.79) in a cohort analysis with confounder matching. Current home gas use was also associated with HDM sensitization (ARR 1.73 (1.43, 2.76)). Current home gas use was related to a stronger (P = 0.006) reduction in the FEV(1) : FVC ratio among HDM-sensitive children (adjusted difference - 6.2% (- 10.0 to - 2.4)) than non-HDM-sensitive children (adjusted difference - 0.3% (- 2.5 to 1.8)).

CONCLUSION

Indoor pollutants from gas combustion may increase the likelihood of initial sensitization to HDM and play a role in the development of atopic asthma. HDM-sensitized children may be more vulnerable to indoor pollutant-induced airway obstruction. The ability of this study to detect such effects may partly reflect unflued gas appliance use among this sample.

Inhaled budesonide for adults with mild-to-moderate asthma: a randomized placebo-controlled, double-blind clinical trial

CONTEXT

Budesonide is an inhaled corticosteroid with high topical potency and low systemic activity recommended in the treatment of chronic asthma.

OBJECTIVE

This study was conducted to determine the efficacy and safety of inhaled budesonide via a breath-activated, multi-dose, dry-powder inhaler.

TYPE OF STUDY

Multicenter randomized parallel-group, placebo-controlled, double-blind, clinical trial.

SETTING

Multicenter study in the university units.

PARTICIPANTS

Adult patients with mild-to-moderate asthma that was not controlled using bronchodilator therapy alone.

PROCEDURES

Comparison of budesonide 400 microg administered twice daily via a breath-activated, multi-dose, dry-powder inhaler with placebo, in 43 adult patients (aged 15 to 78 years) with mild-to-moderate asthma (FEV1 71% of predicted normal) that was not controlled using bronchodilator therapy alone.

MAIN MEASUREMENTS

Efficacy was assessed by pulmonary function tests and asthma symptom control (as perceived by the patients) and the use of rescue medication.

RESULTS

Budesonide 400 microg (bid) was significantly more effective than placebo in improving morning peak expiratory flow (mean difference: 67.9 l/min; P < 0.005) and FEV1 (mean difference: 0.60 l; P < 0.005) over the 8-week treatment period. Onset of action, assessed by morning peak expiratory flow, occurred within the first two weeks of treatment.

CONCLUSIONS

Budesonide via a breath-activated, multi-dose, dry-powder inhaler results in a rapid onset of asthma control, which is maintained over time and is well tolerated in adults with mild-to-moderate asthma.

Prevalence of obstructive lung diseases and respiratory symptoms in relation to living environment and socio-economic group

We wanted to test whether living environment, occupation and social position are risk factors for asthma and chronic bronchitis/emphysema (CBE). The prevalence of bronchial asthma, CBE, respiratory symptoms and smoking habits in a random sample of 12,071 adults aged 20-59 years was assessed in a postal survey with a slightly modified questionnaire previously used in central and northern Sweden (The OLIN studies). Occupation was coded according to a socio-economic classification system. Six different living environment areas were defined; city-countryside, seaside-not seaside and living close to heavy traffic-not living close to heavy traffic. Multiple logistic regression analysis (forward conditional) was applied to estimate the association between the proposed set of risk factors and self-reported obstructive lung diseases and lower respiratory symptoms controlling for age, gender and smoking. After two reminders, the response rate was 70.1% (n=8469); 33.8% of the responders were smokers. In all, 469 subjects (5.5%) stated that they had asthma and 4.6% reported CBE. Besides smoking, which was a risk for both asthma and CBE, there were different risk patterns for self-reported asthma and CBE. In the economically active population there was a tendency that CBE was more common among 'unskilled and semi-skilled workers'. This fact was further emphasized when the population was merged into the two groups 'low social position' and 'middle/high social position', with 'low social position' as a risk for CBE (OR=1.35, 95% CI=1.06-1.72). No social risk factors were identified for asthma. Living close to heavy traffic was a risk factor for asthma (OR=1.29, 95% CI=1.02-1.62) but not for CBE. Apart from this no living environmental risk factors for obstructive pulmonary diseases were identified. Asthma symptoms and long-standing cough were more common among those subjects living close to heavy traffic compared to those not living close to heavy traffic. To conclude, low social position was a risk factor for CBE and living close to heavy traffic was a risk factor for asthma.

The burden of asthma in Australia

In 1997, 27% of Australian children had current wheeze, and this is increasing by 1.4% per year. The prevalence of wheeze among adults is lower and appears to be stable. The prevalence of persistent asthma (wheezing episodes with abnormal airway function between episodes) in children has increased from 5% to 9% in the past 20 years. In adults, the prevalence is 5%-6%. Up to 80% of adults with persistent asthma have abnormal lung function. Asthma deaths in Australia have fallen 28% since peaking in 1989, but the mortality rate is still twice that of England.

Respiratory symptoms, asthma, exercise test spirometry, and atopy in schoolchildren from a Lima shanty town

BACKGROUND

Little is known about the associations between symptoms of asthma, pulmonary function tests, and atopy in developing countries. While asthma in children is often associated with atopy, some studies of wheezing illness have found little or no association, leading to suggestions that there are subgroups of wheezing illness. The ISAAC study recently reported that the prevalence of reported asthma symptoms in Lima, Peru was among the highest in the world, but did not report on the atopic status of the subjects.

METHODS

A cross sectional survey was conducted of children aged 8-10 years who had previously participated in a cohort study of respiratory and diarrhoeal illnesses in infancy. Questionnaires were administered asking about respiratory symptoms and asthma diagnoses, pulmonary function tests were performed before and after exercise on a treadmill, and atopy was determined from skin prick tests and specific serum IgE levels.

RESULTS

A total of 793 children participated in the survey. The prevalence of asthma related symptoms in the last 12 months was 23.2%, but only 3.8% of children reported a recent asthma attack. The mean differences in pretest percentage predicted forced expiratory volume in one second (FEV(1)) were 8.1% (95% CI 2.4 to 13.8) between children who did and did not report an asthma attack in the last 12 months, and 5.3% (95% CI 2.8 to 7.9) in children who did and did not report respiratory symptoms. The corresponding differences in mean percentage fall in FEV(1) after exercise were 3.1% (95% CI -1 to 7.1) and 5.1% (95% CI 3.4 to 6.8). Recent asthma or respiratory symptoms were not associated with atopy in this population (odds ratios 1.29 (95% CI 0.56 to 2.97) and 0.91 (95% CI 0.61 to 1.37), respectively).

CONCLUSIONS

Most asthma in these children was unrecognised and mild. Asthma and asthma symptoms in this population do not seem to be related to atopy.

The relationship between low level nitrogen dioxide exposure and child lung function after cold air challenge

BACKGROUND

Nitrogen dioxide (NO(2)) or home gas appliance use has been inconsistently associated with adverse respiratory outcomes in childhood.

OBJECTIVES

(i) To examine the contribution of home gas appliance type and personal NO(2) exposure. (ii) To examine the relationship between NO(2) exposure and child lung function and respiratory history. (iii) To assess whether these relationships vary by house dust mite sensitization status.

METHODS

A cross-sectional survey of 344 children (71% of the eligible group) with a mean age of 9.1 years from four randomly selected schools in the Australian Capital Territory from July to September 1999. Study measurements included a parental questionnaire, NO(2) exposure by passive gas samplers, skin prick testing for 10 aeroallergens and lung function at rest and after cold air challenge.

