Exercise-induced bronchial hyperresponsiveness and parental ISAAC questionnaire responses

Diagnostic performance of the physical activity-related question of the GINA questionnaire to detect exercise-induced bronchoconstriction in asthma

INTRODUCTION

The aim of the study was to evaluate the diagnostic performance of the item concerning physical activity of the Global Initiative for Asthma (GINA) asthma control questionnaire for detection of exercise-induced bronchoconstriction (EIB) in children and adolescents.

MATERIAL AND METHODS

We divided participants (aged 6-18 years) with a diagnosis of asthma into two groups according to the GINA severity classification: mild/moderate asthma (MMA) and severe therapy-resistant asthma (STRA). We collected anthropometric, clinical and functional data (spirometry) and performed an EIB test. We used item 4 of the GINA questionnaire regarding exercise-induced symptoms to assess the diagnostic power of this instrument.

RESULTS

We included 40 patients (17 with MMA and 23 with STRA) with a mean age of 11.3 years and a mean FEV₁z-score of -0.33, of who 13 (32.5%) were classified as having uncontrolled asthma. Of the patients with uncontrolled asthma, 7 (53.8%) exhibited a decrease in the FEV₁ after the EIB test. We found a higher frequency of EIB in participants with FEV₁ z-score values of less than -1.0 compared to those with a z-score of -1.0 or greater (P = .05). There were no significant differences in the frequency of EIB based on disease severity and control. We also found no association of item 4 (GINA) with EIB. The area under the ROC curve demonstrated that the discriminative power of the GINA questionnaire for the detection of EIB is inadequate (P = .41), with sensitivity of 42.1% and specificity of 57.1%.

CONCLUSIONS

The item concerning physical activity in the GINA questionnaire has insufficient diagnostic power to detect EIB in children and adolescents with asthma.

[Diagnostic performance of the physical activity related question of the GINA questionnaire to detect exercise-induced bronchoconstriction in asthma]

INTRODUCTION

The aim of the study was to evaluate the diagnostic performance of the item concerning physical activity of the Global Initiative for Asthma (GINA) asthma control questionnaire for detection of exercise-induced bronchoconstriction (EIB) in children and adolescents.

MATERIAL AND METHODS

We divided participants (aged 6 to 18 years) with a diagnosis of asthma into two groups according to the GINA severity classification: mild/moderate asthma (MMA) and severe therapy-resistant asthma (STRA). We collected anthropometric, clinical and functional data (spirometry) and performed an EIB test. We used item 4 of the GINA questionnaire regarding exercise-induced symptoms to assess the diagnostic power of this instrument.

RESULTS

We included 40 patients (17 with MMA and 23 with STRA) with a mean age of 11.3 years and a mean FEV₁z-score of -0.33, of who 13 (32.5%) were classified as having uncontrolled asthma. Of the patients with uncontrolled asthma, 7 (53.8%) exhibited a decrease in the FEV₁ after the EIB test. We found a higher frequency of EIB in participants with FEV₁ z-score values of less than -1.0 compared to those with a z-score of -1.0 or greater (p = 0.05). There were no significant differences in the frequency of EIB based on disease severity and control. We also found no association of item 4 (GINA) with EIB. The area under the ROC curve demonstrated that the discriminative power of the GINA questionnaire for the detection of EIB is inadequate (p = 0.41), with sensitivity of 42.1% and specificity of 57.1%.

CONCLUSIONS

The physical activity related question of GINA has insufficient diagnostic power to detect EIB in children and adolescents with asthma.

An independent relation of atopic dermatitis to exercise-induced wheezing in asthmatic children

BACKGROUND

Atopic dermatitis (AD) and exercise-induced asthma (EIA) are common in asthmatic children, and exercise is the most common trigger other than infection for acute onset asthma attack in children. We examined whether AD is related to exercise-induced wheezing (EIW), some proxy for EIA.

METHODS

Japanese version of the International Study of Asthma and Allergies in Childhood questionnaires were used. For 12,405 asthmatic school children, AD was defined as itchy rash coming and going for at least 6 months at any time in the last 12 months with affecting places of flexural parts of body, and severity of AD was rated according to frequency of being kept awake at night with the itch as follows: never in the past 12 months, less than one night per week and one or more nights per week.

RESULTS

Adjusted for frequency of asthma attack, odds ratios (OR) of children with current AD as compared to those without AD for having EIW were 1.32 (95% confidence interval = 1.15-1.52), 1.35 (1.14-1.68) and 1.10 (0.92-1.31) for primary school, junior high school and high school children, respectively. EIW was more likely observed in accordance with increasing severity of AD in the primary school children with ORs of 1.12, 1.59 and 1.54 (p for trend < 0.01), and in the junior high school ones with ORs of 1.18, 1.31, 2.03 (<0.01), respectively.

CONCLUSIONS

AD may be possibly related to EIW. Further studies investigating effect of AD treatment on EIW may be required.

