International Study of Asthma and Allergies in Childhood (ISAAC): rationale and methods

Dermal and bronchial symptoms in children: are they caused by PAH containing parquet glue or by passive smoking?

OBJECTIVE

In 1997 a new source of potential polycyclic aromatic hydrocarbon (PAH) exposure was discovered: very high levels of (PAHs) and benzo-a-pyrene (BaP) were detected in household dust from former American Forces housing in Frankfurt am Main, Germany, built in 1955/1956. This contamination was caused by a parquet glue containing coal tar, the use of which was formerly a standard building practice in Germany. Children were considered to be at special risk for exposure to PAHs when playing on the floor via mouthing. Therefore, the children's symptoms and complaints were analysed for association with PAH contamination in parquet glue and household dust as well as with internal exposure to PAHs via determination of 1-hydroxypyrene in urine samples.

PARTICIPANTS AND METHODS

Two hundred and eighty seven children <6 years of age living more than 12 months in the former US-housing estates are enrolled in this analysis, representing 22.3% of the children <6 years of age living there. Their spot urine samples were analysed for 1-hydroxypyrene. The level of BaP in parquet glue and in household dust was available in the homes of 215 and 212 children, respectively. There were no hints for differences in PAH contamination in parquet glue or in household dust of the participants' flats compared to the flats of the non responders. In 246 cases data on environmental tobacco smoke exposure at home was known as well. Data on symptoms and complaints observed by their parents during the preceding 12 months (1-year prevalence) were obtained using the ISAAC questionnaire (modified).

RESULTS

The following 1-year prevalences were reported: 15% itching eczema in elbows, 10% itching and urticaria, 6% itching in the palate and throat, 20% sneezing and running nose or stuffed nose, 15% nosebleed; 25% wheezing, 42% dry cough, and 60% frequent infectious disease. No consistent associations between symptoms and BaP in parquet glue or in household dust or urinary levels of 1-hydroxypyrene in the children could be found. However, associations between symptoms and exposure to environmental tobacco smoke at home were to be seen, significant for dermal and bronchial symptoms.

CONCLUSION

Informed about PAHs in parquet glue and household dust many parents demanded for total redevelopment of their flats. According to statistical evaluation of the children's symptoms, observed by their parents, no hints for an association with exposure via BaP in parquet glue or household dust were found. However, significant associations between symptoms and the exposure to environmental tobacco smoke were observed, especially bronchial and dermal symptoms. Therefore instead of redevelopment of flats with parquet glue containing coal tar, intensified information on the harmful effects of passive smoking in childhood seems to be mandatory.

Untreated asthma, final height and sitting height/leg length ratio in Chile

OBJECTIVE

There is uncertainty as to whether asthma has an effect on final height. We investigated using subjective and objective assessments whether untreated asthma is associated with final height, leg length and sitting height to leg length ratio in an area of Chile in which almost no one received asthma treatment.

METHODS

We collected data on 1232 males and females aged 22-28 years in a semi-rural area of Chile. Information on asthma was collected using the European Community Respiratory Health Survey (ECRHS) questionnaire. We assessed sensitisation to eight allergens and bronchial hyper-responsiveness (BHR) to methacholine as a dichotomous variable and as a log slope. Information on possible confounders in terms of smoking, birth weight, number of siblings and socio-economic factors such as household possessions, car ownership and education was available.

RESULTS

Regardless of the asthma assessment used, there was no association between asthma symptoms, diagnosis of asthma, atopy, BHR as log slope, binary or categorical and height, leg length or the ratio of sitting height to leg length. The latter was used as a potentially more appropriate measure to assess a detriment of growth.

CONCLUSION

Asthma as assessed in community studies is unrelated to final height or body proportions.

Standard skin prick testing and sensitization to inhalant allergens across Europe--a survey from the GALEN network

Skin prick testing (SPT) is the standard method for diagnosing allergic sensitization but is to some extent performed differently in clinical centres across Europe. There would be advantages in harmonizing the standard panels of allergens used in different European countries, both for clinical purposes and for research, especially with increasing mobility within Europe and current trends in botany and agriculture. As well as improving diagnostic accuracy, this would allow better comparison of research findings in European allergy centres. We have compared the different SPT procedures operating in 29 allergy centres within the Global Allergy and Asthma European Network (GA(2)LEN). Standard SPT is performed similarly in all centres, e.g. using commercial extracts, evaluation after 15-20 min exposure with positive results defined as a wheal >3 mm diameter. The perennial allergens included in the standard SPT panel of inhalant allergens are largely similar (e.g. cat: pricked in all centres; dog: 26 of 29 centres and Dermatophagoides pteronyssinus: 28 of 29 centres) but the choice of pollen allergens vary considerably, reflecting different exposure and sensitization rates for regional inhalant allergens. This overview may serve as reference for the practising doctor and suggests a GA(2)LEN Pan-European core SPT panel.

The child with asthma at school: results from a national asthma survey among schoolchildren in Israel

PURPOSE

To evaluate school absence and restriction in school activities of children with asthma, and to estimate the involvement of the school staff in asthma disabilities.

METHODS

A modified version of the International Study of Asthma and Allergies in Childhood written questionnaire was administered to a national sample of 13-14-year-old schoolchildren across Israel. Questions regarding social and demographic factors, school absence owing to asthma symptoms, and school staff involvement were added.

RESULTS

There were 10,057 complete questionnaires available for analysis; 710 children reported having asthma. Children with asthma were absent on the average 7.3 +/- 9.8 days in the past school year compared with 3.9 +/- 6.3 days in children without (p = .0001). Absenteeism owing to respiratory symptoms was significantly more common in children with asthma and associated with a more severe asthmatic condition. Four percent of the children with asthma were absent from school more than 30 days. Of the children reporting asthma, 25.9% were not allowed to participate in one or more school activities for medical reasons, compared with 4.2% of children without asthma. Of the children with asthma, 44.3% reported that the school nurse knew about their asthma, and only 13.8% reported that the nurse discussed their asthmatic condition with them; 38.2% of children with asthma reported that no one at school knew about their illness.

CONCLUSIONS

Children with asthma are absent annually on average 3.4 days more than children without asthma. School absence is associated with the severity of asthma. A significant percentage of asthmatic children participate less in school activities. School staff awareness of the children illness is not satisfactory.

Lessons Learned for the Study of Childhood Asthma from the Centers for Children's Environmental Health and Disease Prevention Research

The National Children's Study will address, among other illnesses, the environmental causes of both incident asthma and exacerbations of asthma in children. Seven of the Centers for Children's Environmental Health and Disease Prevention Research (Children's Centers), funded by the National Institute of Environmental Health Sciences and the U.S. Environmental Protection Agency, conducted studies relating to asthma. The design of these studies was diverse and included cohorts, longitudinal studies of older children, and intervention trials involving asthmatic children. In addition to the general lessons provided regarding the conduct of clinical studies in both urban and rural populations, these studies provide important lessons regarding the successful conduct of community research addressing asthma. They demonstrate that it is necessary and feasible to conduct repeated evaluation of environmental exposures in the home to address environmental exposures relevant to asthma. The time and staff required were usually underestimated by the investigators, but through resourceful efforts, the studies were completed with a remarkably high completion rate. The definition of asthma and assessment of disease severity proved to be complex and required a combination of questionnaires, pulmonary function tests, and biologic samples for markers of immune response and disease activity. The definition of asthma was particularly problematic in younger children, who may exhibit typical asthma symptoms sporadically with respiratory infections without developing chronic asthma. Medications confounded the definition of asthma disease activity, and must be repeatedly and systematically estimated. Despite these many challenges, the Children's Centers successfully conducted long-term studies of asthma.

Evaluation of the toll-like receptor 6 Ser249Pro polymorphism in patients with asthma, atopic dermatitis and chronic obstructive pulmonary disease

Background

For allergic disorders, the increasing prevalence over the past decade has been attributed in part to the lack of microbial burden in developed countries ('hygiene hypothesis'). Variation in genes encoding toll-like receptors (TLRs) as the receptor system for the first innate immune response to microbial stimuli has been implicated in various inflammatory diseases. We evaluated here the role of a coding variation, Ser249Pro, in the TLR6 gene in the pathogenesis of asthma, atopic dermatitis (AD) and chronic obstructive pulmonary disease (COPD).

Methods

Genotyping of the Ser249Pro polymorphism in 68 unrelated adult patients and 132 unrelated children with asthma, 185 unrelated patients with COPD, 295 unrelated individuals with AD and 212 healthy control subjects was performed by restriction enzyme digestion.

Results

We found a weak association of the 249Ser allele with childhood asthma (p = 0.03). Yet, significance was lost after Bonferroni correction. No association was evident for AD or COPD.

Conclusion

Variation in TLR6 might play a role in the pathogenesis of childhood asthma.

Mould/dampness exposure at home is associated with respiratory disorders in Italian children and adolescents: the SIDRIA-2 Study

AIMS

To report on the relation between home mould and/or dampness exposure and respiratory disorders in a large sample of children and adolescents in Italy, accounting for age at time of exposure.

METHODS

20,016 children (mean age 7 years) and 13,266 adolescents (mean age 13 years) completed questionnaires on indoor exposures and respiratory symptoms/diseases. Statistical analyses were adjusted for sex, age, questionnaire's compiler, area of residence, season of interview, parental educational status, family history of asthma, rhinitis, eczema, chronic obstructive pulmonary disease, presence of gas water heaters, passive smoking, pets, and active smoking (only for adolescents). Population attributable risk % (PAR) was also computed.