RESULTS

Total NO(2) exposure was low with a mean concentration of 10.1 ppb. No associations were found between NO(2) exposure or gas appliance use and asthma, wheeze or baseline lung function. Personal NO(2) exposure was associated with a reduction in forced expiratory volume in one second (FEV1)/forced vital capacity (FVC) after cold air challenge (adjusted difference - 0.12% (- 0.23% to - 0.01%) per 1 ppb increase). After exclusion of children who had home heating changed because of asthma, gas heater use was also significantly associated with a reduction in this measure (adjusted difference - 2.0% (- 3.7% to - 0.2%)). There was some evidence that these reductions were greater among the non-mite-sensitized children.

CONCLUSIONS

The effect of low-level NO(2) exposure on these respiratory outcomes was not marked. The possible effect of low-level NO(2) exposure on non-specific bronchial reactivity requires confirmation. Future studies on NO(2) and respiratory health should include measures of house dust mite sensitization and bronchial hyper-responsiveness.

Asthma in preschool children: prevalence and risk factors

BACKGROUND

The prevalence of asthma in children has increased in many countries over recent years. To plan effective interventions to reverse this trend we need a better understanding of the risk factors for asthma in early life. This study was undertaken to measure the prevalence of, and risk factors for, asthma in preschool children.

METHODS

Parents of children aged 3-5 years living in two cities (Lismore, n=383; Wagga Wagga, n=591) in New South Wales, Australia were surveyed by questionnaire to ascertain the presence of asthma and various proposed risk factors for asthma in their children. Recent asthma was defined as ever having been diagnosed with asthma and having cough or wheeze in the last 12 months and having used an asthma medication in the last 12 months. Atopy was measured by skin prick tests to six common allergens.

RESULTS

The prevalence of recent asthma was 22% in Lismore and 18% in Wagga Wagga. Factors which increased the risk of recent asthma were: atopy (odds ratio (OR) 2.35, 95% CI 1.49 to 3.72), having a parent with a history of asthma (OR 2.05, 95% CI 1.34 to 3.16), having had a serious respiratory infection in the first 2 years of life (OR 1.93, 95% CI 1.25 to 2.99), and a high dietary intake of polyunsaturated fats (OR 2.03, 95% CI 1.15 to 3.60). Breast feeding (OR 0.41, 95% CI 0.22 to 0.74) and having three or more older siblings (OR 0.16, 95% CI 0.04 to 0.71) decreased the risk of recent asthma.

CONCLUSIONS

Of the factors tested, those that have the greatest potential to be modified to reduce the risk of asthma are breast feeding and consumption of polyunsaturated fats.

Genetic susceptibility to asthma and atopy among Chinese in Singapore--linkage to markers on chromosome 5q31-33

BACKGROUND

Asthma and atopy are complex genetic traits, influenced by the interaction of multiple genes and environmental factors. Linkage of these traits to chromosome 5q31-33 has been shown in other populations, but has not been well studied in the Chinese. We studied linkage between asthma and atopy with markers on chromosome 5q31-33 in the Singapore Chinese. This region contains many candidate genes, including the cytokine gene cluster.

METHODS

We recruited 88 Chinese families with at least two affected offspring, totaling 373 subjects, with 125 and 119 sib-pairs for atopy and asthma, respectively. All individuals were genotyped with 19 polymorphic microsatellite markers spanning a distance of 41 cM along chromosome 5q31-33. Affected sib-pair and multipoint linkage analysis was performed.

RESULTS

There was evidence for linkage of the asthma and atopy phenotypes with three markers, D5S2110, D5S2011, and D5S412 (P values of 0.001 to 0.00001). Multipoint analysis further substantiated this (nonparametric linkage scores of 1.8-2.9). These findings suggest that susceptibility genes for asthma and atopy are found in this region in the Chinese.

CONCLUSION

This study has shown linkage of atopy and asthma to chromosome 5q31-33 in a heterogeneous Chinese population. These findings further substantiate the notion that chromosome 5q31-33 contains "universally" important susceptibility genes for these traits.

Asthma in preschool children: prevalence and risk factors

BACKGROUND

The prevalence of asthma in children has increased in many countries over recent years. To plan effective interventions to reverse this trend we need a better understanding of the risk factors for asthma in early life. This study was undertaken to measure the prevalence of, and risk factors for, asthma in preschool children.

METHODS

Parents of children aged 3–5 years living in two cities (Lismore, n=383; Wagga Wagga, n=591) in New South Wales, Australia were surveyed by questionnaire to ascertain the presence of asthma and various proposed risk factors for asthma in their children. Recent asthma was defined as ever having been diagnosed with asthma andhaving cough or wheeze in the last 12 monthsand having used an asthma medication in the last 12 months. Atopy was measured by skin prick tests to six common allergens.

RESULTS

The prevalence of recent asthma was 22% in Lismore and 18% in Wagga Wagga. Factors which increased the risk of recent asthma were: atopy (odds ratio (OR) 2.35, 95% CI 1.49 to 3.72), having a parent with a history of asthma (OR 2.05, 95% CI 1.34 to 3.16), having had a serious respiratory infection in the first 2 years of life (OR 1.93, 95% CI 1.25 to 2.99), and a high dietary intake of polyunsaturated fats (OR 2.03, 95% CI 1.15 to 3.60). Breast feeding (OR 0.41, 95% CI 0.22 to 0.74) and having three or more older siblings (OR 0.16, 95% CI 0.04 to 0.71) decreased the risk of recent asthma.

CONCLUSIONS

Of the factors tested, those that have the greatest potential to be modified to reduce the risk of asthma are breast feeding and consumption of polyunsaturated fats.

Respiratory symptoms, asthma, exercise test spirometry, and atopy in schoolchildren from a Lima shanty town

BACKGROUND

Little is known about the associations between symptoms of asthma, pulmonary function tests, and atopy in developing countries. While asthma in children is often associated with atopy, some studies of wheezing illness have found little or no association, leading to suggestions that there are subgroups of wheezing illness. The ISAAC study recently reported that the prevalence of reported asthma symptoms in Lima, Peru was among the highest in the world, but did not report on the atopic status of the subjects.

METHODS

A cross sectional survey was conducted of children aged 8–10 years who had previously participated in a cohort study of respiratory and diarrhoeal illnesses in infancy. Questionnaires were administered asking about respiratory symptoms and asthma diagnoses, pulmonary function tests were performed before and after exercise on a treadmill, and atopy was determined from skin prick tests and specific serum IgE levels.

RESULTS

A total of 793 children participated in the survey. The prevalence of asthma related symptoms in the last 12 months was 23.2%, but only 3.8% of children reported a recent asthma attack. The mean differences in pretest percentage predicted forced expiratory volume in one second (FEV1) were 8.1% (95% CI 2.4 to 13.8) between children who did and did not report an asthma attack in the last 12 months, and 5.3% (95% CI 2.8 to 7.9) in children who did and did not report respiratory symptoms. The corresponding differences in mean percentage fall in FEV1 after exercise were 3.1% (95% CI –1 to 7.1) and 5.1% (95% CI 3.4 to 6.8). Recent asthma or respiratory symptoms were not associated with atopy in this population (odds ratios 1.29 (95% CI 0.56 to 2.97) and 0.91 (95% CI 0.61 to 1.37), respectively).

