Prevalence of asthma in Melbourne schoolchildren: changes over 26 years

Prevalence and Risk Factors of Asthma and Allergy-Related Diseases among Adolescents (PERFORMANCE) study: rationale and methods

Despite a considerable number of international reports on allergic diseases among children, information about the prevalence and risk factors of asthma and allergy-related diseases among Indian adolescents is relatively sparse. The Prevalence and Risk Factors of Asthma and Allergy-Related Diseases among Adolescents (PERFORMANCE) study has been conceived to study the aetiology of asthma and allergic diseases including rhinoconjunctivitis, atopic eczema and food allergies among adolescents in West Bengal, India, using standardised methods and collaborations. The aims of the study are: 1) to estimate the prevalence and risk factors of asthma and allergic diseases among the adolescents residing in rural, suburban and urban areas of West Bengal; 2) to obtain information about the possible role of lifestyle factors (smoking, diet and physical activity) on the disease prevalence; and 3) to create a network for further investigation on social, environmental and genetic factors affecting the diseases. The PERFORMANCE study comprises two phases. The phase I study will investigate the prevalence and possible contributing factors of asthma and allergic diseases in a defined population. The phase II study will be performed as a follow-up of phase I to assess the incidence of asthma and allergic diseases.

The PERFORMANCE study: investigating the prevalence and risk factors of allergy and asthma among Indian adolescentshttp://ow.ly/jP2v30kmt8u

Age-related changes in childhood wheezing characteristics: A whole population study

BACKGROUND

Wheezing illnesses are characterized by phenotypic variability, which changes with age, but few studies report on a wide age range of children. We studied how prevalence, severity, and triggers of wheeze vary throughout childhood.

METHODS

We analyzed data from a large population-based cohort of children from Leicestershire, UK, who were followed from infancy through late adolescence using postal questionnaires. We used generalized estimating equations to describe age-related changes in prevalence of any wheeze: episodic viral and multiple trigger wheeze; wheeze triggered by exercise, aeroallergens, food/drinks, laughing/crying; and of severe wheeze (frequent attacks, shortness of breath, sleep disturbance, disturbance of daily activities) from age 1-18 years. We analyzed this in the entire cohort (absolute prevalence) and separately among children with wheeze (relative prevalence).

RESULTS

This study included 7670 children. Current wheeze was most common in 1-year-olds (36%) and then decreased in prevalence to reach 17% in children aged 14-17 years. Absolute prevalence of episodic viral wheeze (EVW) decreased with age (from 24% to 7%), while multiple trigger wheeze (MTW) remained relatively constant throughout childhood (8-12%). Among children with wheeze, the proportion with EVW decreased, and the proportion with MTW increased with age. In older children, wheeze triggered by exercise or aeroallergens, and wheeze accompanied by shortness of breath became more frequent, while wheeze triggered by food or laughter, and sleep disturbance decreased in prevalence.

CONCLUSION

Knowledge of these age-related changes in wheezing illness is informative for health care planning and the design of future research projects and questionnaires.

Prevalence of cough throughout childhood: A cohort study

Background

Cough in children is a common reason for medical consultations and affects quality of life. There are little population-based data on the epidemiology of recurrent cough in children and how this varies by age and sex, or between children with and without wheeze. We determined the prevalence of cough throughout childhood, comparing several standardised cough questions. We did this for the entire population and separately for girls and boys, and for children with and without wheeze.

Methods

In a population-based prospective cohort from Leicestershire, UK, we assessed prevalence of cough with repeated questionnaires from early childhood to adolescence. We asked whether the child usually coughed more than other children, with or without colds, had night-time cough or cough triggered by various factors (triggers, related to increased breathing effort, allergic or food triggers). We calculated prevalence from age 1 to 18 years using generalised estimating equations for all children, and for children with and without wheeze.

Results

Of 7670 children, 10% (95% CI 10–11%) coughed more than other children, 69% (69–70%) coughed usually with a cold, 34% to 55% age-dependently coughed without colds, and 25% (25–26%) had night-time cough. Prevalence of coughing more than peers, with colds, at night, and triggered by laughter varied little throughout childhood, while cough without colds and cough triggered by exercise, house dust or pollen became more frequent with age. Cough was more common in boys than in girls in the first decade of life, differences got smaller in early teens and reversed after the age of 14 years. All symptoms were more frequent in children with wheeze.

Conclusions

Prevalence of cough in children varies with age, sex and with the questions used to assess it, suggesting that comparisons between studies are only valid for similar questions and age groups.

Operational definitions of asthma in recent epidemiological studies are inconsistent

OBJECTIVE

The best combination of questions to define asthma in epidemiological asthma studies is not known. We summarized the operational definitions of asthma used in prevalence studies and empirically assess how asthma prevalence estimates vary depending on the definition used.

METHODS

We searched the Thomson Reuters ISI Web of knowledge and included (1) cross-sectional studies (2) on asthma prevalence (3) conducted in the general population and (4) containing an explicit definition of asthma. The search was limited to the 100 most-cited papers or published since January 2010. For each paper, we recorded the asthma definition used and other variables. Then we applied the definitions to the data of the Portuguese National Asthma survey (INAsma) and of the 2005-2006 National Health and Nutrition Examination Survey (NHANES) computing asthma prevalence estimates for the different definitions.

RESULTS

Of 1738 papers retrieved, 117 were included for analysis. Lifetime asthma, diagnosed asthma and current asthma were defined in 8, 12 and 29 different ways, respectively. By applying definitions of current asthma on INAsma and NHANES data, the prevalence ranged between 5.3%-24.4% and 1.1%-17.2%, respectively.

CONCLUSIONS

There is considerable heterogeneity in the definitions of asthma used in epidemiological studies leading to highly variable estimates of asthma prevalence. Studies to inform a standardized operational definition are needed. Meanwhile, we propose a set of questions to be reported when defining asthma in epidemiological studies.

Epidemiology of Respiratory Allergies and Asthma

Asthma has puzzled and confused physicians from the time of Hippocrates to the present day. The word “asthma” comes from a Greek word meaning “panting” (Keeney 1964), but reference to asthma can also be found in ancient Egyptian, Hebrew, and Indian medical writings (Ellul-Micallef 1976; Unger and Harris 1974). There were clear observations of patients experiencing attacks of asthma in the second century and evidence of disordered anatomy in the lung as far back as the seventeenth century (Dring et al. 1689).

High prevalence of asthma symptoms in Warao Amerindian children in Venezuela is significantly associated with open-fire cooking: a cross-sectional observational study

Background

The International Study on Asthma and Allergies in Childhood (ISAAC) reported a prevalence of asthma symptoms in 17 centers in nine Latin American countries that was similar to prevalence rates reported in non-tropical countries. It has been proposed that the continuous exposure to infectious diseases in rural populations residing in tropical areas leads to a relatively low prevalence of asthma symptoms. As almost a quarter of Latin American people live in rural tropical areas, the encountered high prevalence of asthma symptoms is remarkable. Wood smoke exposure and environmental tobacco smoke have been identified as possible risk factors for having asthma symptoms.

Methods

We performed a cross-sectional observational study from June 1, 2012 to September 30, 2012 in which we interviewed parents and guardians of Warao Amerindian children from Venezuela. Asthma symptoms were defined according to the ISAAC definition as self-reported wheezing in the last 12 months. The associations between wood smoke exposure and environmental tobacco smoke and the prevalence of asthma symptoms were calculated by means of univariate and multivariable logistic regression analyses.