RESULTS

Asthma was more strongly related to only early than to only current exposure, both in children (OR 1.80, 95% CI 1.41 to 2.30) and adolescents (OR 1.89, 95% CI 1.38 to 2.59). The same result was found for rhino-conjunctivitis (OR 1.46, 95% CI 1.17 to 1.82), in children, and for wheeze among adolescents (OR 1.56, 95% CI 1.15 to 2.11). In children, wheeze (OR 1.98, 95% CI 1.47 to 2.66) and eczema (OR 1.44, 95% CI 1.09 to 1.91) were more strongly related to mould/dampness when exposed both early and currently; the same occurred in adolescents for rhino-conjunctivitis (1.78, 95% CI 1.30 to 2.45). Although persistent cough/phlegm was significantly related to mould/dampness exposure in children, regardless of exposure timing, no significant association between mould/dampness exposure and eczema or cough/phlegm was found among adolescents. PAR estimates were higher for only early than only current exposures. Avoiding early only exposure would abate wheeze by 6%, asthma or cough/phlegm by 7%, rhino-conjunctivitis in children by 4%, and in adolescents, asthma by 6%, and wheeze by 4%.

CONCLUSIONS

Respiratory disorders such as wheeze and asthma can often be explained by exposure to home mould/dampness, especially early in life. The association seems more evident in children than in adolescents. These findings may suggest the need for environmental prevention strategies.

[Particle pollution and allergies in children. What relationships are found in epidemiological studies?]

Particles in the air influence mortality and morbidity even in concentrations which were considered harmless. This report examines their role in allergies. Studies on children from areas with different degrees of pollution show that the "classical" type of air pollution with high amounts of coarse particles apparently does not induce allergies. Nearly all studies, which characterized exposure on a smaller spatial scale, found that symptoms of asthma and allergic rhinitis were more common in children exposed to traffic-related pollution. Time series and panel studies demonstrate that particle pollution contributes to asthma aggravation. Whether this applies to eczema or allergic rhinitis has hardly been investigated. Overall the studies suggest a special role for traffic-related particles.

Effect of farming environment on sensitisation to allergens continues after childhood

AIMS

The farming environment in childhood has been reported to decrease the risk of sensitisation to allergens. The purpose of the present study was to explore whether later exposure to a farming environment also could affect this sensitisation.

METHODS

A population based sample of 202 women who did not live on a farm and 231 who did. The subjects filled in a questionnaire and underwent skin prick tests for several common and farming related allergens.

RESULTS

The prevalence of sensitisation to any of the allergens was similar in the two groups (37.1 v 34.6% (p = NS). However, compared with women who did not live on a farm, the women who lived on a dairy farm showed a low prevalence of sensitisation to pollens (4.4 v 17.3%, p = 0.01) and cats (3.5 v 10.4%, p = 0.047). The risk of sensitisation to pollens and pets was lowest among women with both a childhood and adulthood farming environment and was dose dependently associated with current contact with farm animals. However, this contact increased the risk of sensitisation to bovine dander.

CONCLUSION

The farming environment may reduce sensitisation to common allergens also after early childhood. However, it may also increase sensitisation to farm allergens.

Upper respiratory symptoms and other health effects among residents living near the World Trade Center site after September 11, 2001

The authors investigated changes in respiratory health after September 11, 2001 ("9/11") among residents of the area near the World Trade Center (WTC) site in New York City as compared with residents of a control area. In 2002, self-administered questionnaires requesting information on the presence and persistence of respiratory symptoms, unplanned medical visits, and medication use were sent to 9,200 households (22.3% responded) within 1.5 km of the WTC site (affected area) and approximately 1,000 residences (23.3% responded) in Upper Manhattan, more than 9 km from the site (control area). Residents of the affected area reported higher rates of new-onset upper respiratory symptoms after 9/11 (cumulative incidence ratio = 2.22, 95% confidence interval (CI): 1.88, 2.63). Most of these symptoms persisted 1 year after 9/11 in the affected area. Previously healthy residents of the affected area had more respiratory-related unplanned medical visits (prevalence ratio = 1.73, 95% CI: 1.13, 2.64) and more new medication use (prevalence ratio = 2.89, 95% CI: 1.75, 4.76) after 9/11. Greater impacts on respiratory functional limitations were also found in the affected area. Although bias may have contributed to these increases, other analyses of WTC-related pollutants support their biologic plausibility. Further analyses are needed to examine whether these increases were related to environmental exposures and to monitor long-term health effects.

Low socioeconomic status as a risk factor for asthma, rhinitis and sensitization at 4 years in a birth cohort

BACKGROUND

The relation between socioeconomic status and allergic diseases in childhood is controversial. Some studies have proposed childhood asthma to be more common in families with low socioeconomic status, while sensitization to airborne allergens seems to be more frequent in individuals with higher socioeconomic status in childhood.

OBJECTIVE

To assess the relation between socioeconomic status and asthma, rhinitis and sensitization in an unselected prospective birth cohort.

METHODS

Four thousand and eighty-nine families with children born 1994-1996 in predefined areas of Stockholm answered questionnaires on environmental factors, socioeconomic status (parental occupation), and symptoms of allergic disease at birth, 1, 2 and 4 years of age. Blood samples taken at 4 years from 2614 children were analysed for specific IgE to common airborne and food allergens. Odds ratios (OR) and 95% confidence intervals (CI) for various outcomes in relation to socioeconomic status were estimated with a multiple logistic regression model, adjusting for potential confounders such as heredity for allergic diseases, maternal smoking, short duration of breastfeeding and house construction.

RESULTS

There was a decreasing risk of asthma and rhinitis with increasing socioeconomic status. The OR for asthma was 0.33 (95% CI 0.17-0.66) and for rhinitis 0.50 (0.32-0.79) comparing the highest and the lowest socioeconomic groups, with a tendency to stronger effects in those with heredity for allergic disease. The risk of sensitization to food allergens also decreased with increasing socioeconomic status; OR 0.65 (0.41-1.02) in the highest socioeconomic group (Ptrend=0.03), which was not clearly seen for airborne allergens.

CONCLUSION

Asthma, rhinitis and sensitization is more common in lower than in higher socioeconomic groups after adjustment for traditional risk factors. This may be related to additional uncontrolled differences in life style and environmental exposures between the groups, and calls for further studies.

Impulse Oscillometry

OBJECTIVES

To generate reference equations in North American children to be used for assessing respiratory function through the forced oscillation (Rfo) technique, and to determine the changes in oscillatory resistance, reactance, and resonant frequency (Fres) in relation to age, body height, and weight.

DESIGN/SETTING

A prospective cross-sectional study performed on healthy children selected according to strict criteria of American Thoracic Society and European Respiratory Society recommendations.

MEASUREMENTS

Triplicate measures were obtained of resistance and reactance at 5, 10, 15, 20, 25, and 35 Hz as well as Fres through the impulse oscillometer (MasterScreen IOS; Jaeger/Toennies; Höchberg, Germany). Two hundred twenty-two white children--normally distributed within the 3- to 10-year age range and 100 to 150 cm in height--were recruited in Montreal, Canada. We used regression analysis to generate multiple predictive equations separately per gender and frequency on age, height, and body weight.

RESULTS

Stepwise multiple regression in both natural and logarithmic forms for height, weight, age, and gender showed that standing height was the only significant predictor for all variables. Minimal variability was noted in each subject among the triplicate measurements (p = 0.68 to 0.96). Coherence was > 0.9 at all oscillating frequencies except 5 Hz (< 0.72), with tendencies to lower values in young children.

CONCLUSIONS

Resistance and Fres decrease by height, but also by age; and reactance increases. As opposed to our past experience with spirometry in compatible age groups, the Rfo technique was well accepted by preschool children.

Prevalence of food allergy and its relationship to asthma and allergic rhinitis in schoolchildren

BACKGROUND

Food allergy (FA) is an important health problem. However, epidemiological studies at the population level are scarce. We assessed the prevalence of FA and its associations with respiratory manifestations among schoolchildren.

METHODS

A total of 6672 schoolchildren aged 9-11 years recruited from 108 randomly chosen schools in six French cities underwent a clinical examination including skin prick test (SPT) to common food and aeroallergens and the standardized protocol of the run test to assess exercise-induced bronchial hyper-responsiveness (EIB). Asthma, allergic rhinitis (AR) and clinical symptoms of FA were determined using a standardized questionnaire completed by parents.

RESULTS

About 2.1% of the children reported symptoms of FA, 1.9% were sensitized to food allergens, and 0.1% had SP-tested FA. The AR was more prevalent than asthma (20.0% lifetime, 11.9% past year vs 9.8%, 8.7% respectively). Reported FA, food sensitization and SP-tested FA were all positively associated with asthma and AR (P < 0.001). These associations persisted also for FA not manifesting as respiratory symptoms (P < 0.001). Asthma and AR remained significantly associated with reported symptoms of FA and allergic sensitization to food allergens after adjustment for confounders as well as for sensitization to aeroallergens. No relationship existed between EIB (9.0%) and FA.

CONCLUSION

The relationships between FA and asthma and AR could be totally explained neither by the existence of respiratory manifestations of FA nor by sensitization to aeroallergens. The FA might intervene differently in asthma and AR.