CONCLUSIONS

Most asthma in these children was unrecognised and mild. Asthma and asthma symptoms in this population do not seem to be related to atopy.

The prevalence of asthma and heart disease in transport workers: a practice-based study

BACKGROUND

There has been widespread concern that the increasing incidence of asthma observed during the late 1980s might have arisen because of environmental pollution, and in particular vehicle pollution. The General Practice Morbidity Survey in 1991/92 (MSGP4) collected data on occupation, employment status, and smoking habit linked individually to each patient record.

OBJECTIVES

To examine whether people with occupations that have high exposure to vehicle exhaust fumes have an increased prevalence of asthma, acute respiratory infections, and ischaemic heart disease (IHD).

METHOD

Men aged 16 to 64 years were grouped by Standard Occupational Classification codes; 93,692 employed and 20,858 not-employed men were studied separately. Those with likely high occupational exposure were grouped together ('all-exposed')--the remainder occupations in corresponding chapters of the code were used as controls. We compared 12-month age and smoking standardised disease prevalence ratios for asthma, chronic obstructive pulmonary disease (COPD), acute respiratory infections (IHD), and all circulatory disorders in the all exposed and individual exposed occupations with their matching controls. Also the mean frequency of consultations per person consulting was calculated for each occupational group and disease.

RESULTS

For employed persons, the prevalence ratio (PR) for asthma in the all-exposed, (116, 95% confidence interval [95% CI] = 101-130) exceeded that for all employed persons (100); however, the difference compared with chapter-matched controls (PR = 97, 95% CI = 92-103), was not statistically significant. Results for COPD were similar. Prevalence ratios in motor mechanics, a high-exposure group, were 98 (95% CI = 70-127) 96 (95% CI = 70-123) for asthma and COPD respectively. Among the employed, prevalence ratios for IHD in all but one of the individual occupation groups examined did not differ from the average, however among those not employed the ratio in the all-exposed (PR = 152, 95% CI = 128-174) exceeded that in the controls (PR = 112, 95% CI = 104-120).

CONCLUSION

Occupational groups exposed to motor vehicle pollution have a marginally increased prevalence of asthma compared with working males generally, though not compared with occupation matched controls. This study has demonstrated a methodology for using GP data to examine occupation-related disease. This could be used in future by augmenting GP data with occupation and smoking information.

The rising prevalence of asthma in young Melbourne adults is associated with improvement in treatment

BACKGROUND

Asthma is a common source of morbidity and is now recognized as a national health priority in Australia. Although a number of epidemiologic studies have been conducted in Australia to determine the prevalence of asthma in adults, it is unclear whether the prevalence is changing.

OBJECTIVES

To determine the prevalence in 1998 of self-reported asthma and respiratory symptoms among young adults and changes in prevalence between 1990 and 1999.

METHODS

Cross-sectional postal survey to 4,455 young adults (aged 20 to 44 years) randomly selected from the electoral rolls of the inner southeastern suburbs of metropolitan Melbourne. The survey instrument was the validated European Community Respiratory Health Survey screening questionnaire, which gathered data on self-reported respiratory symptoms, including whether asthma had been diagnosed. Identically worded questions from similar surveys conducted in 1990, 1992, and 1999 were used to compare changes in prevalence.

RESULTS

A response rate of 72% was achieved in 1998 after three mailings and telephone followup. Forty-two percent reported nasal allergies, 26% wheezed within the past 12 months, and 20% ever had asthma. The prevalence of doctor-diagnosed asthma was 18%, whereas 10% reported using asthma medications within the past 12 months. Nine percent of respondents reported an asthma attack within the past 12 months. The prevalence of having ever had asthma, doctor-diagnosed asthma, and using asthma medications had increased significantly since 1990. However, the prevalence of respiratory symptoms did not significantly change over this time.

CONCLUSIONS

The prevalence of asthma is likely to be rising, but the symptoms of asthma are being better managed in young Melbourne adults.

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.

Is the increase in childhood asthma coming to an end? Findings from three surveys of schoolchildren in Rome, Italy

Time trends in the prevalence of asthma, family history of asthma and atopy in Roman schoolchildren were assessed. The study population consisted of all children (aged 6-14 yrs) attending two primary schools in Rome, situated in urban areas that differed markedly in socioeconomic conditions and environmental pollution. Three questionnaire-based surveys were conducted in 1974, 1992 and 1998 in 2,259, 1,229 and 1,139 children. The prevalence of asthma in males and females increased significantly during 1974-1992 and remained stable from 1992-1998. In age groups born in the subsequent 4-yr periods it increased almost linearly, for children born from 1962-1965 to 1982-1985 (4.4%-12.5%), and remained remarkably stable in children born after 1985. Because the prevalence of asthma had a steeper trend in males than in females (approximately 0.55% x yr(-1) versus 0.25% x yr(-1)), the male:female asthma ratio increased (1:38 in 1974; 1:84 in 1992 and 1:62 in 1998). No single environmental factor, including area of residence, seemed to influence the prevalence of asthma. Family history of asthma and atopy also increased steadily (0.72% x yr(-1) and 0.30% x yr(-1) respectively) more than doubling during the 24-yr study period. The strong relationship between asthma and a family history of atopy not only persisted but also strengthened over time (23.3% of asthmatic children belonged to families with atopic illnesses in 1974 but 44.2% in 1998). The environmental factors that might explain the almost three-fold rise in childhood asthma between 1974 and 1992 remain unknown but the genetic background of the disease has presumably remained unchanged since the early 1970s. The fact that the prevalence of asthma increased no further during the past 6 yrs suggests that the progressive induction of asthma symptoms in genetically predisposed subjects is a self-limiting process that has probably come to an end in the authors' study area.

Interleukin-5: a novel target for asthma therapy

Eosinophilic airway inflammation is the main histologic correlate of airway hyper-responsiveness (AHR) and tissue injury in the pathogenesis of bronchial asthma. There is strong evidence for a central role of CD4+ T-cells secreting pro-allergic Th2-cytokines, such as IL-4 and IL-5, in the induction of airway eosinophilia and AHR. IL-5 appears to be one of the main pro-inflammatory mediators among a growing number of cytokines and chemokines that induce, regulate and sustain eosinophilic airway inflammation. Animal studies provide confirmatory evidence for the important role of IL-5 in the induction and maintenance of eosinophilic airway infiltration leading to altered airway function. Interfering with the action of IL-5 represents one of the new immunomodulatory therapeutic strategies in the treatment of bronchial asthma. Compared to established immunosuppressive agents like steroids, a major advantage of this strategy is the specificity of reducing eosinophilic inflammation, thus possibly acting nearly without side effects. There are several possible ways to inhibit the effects of IL-5 including alteration of the signalling pathway in the IL-5 producing cell by inhibition or modification of transcription factors or the use of antisense oligonucleotides and blocking of the IL-5 protein itself by monoclonal antibodies, soluble IL-5 receptor or antagonists of the IL-5 receptor expressed on the surface of eosinophils. Although preliminary data from the first clinical trials gave rise to skepticism about the efficacy of anti-IL-5 treatment regarding the improvement of lung function of asthmatic patients, further studies with a better defined profile of the target population may provide encouraging results, allowing the introduction of this truly new therapeutic concept.