Results

We included 630 children between two and ten years of age. Asthma symptoms were recorded in 164 of these children (26%). The prevalence of asthma symptoms was associated with the cooking method. Children exposed to the smoke produced by cooking on open wood fires were at higher risk of having asthma symptoms compared to children exposed to cooking with gas (AOR 2.12, 95% CI 1.18 - 3.84). Four percent of the children lived in a household where more than ten cigarettes were smoked per day and they had a higher risk of having asthma symptoms compared to children who were not exposed to cigarette smoke (AOR 2.69, 95% CI 1.11 - 6.48).

Conclusion

Our findings suggest that children living in rural settings in a household where wood is used for cooking or where more than ten cigarettes are smoked daily have a higher risk of having asthma symptoms.

Exposure to cats: update on risks for sensitization and allergic diseases

Cats are the pets most commonly implicated in the etiology of asthma and allergic disease. However, systematic reviews have concluded that there is a lack of evidence to support the idea that cat exposure in early life increases the risk of allergic disease. Indeed, it appears most likely that cat exposure is protective against allergic diseases. Recent large prospective studies have shown that living with a cat during childhood, especially during the first year of a child's life, could be protective. However, any advice given to the parents should also incorporate how new acquisition of cats can affect other family members, especially those who are already sensitized. Research is urgently needed to determine whether the suggested impact of acquisition of cats in adult life is modified by the person's childhood pet ownership, to help parents who seek advice on whether or not to get a cat.

Importance of allergy in asthma: an epidemiologic perspective

There has been a global epidemic of asthma during the past half-century. More recently, the prevalence has leveled off or declined in many Western countries, whereas the prevalence in less affluent nations is still increasing. The reasons for this and the different geographical patterns of asthma prevalence remain unclear. This paper provides an epidemiologic perspective on whether allergen exposure and allergies can explain these trends. In particular, the paper discusses 1) geographical and temporal trends in asthma and the role of allergens and allergy, 2) the importance of nonallergic mechanisms, 3) nonallergenic exposures that may modify the risk of allergies and asthma, and 4) new and emerging risk and protective factors. Although allergy and asthma are closely related, allergen exposure and allergy alone cannot explain current time trends and geographical patterns of asthma. Population-based studies focusing on recently identified risk and protective factors may provide further insight.

Associations between pre-pregnancy obesity and asthma symptoms in adolescents

Background

The high prevalence of children's asthma symptoms, worldwide, is unexplained. We examined the relation between maternal pre-pregnancy weight and body mass index (BMI), and asthma symptoms in adolescents.

Methods

Data from 6945 adolescents born within the Northern Finland Birth Cohort 1986 were used. Prospective antenatal and birth outcome data, including maternal pre-pregnancy weight and BMI, and asthma symptoms in adolescent offspring at age 15–16 years, were employed. Logistic regression analyses were performed to examine the associations between relevant prenatal factors and asthma symptoms during adolescence.

Results

Current wheeze (within the past year) was reported by 10.6% of adolescents, and physician-diagnosed asthma by 6.0%. High maternal pre-pregnancy BMI was a significant predictor of wheeze in the adolescents (increase per kilogram per square metre unit; 2.7%, 95% CI 0.9 to 4.4 for ever wheeze; 3.5%, 95% CI 1.3 to 5.8 for current wheeze), and adjusting for potential confounders further increased the risk (2.8%, 95% CI 0.5 to 5.1; 4.7%, 95% CI 1.9 to 7.7, respectively). High maternal pre-pregnancy weight, in the top tertile, also significantly increased the odds of current wheeze in the adolescent by 20% (95% CI 4 to 39), and adjusting for potential confounders further increased the risk (OR=1.52, 95% CI 1.19 to 1.95). Results were similar for current asthma. Furthermore, these significant associations were observed only among adolescents without parental history of atopy but not among those with parental history of atopy.

Conclusions

The association demonstrated here between maternal pre-pregnancy overweight and obesity, and asthma symptoms in adolescents suggests that increase in asthma may be partly related to the rapid rise in obesity in recent years.

Asthma management and asthma control in São Paulo, Brazil and Uppsala, Sweden: a questionnaire-based comparison

BACKGROUND AND AIMS

The Global Initiative Against Asthma (GINA) was developed to meet the global challenge of asthma. GINA has been adopted in most countries and comparison of asthma management in different parts of the world may be of help when assessing the global dissemination of the guideline. The overall goals in GINA include that asthma patients should be free of symptoms, acute asthma attacks and activity limitations. The aim of the present study was to compare asthma management and asthma control in São Paulo, Brazil and Uppsala, Sweden.

MATERIALS AND METHODS

Information was collected from asthmatics in São Paulo and Uppsala with a questionnaire. The questionnaire dealt with the following issues: symptoms, smoking, self-management, hospital visits, effect on school/work and medication.

RESULTS

The São Paulo patients were more likely to have uncontrolled asthma (36% vs 13%, P < 0.001), having made emergency room visits (57% vs 29%, P < 0.001) and having lost days at school or work because of their asthma (46% vs 28%, P = 0.03) than the asthmatics from Uppsala. There were no difference in the use of inhaled corticosteroids, but the Brazilian patients were more likely to be using theophylline (18% vs 1%, P = 0.001) and less likely to be using long-acting beta-2 agonists (18% vs 37%, P < 0.001).

CONCLUSION

We conclude that the level of asthma control was lower among the patients from São Paulo than Uppsala. Few of the patients in either city reached the goals set up by GINA. Improved asthma management may therefore lead to health-economic benefits in both locations.

Exposure to traffic exhaust and night cough during early childhood: the CCAAPS birth cohort

Though studies have investigated the association between air pollution and respiratory health outcomes in children, few have focused on night cough. The study objective was to simultaneously evaluate family factors (i.e., race, gender, maternal and paternal asthma, and breastfeeding), health (allergen sensitization and wheezing symptoms), home factors (dog, cat, mold, endotoxin, and dust mite), and other environmental exposures (traffic exhaust and second-hand tobacco smoke) for associations with recurrent dry night cough (RNC) during early childhood. A structural equation model with repeat measures was developed assessing RNC at ages one, two, and three. The prevalence of RNC was relatively large and similar at ages, one, two, and three at 21.6%, 17.3%, and 21.1%, respectively. Children exposed to the highest tertile of traffic exhaust had an estimated 45% increase in risk of RNC compared with children less exposed (adjusted OR 1.45, 95% CI: 1.09, 1.94). Also, wheezing was associated with a 76% higher risk of RNC (adjusted OR 1.76, 95% CI: 1.36, 2.26). A protective trend for breastfeeding was found with a 27% reduction in risk associated with breastfeeding (adjusted OR 0.73, 95% CI: 0.53, 1.01). No other factors were significant. These results suggest that traffic exhaust exposure may be a risk factor for night cough in young children.

Serum polycyclic aromatic hydrocarbons among children with and without asthma: correlation to environmental and dietary factors

BACKGROUND

Children from low-income families may be subject to high exposures to polycyclic aromatic hydrocarbons (PAH) which can lead to respiratory disorders. This study aims to establish methods for assessing total PAH exposure of asthmatic and non-asthmatic children from low-income families; to estimate serum PAH concentrations of these children, and to estimate the relative importance of the environmental pathways for PAH exposure.

MATERIALS AND METHODS

A total of 75 (61 asthmatic, 14 non-asthmatic) Saudi children 15 years old and below were included to participate in this cross-sectional study. Each participant answered a generalized questionnaire with dietary questions. Serum PAH were measured using HPLC with UV detection.