Changes in respiratory and allergic symptoms in schoolchildren from 1996 to 2002, results from the ISAAC surveys in Antwerp (Belgium)

Two cross sectional surveys (1995/1996 and 2001/2002) were carried out according to the ISAAC protocol among 6-7 and 13-14 year old schoolchildren in Antwerp, Belgium. A total of 8244 children participated in 1996 and 8159 children in 2002. No significant differences in current prevalence of asthma and asthma medication was found in 6-7 year olds and 13-14 year old girls. Significantly less asthma and asthma medication was reported by 13-14 year old boys in 2002. Symptoms of wheeze had lower occurrence in all groups in 2002, which was significant for older age group. Current prevalence of rash was significantly higher in the 6-7 year olds in 2002. No such increase was found for rash in the older age groups but they reported significantly more rhinitis. No differences were found between urban and suburban Antwerp in either survey. No clear changes in the occurrence of asthma were found for school children in Antwerp while wheeze was reported less in 2002 compared to 1996. Allergic disorders had higher occurrences in schoolchildren in 2002.

Smoking among adults in Syria: proxy reporting by 13-14 year olds

Despite active epidemiological research related to smoking in Syria in the past few years, there is currently no population-based prevalence data for adult smoking in this country. This study presents the first such figures based on information about the smoking habits of 3066 couples in Aleppo, Syria collected during a survey on respiratory morbidity among 13-14-year-old youths. Reports from the young people indicated levels of parental smoking to be 54% for men and 18% for women. This figure for women is twice that reported previously. The mean number of smokers within the studied households was one smoker per household. Smoking among women was found to be strongly associated with their educational status and their spouse's smoking status. This information is of major importance for public health efforts to deal with the smoking epidemic in Syria, as it indicates a hidden epidemic of smoking among women, most likely due to under-reporting.

A comparison of risk factors for wheeze and recurrent cough in preschool children

In a study of 2,978 Danish children aged 5 years from two suburban counties of Copenhagen, carried out in 1998, the authors compared risk factor profiles for wheeze and recurrent cough without wheeze by using polytomous logistic regression to clarify whether the two conditions are likely to have the same etiology. Data were obtained 1) by a mailed parental questionnaire (International Study of Asthma and Allergies in Childhood questions and supplementary questions on cough, sociodemography, perinatal factors, and environmental exposure); 2) through general practitioners (familial allergic disease); and 3) from the National Medical Birth Register (birth weight). Wheeze (WH) was defined as more than one episode of wheeze within the last 12 months (irrespective of cough status) and recurrent cough without WH (RC) as cough occurring outside colds and usually lasting for periods of more than 1 week in children with no more than one attack of wheeze within the last 12 months. Risk factors for comparison were selected as those that, after repeated stepwise logistic regression, remained significant for children with WH or RC. Significant differences were found for gender (p = 0.003), gestational age (p = 0.0002), maternal history of asthma (p = 0.0008), and standard of housing condition (p = 0.04)-all risk factors for WH but not RC. Results may suggest that the two conditions have different etiologies.

Seasonal rhinitis, clinical characteristics and risk factors for asthma

BACKGROUND

The aim was to determine the clinical characteristics of patients with seasonal rhinitis (SR) and to disclose differences in the treatment of SR between an adult allergy clinic and other clinics over time.

METHODS

A retrospective study was conducted based on clinical records of 774 out of 955 patients diagnosed with SR in an adult allergy clinic between 1 January 1991 and 31 December 2003.

RESULTS

The mean age of the patients was 29.1 +/- 9.29 years and 62.7% were female. The most common major complaints of the patients were nasal symptoms in 82.3%. The mean duration of the disease was 6.76 +/- 6.8 years. The patients were symptomatic with a mean of 3.5 +/- 1.7 months a year, mostly during the period between April and July. Skin prick tests were positive in 685 patients (90.3%), where the most common sensitivity was against timothy grass (85.1%). The most common accompanying allergic diseases were food hypersensitivity in 14%, bronchial asthma in 13.4%, and drug allergy and/or intolerance in 9.6%. Although the use of specific immunotherapy and short-acting sedative antihistamines decreased over time, the use of nasal steroids and long-acting nonsedative antihistamines tended to increase before admission to our clinic. Older age (OR: 1.77, 95% CI: 1.06-2.94), presence of familial atopy (OR: 1.72, 95% CI: 1.04-2.85), respiratory symptoms (OR: 2.10, 95% CI: 1.75-2.50), ocular symptoms (OR: 0.77, 95% CI: 0.61-0.98) and metal allergy (OR: 0.25, 95% CI: 0.07-0.89) were associated with the development of asthma in patients with SR.

CONCLUSION

SR lasts approximately 3.5 months and the main cause in Ankara, Turkey is grass pollen sensitivity. Patients with any other allergic conditions make up 39.8% of the patients. SR patients are referred to allergy clinics quite late, which might be due to SR not being considered as a serious disease.

Is the global rise of asthma an early impact of anthropogenic climate change?

The increase in asthma incidence, prevalence, and morbidity over recent decades presents a significant challenge to public health. Pollen is an important trigger of some types of asthma, and both pollen quantity and season depend on climatic and meteorologic variables. Over the same period as the global rise in asthma, there have been considerable increases in atmospheric carbon dioxide concentration and global average surface temperature. We hypothesize anthropogenic climate change as a plausible contributor to the rise in asthma. Greater concentrations of carbon dioxide and higher temperatures may increase pollen quantity and induce longer pollen seasons. Pollen allergenicity can also increase as a result of these changes in climate. Exposure in early life to a more allergenic environment may also provoke the development of other atopic conditions, such as eczema and allergic rhinitis. Although the etiology of asthma is complex, the recent global rise in asthma could be an early health effect of anthropogenic climate change.

The prevalence, severity and seasonal variations of asthma, rhinitis and eczema in Taiwanese schoolchildren

The prevalence of asthma is increasing in Taiwan but data remain limited. The aim of this study was to determine the prevalence, severity, demographic and seasonal variations of asthma, rhinitis, and eczema in Taiwan. Using a one-stage stratified cluster random sampling, first grade (aged 6-8) and eighth grade (aged 13-15) students from Taoyuan, northern Taiwan, were invited to participate in this survey. The results showed a total of 6190 students, 3079 aged 6-8 and 3111 aged 13-15, completed this survey. In general, children aged 6-8 had significantly higher prevalence rates of diagnosed asthma, rhinitis, and eczema than children aged 13-15 (12.2%, 29.8%, and 10.2% vs. 9.6%, 18.3%, and 4.7%, respectively). Similarly, children aged 6-8 had significantly higher proportions of allergic symptoms, except for exercise-induced wheezing (5.8% vs. 17.8%, p < 0.0001). Among those with allergic disorders, children aged 6-8 presented a greater severity of wheezing attacks in the last 12 months. As regards gender, boys aged 6-8 had a significantly higher proportion of asthma or rhinitis symptoms than girls aged 6-8 but not in children aged 13-15. In children aged 6-8, asthma and rhinitis peaked in winter, especially in December. However, children aged 13-15 had two peaks (winter and summer) for asthma or rhinitis.

Randomized, controlled trial of dexamethasone in neonatal chronic lung disease: 13- to 17-year follow-up study: II. Respiratory status, growth, and blood pressure

OBJECTIVES

To study the growth, health status, and respiratory outcomes at 13 to 17 years of infants enrolled in a double-blind, randomized, controlled trial of dexamethasone for the treatment of neonatal chronic lung disease.

PARTICIPANTS

A total of 287 infants who were chronically dependent on supplementary oxygen between 2 and 12 weeks of age were recruited from 31 centers in 6 countries to a double-blind, randomized, controlled trial of dexamethasone base (0.5 mg/kg per day for 1 week) or placebo, and survivors were evaluated at 3 years. Children from the 25 British and Irish centers were traced for reassessment at 13 to 17 years of age.

OUTCOME MEASURES

Respiratory symptoms, lung-function testing, height, weight, head circumference, blood pressure, health resource usage, and school absences.

RESULTS

There was no significant difference in respiratory outcomes between the dexamethasone and placebo groups. Lung function was impaired but with no difference between the 2 groups. Growth was also impaired in both groups, with height z score of -0.7, weight z score of -0.4, and head circumference z score of -1.1. Systolic blood pressure was >95th percentile for age and height for 15% of children, but with no difference between the 2 groups. There was no difference in the numbers of hospital admissions for respiratory causes or other causes.

CONCLUSIONS

Despite a shorter duration of neonatal assisted ventilation, there is no evidence that dexamethasone use is associated with long-term improvement in lung function. Impaired growth and poor health status are long-term consequences of neonatal chronic lung disease, irrespective of exposure to neonatal dexamethasone.

Adolescent respiratory symptoms--girls are at risk: the Young-HUNT study, Norway

The objective was to study sex differences in adolescence regarding prevalence of asthma and current wheeze and to explore the association between respiratory symptoms and hereditary, lifestyle and socioeconomic factors. Young-HUNT included data comprehensive questionnaire on health, disease, lifestyle and social factors from 8817 teenagers 13-19 years conducted in 1995/97 (89% response rate). Questionnaire on respiratory symptoms was based on the International Study of Asthma and Allergy in Childhood (ISAAC). In age groups 13-16 and 17-19 years, current wheeze was reported by 29.0% and 33.5% among girls and 20.4% and 22.1% among boys, whilst the corresponding figures for asthma were 8.5% and 12.2% among girls and 7.1% and 7.0% among boys. Both wheeze and asthma were significantly more prevalent and increased with age in girls compared to boys. Heredity was associated with asthma, but the association was strongest between parents and children of the same sex. Environmental smoking was associated with asthma and wheeze in girls only. Girls reported more asthma and wheeze in association with overweight compared to boys. Girls reported more wheeze and asthma than boys and seemed more susceptible to risk factors such as environmental smoking and overweight than boys. Moreover, girls with mothers having asthma were more likely to be diagnosed as asthmatics themselves.