Acute asthma exacerbations and air pollutants in children living in Belfast, Northern Ireland

The incidence of childhood asthma, a common condition, is on the rise worldwide. Despite reductions in the emission of urban smoke, traffic pollution is now a major worldwide problem. Belfast, Northern Ireland, is an old industrial city with major pollution problems. In this study, the authors investigated the rates of acute asthma admissions to Belfast's major children's emergency department. The admissions were studied, relative to day-to-day fluctuations in thoracic particulate matter, sulfur dioxide, nitrogen dioxide, nitric oxide, oxides of nitrogen, ozone, carbon monoxide, benzene, temperature, and rainfall. Daily admissions for acute asthma at the emergency department of the Royal Belfast Hospital and average daily pollution were recorded for the 3-yr period between January 1, 1993, and December 31, 1995. The authors used Poisson regression to assess independent association(s). Individually, small associations were seen for thoracic particulate matter (relative risk = 1.10), sulfur dioxide (relative risk = 1.09), nitrogen dioxide (relative risk = 1.11), nitric oxide (relative risk = 1.07), oxides of nitrogen (relative risk = 1.10), carbon monoxide (relative risk = 1.07), and benzene (1.14); no associations were noted between meteorological factors (temperature and rainfall) or ozone and asthma emergency-department admissions. The authors adjusted for the aforementioned parameters, and benzene level was the only variable associated independently with asthma emergency-department admissions in children. Benzene may be a more reliable method of measuring exposure to vehicle exhaust emissions than measurements of other pollutants.

Diet, serum fatty acids, and atopic diseases in childhood

BACKGROUND

The reasons behind the reported increase in the occurrence of childhood atopic sensitization rates are unclear. We wanted to evaluate the association between dietary fats, serum fatty acids, and the occurrence and development of atopic diseases.

METHODS

From a longitudinal database of a population-based sample, 231 sex- and age-matched pairs in 1980 and 154 pairs in 1986 were chosen, between whom we compared the dietary data, serum fatty acid composition, and occurrence of atopic diseases. The same variables were also compared between those who developed atopic disease later and those who did not during the 9-year follow-up.

RESULTS

Examination of the dietary data in 1980 for those who had developed atopic disease compared with those who had remained healthy showed that the atopic children had used less butter before the expression of atopy. According to the cross-sectional data, the children with atopic disease consumed more margarine (mean 8.6 vs 7.3 [P = 0.04]), and less butter (mean 9.4 vs 11.6 g/1000 kcal [P = 0.002]), than the nonatopic children in 1980. Differences supporting these dietary findings were similarly found in the serum fatty acid data.

CONCLUSION

The diet of the atopic children differed from that of the nonatopic children in the consumption of polyunsaturated fat.

Familial aggregation and heritability of adult lung function: results from the Busselton Health Study

Decreased spirometric indices are characteristic of asthma and other respiratory diseases. The aim of this study was to investigate the genetic and environmental components of variance of forced expiratory volume in one second (FEV1) and forced vital capacity (FVC) measured in adulthood in an Australian population-based sample of 468 Caucasian nuclear families. The inter-relationships of the genetic determinants of these traits with asthma and atopic rhinitis were also investigated. Serial cross-sectional studies were conducted in the town of Busselton in Western Australia between 1966 and 1981 and follow-up of previous attendees was undertaken in 1995. Data from each subject included in this study were from a single survey in adulthood (25-60 yrs of age) when the subject was as close to age 45 yrs as possible. Multivariate analysis suggested that FEV1 and FVC levels were associated with age, sex, height, tobacco smoke exposure, asthma and atopic rhinitis. After adjustment for relevant covariates, FEV1 levels had a narrow-sense heritability (h2N) of 38.9% (SE 9.1%). FVC levels had an h2N of 40.6% (SE 8.9%). Extended modelling demonstrated little overlap in the genetic determinants of asthma or atopic rhinitis and either FEV1 or FVC levels. The results of this study were consistent with the existence of important genetic determinants of adult lung function that are independent of asthma or other atopic disease, cigarette smoking, height, age or sex.

Family size, day-care attendance, and breastfeeding in relation to the incidence of childhood asthma

A hypothesis has been suggested stating that children exposed early to infections are less likely to develop atopy or asthma. The authors investigated the relation between risk of childhood asthma and number of siblings as well as day-care attendance, as factors possibly increasing the likelihood of early infections, and breastfeeding as a factor reducing them. A case-control study was carried out in Montréal, Canada, between 1988 and 1995 that included 457 children diagnosed with asthma at 3--4 years of age and 457 healthy controls. Cases followed for 6 years were later classified as persistent or transient by the symptoms and use of medication after diagnosis. Among cases diagnosed at 3--4 years of age, the adjusted odds ratio for asthma was 0.54 (95% confidence interval (CI): 0.36, 0.80) for one sibling and 0.49 (95% CI: 0.30, 0.81) for two or more. The adjusted odds ratio for day-care attendance before 1 year of age was 0.59 (95% CI: 0.40, 0.87). Results were similar with persistent cases. Among transient cases (who possibly had an infection with wheezing at 3--4 years of age), day-care attendance and a short duration of breastfeeding resulted in increased risk. The results support the hypothesis that opportunity for early infections reduces the risk of asthma.

Prevalence, morbidity and management of adult asthma in South Australia

This paper reviews asthma-related data obtained between 1987 and 1997 from self-report population surveys of adults in South Australia. A multistage, systematic, clustered area sample of adults (>15 years) was selected from a random sample of Australian Bureau of Statistics collector districts, and interviewed at home by trained health interviewers. The self-report prevalence of doctor-diagnosed asthma increased from 5.6% in 1987 to 12.2% in 1997. Morbidity measured as days lost from usual activities and nights awakened by asthma remained high, but hospitalization rates are trending down. The ownership of asthma action plans peaked in 1995 and has declined. The ownership of peak flow meters increased between 1992 and 1997, and the ownership of nebulisers remained constant. Evidence-based interventions are required to improve asthma management.

Allergy markers in respiratory epidemiology

Assessing allergy by measurement of serum immunoglobulin (Ig) E antibodies is fast and safe to perform. Serum antibodies can preferably be assessed in patients with dermatitis and in those who regularly use antihistamines and other pharmacological agents that reduce skin sensitivity. Skin tests represent the easiest tool to obtain quick and reliable information for the diagnosis of respiratory allergic diseases. It is the technique more widely used, specific and reasonably sensitive for most applications as a marker of atopy. Measurement of serum IgE antibodies and skin-prick testing may give complimentary information and can be applied in clinical and epidemiological settings. Peripheral blood eosinophilia is less used, but is important in clinical practice to demonstrate the allergic aetiology of disease, to monitor its clinical course and to address the choice of therapy. In epidemiology, hypereosinophilia seems to reflect an inflammatory reaction in the airways, which may be linked to obstructive airflow limitation.

Prevalence of asthma symptoms in Omani schoolchildren

OBJECTIVES

To determine the prevalence of asthma in Omani schoolchildren using the International Study of Asthma and Allergies in Children (ISAAC) protocols.

METHOD

The ISAAC-written questionnaire was completed by a total of 7,067 Omani schoolchildren (3,893 children aged 6-7 years of which 56% were boys and 3,174 aged 13-14 years of which 51% were boys) from the 10 health regions in the country.