RESULTS

Serum naphthalene and pyrene were significantly elevated among asthmatic children (p-values = 0.007 and 0.01, respectively). Serum acenaphthylene, fluorine and 1,2-benzanthracene, on the other hand, were significantly higher among non-asthmatics (p-values = 0.001, 0.04 and 0.03, respectively). There was a significant correlation between the presence of a smoker in the family and serum concentrations of carbazole, pyrene, 1,2-benzanthracene and benzacephenanthrylene (R = 0.37, 0.45, 0.43, 0.33; p-values = 0.01, 0.0002, 0.003 and 0.025, respectively). Significant correlations were elicited between daily meat intake and serum levels of acenaphthylene, benzopyrene and 1,2-benzanthracene (R = 0.27, 0.27, 0.33; p-values = 0.02 and < 0.001, respectively).

CONCLUSION

Among the children, serum PAH were significantly correlated to meat intake as well as presence of smokers at home. Public health awareness should be enhanced by educating parents to take certain precautions at home, such as preventing indoor smoking and reducing the intake of grilled and smoked meat by children so as to decrease their exposure to carcinogenic PAH.

Prevalence of childhood allergic diseases in central Taiwan over the past 15 years

BACKGROUND

The prevalence of asthma, allergic rhinitis and atopic eczema in children from the developed and developing countries has been increasing.

METHODS

Three epidemiological surveys of the prevalence of bronchial asthma, allergic rhinitis and atopic eczema in schoolchildren in Taichung, located in central Taiwan, were conducted in 1987, 1994, and 2002. The first questionnaire was used before the International Study of Asthma and Allergies in Childhood (ISAAC) written questionnaire was developed; the last two surveys were modified using ISAAC questionnaires.

RESULTS

A total of 37,801, 75,960, and 11,580 children were studied in 1987, 1994 and 2002, respectively. The prevalence of allergic diseases had increased in the past two decades. Results indicate that the prevalence of bronchial asthma had risen, from 2.19% in 1987, and 3.54% in 1994, to 6.99% in 2002. Regardless of sex, the prevalence of bronchial asthma decreased with increasing age. The prevalence of allergic rhinitis was 5.1% in 1987, 12.46% in 1987, and 27.59% in 2002, and the prevalence of atopic eczema was 1.10% in 1987, 1.88% in 1994, and 3.35% in 2002.

CONCLUSION

There has been a significant increase in the prevalence of bronchial asthma, allergic rhinitis and atopic dermatitis in Taichung schoolchildren from 1987 to 2002.

Increasing prevalence of asthma, allergic rhinitis but not eczema in 5- to 8-yr-old Maltese children (ISAAC)

The International Study of Asthma and Allergies in Childhood (ISAAC) was the first worldwide study carried out with standardized questionnaires in order to create a reliable global map of childhood allergy. Phase 1 of the study was carried out in the Maltese Islands in 1994/95 while a similar study (phase 3) was repeated 7 yr later (2001/02). In this paper, the data obtained from 3816 5- to 8-yr-olds (80% response rate) in phase 3 were compared to that obtained from 3509 5- to 8-yr-olds (78.5% response rate) in phase 1 of the study in order to evaluate whether the problem of allergic conditions in Maltese schoolchildren was indeed changing. About 30.2% (phase 3) vs. 19.1% (phase 1) (p < 0.0001) of the participants were wheezers 'ever' while 14.8% vs. 8.8% (p < 0.0001) were current wheezers and 14.8% vs. 7.5% (p < 0.0001) were labelled as asthmatics. Of these wheezing children, 13.3% vs. 6.2% (p = 0.0002) had a wheezing episode severe enough to limit speech. Nasal problems were present in 28.8% of Maltese children in 2001 and in 23.4% in 1994 (p < 0.0001) and 24.4% vs. 20.7% (p < 0.0001) of all respondents persisted with these symptoms up to the year of answering the questionnaire. Hayfever had been diagnosed in 22.2% vs. 14.7% (p < 0.0001) of all the children. About 6.7% vs. 7.0% (p = 0.61) of respondents had an recurring itchy rash suggestive of eczema for at least 6 months of their lives and 5.4.% vs. 5.5% had it currently. In 1994, the prevalence of wheezing and eczema were slightly lower than the global mean, unlike the case of rhinitis, which in Malta was commoner than the world average, while in 2001 wheezing together with rhinitis surpassed the global mean as well. These results indicate a rising prevalence of wheezing and rhinitis but not eczema in Maltese children. Asthma seemed to be better controlled and all three allergic conditions more likely to be diagnosed.

[Allergic respiratory diseases and outdoor air pollution]

INTRODUCTION

After having increased for some time, the prevalence of allergic diseases may have reached a plateau. During this increase, considerable concomitant changes in air pollution have occurred. Photo-oxidant air pollution, related to traffic, has become preponderant. The implication of air pollution in the epidemic of allergies is still debated.

BACKGROUND

Experimental studies have suggested that the effect of air pollutants, including particulates and ozone, on the worsening and even the induction of allergies is biologically plausible. In addition, epidemiological studies have shown a short term impact of the peaks of air pollution on exacerbations of asthma. On the other hand, the results of epidemiological studies dealing with the long-term effects of chronic exposure to air pollution on the prevalence of allergies are less consistent.

VIEWPOINTS

The implementation of new-born cohorts, the use of dispersion models to improve exposure assessment and the study of gene-environment correlations, should increase our knowledge of the role of traffic-related air pollutants in the development of allergies and identify subjects more sensitive to their effects.

CONCLUSIONS

Some traffic-related air pollutants may have played a more important role in the increase in the prevalence of allergies than was assumed from the first epidemiological studies.

Nutrition and children's respiratory health in Guangzhou, China

OBJECTIVE

To investigate the role of nutrition in children's respiratory health in subjects participating in a study on air pollution and respiratory health.

STUDY DESIGN

Cross-sectional survey.

METHODS

The relationships between consumption of fresh fruit, vegetables and milk and pulmonary function (forced expiratory volume in 1 s, FEV(1)) and respiratory symptoms (phlegm with cold, phlegm without cold, cough with cold, and cough without cold) were examined in 2228 children (age 10.07+/-0.86 years) in Guangzhou, China.

RESULTS

A positive association was found between consumption of leafy vegetables and lung function in children. Subjects with the highest consumption of leafy vegetables had significant higher FEV(1) values than subjects who ate leafy vegetables less than once per week (1.68 l vs 1.56 l; P=0.047). Children with high consumption of fresh fruit and milk had higher lung function values than children with low consumption, although the differences were not statistically significant. Milk consumption was a protective factor for phlegm with cold, cough with cold, and cough without cold [odds ratio (OR) 0.62, 95% confidence interval (CI) 0.39-0.97; OR 0.53, 95% CI 0.36-0.79; OR 0.43, 95% CI 0.21-0.92, respectively, in the highest intake group]. Consumption of vegetables was a protective factor for cough with cold (P for trend=0.003) and cough without cold (P for trend=0.028). Consumption of fresh fruit was marginally associated with reduced prevalence of respiratory symptoms.

CONCLUSIONS

This study suggests that dietary nutrients are important protective factors for children's respiratory health. Following-up these children may provide more evidence to confirm these associations.

Air pollution and ED visits for asthma in Australian children: a case-crossover analysis

OBJECTIVE

We aimed to determine the effects of ambient air pollutants on emergency department (ED) visits for asthma in children.