Validation of the International Study of Asthma and Allergies in Children (ISAAC) and U.K. criteria for atopic eczema in Ethiopian children

BACKGROUND

Reliable diagnostic criteria for atopic eczema (AE) are essential in order to make international comparisons and to identify possible disease risk factors. Little is known about the prevalence of atopic eczema and validity of diagnostic criteria for AE in developing countries where English is not the first language.

OBJECTIVES

We sought to determine the prevalence of AE in an area of urban and rural Ethiopia, and to compare the predictive values of different questionnaire and examination methods for diagnosing AE in this population.

METHODS

We conducted a cross-sectional survey of 7915 children aged 1-5 years living in and around the town of Jimma in southwest Ethiopia. AE prevalence was assessed in two ways: (i) by using the International Study for Asthma and Allergies in Childhood (ISAAC) questionnaire, and (ii) using the U.K. refinement of Hanifin and Rajka's diagnostic criteria. All possible cases identified by screening questions and random samples of controls were then examined by an experienced local paediatrician, who acted as a reference standard to determine the predictive value of the criteria used to diagnose AE.

RESULTS

The overall 1-year period prevalence of AE according to ISAAC and U.K. criteria was 4.4%[95% confidence interval (CI) 3.95-4.85] and 1.8% (95% CI 1.5-2.1), respectively. Corresponding point prevalence estimates (symptoms in the last week) were 1.8% for ISAAC and 1.3% for the U.K. criteria. The positive predictive values of the ISAAC and U.K. criteria questions for AE symptoms still reported to be present (in the last week) at the doctor's examination were 48.8% and 55.5%, respectively. Corresponding negative predictive values were 90.5% and 90.1%, respectively. The sign of visible flexural dermatitis (a component of the U.K. criteria) when used alone had positive and negative predictive values of 57% and 91%, respectively.

CONCLUSIONS

Neither the ISAAC nor U.K. criteria performed especially well in predicting cases of AE in this survey. Possible reasons include problems with questionnaire translation, cultural conceptions of terminology, asking parents rather than the child about symptoms, the transient nature of AE signs, and differences in what a doctor perceives to constitute a typical case of AE. The results do not preclude the use of standardized diagnostic criteria alongside a doctor's examination in future surveys of Ethiopian children, and knowledge of the criteria's limited predictive value should help to interpret study findings that have employed such criteria. Consideration should be given to adopting the sign of visible flexural dermatitis as a standard for estimating the point prevalence of AE throughout the world because it is less susceptible to problems with translation and interpretation.

No increase in the prevalence of asthma, allergies, and atopic sensitisation among children in Germany: 1992-2001

BACKGROUND

From 1970 to 1990 increasing rates of asthma and allergic sensitisation were observed in several countries. The aim of this study was to investigate time trends in the prevalence of asthma and allergic sensitisation among school children in Germany between 1992 and 2001.

METHODS

Parental reports of asthma, hay fever, and wheezing and measurements of specific serum IgE antibodies were investigated in six serial cross sectional surveys of 9-11 year old school children in three study areas in south west Germany.

RESULTS

A total of 6762 school children of mean age 10 years (mean participation rate 77.9%) took part in the investigation in the three study areas. Over the 9 year study period no increase in the prevalence of current wheezing and asthma was observed. In addition, the prevalence of atopic sensitisation remained unchanged during the observation period.

CONCLUSIONS

These data, using parental reports and objective measures of allergy, suggest that there has been no further increase in the prevalence of asthma and atopy since 1992. The epidemic may thus have reached a plateau.

Diverging prevalence trends of atopic disorders in Norwegian children. Results from three cross-sectional studies

BACKGROUND

During the last decades there has been extensive epidemiological research to explore the increasing prevalence of asthma and allergy in childhood. The worldwide variations in prevalence of these diseases necessitate regional rapports. Furthermore, time-trend analyses with comparable methods are important in order to monitor the rapidly changing prevalence of these diseases.

METHODS

Three cross-sectional questionnaire-based studies of asthma and allergy in schoolchildren were conducted in the counties of Troms and Finnmark, in northern Norway in 1985, 1995 and 2000. The two former studies included children from randomly selected primary schools (n = 1794/1985, n = 1432/1995). The latter study was a part of ISAAC-II Europe study (n = 3853). Identical items of asthma and allergy were employed. The analyses comprised only children 9-11 years of age.

RESULTS

The prevalence of asthma was 9.3, 13.2 and 13.8% in 1985, 1995 and 2000, respectively. However, great gender differences were detected; the prevalence of asthma increased in males from 1995 to 2000, from 14.1 to 17.0%, RR = 1.2 (95% CI 1.0-1.5), but decreased in females 1995 to 2000, from 12.3 to 10.5%, RR = 0.9 (95% CI 0.7-1.1). Furthermore, in children with asthma, a changing trend was found in the external factors that perceived symptoms, from typical allergens towards other, unspecific agents. The prevalence of self-reported atopic eczema/dermatitis syndrome (AEDS) was 13.4, 21.1 and 20.8% in 1985, 1995 and 2000, respectively. The prevalence of self-reported allergic rhinoconjunctivitis was in 16.5, 24.7 and 29.6% 1985, 1995 and 2000, respectively, RR (2000/1995) = 1.2 (95% CI 1.1-1.3).

CONCLUSION

The prevalence of asthma in girls has reached a plateau and even decreased from 1995 to 2000 which is in contrast to the asthma prevalence in boys that tends to continuously increase. The prevalence of AEDS which increased substantially between 1985 and 1995 did not change from 1995 to 2000. However, the prevalence of allergic rhinoconjunctivitis increased steadily from 1985, 1995 to 2000.

Traffic related air pollution as a determinant of asthma among Taiwanese school children

BACKGROUND

There is evidence that long term exposure to ambient air pollution increases the risk of childhood asthma, but the role of different sources and components needs further elaboration. To assess the effect of air pollutants on the risk of asthma among school children, a nationwide cross sectional study of 32 672 Taiwanese school children was conducted in 2001.

METHODS

Routine air pollution monitoring data for sulphur dioxide (SO2), nitrogen oxides (NOx), ozone (O3), carbon monoxide (CO), and particles with an aerodynamic diameter of 10 microm or less (PM10) were used. Information on individual characteristics and indoor environments was from a parent administered questionnaire (response rate 93%). The exposure parameters were calculated using the mean of the 2000 monthly averages. The effect estimates were presented as odds ratios (ORs) per 10 ppb changes for SO2, NOx, and O3, 100 ppb changes for CO, and 10 microg/m3 changes for PM10.

RESULTS

In a two stage hierarchical model adjusting for confounding, the risk of childhood asthma was positively associated with O3 (adjusted OR 1.138, 95% confidence interval (CI) 1.001 to 1.293), CO (adjusted OR 1.045, 95% CI 1.017 to 1.074), and NOx (adjusted OR 1.005, 95% CI 0.954 to 1.117). Against our prior hypothesis, the risk of childhood asthma was weakly or not related to SO2 (adjusted OR 0.874, 95% CI 0.729 to 1.054) and PM10 (adjusted OR 0.934, 95% CI 0.909 to 0.960).

CONCLUSIONS

The results are consistent with the hypothesis that long term exposure to traffic related outdoor air pollutants such as NOx, CO, and O3 increases the risk of asthma in children.

Allergen-specific sensitization in asthma and allergic diseases in children: the study on farmers' and non-farmers' children

BACKGROUND

Farmers' children are less frequently sensitized to common allergens than the non-farmers' children, but less is known about their sensitization to other allergens and its association with clinical diseases.

OBJECTIVE

To examine the association of farm environment with atopic sensitization, allergic diseases, expression of allergen-induced symptoms, and the importance of specific sensitization against 'common' (timothy, dog, cat, birch, Dermatophagoides pteronyssimus, mugwort) and 'other' (cockroach, horse, Lepidoglyphus destructor, cow) allergens for asthma and allergic diseases in children.

METHODS

A cross-sectional study including 344 farmers' and 366 non-farmers' children aged 6-13 years in eastern Finland, using a self-administered written questionnaire and skin prick tests against the above-mentioned allergens.

RESULTS

Farmers' children had less asthma and allergic diseases and were less often sensitized against common allergens than the non-farmers' children. However, little difference was observed in sensitization against the other allergens between the farmers' (17.2%) and non-farmers (14.5%) children [adjusted odds ratios (aOR) 1.11 (0.71-1.72)]. Being sensitized against only other allergens, without sensitization against common allergens, was unrelated to asthma or allergic diseases. Among the single allergens, sensitization against pets or pollen, or against horse or cow, had the strongest association with asthma, hayfever, and atopic eczema; no such association was seen in D. pteronyssimus, mugwort, cockroach, or L. destructor. Farmers' children had significantly less often symptoms of allergic rhinitis in contact with dog (aOR 0.32%, 95% confidence interval (CI) 0.15-0.67), cat (aOR 0.45, 0.22-0.88), or pollen (aOR 0.58%, 95% CI 0.37-0.90) than the non-farmers' children.