RESULTS

The estimated mean national 12-month prevalence of any wheeze, night waking with wheeze, speech limiting wheeze and exercise wheeze were respectively 7.8%, 3.5%, 3.2% and 6.9% for the 6-7 year age group and 8.9%, 2.9%, 4.0% and 19.2% for the 13-14 year age group. Both age groups reported high prevalence of night cough (19.6% and 20.9% in the younger and the older children respectively). The prevalence of self-reported asthma diagnosis was higher in the older age group (20.7% vs. 10.5%, p<0.001). In the younger age group, the diagnosis of asthma was more common in boys (12.5% vs. 8.0%, p>0.001), but there was no significant difference between the two sexes in the older age group (22.0% of boys vs. 20.5% of girls). There was nearly three-fold difference in the prevalence of self-reported diagnosis of asthma between the regions with the highest and the lowest prevalence of asthma for both young and older children (from 5.3% and 9.5% in Musandam to 14.2% and 30.6% in South Sharqiya, respectively).

CONCLUSION

The results of this first epidemiological survey of asthma in Oman indicate that asthma is common in Omani children and adolescents. Night cough is the most frequent symptom. There is also significant regional variation in prevalence of asthma symptoms and diagnosis within the country and this requires further investigation.

Infection of mice with the helminth Strongyloides stercoralis suppresses pulmonary allergic responses to ovalbumin

Asthma and helminth infections induce similar immune responses characterized by the presence of peripheral blood eosinophilia and elevated serum IgE levels. Epidemiological surveys have reported either increases or decreases in the development of atopic diseases and asthma based on the prevalence of helminth infections in the population. The aim of this study was to determine if a pre-existing helminth infection would increase or decrease subsequent allergic responses to an unrelated allergen in the lungs. BALB/cByJ mice were infected with the nematode parasite Strongyloides stercoralis prior to ovalbumin (OVA) immunization and intratracheal challenge. Bronchoalveolar lavage (BAL) and fluid (BALF) were collected 3 days post-challenge and cellular and humoral immune responses were measured. Intracellular cytokine staining revealed increased IL-4 and IL-5 producing cells in BAL from mice infected with S. stercoralis before OVA sensitization. Increased IL-5 protein levels and decreased IFN-gamma protein levels were also observed in the BALF. There was, however, no increase in airway eosinophil accumulation in mice infectd with parasites before sensitization with OVA as compared to mice exposed to OVA alone. Furthermore, eotaxin levels in the lungs induced by OVA was suppressed in mice infected with the parasite before OVA sensitization. The development of OVA specific IgE responses in BALF was also impaired in mice infected with the parasite before sensitization with OVA. These results suggest that a pre-existing helminth infection may potentiate a systemic Type 2-type response yet simultaneously suppress in the lungs allergen-specific IgE responses and eotaxin levels in response to subsequent exposure to allergens.

Increased prevalence of asthma in Saudi Arabia

BACKGROUND

Bronchial asthma is among the most common chronic illnesses of childhood. A number of reports in the recent past suggest that the prevalence of asthma is increasing globally.

OBJECTIVE

To investigate the changing prevalence of asthma in the Kingdom of Saudi Arabia.

SUBJECTS AND METHODS

Two populations of schoolchildren between the ages of 8 and 16 years were studied using an internationally designed protocol in 1986 and 1995. The questionnaire used in these studies was very similar to the one used in the International Study of Allergy and Asthma in Childhood. A total of 2,123 school-children in 1986 (Jeddah and Riyadh) and 1,008 schoolchildren in 1995 (Hail and Gizan) were enrolled in the surveys. These cross-sectional studies of randomly selected schoolchildren were statistically analyzed using ANOVA and a Z test.

RESULTS

The comparison of data between Riyadh versus Hail (inland desert dry environment) and Jeddah versus Gizan (coastal humid environment) revealed that the prevalence of asthma in the similar populations increased significantly from 8% in 1986 to 23% in 1995 (P < .0001). Likewise, the prevalence of allergic rhinitis also increased from 20% to 25% (P < .003) since 1986. However, no significant change in the prevalence of eczema (from 12% to 13%) was noted between 1986 and 1995.

CONCLUSIONS

The study indicates that there was a significant increase in the prevalence of bronchial asthma and, to a lesser extent, in the prevalence of allergic rhinitis in the Kingdom of Saudi Arabia during this 9-year period. The study also revealed increased exposure to environmental factors such as tobacco smoke and indoor animals in Saudi houses. It seems that the continuing changes in contemporary life may well have contributed to the increased prevalence of asthma in the country.

Risk factors associated with bronchial asthma in school going children of rural Haryana

Bronchial asthma is one of the most common illnesses in children. Factors influencing development of asthma have not been studied in rural population. 2000 school going children from five schools of Chhainsa and Dayalpur Primary Health Centre area in Ballabgarh Block of Haryana state were screened for presence of symptoms of asthma using a questionnaire suggested by International Study of Asthma and Allergy in Children (ISSAC). 40 children were identified as cases of bronchial asthma. For each child with asthma two age and sex matched non-asthmatic controls were selected from the study population. History, clinical examination and in-depth interview were carried out for all cases and controls. Factors associated with presence of symptoms of asthma on multivariate analysis were passive smoking (OR 3.33, 95% CI 1.85-7.65), pets at home (OR 5.5, 95% CI 1.04-29.15), and absence of windows in living rooms (OR 4.03, 95% CI 1.17-13.79). Factors such as family history of asthma, history of worm infestation, fuel used for cooking, location of kitchen and food allergy were not significant on statistical analysis. Thus, passive smoking, inadequate ventilation and pets (dogs and cats) at home are significant risk factors associated with presence of symptoms of asthma in rural children.

Prevalence of asthma and other allergic diseases in an adolescent population: association with gender and race

OBJECTIVES

To estimate the prevalence and severity of asthma in an adolescent population by sex and race.

METHODS

Cross-sectional, population-based survey of school children.

SETTING

Midwestern city experiencing damage from the 1993 Mississippi River flood.

PARTICIPANTS

2,693 children attending grades 7 to 12.

MEASUREMENTS

Questions from the International Study of Asthma and Allergies in Childhood (ISAAC).

RESULTS

Two thousand six hundred ninety-three children were surveyed, for a response rate of 90%. In this population, 16.4% reported having ever been diagnosed with asthma; 25% reported wheezing in the last 12 months; 32% reported symptoms of rhinitis in the last 12 months; and 22% reported ever having hay fever. The prevalence rate for current asthma was 12.6%. Female students had significantly greater prevalence rates for current asthma (16.4% vs 9.0%, OR = 1.85); ever-diagnosed asthma (18.5% vs 14.3%, OR = 1.36); wheezing > or = 4 times in the last 12 months (12.0% vs 5.6%, OR = 1.95); current rhinitis (38.7% vs 25.4%, OR = 1.73); and hay fever (26.4% vs 18.4%, OR = 1.57). All associations with sex remained significant, except ever-diagnosed asthma, after controlling for other known risk factors in logistic regression. African-Americans had higher prevalence rates than other races with differences reaching statistical significance for ever-diagnosed asthma and current asthma; however, these relationships did not remain significant after controlling for other known risk factors in logistic regression.

CONCLUSIONS

Our prevalence rates were similar to those reported by other studies that used the ISAAC questionnaire. Female students reported significantly more asthma, wheezing, rhinitis, and hay fever than male students. Female students also reported more severe symptoms and a greater number of emergency room and hospital admissions.

Interventions for educating children who have attended the emergency room for asthma

BACKGROUND

Asthma is one of the most common reasons for paediatric admissions to hospital, with substantial cost to the community. There is some evidence to suggest that many hospital admissions could be prevented with effective education about asthma and its management.