METHODS

We obtained routinely collected ED visit data for asthma (ICD9 493) and air pollution (PM(10), PM(2.5), O(3), NO(2), CO and SO(2)) and meteorological data for metropolitan Sydney for 1997-2001. We used the time stratified case-crossover design and conditional logistic regression to model the association between air pollutants and ED visits for four age-groups (1-4, 5-9, 10-14 and 1-14 years). Estimated relative risks for asthma ED visits were calculated for an exposure corresponding to the inter-quartile range in pollutant level. We included same day average temperature, same day relative humidity, daily temperature range, school holidays and public holidays in all models.

RESULTS

Associations between ambient air pollutants and ED visits for asthma in children were most consistent for all six air pollutants in the 1-4 years age-group, for particulates and CO in the 5-9 years age-group and for CO in the 10-14 years age-group. The greatest effects were most consistently observed for lag 0 and effects were greater in the warm months for particulates, O(3) and NO(2). In two pollutant models, effect sizes were generally smaller compared to those derived from single pollutant models.

CONCLUSION

We observed the effects of ambient air pollutants on ED attendances for asthma in a city where the ambient concentrations of air pollutants are relatively low.

Aspirin and Reye syndrome: a review of the evidence

Reye syndrome is an extremely rare but severe and often fatal disease. Death occurs in about 30-40% of cases from brainstem dysfunction. The disease typically is preceded by a viral infection with an intermediate disease-free interval of 3-5 days. The biochemical explanation for Reye-like symptoms is a generalized disturbance in mitochondrial metabolism, eventually resulting in metabolic failure in the liver and other tissues. The etiology of 'classical' Reye syndrome is unknown. Hypothetically, the syndrome may result from an unusual response to the preceding viral infection, which is determined by host genetic factors but can be modified by a variety of exogenous agents. Thus, several infections and diseases might present clinically with Reye-like symptoms. Exogenous agents involve a number of toxins, drugs (including aspirin [acetylsalicylic acid]), and other chemicals. The 'rise and fall' in the incidence of Reye syndrome is still poorly understood and unexplained. With a few exceptions, there were probably no new Reye-like diseases reported during the last 10 years that could not be explained by an inherited disorder of metabolism or a misdiagnosis. This may reflect scientific progress in the better understanding of cellular and molecular dysfunctions as disease-determining factors. Alternatively, the immune response to and the virulence of a virus might have changed by alteration of its genetic code. The suggestion of a defined cause-effect relationship between aspirin intake and Reye syndrome in children is not supported by sufficient facts. Clearly, no drug treatment is without side effects. Thus, a balanced view of whether treatment with a certain drug is justified in terms of the benefit/risk ratio is always necessary. Aspirin is no exception.

Asthma in rural Bangladeshi children

OBJECTIVE

Although bronchial asthma causes a great deal of morbidity among children in Bangladesh, few epidemiological studies addressed this problem. The study aims to determine the prevalence of wheezing and its association with environmental and host factors.

METHODS

A total of 1587 children aged 60-71 mth living in 50 villages in rural Bangladesh at Matlab was studied. Trained field workers interviewed caretakers of these children to diagnose wheezing using an adopted questionnaire of the International Studies of Asthma and Allergies in Childhood (ISAAC). History of pneumonia among wheezing and non-wheezing children during their childhood was obtained from the surveillance records.

RESULTS

The prevalence of wheezing in the last 12 mth prior to survey was 16.1% (95% CI: 14.3%, 18.0%), significantly higher among children who had attacks of pneumonia during their infancy compared to children who did not (23.0% vs 14.6%, p< 0.0001). Risk factors associated with wheezing were pneumonia at ages 0-12 m (OR= 1.50, 95% CI 1.08, 2.10) and 13-24 m (OR= 2.12, 1.46, 3.08), maternal asthma (OR=3.01, 95% CI 2.02, 4.47), paternal asthma (OR= 3.12, 95% CI 1.85, 5.26), maternal eczema (OR=1.81, 95% CI 1.14, 2.87) and family income 100 pounds US$ (OR for US$ 51-99= 1.63, 95% CI 1.05, 2.53; OR for US$ 50 pounds = 2.12, 95% CI 1.31, 3.44).

CONCLUSION

Our results suggest that wheezing is a significant cause of morbidity among children in rural Bangladesh. Greater efforts are needed to prevent pneumonia among children during their infancy to reduce the chances of subsequent development of wheezing.

[Asthma on the island of Reunion: an analysis of the severity and therapeutic management]

INTRODUCTION

Asthma is a common condition on the island of La Reunion but there are no epidemiological studies that analyse the prevalence, severity and management of the patients.

METHODS

Two studies were undertaken: a CPAM (health insurance) study of 187 patients and an analysis of the data from 253 patients attending a specialist hospital clinic.

RESULTS

In these two studies we found 40% of patients were in GINA group 3 compared with 10% in metropolitan France. Recourse to the emergency department and admission to intensive care were common. There was under-evaluation by the treating physicians who did not classify patients correctly. This under-evaluation also occurred in prescribing with only 1/3 of asthmatics in stages 2 and 3 receiving inhaled corticosteroids. Patient education was poor with 30% receiving a demonstration of inhaler technique and 31% a functional evaluation.

CONCLUSION

These studies show that the severity profile of asthma on La Reunion is comparable to that in other oceanic countries like Australia and New Zealand rather than metropolitan France. A population study is needed to assess the prevalence of asthma on the island of La Reunion.

Children's homes--determinants of moisture damage and asthma in Finnish residences

Certain housing characteristics increase the risk for moisture damage, which has been associated with increased risk for asthma in children. Modeling moisture damage as a function of these characteristics could therefore provide a simple tool to estimate building-related risk for asthma. This study aimed to find out specific associations between asthma case-control status of children and moisture damage and housing characteristics. The data consisted of information on 121 asthmatic children and predominately two age-, gender- and place of residence-matched control children for every case, and information on moisture damage and housing characteristics in the homes of the children. In a previous study, we found a statistically significant association between moisture damage observations in main living areas and asthma in children. Using logistic regression, five models were formulated to predict moisture damage status of the homes and moisture damage status of living areas. The models were able to classify the damage status correctly in 65.0-87.7% of the homes (kappa values 0.10-0.47) as functions of housing characteristics. None of the models qualified as a significant determinant of the case-control status of the children.

PRACTICAL IMPLICATIONS

It can be hypothesized that building-related risk for asthma could be roughly estimated using models predicting moisture damage status of buildings as a function of easily obtainable housing characteristics. The results of this study indicated that, with a moderate certainty, it is possible to model moisture damage status of buildings using housing characteristics. However, the models developed did not associate with asthma in children. In conclusion, it was not possible to estimate the risk for asthma by studying housing characteristics only, but detailed information on moisture damage (e.g. location of damage) was crucial for such estimation.

Does antibiotic exposure during infancy lead to development of asthma?: a systematic review and metaanalysis

OBJECTIVES

To determine the association between antibiotic exposure in the first year of life and the development of childhood asthma.

DESIGN

Metaanalysis of observational studies retrieved through systematic search of all available electronic data sources. Studies included in the metaanalyses were those with populations exposed to one or more courses of antibiotics during the first year of life, and asthma diagnosis was defined as diagnosis by a physician between the age of 1 to 18 years.

SETTING

Retrospective and prospective studies published in the English-language literature from 1966 to present.