CONCLUSION

Farm environment reduces the occurrence of asthma, allergic diseases, and atopic sensitization in children, and also the occurrence of allergen-induced rhinitis. Remarkable differences were observed between single allergens in their association with allergic disease, stressing the importance of allergen selection when defining atopy in epidemiological studies.

Effect of cooked and raw egg consumption on ovalbumin content of human milk: a randomized, double-blind, cross-over trial

BACKGROUND

Maternal avoidance of egg intake has been recommended to treat egg allergy in breastfed infants.

OBJECTIVE

To determine if the concentration of ovalbumin (OVA) in human milk is directly related to the quantity and form of egg consumed by breastfeeding mothers.

METHODS

Randomized, blinded, cross-over, intervention trial. Breastfeeding women (n = 41) attended four clinic days between 11 and 14 weeks of lactation and on each day were randomly allocated to receive a test breakfast, identical except for the egg content (no egg, one raw egg, half a cooked egg or one cooked egg). Breast milk samples were collected at two hourly intervals for 8 h and their OVA concentration measured by ELISA.

RESULTS

There was a direct, dose-response between the amount of cooked egg ingested and the peak OVA concentration (no egg 0.05 ng/mL [95% confidence interval (CI), 0.01-0.11], half a cooked egg 2.24 ng/mL [95% CI, 0.57-3.91], one cooked egg 3.16 ng/mL [95% CI, 1.41-4.91], n = 41, P<0.05) as well as the total OVA excretion (no egg 0.18 ng/mL/h [95% CI, 0.04-0.39], half a cooked egg 4.93 ng/mL/h [95% CI, 1.40-8.46], one cooked egg 9.14 ng/mL/h [95% CI, 4.25-14.03], n = 41, P<0.05). The peak concentration and total OVA excretion in response to one raw egg did not differ from ingesting half a cooked egg. There was no detectable OVA in the breast milk of 24% (10/41) women up to 8 h after any egg challenge.

CONCLUSION

OVA was detected in the breast milk of lactating women up to 8 h after a controlled intake of egg. A dose-response correlation was indicated. As excretion of OVA in human milk appears to be a normal phenomenon, further studies need to determine the threshold of OVA excretion that leads to symptoms in egg-allergic breastfed infants.

Regional variation of airway hyperresponsiveness in children with asthma

Families with asthmatic children were recruited to take part in a multi-centre collaborative study into the genetics of asthma. Detailed phenotypic information was collected on all family members including: lung function, anthropomorphic measurements, response to methacholine challenge, skin prick testing, serum IgE measurements and a detailed nurse-administered questionnaire. Families were eligible for entry into the study if they had two children with a doctor-diagnosis of asthma. Bennett/Twin nebulisers were supplied to each centre from a single source and these were calibrated to determine gravimetric nebuliser output prior to use. Asthmatic probands from each centre had similar degrees of asthma severity and atopy. There was no significant difference in the sex ratios or ages of the probands or numbers of parents with a history of smoking in the families recruited at each centre. However, there was a significant difference in the number of children with airway hyperresponsiveness, with 90% of the North Staffordshire group but only 60% of the Sheffield group having a PC20 of <8 mg/ml for methacholine. This difference highlights the difficulty of using families from different centres in genetic and epidemiological studies.

The use of non-bronchoscopic brushings to study the paediatric airway

Background

The use of cytology brushes for the purpose of obtaining respiratory cells from adults for clinical and research purposes is well established. However, the safety and utility of non-bronchoscopic brushings to study the paediatric airway has not been assessed. The purpose of this study was to assess the practicality of using non-bronchoscopic brushing to sample epithelial cells from children for investigation of epithelial function in health and disease using a wide range of molecular and cellular techniques.

Methods

Non-bronchoscopic brushing was investigated in a non-selected cohort of healthy, and mildly asthmatic children presenting for surgery unrelated to respiratory conditions, at the major children's hospital in Perth. Safety and side-effects of the procedure were assessed. Cell number, phenotype and viability were measured for all samples. The potential of these cells for use in long-term cell culture, immunohistochemistry, western blotting, quantitative PCR and gene arraying was examined.

Results

Non-bronchoscopic brushing was well tolerated in all children. The only significant side effect following the procedure was cough: nursing staff reported cough in 20% of patients; parents reported cough in 40% of patients. Cells sampled were of sufficient quantity and quality to allow cell culture in 93% of samples. Similarly, protein and RNA extracted from the cells was suitable for investigation of both gene and protein expression using micro-array and real-time PCR.

Conclusion

Non-bronchoscopic brushing in children is safe and easy to perform, and is not associated with any complications. Using this technique, adequate numbers of epithelial cells can be retrieved to allow cell culture, western blotting, real time PCR, and microarray analysis. The purpose of this study is to demonstrate the utility of non-bronchoscopic airway brushing to obtain and study epithelial cells and to encourage others so that we can accelerate our knowledge regarding the role of the epithelium in childhood respiratory disease.

The primary prevention of asthma in children study: design of a multifaceted prevention program

The PREVASC study addresses the primary prevention of asthma in infants and small children. The objective of this study is to investigate whether a multifaceted prenatally started intervention strategy in high-risk infants leads to a decrease in the occurrence of (severe) asthma and whether a refinement of the prevention strategy leads to an increase in the adherence to the prevention program. The primary prevention program includes house dust mite impermeable bed coverings, education on breast feeding, hypoallergenic feeding, timing of introduction of solid food and smoking cessation. A total of 888 infants were prenatally included. By the time of inclusion the mothers were 3-7 months pregnant. About 27 infants were excluded from the study and 18 dropped out. Of the remaining 843 infants 535 had a first-degree familial predisposition of asthma (high-risk group), whereas a reference group of 308 (162 boys) infants was not predisposed for asthma in the first-degree (low-risk group). To evaluate the (cost-)effectiveness of the preventive intervention, 222 (118 boys) infants of the high-risk group allocated to the intervention group and 221 (112 boys) allocated to a control group are followed up. The low-risk infants served as controls to evaluate the predictive value of high risk (first-degree familial predisposition of asthma). The infants are followed from the prenatal stage until they reach the age of 6 yr. The remaining 92 high-risk infants were included in an optimized randomized-clinical adherence trial (RCAT). Of these 92 infants, 45 (20 boys) were allocated to an intervention group and 47 (24 boys) to a control group. Until now all infants have been followed for at least 1 yr.

Current asthma and respiratory symptoms among pupils in relation to dietary factors and allergens in the school environment

The aim was to study asthma and allergy in relation to diet and the school environment. Pupils (5-14 years) in eight schools received a questionnaire, 1014 participated (68%). Settled dust was collected on ALK-filters and analyzed for allergens from cat (Fel d 1), dog (Can f 1), horse (Equ cx), house dust mites (Der p 1, Der f 1), and cockroach (Bla g 1) by ELISA. In total, 6.8% reported cat allergy, 4.8% dog allergy, 7.7% doctor's diagnosed asthma and 5.9% current asthma, and 7.8% reported wheeze. Current asthma was less common among those consuming more fresh milk (P < 0.05) and fish (P < 0.01). Poly-unsaturated fatty acids was associated with more wheeze (P < 0.05), olive oil was associated with less doctors' diagnosed asthma (P < 0.05). Totally, 74% of the classrooms had mean CO(2) <1000 ppm. The median concentration per gram dust was 860 ng/g Fel d 1, 750 ng/g Can f 1 and 954 U/g Equ cx. Horse allergen was associated with more wheeze (P < 0.05), daytime breathlessness (P < 0.05), current asthma (P < 0.05) and atopic sensitization (P < 0.05). Dog allergen was associated with wheeze (P < 0.05) and daytime breathlessness (P < 0.05). The associations between allergens and respiratory symptoms were more pronounced among those consuming margarine, not consuming butter, and with a low intake of milk. In conclusion, cat, dog and horse allergens in schools could be a risk factor for asthma and atopic sensitization, and dietary factors may interact with the allergen exposure.

PRACTICAL IMPLICATIONS

Previous school studies performed by us in mid-Sweden, showed that most classrooms did not fulfill the ventilation standards. In this study, most of the classrooms fulfilled the ventilation standard, but despite that had widespread allergen contamination. Most previous studies have focused on cat allergen, but our study has shown that also dog and horse allergens can be risk factors for asthma and allergy in schools. As allergens are transported from other environments, mainly the home environment, the main prevention should be to minimize transfer of allergens. This could be achieved by reducing contacts with furry pets and horses, or using different clothes at home and at school (e.g. school uniforms). Increased cleaning in the schools may reduce allergen levels, but the efficiency of this measure must be evaluated in further intervention studies. Finally, our study supports the view that dietary habits among pupils should not be neglected and interaction between dietary factors and indoor allergen exposure needs to be further investigated.