OBJECTIVES

To conduct a systematic review of the literature in order to identify whether asthma education leads to improved health outcomes in children who have attended the emergency department for asthma.

SEARCH STRATEGY

We searched the Cochrane Airways Group trials register, including Medline, Embase, and Cinahl databases, and reference lists of trials and review articles.

SELECTION CRITERIA

Randomised controlled trials or controlled clinical trials of asthma education for children who had attended the emergency department for asthma, with or without hospitalisation, within the previous 12 months.

DATA COLLECTION AND ANALYSIS

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

MAIN RESULTS

Eight trials involving 1407 patients were included, in all the education was provided by nurses or researchers. Compared to control (usual care or lower intensity education) education did not reduce subsequent emergency department (ED) visits [4 trials; relative risk (RR)= 0.87, 95% confidence interval (CI) 0.37 to 2.08], hospital admissions [5 trials; RR=0.74, 95% CI 0.38 to 1.46] and unscheduled doctor visits [5 trials; RR= 0.74, 95% CI 0.49 to 1.12). Each analysis showed evidence of heterogeneity among the studies (P<0.01). Subgroup analyses by the overall difference in scale of intervention between treatment and control groups (comprehensive programme versus information only) or the timing of the intervention/recruitment (early versus delayed) gave similar results to the main analysis and still revealed significant heterogeneity between trials.

REVIEWER'S CONCLUSIONS

On the basis of the published trials, there is no firm evidence to support the use of asthma education for children who have attended the emergency department for asthma as a means of reducing subsequent ED visits, hospital admissions or unscheduled doctor visits. Some trials appeared to show clear evidence of benefit, but reasons for differences between these and the negative studies is not clear. More research is required

Continued increase in the prevalence of asthma and atopy

AIMS

To describe the change in the prevalence of wheeze, diagnosed asthma, and atopy in Wagga Wagga, NSW, Australia, between 1992 and 1997, and to compare this to the increase in prevalence reported between 1982 and 1992.

METHODS

A cross sectional study of the prevalence of respiratory symptoms and atopy in schoolchildren aged 8-11 years (n = 1016, response rate 71%) in 1997 compared with studies of similar design in 1992 (response rate 83%, n = 850) and 1982 (response rate 88%, n = 769). Main outcome measures were respiratory symptoms measured by parent completed questionnaire and atopy measured by skin prick tests.

RESULTS

Between 1992 and 1997, the prevalence of wheeze increased by 5.1% (95% CI 1.2 to 9.0), asthma diagnosis by 8.1% (95% CI 3.8 to 12.4), and atopy by 6.7% (95% CI 2.2 to 11.2). Similar increases in prevalence had been found between 1982 and 1992.

CONCLUSIONS

The prevalence of wheeze, asthma diagnosis, and atopy in Wagga Wagga has continued to increase.

Bronchial hyperresponsiveness to 4.5% hypertonic saline indicates a past history of asthma-like symptoms in children

SUMMARY. To evaluate the importance of a past history of asthma-like symptoms over a period of 2 years and current bronchial hyperreactivity (BHR), 538 randomly selected schoolchildren, initially aged 7-8 years, were examined. At yearly intervals, three standardized questionnaires, including items from the ISAAC panel, were answered by parents. Following the last questionnaire, BHR to 4.5% hypertonic saline (HS) was recorded. In survey 1, lifetime prevalence of asthma was 4.9%. During the 12-month period, prevalence of wheeze and dyspnea ranged between 9.3 and 5.2% (Survey 1) and 5.9% and 4.4% (Survey 2). Among children with wheeze or dyspnea in Survey 3, BHR (defined as a fall of baseline FEV(1) > or = 15%) was significantly more frequent (50.0% and 60.7%, respectively) than among children without these symptoms (12.8%, P < 0.001, and 12.8%, P < 0.001, respectively). The negative predictive value of BHR to have neither wheeze nor dyspnea was about 88% and did not vary throughout the study (Survey 1, 87%; Survey 2, 88%; Survey 3, 88%). The relative risk of showing BHR was significantly increased in children with wheeze (survey 2, odds ratio (OR) 3.0 (95% confidence interval (CI) 1.0-8.7)) or dyspnea (Survey 1: OR 5.9 (95% CI 1.9-18.5), Survey 3: 5.2 (1.7-16.2), but not in children with dry cough or nocturnal cough (data not shown). Wheeze and dyspnea occurred repeatedly in the same individuals with BHR in a high percentage of children (83.3% and 76.5%, respectively). In conclusion, there is a strong association between recent and previous dyspnea and current BHR, and it indicates intraindividual persistence of symptom history.

Tendência secular da doença respiratória na infância na cidade de São Paulo (1984-1996)

OBJETIVO: Estimar a prevalência e a distribuição social da doença respiratória na infância, estabelecer a tendência secular dessa enfermidade e analisar sua determinação, com base nos dados coletados por dois inquéritos domiciliares realizados na cidade de São Paulo, SP, em 1984/85 e em 1995/96. MÉTODOS: Os inquéritos estudaram amostras probabilísticas da população residente na cidade com idades entre zero e 59 meses (1.016 em 1984/85 e 1.280 em 1995/96). Nos dois inquéritos estimou-se a prevalência instantânea da doença respiratória alta (acima da epiglote) e da doença respiratória baixa com e sem chiado à ausculta pulmonar. A ocorrência da doença respiratória foi aferida por exames clínicos realizados em dias aleatórios, nos próprios domicílios das crianças, por médicos pediatras devidamente treinados e padronizados quanto ao diagnóstico da doença. Os exames clínicos incluíam a anamnese do dia, antecedentes de doença respiratória e o exame físico completo da criança, incluindo inspeção da orofaringe, otoscopia e ausculta pulmonar. Nos dois inquéritos, os exames foram distribuídos ao longo de um período de cerca de 12 meses, de modo a garantir uma varredura uniforme das várias áreas da cidade ao longo das quatro estações. O estudo da distribuição social da doença respiratória levou em conta tercis da renda familiar per capita em cada um dos inquéritos. A estratégia analítica para estudar os determinantes da evolução da prevalência da doença na população empregou modelos hierárquicos de causalidade, análises multivariadas de regressão e procedimentos análogos aos utilizados para calcular riscos atribuíveis populacionais. RESULTADOS/CONCLUSÕES: Houve entre os inquéritos aumentos expressivos na prevalência instantânea da doença respiratória alta (de 22,2% para 38,8%) e da doença respiratória baixa sem e com chiado (de 6,0% para 10,0% e de 0,8% para 2,8%, respectivamente). No caso da doença alta e da doença baixa sem chiado, o aumento é generalizado nos vários estratos sociais, o que não altera, no período, a situação discretamente menos favorável dos estratos de menor renda. No caso da doença baixa com chiado, o aumento se restringe aos estratos de renda baixa e intermediária, sendo particularmente intenso no estrato de menor renda, o que determina o surgimento de uma forte relação inversa entre a doença e a renda familiar. Mudanças positivas em determinantes distais das doenças respiratórias (renda familiar e escolaridade materna) e em variáveis relacionadas à salubridade das moradias justificariam declínio modesto e não aumento das doenças respiratórias na cidade. O aumento na freqüência a creches, observado no período, poderia contrabalançar o efeito positivo das melhorias em variáveis socioeconômicas e ambientais, mas não seria suficiente para justificar o aumento das doenças respiratórias na cidade.