RESULTS

Eight studies (four prospective and four retrospective) examined the association between exposure to at least one course of antibiotics and development of childhood asthma. The total number of subjects for the analysis comparing exposure to at least one antibiotic to no exposure in the first year of life was 12,082 children and 1,817 asthma cases. In the dose-response analysis, we included data from a total of 27,167 children and 3,392 asthma cases. The pooled odds ratio (OR) for the eight studies was 2.05 (95% confidence interval [CI], 1.41 to 2.99). The association was significantly stronger in the retrospective studies (OR, 2.82; 95% CI, 2.07 to 3.85) than the prospective studies (OR, 1.12; 95% CI, 0.88 to 1.42). Five of the eight studies examined whether the association was related to the number of courses of antibiotics taken in the first year of life. The overall OR for the dose-response analysis was 1.16 (95% CI, 1.05 to 1.28) for each additional course of antibiotics; however, this association was not significantly stronger in the retrospective studies (OR, 1.37; 95% CI, 1.18 to 1.60) relative to the prospective studies (OR, 1.07; 95% CI, 0.95 to 1.20).

CONCLUSIONS

Exposure to at least one course of antibiotics in the first year of life appears to be a risk factor for the development of childhood asthma. Because of the limitations of the studies conducted to date, additional large-scale, prospective studies are needed to confirm this potential association.

Environmental and dietary risk factors for infantile atopic eczema among a Slovak birth cohort

Infantile atopic eczema (AE) is a risk marker for future asthma. This study assesses the contribution of modifiable exposures to infantile AE. If modifiable exposures contribute substantially to infantile AE, its prevention might be a sensible approach to asthma prevention. Pregnant women (n = 1978) were systematically recruited from maternity hospitals of the Slovak Republic; their birthed cohort of 1990 children were prospectively followed for 1 yr. Children's exposures to selected environmental and dietary factors were assessed via maternal questionnaires administered at delivery and 1 yr of age. A child was considered to have AE, based on physical examination (SCORAD index >2) or mother's report of a previous physician diagnosis. Multivariate logistic regression was used to calculate adjusted odds ratios and percent total regression scores (TRS) for each variable. At 1 yr of age 1326 (67%) of the children remained in the cohort and 207 (15.6%) developed AE. Various modifiable environmental and dietary exposures increased the likelihood of AE (ownership of cats; consumption of infant formula, eggs, and fish) while others decreased the likelihood of AE (ownership of livestock; exclusive breast feeding for > or =4 months). Overall, modifiable exposures contributed less to the TRS than did non-modifiable exposures (38% vs. 62%, respectively). The modifiable exposure category that contributed most to the TRS was infant feeding practices (27.5% TRS). Modifiable exposures -- especially those related to infant feeding practices -- significantly contribute to infantile AE, although modifiable factors contribute less overall than do non-modifiable exposures.

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

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

Prevalence of asthma, eczema and allergic rhinitis: two surveys, 6 years apart, in Kota Bharu, Malaysia

OBJECTIVE

This study was undertaken to determine the prevalence of asthma, eczema, and allergic rhinitis in school children in Kota Bharu, Malaysia, and in so doing to determine the differences in symptom prevalence rates of asthma, and atopic diseases in Kota Bharu school children between 1995 and 2001.

METHODOLOGY

In two studies (1995 and 2001), year one primary school (PS) pupils (6-7 years old) and secondary school (SS) year two pupils (13-14 years old) were randomly selected from the district of Kota Bharu, Kelantan, Malaysia. In 1995, 3939 PS children and 3116 SS children participated, and in 2001 3157 PS children and 3004 SS children participated. The Phase I International Study of Asthma and Allergies in Childhood prevalence written questionnaire and video questionnaire (only shown to SS children) were used in both studies.

RESULTS

The written questionnaire showed no significant changes in the prevalence (1995, 2001) of ever wheeze (8.3%, 6.9%P = 0.06), current wheeze (5.4%, 4.3%P = 0.08), exercise-induced wheeze (EIW; 3.9%, 3.7%P = 0.63), and rhinoconjunctivitis (4.6%, 5%P = 0.42) among PS children. The prevalence of flexural itchy rash increased from 14% to 17.6% (P = 0.004) and night cough decreased from 20.4% to 17.5% (P = 0.005). There were also no significant changes in these symptoms among SS children (1995, 2001): ever wheeze (10.7%, 12%P = 0.37), current wheeze (6.8%, 5.7%P = 0.20), EIW (9.9%, 11.6%P = 0.28), night cough (21.6%, 24%P = 0.39), rhinoconjunctivitis (11%, 15%P = 0.11), and flexural itchy rash (12%, 13%P = 0.11). The video questionnaire showed no significant changes in the prevalence of symptoms in the previous 12 months (1995 vs 2001) for wheeze at rest (3.8%, 2.8%P = 0.12), EIW (6.9%, 8.8%P = 0.32), waking with wheeze (1.7%, 1.7%P = 1.0), and severe wheeze (2.1%, 3%P = 0.12). Night cough in the previous 12 months increased significantly from 5.1% to 8.3% (P = 0.007).

CONCLUSION

Although asthma and atopic disorders are common in this country, the results revealed no major changes in the prevalence rates of these diseases over a period of 6 years.

The burden of asthma in children: an Australian perspective

The burden of asthma among children is high in Australia compared with many other countries. Recent data show that 14-16% of children report a diagnosis of asthma that remains a problem. Boys, children under the age of 5 years and urban indigenous children experience a greater burden of asthma than other children. More than one-third of children with asthma have sleep disturbance due to the illness and 60% have missed school and/or experienced other restrictions in their activities due to the disease. Despite this, there is continuing evidence of under-utilisation of effective treatment for the disease. Asthma is a major cause of healthcare utilisation among children. Since the early 1990s, there has been a decline in both hospitalisation rates and general practitioner consultation rates for asthma among children. It remains to be seen whether this favourable trend will continue and extend into the adult age range.

Changing prevalence of asthma in Taiwanese adolescents: two surveys 6 years apart

This study compared the prevalence of asthma among Taiwanese adolescents with individual-level risk factors and municipal-level air pollution and meteorology data to determine whether changes in these factors could explain the observed change in prevalence. We conducted two national surveys of respiratory illness and symptoms in Taiwanese middle-school students in 1995-96 and 2001. The effects of personal and environmental factors were assessed and temporal changes of outdoor monitoring data were also compared with asthma prevalence difference. A total of 44,104 children from the 1995-96 survey and 11,048 children from the 2001 survey attended schools located within 1 km of 22 monitoring stations. Lifetime prevalences of physician-diagnosed and questionnaire-determined asthma increased during this period. After adjustment for potential risk factors, the prevalence differences were statistically unchanged. Although parental education level contributed most, changes in investigated personal and environmental factors might not explain the observed changes in asthma prevalence. Municipalities with higher temperature increase were significantly associated with prevalence difference in questionnaire-determined asthma. We concluded that correlates of the investigated individual-level factors, which have changed over time, still underlie changes in asthma prevalence. Increasing temperature might be the main reason for the rising trends of asthma in Taiwanese adolescents.

Use of antibacterials in infancy: clinical implications for childhood asthma and allergies

Evidence from experimental studies in rodents and results from epidemiologic studies with a retrospective design suggest a possible causal association between antibacterial use in early childhood and asthma. Such an association is thought to be mediated by antibacterial-induced alterations in the intestinal flora, leading to a skewing of the immune system of young children toward an atopic phenotype. However, results from recently conducted prospective studies suggest that the previously observed association between antibacterial use in early childhood and asthma is not one of 'cause and effect' but rather that frequent antibacterial use in early childhood may be a marker of an increased risk of being diagnosed with asthma later in childhood. Although antibacterials should not be used excessively in young children, their use in early childhood is not likely to explain the increased prevalence of asthma and allergies in children in industrialized countries.