Prevalence of asthma and allergic disorders in regional, rural, and indigenous children aged 6-8 years in Tasmania

Objective: Asthma and allergic diseases are poorly described in rural areas. The objective of this study was, therefore, to determine the prevalence of wheezing, asthma, and other allergic disorders among children living in regional and rural Tasmania. Methodology: Data from a cross-sectional survey using standardized questionnaires of asthma, allergic conditions and food allergies were collected from 39 primary schools across North West Tasmania. We enrolled 1075 children between 6 and 8 years. The main outcomes were prevalences of wheezing, asthma, and other allergic disorders further stratified by sex and indigenous status. Results: Baseline characteristics were as follows: median age 8.1 years (IQR: 7.6, 8.7) with equal sex distribution, most (80.1%) attended public schools and 11.0% identified as indigenous. We report prevalences of current wheezing (22.7%), allergic rhinoconjunctivitis (16.3%) and atopic eczema (16.6%), with higher prevalences among boys (except eczema). Food allergies were reported in 8.6% and food-related anaphylaxis in 1.6% of the sample. Indigenous children had significantly higher prevalence of current wheezing (indigenous 31.1% versus non-indigenous 21.6%; p = 0.02). Further, children with current wheezing and no asthma diagnosis, had similar prevalence of other atopic diseases (hayfever 31.4%, eczema 44.0%, and food reaction 23.2%) compared with diagnosed asthmatics, although likely shared the illness. Conclusions: Childhood asthma is more prevalent in regional Tasmania compared with national estimates, especially among indigenous children. This appears not to be driven by an allergic response. Also, a significant proportion of children are likely to have undiagnosed asthma which has implications for rural health service delivery.

Predictors of asthma following severe respiratory syncytial virus (RSV) bronchiolitis in early childhood

BACKGROUND

We sought to identify predictors of asthma development following severe early childhood RSV bronchiolitis. Different definitions of asthma were also compared.

METHODS

This longitudinal, observational study (N = 343) followed patients (<2 years old) from a placebo-controlled trial (N = 979) of montelukast after RSV bronchiolitis to identify clinical, demographic, or biochemical predictors of asthma, atopic disorders, and chronic asthma therapy use at 6 years of age (Clinical Trials Registry Number: NCT01140048). Asthma (primary definition) was based on parental identification of wheeze at 6 AND 12 months before 6 years of age; definitions based on physician diagnosis as well as parental identification of wheeze at 6 OR 12 months (to consider seasonal effect) were also assessed. Post-hoc analyses evaluated agreement among asthma diagnosis criteria.

RESULTS

Prevalence of asthma (primary definition by parental identification), asthma (physician diagnosis), atopic disorders, and chronic asthma therapy use (parental identification) was 6.1%, 22.4%, 36.2%, and 14.5%, respectively. Predictors for asthma (primary definition) included male gender, a relative with asthma, and RAST positive for dog dander; for physician diagnosis of asthma, high severity score for RSV bronchiolitis, high respiratory rate, and asthma diagnosis before enrollment. Predictors of atopic disorders included allergic rhinitis before enrollment, a relative with asthma, and the plasma biomarkers IL-5, IL-16, and IL-18. Predictors of chronic asthma therapy use included asthma diagnosis before enrollment and geographic region (Europe and Africa). Only 42% of patients with asthma (primary definition) also met the asthma definition by physician diagnosis and chronic asthma therapy use.

CONCLUSION

Among children with early RSV bronchiolitis, hereditary factors (i.e., having a relative with asthma) and RSV bronchiolitis severity were predictors of asthma and atopic disorders at 6 years of age. Of interest, there was poor agreement among the asthma definitions evaluated. Pediatr Pulmonol. 2016;51:1382-1392. © 2016 Wiley Periodicals, Inc.

Validation of a Comprehensive Early Childhood Allergy Questionnaire

BACKGROUND

Parental questionnaires to assess incidence of pediatric allergic disease have been validated for use in school-aged children. Currently, there is no validated questionnaire-based assessment of food allergy, atopic dermatitis (AD), and asthma for infants and young children.

METHODS

The Comprehensive Early Childhood Allergy Questionnaire was designed for detecting AD, asthma, and IgE-mediated food allergies in children aged 1-5 years. A nested case-control design was applied. Parents of 150 children attending pediatric outpatient clinics completed the questionnaire before being clinically assessed by a pediatrician for allergies. Sensitivity, specificity, and reproducibility of the questionnaire were assessed.

RESULTS

Seventy-seven children were diagnosed with one or more current allergic diseases. The questionnaire demonstrated high overall sensitivity of 0.93 (95% CI 0.86-0.98) with a specificity of 0.79 (95% CI 0.68-0.88). Questionnaire reproducibility was good with a kappa agreement rate for symptom-related questions of 0.45-0.90.

CONCLUSIONS

Comprehensive Early Childhood Allergy Questionnaire accurately and reliably reflects the presence of allergies in children aged 1-5 years. Its use is warranted as a tool for determining prevalence of allergies in this pediatric age group.