Prevalência de asma em adolescentes urbanos de Santa Maria (RS): Projeto ISAAC - International Study of Asthma and Allergies in Childhood

INTRODUÇÃO: A asma é a doença crônica mais comum entre adolescentes. OBJETIVO: Determinar a prevalência de asma e sintomas relacionados utilizando o protocolo do International Study of Asthma and Allergies in Childhood (ISAAC) em adolescentes de Santa Maria (RS). MÉTODO: Estudo transversal, em que foram avaliados 3.066 escolares urbanos (13-14 anos) de Santa Maria (RS), selecionados por amostragem aleatória, conforme protocolo do ISAAC. Os dados foram coletados de março a junho de 2003 utilizando-se questionário padronizado do ISAAC. O questionário foi respondido pelos adolescentes em sala de aula, na presença dos pesquisadores. RESULTADOS: O número de questionários válidos devolvidos foi de 3.066 (95,5%). A prevalência dos sintomas de asma nos adolescentes foi: sibilos alguma vez na vida em 42,1% dos adolescentes; sibilos nos últimos doze meses em 16,7%; quatro crises ou mais de sibilos nos últimos doze meses em 1,9%; sono perturbado em uma ou mais noites por semana nos últimos doze meses em 3,8%; prejuízo na fala nos últimos doze meses em 3,8%; asma alguma vez na vida em 14,9%; sibilos após exercícios nos últimos doze meses em 19%; tosse seca à noite nos últimos doze meses em 32,4% deles. Houve valores significativamente superiores no sexo feminino. CONCLUSÃO: A prevalência dos sintomas relacionados à asma em adolescentes urbanos de Santa Maria mostrou-se elevada, predominando entre as meninas. Ficou entre a média internacional e foi inferior aos dados observados nas capitais brasileiras. Estes dados reforçam a necessidade de estudos regionais para o melhor entendimento da prevalência da asma no Brasil.

Longitudinal study on the relationship between cat allergen and endotoxin exposure, sensitization, cat-specific IgG and development of asthma in childhood--report of the German Multicentre Allergy Study (MAS 90)

BACKGROUND

Controversial data have emerged regarding the question whether cat exposure in childhood favours or decreases the risk of sensitization and allergic airway disease. In a prospective birth-cohort study, we assessed the association between longitudinal cat allergen exposure, sensitization (immunoglobulin E, IgE), IgG antibody (ab) levels to cat and the development of asthma in children up to the age of 10 years.

METHODS

Of 1314 newborn infants enrolled in five German cities in 1990, follow-up data at age 10 years were available for 750 children. Assessments included yearly measurements of specific serum IgE to cat and at age 6 and 18 months, 3, 4 and 10 years measurement of cat allergen Fel d 1 in house dust samples. Additionally, Fel d 1-specific IgG ab were determined in 378 serum samples of 207 children. Endotoxin exposure in mattress dust was measured in a subgroup of 153 children at age 10 years. From age 4 years on, International Study of Asthma and Allergy in Childhood (ISAAC) questionnaires were completed yearly in order to assess the prevalence of wheeze and asthma.

RESULTS

Serum IgG-levels to cat showed a large variation, however, intraindividually values showed rather constant concentration over a longer time period. The IgG levels at school-age correlated with cat allergen exposure during the first 2 years of life. Specific IgE to cat was clearly associated with wheeze ever, current wheeze and bronchial hyperresponsiveness (BHR), this was also observed for children with specific IgE ab to cat (>0.35 kU/l) plus IgG levels above 125 U/ml. A large percentage of very highly exposed children showed high IgG but no IgE responses to cat, however, not all highly exposed children were found to be protected from sensitization. Children with IgG but without IgE ab to cat showed the lowest prevalence of wheeze ever and current wheeze despite high cat allergen exposure, however, this trend did not achieve significance. While homes of cat owners showed higher Fel d 1 concentrations than homes without cats, homes of cat owners were not found to have higher endotoxin levels in carpet dust samples than homes without cats.

CONCLUSIONS

We could confirm that high cat allergen exposure in a cohort with lower community prevalence of cats is associated with higher serum IgG and IgE levels to cat in schoolchildren. Sensitization to cat allergen (IgE) is a risk factor for childhood asthma. While exposure to cat allergen during infancy is associated with sensitization (IgE), only in the very highly exposed children the likelihood of sensitization (IgE) is decreased and high IgG levels to cat without IgE were associated with low risk of wheeze. However, cat-specific IgG ab levels did not protect children with IgE-mediated sensitization from wheeze.

Modest increase in seasonal allergic rhinitis and eczema over 8 years among Estonian schoolchildren

We studied time trends in the prevalence of asthma and allergic diseases in Estonian children born before and after the collapse of the Soviet Union, as this event markedly altered the lifestyle in Estonia. Two identical cross-sectional studies were performed as part of phase I and phase III of the International Study of Asthma and Allergies in Childhood (ISAAC). Children, aged 6-7 yr (n = 3070 in 1993-94 and 2383 in 2001-02) and 13-14 yr (n = 3476 and 3576, respectively), completed ISAAC core-written questionnaires, and 13-14-yr olds (n = 3427 and 3259, respectively) also video questionnaires. The prevalence of respiratory symptoms was mostly similar in the two studies. Despite this, the prevalence of diagnosed asthma increased. This was probably due to modified diagnostic criteria and increased awareness. Furthermore, the prevalence of rhinitis during the pollen season increased, e.g., rhinitis in May from 1.7% to 3.5%; sex-adjusted prevalence odds ratio (POR) 2.09 (95% confidence interval 1.47-2.96) in 6-7-yr olds, and from 2.6% to 5.5%; POR 2.22 (1.72-2.87) in 13-14-yr olds. The prevalence of flexural dermatitis also increased from 12.0% to 13.5%; POR 1.20 (1.02-1.41) in 6-7-yr olds, and from 7.7% to 9.4%; POR 1.26 (1.07-1.50) in 13-14-yr olds. The increase was similar in children born before and after the regaining of Estonian independence, indicating that the influence of factors related to a Western lifestyle and affecting the prevalence of allergic symptoms is not restricted to infancy, but may be operative throughout childhood.

Population disparities in asthma

The prevalence of asthma in the United States is higher than in many other countries in the world. Asthma, the most common chronic disease of childhood in the United States, disproportionately burdens many socioeconomically disadvantaged urban communities. In this review we discuss hypotheses for between-country disparities in asthma prevalence, including differences in "hygiene" (e.g., family size, use of day care, early-life respiratory infection exposures, endotoxin and other farm-related exposures, microbial colonization of the infant bowel, exposure to parasites, and exposure to large domestic animal sources of allergen), diet, traffic pollution, and cigarette smoking. We present data on socioeconomic and ethnic disparities in asthma prevalence and morbidity in the United States and discuss environmental factors contributing to asthma disparities (e.g., housing conditions, indoor environmental exposures including allergens, traffic air pollution, disparities in treatment and access to care, and cigarette smoking). We discuss environmental influences on somatic growth (low birth weight, prematurity, and obesity) and their relevance to asthma disparities. The relevance of the hygiene hypothesis to the U.S. urban situation is reviewed. Finally, we discuss community-level factors contributing to asthma disparities.

[Time trends and geographical variations in the prevalence of symptoms of allergic rhinitis in 6-7-year-old children from eight areas of Spain according to the ISAAC]

BACKGROUND

Phase III of the International Study of Asthma and other Allergies in Childhood (ISAAC) was carried out in schoolchildren aged 6-7 years from eight areas of Spain to estimate time trends and geographic variations in the prevalence of symptoms of allergic rhinitis (AR).

MATERIAL AND METHOD

A standard and validated questionnaire was used following ISAAC methodology and was completed by the schoolchildren's parents. The prevalence of symptoms of AR in Phase I (1993-1994) and Phase III (2001-2002) was compared. Eight centers participated: Asturias, Barcelona, Bilbao, Cartagena, Castellón, Madrid, Pamplona and Valencia. Poisson regression was used in the analysis.

RESULTS

A total of 25,113 schoolchildren were studied with a median participation of 81.7 %. In all centers, AR symptoms tended to increase, with a prevalence ratio of rhinoconjunctivitis in the previous year of 1.61 (95 % confidence interval: 1.48-1.76) when both phases, adjusted by gender, center, and seasonal variation, were compared. The prevalence of AR symptoms was higher in boys than in girls. Wide variations in the prevalence of AR were observed across centers with a higher prevalence in Asturias, Madrid, Cartagena and Bilbao. Lower prevalences were reported in Barcelona, Castellón and Pamplona.

CONCLUSIONS

There seems to have been a general increase in AR symptoms. Substantial variations between centers suggested that there may be local differences in risk factors. Intense research will be required for satisfactory preventive actions.

Association of a STAT 6 haplotype with elevated serum IgE levels in a population based cohort of white adults

BACKGROUND

Several studies have shown linkage of chromosome 12q 13-24 with atopy related phenotypes. Among candidate genes in this region is STAT6 (signal transducer and activator of transcription), which is essential for Th2 cell differentiation, recruitment, and effector function.

METHODS

We evaluated six polymorphisms of STAT6 for evidence of associations with serum IgE levels and atopic diseases in a population based cross sectional cohort of 1407 German adults. Genotyping was performed using the matrix assisted laser desorption ionisation-time of flight mass spectrometry method. Haplotypes were estimated using the SAS/Genetics module, and population-derived IgE percentiles (50% IgE>53 kU/l, 66% IgE>99 kU/l and 90% IgE>307 kU/l) were modelled as outcome variables in haplotype trend regression analysis.

RESULTS

All polymorphisms were genotyped successfully. Haplotype reconstruction revealed 8/64 possible haplotypes, reaching estimated frequencies of 1% or more. One polymorphism in intron 2 (rs324011) showed a significant association with total serum IgE (p = 0.015). A STAT6 risk haplotype for elevated IgE showing odds ratios of 1.7 (p = 0.015) for IgE cut-off 100 kU/l, and 1.54 (p = 0.032), 1.6 (p = 0.025), and 2.54 (p = 0.007) for IgE percentiles 50%, 66%, and 90%, respectively was detected. The increased risk of this haplotype was confirmed by linear haplotype trend regression on log transformed IgE values (p = 0.007). Analysis further revealed a risk haplotype for specific sensitisation and a risk haplotype for asthma.