Cough quality in children: a comparison of subjective vs. bronchoscopic findings

Background

Cough is the most common symptom presenting to doctors. The quality of cough (productive or wet vs dry) is used clinically as well as in epidemiology and clinical research. There is however no data on the validity of cough quality descriptors. The study aims were to compare (1) cough quality (wet/dry and brassy/non-brassy) to bronchoscopic findings of secretions and tracheomalacia respectively and, (2) parent's vs clinician's evaluation of the cough quality (wet/dry).

Methods

Cough quality of children (without a known underlying respiratory disease) undergoing elective bronchoscopy was independently evaluated by clinicians and parents. A 'blinded' clinician scored the secretions seen at bronchoscopy on pre-determined criteria and graded (1 to 6). Kappa (K) statistics was used for agreement, and inter-rater and intra-rater agreement examined on digitally recorded cough. A receiver operating characteristic (ROC) curve was used to determine if cough quality related to amount of airway secretions present at bronchoscopy.

Results

Median age of the 106 children (62 boys, 44 girls) enrolled was 2.6 years (IQR 5.7). Parent's assessment of cough quality (wet/dry) agreed with clinicians' (K = 0.75, 95%CI 0.58–0.93). When compared to bronchoscopy (bronchoscopic secretion grade 4), clinicians' cough assessment had the highest sensitivity (0.75) and specificity (0.79) and were marginally better than parent(s). The area under the ROC curve was 0.85 (95%CI 0.77–0.92). Intra-observer (K = 1.0) and inter-clinician agreement for wet/dry cough (K = 0.88, 95%CI 0.82–0.94) was very good. Weighted K for inter-rater agreement for bronchoscopic secretion grades was 0.95 (95%CI 0.87–1). Sensitivity and specificity for brassy cough (for tracheomalacia) were 0.57 and 0.81 respectively. K for both intra and inter-observer clinician agreement for brassy cough was 0.79 (95%CI 0.73–0.86).

Conclusions

Dry and wet cough in children, as determined by clinicians and parents has good clinical validity. Clinicians should however be cognisant that children with dry cough may have minimal to mild airway secretions. Brassy cough determined by respiratory physicians is highly specific for tracheomalacia.

What plays a role in the choice of inhaler device for asthma therapy?

Inhalation is the preferred route of delivery for anti-asthma drugs. However, in reality inhalers are often prescribed on an empirical basis rather than on evidence-based awareness. Asthma management guidelines also guide inhaler choice, but they offer non-specific advice regarding inhaler choice, are very long and complicated and not conducive to rapid assimilation by a busy GP. In addition, device selection criteria differ according to who you are asking (i.e. the inhalation technologist, the physician or the patient). The ideal inhaler should be small and have a guided sequence of inhalation, leading patients in a logical sequence of events through the inhalation manoeuvre. It should be breath-activated, releasing medication only when all prerequisites for successful inhalation are met. Most importantly, there should be flow-independent deposition of drug in the lungs and feedback on the successfully performed inhalation manoeuvre to reassure the patient that the drug has been successfully released from the inhaler. The ideal inhaler should also have a low intrinsic airflow resistance, making it suitable for use by patients who have a low inspiratory airflow (e.g. children and elderly patients). In order to check for compliance, the ideal inhaler should have an accurate dose counter which is linked to correct inhalation rather than simply to dose release, and patients should be able to use an identical inhaler device to deliver each of their different medications. Finally, from an environmental and cost-effectiveness point of view, the ideal inhaler should be refillable. Among the currently available dry powder inhalers the Novolizer device fulfils several characteristics of an ideal inhaler for the treatment of asthma and chronic obstructive pulmonary disease (COPD).

Stabilization of asthma prevalence among adolescents and increase among schoolchildren (ISAAC phases I and III) in Spain

BACKGROUND

Most studies show a steep increase in asthma prevalence in the last decades, although few studies had applied the same methodology. Recent reports point out the possibility that the epidemic has come to an end. We have studied the prevalence of asthma in a very large sample of children, repeating the study eight years apart.

METHODS

Repeated cross-sectional studies using the International Study of Asthma and Allergies in Childhood (ISAAC) protocol in a sample of Spanish schoolchildren 6-7 (parent-reported) and 13-14 (self-reported) years old in 1994-95 (phase I) and 2002-2003 (phase III). The number of participants was 42 417 in phase I and 42 813 in phase III. The participation rate was over 87% (13-14 years) and 70% (6-7 years).

RESULTS

The prevalence of wheezing in the previous year in children aged 13-14 years was 9.0 and 9.3% for boys and 9.6 and 9.2% for girls for phases I and III, respectively. Children 6-7 years of age showed a substantial increase in wheezing in the previous year (7.0 and 10.7% for boys and 5.3 and 8.2% for girls). Other symptoms and severity indexes followed the same patterns.

CONCLUSIONS

In the last 8 years, the prevalence of asthma has not changed in 13-14-year-old Spanish children but has increased substantially in 6-7-year olds.

Nutritional factors, parasite infection and allergy in rural and suburban Vietnamese school children

Urban areas often have more allergy than rural areas. Dietary patterns and parasite infection have been suggested as possible related factors. This study evaluated the prevalence of allergy in school children in one rural and suburban area of Vietnam where parasite infection is common. A total of 195 children aged 9 to 13 years old completed a self-administered allergy questionnaire and provided blood and stool samples for analysis. Nutritional status, dietary intake and parasite infection were determined in all participants. Allergy was more common in girls (10.7% vs. 7.6%), suburban children (11.8% vs. 6.9%), children with weight-for-age (16.7% vs. 6.0%) and height-for-age (14.8% vs. 4.9%) in the 10th to 75th percentile compared to <3rd percentile, and in children without trichuriasis compared to light trichuriasis (12.5% vs. 9.3%), although none of these comparisons were statistically significant. Logistic regression adjusted for sex, age and area of residence revealed no association between allergy and nutritional status, food intake or parasite infection. Intake of riboflavin, however, was negatively associated with allergy (OR=0.00, 95% CI:0.00-0.65, p=0.038). In conclusion, we were unable to detect any association between allergy and nutritional status, diet, or parasite infection. However, in a population with high undernutrition and parasite infection, the prevalence of allergy was low and the extremely low intake of riboflavin was associated with a higher risk of allergy.

[Identification of the allergenic taxa of pollen in patients with pollinosis to determine the risk season]

BACKGROUND

Determining the risk season for the presence of pollen in the atmosphere aids primary care physicians in the diagnosis and treatment of allergic diseases. Our objective was to identify the taxa of pollen that cause allergic rhinoconjunctivitis in a sample of patients from a health center who presented seasonal symptoms.

METHODS

We designed an observational, cross-sectional, non-randomized study to be carried out in the Cazoña Health Center in Santander, Spain. We selected 30 volunteers of both sexes, aged between 13 and 69 year old, who suffered seasonal rhinoconjunctivitis symptoms and who had always lived in Santander. Patients underwent skin-prick tests with the 25 pollen extracts routinely used in Spain, house dust mite (HDM), cat dander and Alternaria extracts by means of the Prick-Film system. The test result was expressed as the percentage of the papule area caused by histamine. Measurement was performed by scanning the copied papule area with the Prick-Scan program for PC.