Effect of allergist intervention on patient-centered and societal outcomes: allergists as leaders, innovators, and educators

Atopic disorders, which afflict millions of Americans and hundreds of millions worldwide, are at epidemic levels with concomitant increases in morbidity and mortality. Environmental and lifestyle changes over the past three to five decades are proposed causes for this pandemic and as such present major burdens to reverse. The scope of allergy practice bridges directly on this challenge. Allergy as a specialty is a major leader in developing effective strategies to confront this epidemic. Allergists have made major contributions to the understanding of the risk factors, immunology, pathophysiology, immunomodulation, and prevention of atopic and immunologic disorders. Allergist epidemiologists and clinicians have helped develop and implement national and international guidelines in the recognition, management, and prevention of asthma and rhinitis. Allergist clinical researchers are active in (1) outcomes research that demonstrates convincingly the value of allergy as a specialty in asthma, allergic rhinitis, anaphylaxis, drug and food allergy, and other atopic disorders, (2) National Institutes of Health clinical trials that will form the basis for the future treatment of asthma and allergic disease, and (3) pharmaceutical trials that evaluate new, effective, and safe medication to treat atopic disease. Allergist educators, comprising academic and practicing allergists, supported by allied health professionals, national associations, and affiliated lay organizations, provide comprehensive education to fellows, residents, colleague physicians, media, the public, and patients. Documentation of the value of allergists in improving patient-centered and societal outcomes in their core domain, allergy, is the appropriate final topic contribution in the important series "New millennium: The conquest of allergy."

Inhaled salmeterol/fluticasone propionate combination. A pharmacoeconomic review of its use in the management of asthma

Cost estimates from developed countries indicate that asthma accounts for up to 2% of the economic cost of all diseases. A large proportion of asthma-related costs are attributable to poor asthma control. Treatment strategies which improve clinical outcomes in patients with asthma, therefore, have the potential for significant economic benefits, and it is important to evaluate new asthma therapies for cost effectiveness. Several studies have established that salmeterol and fluticasone propionate combined in a single dry powder inhalation device are at least as effective as a combination of the 2 drugs administered via separate dry powder inhalers and more effective than monotherapy with fluticasone propionate or budesonide. Importantly, pharmacoeconomic analysis of several of these studies show that the salmeterol/fluticasone propionate combination is cost effective relative to monotherapy with fluticasone propionate or budesonide. Although the total cost of asthma management tended to be slightly higher with salmeterol/fluticasone propionate than with inhaled corticosteroid monotherapy, in most cases mean cost-effectiveness ratios were lower (i.e. more favourable) for salmeterol/fluticasone propionate than either fluticasone propionate or budesonide. Cost effectiveness was assessed according to 3 end-points: successfully treated weeks, symptom-free days and episode-free days. Mean cost-effectiveness ratios consistently favoured salmeterol/fluticasone propionate over the comparator drug for the end-point successfully treated weeks, and in most cases the other 2 end-points also favoured the combination product over the comparator. In a further study, salmeterol/fluticasone was also less costly than therapy with formoterol and budesonide administered via 2 separate inhalers. Studies of health-related quality of life (HR-QOL) using the Asthma Quality of Life Questionnaire indicate that salmeterol/fluticasone propionate produces clinically meaningful improvements in overall HR-QOL relative to salmeterol monotherapy or placebo. Improvements in overall HR-QOL were statistically significantly greater for salmeterol/fluticasone propionate than with fluticasone propionate or budesonide alone, although the differences between treatments did not exceed the threshold for clinical significance. In conclusion, short term cost-effectiveness data show that salmeterol/fluticasone propionate is more cost effective than the inhaled corticosteroids budesonide and fluticasone propionate alone. The combination product also appears to improve HR-QOL relative to placebo or salmeterol alone.

Inhaled fluticasone propionate. A pharmacoeconomic review of its use in the management of asthma

Contemporary asthma management guidelines list inhaled corticosteroids as the preferred controller medication for patients with persistent asthma. Despite the availability of explicit guidelines, there is evidence that these agents are underused and that guidelines are not always adhered to. Fluticasone propionate is one of several inhaled corticosteroids used for the treatment of asthma. Like other agents of its class, its efficacy is backed by extensive clinical data. More recently, the quality of life of recipients of fluticasone propionate and its relative cost effectiveness have been investigated. A series of comparative analyses show that inhaled fluticasone propionate is more cost effective than oral zafirlukast and triamcinolone acetonide and slightly more cost effective than flunisolide in adult patients with asthma. Analyses used cost per symptom-free day and/or cost per successfully treated patient as outcome measures and were generally conducted from the perspective of the third-party payer. When administered at a microgram dose of half or less than budesonide (as is therapeutically appropriate), the cost effectiveness of fluticasone propionate was similar to or better than that of budesonide. In children, fluticasone propionate was more cost effective per treatment success compared with inhaled sodium cromoglycate. Quality-of-life assessments in patients with mild to moderate disease show that inhaled fluticasone propionate achieved improvements which were deemed to be clinically meaningful in patients with mild to moderate asthma; these changes were significantly greater than those achieved with oral zafirlukast, inhaled triamcinolone acetonide or placebo. Greater improvements were evident with inhaled fluticasone propionate in patients with severe disease.

CONCLUSIONS

In addition to the considerable body of clinical evidence supporting the use of inhaled fluticasone propionate in patients with asthma, accumulating short term cost-effectiveness data also suggest that this agent can be administered for a similar or lower cost per outcome than other inhaled corticosteroids or oral zafirlukast. Importantly, the clinical benefits offered by fluticasone propionate in patients with persistent asthma are accompanied by clinically significant improvements in quality of life.

Prevalence and predictors of rhinitis in Danish children and adolescents

BACKGROUND

The prevalence of self-reported symptoms of allergic rhinitis is increasing in many countries, but the reasons for this trend are not well understood. Data from a 6-year follow-up study of a population sample of children and adolescents (n=408), aged 7-17 years at enrolment in 1986, were analyzed to investigate the prevalence and predictors of self-reported rhinitis.

METHODS

Case history was used to assess the presence or absence of rhinitis (sneezing and running or blocked nose not associated with a cold), asthma, and eczema. Pulmonary function, skin prick test reactivity, and airway responsiveness to histamine were measured in all participants; a screening test for IgE antibodies to common allergens (Magic Lite SQ, Allergy Screen, ALK, Denmark) was performed in 237 (58%) of the participants.

RESULTS

The point prevalence of rhinitis increased from the first to the second survey, 14% and 22%, respectively; 54 (13%) of the subjects reported rhinitis only at the second survey (new rhinitis). Confining the analysis to participants without symptoms of rhinitis at the first survey showed that self-reported eczema (relative risk [RR] 2.3, 95% confidence interval [CI] 1.2-4.7), airway hyperresponsiveness (RR 2.5, CI 1.8-3.0), atopy to grass pollen (RR 2.6, CI 1.7-3.3), atopy to dog dander (RR 2.4, CI 1.6-3.3), and atopy to house-dust mite (RR 2.7, CI 1.4-5.2) at the first survey predicted an increased risk of the presence of rhinitis at the second survey. A positive Allergy Screen test at enrollment was associated with an increased risk of self-reported rhinitis at follow-up (RR 2.4, CI 1.4-3.4).