CONCLUSION

The data indicate that genetic variants within STAT6 contribute significantly to IgE regulation and manifestation of atopic diseases.

Long-term pulmonary morbidity in survivors of congenital diaphragmatic hernia

Our objective was to study long-term respiratory outcomes of congenital diaphragmatic hernia (CDH) treated in the perinatal period. This was a cohort study with 26 adolescent survivors and age- and gender-matched controls. Medical histories were retrieved from hospital charts and questionnaires. Pulmonary function testing included measurement of maximum inspiratory and expiratory pressures (MIPS and MEPS) and maximum voluntary ventilation (MVV). Unpaired two-tailed t-test and nonlinear regression were used for statistical analysis. Significant differences were found in forced expiratory volume in one second (FEV(1)) (79% +/- 16% vs. 94% +/- 10%, P < 0.001), FEF(25-75) (62% +/- 24% vs. 84% +/- 15%, P < 0.001), FRC (114% +/- 20% vs. 95% +/- 13%, P < 0.001), RV/TLC (31% +/- 10% vs. 22% +/- 6%, P < 0.001), MVV (74% +/- 16% vs. 90% +/- 13%, P < 0.001), and MIPS (69% +/- 19% vs. 84% +/- 16%, P < 0.01), with numbers indicating percent predicted of reference values +/- SD. Reduction of MVV was not independent from FEV1 (r = 0.83). Forty-eight percent of patients vs. 4% of controls showed significant improvement of FEV1 after bronchodilators (86% +/- 15 vs. 98% +/- 10, P < 0.01). Forty-six percent of patients had abnormalities of the chest wall or spinal column such as pectus excavatum, pectus carinatum, and scoliosis, mostly mild or moderate. In conclusion, long-term respiratory outcome in adolescent CDH is associated with mild to moderate airway obstruction, a high prevalence of response to bronchodilators, and decreased inspiratory muscle strength. This should guide follow-up scheduling and should be taken into account for perioperative and critical care management.

Prevalence of asthma and asthma-like symptoms in inner-city schoolchildren

This study investigates the prevalence of asthma and asthma-related symptoms in New Orleans inner-city schoolchildren. A cross-sectional survey of 1535 elementary, middle, and high school children (aged 5-18) was conducted by using the International Study of Asthma and Allergies in Childhood (ISAAC) written questionnaire. Lifetime prevalence of wheezing was 39.4%, and lifetime prevalence of asthma was 24.4%. Wheezing during the previous 12 months was reported by 25.7% of the sample. Twenty-one percent of respondents reported having one or more attacks of wheezing per year, with 5.6% reporting four or more attacks per year. Many participants reported sleep disturbance (15.4%), with 6.2% reporting sleep disturbance more than once a week. The 12-month rate of speech limitation due to asthma exacerbation was 6.6%. Exercise-induced asthma was reported by 16.9% of the students, and nocturnal cough (not associated with cold) was reported by 27.3%. Overall, boys reported higher rates of symptoms than girls, and younger children (aged 6-7) reported greater symptoms than older children (aged 13-14). These findings show that prevalence of asthma in this population is elevated, and the ISAAC written questionnaire successfully identified inner-city children at risk for asthma in New Orleans.

Fitness and physical activity in children with asthma

Asthma remains the most common chronic disease in childhood, reportedly affecting up to 25% of children in Western urban environmental settings. There seems to be a common perception that asthmatic children have a reduced capacity for exercise. Surprisingly, there is conflicting evidence in the literature in relation to this position. In this review, we present an overview of the literature in which habitual physical activity and fitness levels, including aerobic fitness, of asthmatic and non-asthmatic children are compared. There is contradictory evidence regarding the aerobic fitness levels of asthmatic children and adolescents, and it remains unclear whether significant differences exist between asthmatic children and their non-asthmatic counterparts. There is limited information concerning the relative anaerobic fitness of asthmatic children and adolescents; however, this is also conflicting. During childhood and adolescence, asthmatic individuals seem to have physical activity levels comparable with those of the normal paediatric population. However, differences in physical activity levels may develop during the time of maturation from adolescence into adulthood. Accordingly, it is not possible to establish a definitive conclusion about the issue in either children or adults. Further research with well designed methodologies is needed in order to determine whether asthmatic children and adolescents have different aerobic fitness, anaerobic fitness and physical activity levels when compared with the normal paediatric population.

A comparison of genetic and environmental variance structures for asthma, hay fever and eczema with symptoms of the same diseases: a study of Norwegian twins

BACKGROUND

We compared patterns of genetic and environmental influences on variation in liability for asthma, hay fever and eczema with those for symptoms of the same diseases, and determined how common sets of genes and environmental factors contribute to the relationship between diseases and symptoms among Norwegian twins.

METHODS

Analyses were based on self-reported asthma, hay fever and eczema and symptoms of the same diseases among 3334 pairs of Norwegian twins aged 18-35 years. Structural equation modelling was conducted to estimate the genetic and environmental variance structures.

RESULTS

For all diseases the concordances and the twin correlations were higher among monozygotic than among dizygotic twins. The results of the modelling confirmed that genetic effects were substantial for the diseases, and were more moderate for symptoms. The phenotypic correlation between disease and symptom was 0.67 for asthma and wheeze (a/w), 0.64 for hay fever and sneeze (hf/s), and 0.54 for eczema and itch (e/i). Decomposition of these correlations into genetic (G) and environmental (E) pathways revealed that G = 0.48 and E = 0.19 for a/w, G = 0.40 and E = 0.24 for hf/s, and G = 0.34 and E = 0.20 for e/i. For the diseases, the specific sources of genetic variance accounted for more variation than the specific environmental variance. Variance decomposition revealed that specific sources of variance were primarily explained by genetic effects for diseases and by environmental influences for symptoms.

CONCLUSIONS

Genetic effects account for greater variation in reported diseases than symptoms. Co-occurrence of diseases and symptoms is mainly explained by genetic effects common to both phenotypes, but non-shared environment is also important.

Serum ovalbumin-specific immunoglobulin G responses during pregnancy reflect maternal intake of dietary egg and relate to the development of allergy in early infancy

BACKGROUND

The value of allergen elimination diets during pregnancy for primary prevention of infant allergy has been questioned. However, dietary compliance may influence effectiveness.

OBJECTIVES

To monitor egg intake during a randomized controlled trial of egg avoidance throughout pregnancy and lactation by serial measurements of serum ovalbumin (OVA) IgG concentration in conjunction with dietary diary record and also, to analyse specific IgG concentrations at birth in relation to infant allergic outcome.

METHODS

Pregnant women, with personal or partner atopy, were randomized to complete dietary egg exclusion or an unmodified healthy diet before 20 weeks gestation. The infants were evaluated for atopy at 6 months of age. Serum food-specific IgG concentrations were determined by ELISA in maternal samples collected at study recruitment and during labour, and in infant samples at birth (umbilical cord).

RESULTS

Serum-specific IgG to OVA, but not the unrelated allergen, cow's milk beta-lactoglobulin, decreased over pregnancy in egg-avoiding women only (P<0.001). Cord OVA IgG concentration correlated with maternal IgG at delivery (r=0.944; P<0.001), and for infants born to atopic women, cord concentration was higher than that of their mother's (P<0.001). Infants with the lowest and highest cord IgG concentrations were the least likely, and those with mid-range concentrations were the most likely, to be atopic by 6 months of age (P=0.008).

CONCLUSION

Serum OVA IgG concentration reflects egg consumption, thereby indicating dietary allergen doses to which the developing immune system might be exposed. Trans-placental maternal IgG must be considered among early life factors that regulate infant atopic programming.

Serum concentrations of interferon-gamma and intercellular adhesion molecule-1 eight years after an early respiratory syncytial virus infection

BACKGROUND

Respiratory syncytial virus (RSV) infection may influence the development of recurrent wheezing and atopy, but the mechanisms are unclear.

OBJECTIVE

The purpose was to evaluate serum concentrations of soluble intercellular adhesion molecule-1 (sICAM-1), CD14, IgE, IL-5 and IFN-gamma in children 6-10 years after an RSV infection and their correlation with subsequent asthma and atopy.

METHODS

Fifty-one subjects admitted to hospital for RSV infection during the first year of life and controls matched for birth date and sex underwent clinical examinations including lung function, skin prick and blood tests.

RESULTS

The RSV subjects had significantly higher serum concentrations of IFN-gamma and sICAM-1 than the controls (for IFN-gamma 224.9 pg/mL (standard deviation (SD) 271.3) vs. 187.1 pg/mL (372.9), difference 37.8 pg/mL, 95% confidence interval (CI) -90.3 to 166.0, P = 0.05; for sICAM-1 170.2 ng/mL (SD 63) vs. 147.8 ng/mL (SD 57), difference 22.4 ng/mL, 95% CI -1.4 to 46.1, P = 0.04). The RSV subjects with asthma had significantly higher concentrations of IFN-gamma than the controls with asthma, and the RSV subjects with wheezing during the previous 12 months had significantly higher concentrations of both IFN-gamma and sICAM-1 than the controls with wheezing.

CONCLUSIONS

Children hospitalized for RSV infection in infancy still differ in IFN-gamma and sICAM-1 production 6-10 years after the infection. The data suggest that the pathomechanism of asthma and wheezing after an early RSV infection may be different from that of children without an early RSV infection.