RESULTS

All patients were positive to grass pollen, 26 % were sensitized to grass pollen only and 23 % were also sensitized to other non-pollen allergens. Twenty-seven percent tested positive to Plantago, 20 % to Quercus and 13 % to Morus; the remaining pollen extracts were positive in less than 10 %. Fifty-six percent of the patients were positive to HDM and 6 % to cat dander.

CONCLUSIONS

A warning period for pollinosis patients in the city of Santander can be defined. In our case, the important period is the grass pollen season, since the remaining pollen taxa sensitized few patients. Most of our patients were also sensitized to HDM.

Cough, wheezing and asthma in children: lesson from the past

Recurrent cough is an important medical and sometimes frustrating problem encountered by pediatricians, especially if it is not associated with wheeze or other evidence of systemic disease. In the past, many children with chronic cough have been diagnosed as asthmatic. However, epidemiological, clinical and laboratory studies conducted over the last ten years elucidated many aspects of the relationship between cough and bronchoconstriction. It is difficult to make a diagnosis of asthma on cough alone, but the setting in which the patient is seen (i.e., in a primary care setting or ain a specialistic clinic) may address doctors to the right diagnosis. A prudent ''wait and see'' approach may be useful in many occasions.

[Chronic cough in childhood]

INTRODUCTION

Although less frequent than viral induced recurrent cough; chronic cough remains a sometimes difficult to resolve diagnostic tool.

STATE OF THE ART

Most authors estimate that a cough can by considered as chronic after three weeks of duration. Few papers have been published concerning etiologic diagnosis of chronic cough in childhood but these indicate the same main causes as in adults: cough variant asthma, postnasal drip syndrome, gastro-esophageal reflux. Nevertheless, each age bracket presents specific diagnosis: malformations between zero and one year, psychogenic cough in adolescents.

PERSPECTIVES

New techniques as induced sputum studies helps to refine chronic cough diagnosis in childhood (after 7 years). Eosinophilic bronchitis, associated or not to bronchial hyperresponsiveness has important therapeutic consequences because associated with a favourable response to corticosteroids. Other techniques will be developed in the future (exhaled NO for example).

CONCLUSIONS

Chronic cough in childhood must be investigated from an anatomic point of view and on frequency arguments. Control and removal of the cough will only be obtained if a precise diagnosis and a suitable treatment are reached.

Incidence and prevalence of asthma and allergic rhinitis: a cohort study of Finnish adolescents

Only limited data are available about the incidence of asthma and allergic rhinitis based on prospective longitudinal studies throughout childhood into adult life. The main purpose of the study was to estimate the incidence rate of asthma and allergic rhinitis from birth to early adulthood. We also estimated the prevalences of these diseases at 16, 22, and 32 years of age. The data were drawn from a follow-up survey of a Finnish urban age cohort (1967 birth cohort, N = 2269) from age 16 to age 32 years. All data were based on self-report. The prevalence of asthma from age 16 to age 32 years changed from 3.0% to 5.0% (males from 3.3% to 4.9%; females from 2.7% to 5.1%); and that of allergic rhinitis from 17.5% to 26.0% (males from 18.7% to 27.8%; females 16.2% to 24.5%), respectively. The overall incidence rate of asthma was approximately 2.1 new cases per 1000 person-years (95% CI = 1.6-2.8). There was a tendency for boys to have a higher incidence rate of asthma than girls in childhood before 16 years of age: gender difference was reversed from period 17 to 22 years of age. In early adulthood (23-32 years), incidence rates were equal in both sexes. The incidence rate for allergic rhinitis in males was 13.4 per 1000 person-years (95% CI- 11.8-14.8), slightly greater than in females, 11.4 (95% CI = 10.1-12.8). Among both genders, the highest incidence rate of allergic rhinitis was between 17 and 22 years. Our study adds to the limited knowledge on the incidence rates of asthma and allergic rhinitis.

[Satellite symposium: Asthma in the World. Asthma among children in Latin America]

The prevalence of respiratory symptoms related to asthma in children from Latin America has been largely ignored. This region participated in phases I and III of the International Study of Asthma and Allergies in Childhood (ISAAC) with 17 participating centers in phase I and 78 centers in phase III. Data were obtained on asthma, rhinitis and eczema from countries and centers with markedly different climactic, cultural and environmental conditions and socioeconomic development. The results for phase I are presented herein because data from phase III are currently being revised at the ISAAC international data control center and will be officially available in the second half of 2004. Phase I provided important information on the prevalence of asthma in the participating countries and demonstrated wide variation among centers in the same country and among countries. The participating Latin American countries are all developing countries and share more or less the same problems related to low socioeconomic status. Therefore, the results and figures should be analyzed within that context. The range for accumulative and current asthma symptoms in children from the Latin American countries that participated in phase I (89,000) were as follows: the prevalence of asthma ranged from 5.5% to 28% in children aged 13-14 years and from 4.1% to 26.9% in children aged 6-7 years. The prevalence of wheezing in the previous 12 months ranged from 6.6% to 27% in children aged 13-14 years and from 8.6% to 32.1% in children aged 6-7 years. The high figures for asthma in a region with a high level of gastrointestinal parasites infestation, a high burden of acute respiratory and gastrointestinal infections occurring early in life, severe environmental and hygiene problems, suggest that these factors, considered as protective in other (developed) regions of the world, do not have the same effect in this region. Furthermore, those aggressive environmental conditions acting together from very early in life might condition different asthmatic phenotypes with more severe clinical presentation in infancy (first 2 years of life), lower atopy and enhanced airways reactivity. The present study indicates that the prevalence of asthma and related symptoms in Latin America is as high and variable as described previously for industrialized or developed regions of the world and that the environmental risk factors, mainly related with poverty, could be responsible for the different clinical and functional presentations of asthma in children from developing regions.

Change in prevalence of asthma in Danish children and adolescents

BACKGROUND

There is evidence suggesting that the prevalence of asthma has increased, especially in industrialized countries.

OBJECTIVE

To investigate whether the prevalence of asthma in Danish children and adolescents has changed during the past 15 years.

METHODS

Serial cross-sectional studies of 2 different random population samples of children aged 7 to 17 years, living in urban Copenhagen, Denmark, were performed 15 years apart. The first cohort was investigated in 1986 (n = 527) and the second in 2001 (n = 480). The same methods were applied at both occasions. Skin test reactivity was measured using standard techniques. Asthma was defined on the basis of questionnaire responses and was regarded as nonatopic (intrinsic) if no positive reactions were observed on the skin test and as atopic (extrinsic) if at least 1 positive reaction was noted. Current asthma was defined as symptoms within the preceding 12 months.

RESULTS

The prevalence of current asthma increased from 5.3% in 1986 to 11.7% in 2001. This was primarily due to an increase in intrinsic asthma, which was 4.2-fold (1.5% to 6.4%), compared with extrinsic asthma, which increased only 1.4-fold (3.8% to 5.5%). The changes were more pronounced in girls.

CONCLUSIONS

The prevalence of asthma has increased substantially during the past 15 years. The observed striking increase in intrinsic asthma suggests the possibility of a more heterogeneous disorder, involving more important factors than atopy. Furthermore, our findings suggest that asthma might be shifting toward female predominance in childhood.

Atopic dermatitis and respiratory symptoms in Russian and northern Norwegian school children: a comparison study in two arctic areas and the impact of environmental factors

BACKGROUND

The increase in atopic diseases during recent decades has been related to environmental factors such as indoor and outdoor pollution and the ingestion of certain foods. On the other hand, studies from Eastern Europe (with heavy air pollution) have reported a lower prevalence of atopic diseases and sensitization in their schoolchildren than in children living in Western Europe.