CONCLUSIONS

This longitudinal population study of children and adolescents showed an age-related increase in the point prevalence of self-reported rhinitis; furthermore, sensitization to common aeroallergens, airway hyperresponsiveness, and the presence of self-reported eczema were significantly associated with an increased risk of subsequent development of rhinitis.

Budesonide inhalation suspension: a review of its use in infants, children and adults with inflammatory respiratory disorders

Budesonide, a topically active corticosteroid, has a broad spectrum of clinically significant local anti-inflammatory effects in patients with inflammatory lung diseases including persistent asthma. In infants and young children with persistent asthma, day- and night-time symptom scores, and the number of days in which beta2-agonist bronchodilators were required, were significantly lower during randomised, double-blind treatment with budesonide inhalation suspension 0.5 to 2 mg/day than placebo in 3 multicentre trials. Significantly fewer children discontinued therapy with budesonide inhalation suspension than with placebo because of worsening asthma symptoms in a study that included children who were receiving inhaled corticosteroids at baseline. Recent evidence indicates that budesonide inhalation suspension is significantly more effective than nebulised sodium cromoglycate in improving control of asthma in young children with persistent asthma. At a dosage of 2 mg/day, budesonide inhalation suspension significantly reduced the number of asthma exacerbations and requirements for systemic corticosteroids in preschool children with severe persistent asthma. In children with acute asthma or wheezing, the preparation was as effective as, or more effective than oral prednisolone in improving symptoms. In children with croup, single 2 or 4mg dosages of budesonide inhalation suspension were significantly more effective than placebo and as effective as oral dexamethasone 0.6 mg/kg or nebulised L-epinephrine (adrenaline) 4mg in alleviating croup symptoms and preventing or reducing the duration of hospitalisation. Early initiation of therapy with budesonide inhalation suspension 1 mg/day appears to reduce the need for mechanical ventilation and decrease overall corticosteroid usage in preterm very low birthweight infants at risk for chronic lung disease. In adults with persistent asthma, budesonide inhalation suspension < or =8 mg/day has been compared with inhaled budesonide 1.6 mg/day and fluticasone propionate 2 mg/day administered by metered dose inhaler. Greater improvements in asthma control occurred in patients during treatment with budesonide inhalation suspension than with budesonide via metered dose inhaler, whereas fluticasone propionate produced greater increases in morning peak expiratory flow rates than nebulised budesonide. Several small studies suggest that the preparation has an oral corticosteroid-sparing effect in adults with persistent asthma and that it may be as effective as oral corticosteroids during acute exacerbations of asthma or chronic obstructive pulmonary disease. The frequency of adverse events was similar in children receiving budesonide inhalation suspension 0.25 to 2 mg/day or placebo in 12-week studies. During treatment with budesonide inhalation suspension 0.5 to 1 mg/day in 3 nonblind 52-week studies, growth velocity in children was generally unaffected; however, a small but statistically significant decrease in growth velocity was detected in children who were not using inhaled corticosteroids prior to the introduction of budesonide inhalation suspension. Hypothalamic-pituitary-adrenal axis function was not affected by short (12 weeks) or long (52 weeks) term treatment with nebulised budesonide. In conclusion, budesonide inhalation suspension is the most widely available nebulised corticosteroid, and in the US is the only inhaled corticosteroid indicated in children aged > or =1 year with persistent asthma. The preparation is suitable for use in infants, children and adults with persistent asthma and in infants and children with croup.

Does the use of antibiotics in early childhood increase the risk of asthma and allergic disease?

BACKGROUND

One of the mechanisms evoked to explain the increasing prevalences of asthma and allergy, in particular among children, is the 'Western lifestyle' or 'hygiene' hypothesis. As early childhood infections are assumed to hold a protective effect on the development of asthma and allergies, the use of antibiotics at that sensitive age may lead to an increased risk of asthma and allergy.

OBJECTIVE

The aim of this study is to investigate the association between the use of antibiotics in the first year of life and the subsequent development of asthma and allergic disorders.

METHODS

In a population-based sample of 7-and-8-year-old children questionnaire and skin prick test data were collected from 1206 and 675 subjects, respectively. Prevalence rates of asthma, allergic disorders and skin test positivity were compared between children with and without early life use of antibiotics, taking into account other possible risk factors including early respiratory infections. The effect of genetic predisposition was investigated by stratified analyses of children with and without parental hay fever.

RESULTS

The use of antibiotics during the first year of life was significantly associated with asthma (OR = 1.7, 95% CI 1.0-3.1), hay fever (OR = 2.3, 95% CI 1.3-3.8) and eczema (OR = 1.3, 95% CI 1.0-1.8). No significant relationship was found with skin test positivity (OR = 1.1, 95% CI 0.7-1.7). After stratification for the presence of parental hay fever, children without parental hay fever did not show any significant associations between antibiotics use and asthma or allergy, whereas in children with parental hay fever the use of antibiotics was significantly related with asthma (OR = 2.3, 95% CI 1.1-5.1), hay fever (OR = 2.8, 95% CI 1.5-5.1) and eczema (OR = 1.6, 95% CI 1.0-2.6), and of borderline statistical significance with skin test positivity (OR = 1.6, 95% CI 0.9-3.0).

CONCLUSION

Early childhood use of antibiotics is associated with an increased risk of developing asthma and allergic disorders in children who are predisposed to atopic immune responses. These findings support recent immunological understanding of the maturation of the immune system.

Diet and childhood asthma in a society in transition: a study in urban and rural Saudi Arabia

BACKGROUND

The causes of the worldwide increases in asthma and allergic diseases in childhood, which seem to relate to increasing prosperity, are unknown. We have previously hypothesised that a reduction in the antioxidant component of the diet is an important factor. An investigation was undertaken of dietary and other risk factors for asthma in Saudi Arabia where major lifestyle differences and prevalences of allergic disease are found in different communities.

METHODS

From a cross sectional study of 1444 children with a mean age of 12 (SD 1) years in Jeddah and a group of rural Saudi villages, we selected 114 cases with a history of asthma and wheeze in the last 12 months and 202 controls who had never complained of wheeze or asthma, as recorded on the ISAAC questionnaire. Risk factors for asthma and allergies (family history, social class, infections, immunisations, family size, and diet) were ascertained by questionnaire. Atopy was assessed by skin prick testing.

RESULTS

In univariate analyses, family history, atopy, and eating at fast food outlets were significant risk factors for wheezy illness, as were the lowest intakes of milk and vegetables and of fibre, vitamin E, calcium, magnesium, sodium, and potassium. These differences were present also in the urban children considered separately. Sex, family size, social class, infections, and parental smoking showed no relationship to risk. In multiple logistic regression analysis, urban residence, positive skin tests, family history of allergic disease, and the lowest intakes of vitamin E, magnesium and sodium related significantly and independently to risk. The lowest tertile of intake of vitamin E was associated with a threefold (95% CI 1.38 to 6.50) increase in risk when adjusted for the other factors. Intake of milk and vegetables both showed inverse linear relationships to being a case.

CONCLUSIONS

This study suggests that dietary factors during childhood are an important influence in determining the expression of wheezy illness, after allowing for urban/rural residence, sex, family history, and atopy. The findings are consistent with previous studies in adults and with the hypothesis that change in diet has been a determinant of the worldwide increases in asthma and allergies.