Single nucleotide polymorphism screening and association analysis--exclusion of integrin beta 7 and vitamin D receptor (chromosome 12q) as candidate genes for asthma

BACKGROUND

The human genes coding for integrin beta 7 (ITGB7) and vitamin D receptor (VDR) are two of the several candidate genes for asthma and related phenotypes found in a promising candidate region on chromosome 12q that has been identified in multiple genomewide screens and candidate gene approaches.

METHODS

All exons, including parts of the neighbouring introns, and the predicted promoter region of the ITGB7 gene were screened for common polymorphisms in 32 independent asthmatic and healthy probands, resulting in the detection of two single nucleotide polymorphisms (SNPs) unknown so far. In addition to these SNPs, five already described SNPs of the ITGB7 and one in the human VDR gene were analysed in a Caucasian sib pair study of 176 families with at least two affected children, using matrix assisted laser desorption/ionization time of flight mass spectrometry. All confirmed SNPs were tested for linkage/association with asthma and related traits (total serum IgE level, eosinophil cell count and slope of the dose-response curve after bronchial challenge).

RESULTS

Two new variations in the ITGB7 gene were identified. The coding SNP in exon 4 causes a substitution of the amino acid GLU by VAL, whereas the other variation is non-coding (intron 3). None of the eight analysed SNPs, of either the ITGB7 or the VDR genes, showed significant linkage/association with asthma or related phenotypes in the family study.

CONCLUSIONS

These findings indicate that neither the human ITGB7 nor the VDR gene seem to be associated with the pathogenesis of asthma or the expression of related allergic phenotypes such as eosinophilia and changes in total IgE level.

Prevalência e gravidade de sintomas relacionados à asma em escolares e adolescentes no município de Duque de Caxias, Rio de Janeiro

INTRODUÇÃO: A asma é considerada a doença crônica mais comum na infância. Entretanto, há poucos estudos sobre sua prevalência em nosso meio. OBJETIVO: Avaliar prevalência e gravidade de sintomas de asma em escolares e adolescentes de Duque de Caxias (RJ). MÉTODO: Estudo transversal utilizando o questionário do International Study of Asthma and Allergies in Childhood. A amostra foi composta por alunos de 6, 7, 13 e 14 anos. RESULTADOS: Foram avaliados 4.040 alunos de 13 e 14 anos e 2.334 de 6 e 7 anos. A freqüência de sibilos nos últimos doze meses foi de 27,7% entre os mais jovens e de 19% entre os adolescentes (p < 0,0001). No primeiro grupo houve predomínio do sexo masculino (29,9% vs 25,6%, p = 0,01) e no segundo do feminino (21,9% vs 15,8%, p < 0,0001). Não existiram diferenças entre as faixas etárias relacionadas ao diagnóstico prévio de asma (cerca de 10%). Sibilância aos exercícios físicos foi mais prevalente entre os adolescentes (21,4% vs 7,8%, p < 0,0001). A gravidade dos sintomas foi maior entre as adolescentes (asma grave: 6,6% vs 4,4%, p = 0,001), não havendo diferenças entre gêneros aos 6 e 7 anos. CONCLUSÃO: A prevalência de asma em Duque de Caxias é alta, comparável à de outros municípios brasileiros e latino-americanos. Os valores são superiores aos 6 e 7 anos, quando os sintomas predominam no sexo masculino. Entre os adolescentes, a prevalência e a gravidade dos sintomas são maiores no gênero feminino, fato de observação recente e que parece representar novo comportamento epidemiológico da asma.

Exhaled nitric oxide in a population-based study of asthma and allergy in schoolchildren

Exhaled nitric oxide (NO) reflects inflammation in the lower airways and is well adapted for use in children. The aims of this study were to investigate the distribution of the fraction of expired NO (FENO) in school children and to compare FENO and spirometry in relation to the International Study of Asthma and Allergies in Childhood questionnaire. The study was performed in 959 randomly selected 13-14-year-old school children in Uppsala, Sweden. Exhaled NO was measured at an inhalation rate of 0.1 l/s (FENO0.1) and a spirometric test was performed and data from these measurements were related to questionnaire data. Exhaled NO was measured according to American Thoracic Society recommendations, except the use of a mouth wash and an exhalation flow rate of 0.1 l/s. The distribution of the mean FENO0.1 values was skewed, with a preponderance of very low levels and a widespread tail of values ranging up to 102 parts per billion (ppb). Boys exhibited significantly higher mean FENO0.1 values than girls, 5.2 (4.7-5.7) vs 4.4 (4.0-4.8) ppb (geometric mean and 95% CI), P <0.01). Children who reported wheezing in the last year had higher FENO0.1 values than children that had not, 8.5 (7.1-10.2) vs 4.3 (4.0-4.6) ppb, P <0.001). The same association was found to most symptoms indicating hay fever and eczema. In contrast to this, only weak or inconsistent associations were found between asthma and spirometric indices. Exhaled NO levels were found to be independently related to male gender, wheeze and rhinoconjuctivitis but not to current eczema. In conclusion, exhaled NO was closely associated with reported asthma and allergy symptoms whereas spirometric indices such as percent predicted forced expiratory volume in 1 s were not. As most asthma cases in a population are mild, the findings suggest that exhaled NO is a sensitive marker of asthma and allergy.

The World Trade Center residents' respiratory health study: new-onset respiratory symptoms and pulmonary function

The destruction of the World Trade Center (WTC) on 11 September 2001 in New York City resulted in the massive release of pulverized dust and combustion products. The dust and smoke settled in the surrounding area, which encompassed a large residential community. We hypothesized that previously normal residents in the community surrounding the former WTC would have an increased incidence of persistent respiratory symptoms and abnormalities in screening spirometry. A hybrid cross-sectional and retrospective cohort study using a symptom-based questionnaire and onsite screening spirometry in residents in an exposed area and in a control area was performed 12 +/- 4 months after the collapse. Surveys were analyzed from 2,812 residents. New-onset respiratory symptoms were described by 55.8% of residents in the exposed area, compared with 20.1% in the control area after the event. Persistent new-onset symptoms were identified in 26.4 versus 7.5% of residents in the exposed area versus control area, respectively. No differences in screening spirometry between the groups were detected. A small pilot study suggested the possibility of an increase in bronchial hyperresponsiveness in exposed participants with persistent symptoms. The data demonstrate an increased rate of new-onset and persistent respiratory health effects in residents near the former WTC compared with a control population.

Sex differences in factors associated with childhood- and adolescent-onset wheeze

RATIONALE

Factors predicting the development of wheeze may differ between sexes and between childhood and adolescence.

METHODS

A New Zealand birth cohort of 1,037 children was followed to age 26. For this analysis, those reporting recurrent wheezing at two or more assessments were classified as "wheezers." We examined risk factors for development of wheeze before age 10 (childhood) and subsequently (adolescent-onset) for males and for females separately using Cox regression modeling.

RESULTS

Males more often developed childhood wheeze (p = 0.002) and females adolescent-onset wheeze (p < 0.001). Maternal atopy (asthma or hay fever) was a risk factor for childhood wheeze in both sexes (hazard ratio [HR], 1.48, p < 0.05 for males; HR, 2.37, p < 0.001 for females). Paternal atopy also influenced childhood wheeze, significantly for males (HR, 1.72; p = 0.01), and similarly but not significantly for females (HR, 1.70; p = 0.08). For adolescent-onset wheeze, neither maternal (HR, 1.41; p = 0.19) nor paternal history (HR, 0.73; p = 0.42) was a risk factor in males, but maternal history (HR, 2.08; p < 0.01) was a significant risk factor for females. When both age ranges were combined, providing greater power for analysis, paternal history was a stronger risk factor for wheeze in females (HR, 1.62; p = 0.02) than in males (HR, 1.35; p = 0.12).

CONCLUSION

The influence of parental atopy on the development for wheeze differs between males and females and between childhood- and adolescent-onset wheeze.

Early life risk factors for atopic dermatitis in Ethiopian children

BACKGROUND

Atopic dermatitis (AD) has increased in prevalence in many countries in recent decades, but the risk factors for AD in developing countries are unknown. Helminthic parasites may play a role in protecting against allergic disease, but few studies have investigated the association of AD with parasitic infection.

OBJECTIVE

To establish the independent effects of parasitic infection and other early life factors on the risk of AD in Ethiopia.

METHODS

We conducted a cross-sectional survey and nested case-control study of children age 1 to 5 years in Jimma and surrounding rural areas in southwest Ethiopia. Cases were defined according to the International Study of Asthma and Allergies in Childhood criteria for AD and confirmed by clinical examination. Information on lifestyle and other potential risk factors was collected by parental questionnaire, and stool samples were analyzed for parasites.

RESULTS

Complete data were obtained on 306 AD cases defined by International Study of Asthma and Allergies in Childhood criteria (prevalence, 4.4%) and 426 controls. There was no reduction in the risk of AD in relation to intestinal parasite infection; in fact, AD was increased in subjects with Trichuris (1.61; 95% CI, 1.14-2.26). The risk of AD was also unrelated to family size, crowding in the home, or breast-feeding, but was related to previously unrecognized factors including malaria and access to piped drinking water. Similar findings were apparent in cases and controls confirmed by clinical examination.

CONCLUSION

Neither intestinal parasite infection nor other proposed risk factors for AD appear to be related to the presence of the condition in young children in Ethiopia, suggesting that other factors may be more important in this population.