OBJECTIVES

This study compares the frequency of atopic diseases and respiratory symptoms in two geographically close arctic areas and points to possible risk factors for development of the diseases.

METHODS

A total of 1734 schoolchildren (1183 in Nikel and 551 in Sør-Varanger) were studied using identical, four-page, self-administered questionnaires.

RESULTS

Atopic diseases were reported in 38.7% of Norwegian and in 24.2% of Russian children (P < 0.001). Atopic dermatitis (AD) (23.6% vs 7.9%; P < 0.001) and allergic rhinoconjunctivitis (AR) (20.6% vs 14.7%; P < 0.001) occurred more frequently in Sør-Varanger, whereas 'self-reported' asthma (12.3% vs 13.1%) was similar in both areas. However, respiratory symptoms such as coughing, wheezing, breathlessness and bronchitis were 3-4 times more frequent in Nikel (P < 0.001).

CONCLUSION

This study disproves a previous hypothesis, i.e. that air pollution must be a major risk factor for the development of atopic diseases. Nevertheless, respiratory tract symptoms may be provoked by environmental pollution. Possible explanations for the higher frequency of atopic diseases in Sør-Varanger may be found in socio-economic and lifestyle differences between the two populations.

Relationship between socioeconomic status and asthma: a longitudinal cohort study

BACKGROUND

There is conflicting information about the relationship between asthma and socioeconomic status, with different studies reporting no, positive, or inverse associations. Most of these studies have been cross sectional in design and have relied on subjective markers of asthma such as symptoms of wheeze. Many have been unable to control adequately for potential confounding factors.

METHODS

We report a prospective cohort study of approximately 1000 individuals born in Dunedin, New Zealand in 1972-3. This sample has been assessed regularly throughout childhood and into adulthood, with detailed information collected on asthma symptoms, lung function, airway responsiveness, and atopy. The prevalence of these in relation to measures of socioeconomic status were analysed with and without controls for potential confounding influences including parental history of asthma, smoking, breast feeding, and birth order using cross sectional time series models.

RESULTS

No consistent association was found between childhood or adult socioeconomic status and asthma prevalence, lung function, or airway responsiveness at any age. Having asthma made no difference to educational attainment or socioeconomic status by age 26. There were trends to increased atopy in children from higher socioeconomic status families consistent with previous reports.

CONCLUSIONS

Socioeconomic status in childhood had no significant impact on the prevalence of asthma in this New Zealand born cohort. Generalisation of these results to other societies should be done with caution, but our results suggest that the previously reported associations may be due to confounding.

Acute effects of urban ambient air pollution on respiratory symptoms, asthma medication use, and doctor visits for asthma in a cohort of Australian children

We enrolled a cohort of primary school children with a history of wheeze (n=148) in an 11-month longitudinal study to examine the relationship between ambient air pollution and respiratory morbidity. We obtained daily air pollution (ozone, particulate matter less than 10 microm, and nitrogen dioxide), meteorological, and pollen data. One hundred twenty-five children remained in the final analysis. We used logistic regression models to determine associations between air pollution and respiratory symptoms, asthma medication use, and doctor visits for asthma. There were no associations between ambient ozone concentrations and respiratory symptoms, asthma medication use, and doctor visits for asthma. There was, however, an association between PM(10) concentrations and doctor visits for asthma (RR=1.11, 95% CI=1.04-1.19) and between NO(2) concentration and wet cough (RR=1.05, 95% CI=1.003-1.10) in single-pollutant models. The associations remained significant in multipollutant models. There was no consistent evidence that children with wheeze, positive histamine challenge, and doctor diagnosis of asthma reacted differently to air pollution from children with wheeze and doctor diagnosis of asthma and children with wheeze only. There were significant associations between PM(10) levels and doctor visits for asthma and an association between NO(2) levels and the prevalence of wet cough. We were, however, unable to demonstrate that current levels of ambient air pollution in western Sydney have a coherent range of adverse health effects on children with a history of wheezing.

Microorganisms and volatile organic compounds in airborne dust from damp residences

Airborne dust samples from damp (n = 9) and control (n = 9) residences were analyzed for microorganisms (molds and bacteria), bacterial markers (3-hydroxy fatty acids and muramic acid), and adsorbed volatile organic compounds (VOCs). The number of mold species was greater in the damp residences than in the controls (23 vs.18) and nine mold species were found only in damp residences. The levels of 3-hydroxy fatty acids and muramic acid correlated better in damp residences than in controls, indicating that damp conditions affect the bacterial flora of airborne dust. Identifications made by culture and microscopy of the major molds found, i.e. Aspergillus, Cladosporium, and Penicillum, coincided with the identification of VOCs known to be produced by these species. A number of additional VOCs irritating to the skin, eyes, or respiratory tract were also found. The results from this pilot study illustrate the diversity of microorganisms and VOCs present in the indoor environment and suggest that analysis of airborne dust may help to assess human exposure to microorganisms and chemical compounds.

Repeatability of bronchial responsiveness to mannitol dry powder in children with asthma

Our objective was to determine the repeatability of bronchial responsiveness to mannitol dry powder (MDP) as an objective marker of asthma in children. MDP challenge was performed in children with stable asthma at the same time of the day on two separate occasions within a week. The test was terminated after a 15% fall of forced expiratory volume in 1 sec (FEV1) and the provocative dose to produce a 15% fall in FEV1 (PD15) were calculated. Seventeen children (aged 9-16 years) on inhaled corticosteroids (200-1,500 mcg) were studied. Mean baseline FEV1 before the challenges were 95% (81-119) and 96% (74-121), respectively, with a standard deviation of differences of 5.2%. PD(15) values ranged from 7-387 mg, with a geometric mean of 38 mg for the first and 49 mg for the second test. Of the 17, all but two pairs of tests achieved a PD15 within one dose of capsules. Four children had a negative challenge on two occasions. A high relative reliability was reflected by a concordance coefficient of 0.86. In conclusion, MDP is a convenient challenge which is easy to administer and is well-tolerated by children. It is a highly reproducible test of airway responsiveness in children with moderate to severe persistent asthma on inhaled corticosteroids within 7 days under laboratory conditions.

Age-specific relationship between CD14 and atopy in a cohort assessed from age 8 to 25 years

CD14 influences postnatal switching of T helper cell responses. CD14 C-159T has been associated with altered CD14 and IgE levels in cross-sectional studies. Identifying whether associations vary with age requires data from children of the same age followed longitudinally over many years. In this study, an unselected population with extensive longitudinal data was used to test the hypothesis that CD14 C-159T was associated with early-onset atopy. A total of 305 subjects were assessed on up to seven occasions between ages 8 and 25 years by questionnaire, histamine challenge, and skin prick test. For atopy, airway hyperresponsiveness (AHR), and wheeze, each subject was classified as having early onset, late onset, or no disease onset during follow-up. Compared with subjects with -159CT and -159TT, subjects with -159CC had an odds ratio of 2.2 (p = 0.018) for early-onset atopy and an odds ratio of 2.6 (p = 0.019) for early-onset AHR. Cross-sectional analysis showed increased prevalence of -159CC in subjects with atopy and AHR in childhood but not adulthood. These data suggest that the influence of CD14 -159C on the atopic phenotype may be age specific, exerting an effect during midchildhood, which is no longer apparent by early adulthood.