Exercise-induced wheezing among Japanese pre-school children and pupils

BACKGROUND

Exercise-induced wheezing (EIW) may be a symptom of asthma and is a predictor of exercise-induced bronchoconstriction, transient narrowing of the lower airway following exercise in the presence or absence of diagnosed asthma. Population-based studies with a large sample of EIW in relation to age, sex, current asthma severity and medication usage have been sparse.

METHODS

International Study of Asthma and Allergies in Childhood questionnaires were distributed at 885 nurseries, 535 primary schools, 321 junior high schools and 190 high schools, respectively, across Japan, and the corresponding data on 46,597, 41,216, 45,960 and 51,104 children were analyzed.

RESULTS

Prevalence of EIW was 4.8, 4.7, 17.9 and 15.4% for each of the four educational facility types, respectively. Among 24,103 current asthmatics, 20.9, 28.7, 76.1 and 73.6% of subjects for the 4 educational facility groups reported to have experienced EIW, respectively. Severity of current asthma was associated with the risk of EIW; odds ratio (95% confidence interval) of children with asthma attack every day for having EIW once a week or more, using intermittent asthmatics as reference group, were 24.48 (19.33 to 31.01) adjusted for other covariates. Among current asthmatic kindergartners, increase in risk for EIW due to ascending severity of current asthma was mitigated by daily use of leukotriene receptor antagonist (p for interaction = 0.071).

CONCLUSIONS

EIW was not rare among current asthmatic children. An increased risk for EIW was in accordance with increasing severity of current asthma and this relation was mitigated with leukotriene receptor antagonist daily use among kindergartners.

Exercise-induced wheeze, urgent medical visits, and neighborhood asthma prevalence

OBJECTIVE

Exercise-induced wheeze (EIW) may identify a distinct population among asthmatics and give insight into asthma morbidity etiology. The prevalence of pediatric asthma and associated urgent medical visits varies greatly by neighborhood in New York City and is highest in low-income neighborhoods. Although increased asthma severity might contribute to the disparities in urgent medical visits, when controlling for health insurance coverage, we previously observed no differences in clinical measures of severity between asthmatic children living in neighborhoods with lower (3%-9%) versus higher (11%-19%) asthma prevalence. Among these asthmatics, we hypothesized that EIW would be associated with urgent medical visits and a child's neighborhood asthma prevalence.

METHODS

Families of 7- to 8-year-old children were recruited into a case-control study of asthma through an employer-based health insurance provider. Among the asthmatics (n = 195), prevalence ratios (PRs) for EIW were estimated. Final models included children with valid measures of lung function, seroatopy, and waist circumference (n = 140).

RESULTS

EIW was associated with urgent medical visits for asthma (PR, 2.29; P = .021), independent of frequent wheeze symptoms. In contrast to frequent wheeze, EIW was not associated with seroatopy or exhaled NO, suggesting a distinct mechanism. EIW prevalence among asthmatics increased with increasing neighborhood asthma prevalence (PR, 1.09; P = .012), after adjustment for race, ethnicity, maternal asthma, environmental tobacco smoke, household income, and neighborhood income.

CONCLUSIONS

EIW may contribute to the disparities in urgent medical visits for asthma between high- and low-income neighborhoods. Physicians caring for asthmatics should consider EIW an indicator of risk for urgent medical visits.

Parent-reported ISAAC written questionnaire may underestimate the prevalence of asthma in children aged 10-12 years

OBJECTIVES

The aim of the present study was to compare the validity of the International Study of Asthma and Allergies in Childhood (ISAAC) written (WQ) and audiovisual questionnaires (AVQ 3.0) in two age-groups (10-12 and 13-15 years, respectively).

METHODS

The 13-15 year olds performed the self-completed the WQ and AVQ on the same day. The 10-12 year olds performed the self-completed the AVQ and the parent-completed WQ was completed by their parents. The methacholine challenge test was conducted in 10-12 year olds from one elementary school.

RESULTS

In 10-12 year olds, the AVQ detected a generally higher prevalence of asthma symptoms than WQ. In 13-15 year olds, this was reversed. In 10-12 year olds, poor agreement was found between the parent-completed WQ and the self-reported AVQ. In 13-15 year olds, moderate agreement was found between the self-reported WQ and AVQ. Low sensitivity was found, in predicting bronchial hyper-responsiveness (BHR) for all questions of both WQ and AVQ in 10-12 year olds. However, the AVQ had slightly higher sensitivity than WQ, with the exception of wheeze ever, although it was not statistically significant.

CONCLUSION

The ISAAC AVQ may be another effective instrument for assessing the prevalence of asthma symptoms in children aged 10-12 years, whereas the parent-reported-WQ may underestimate the prevalence of asthma symptoms in this age-group.

A longitudinal study of allergy and intestinal helminth infections in semi urban and rural areas of Flores, Indonesia (ImmunoSPIN Study)

Background

The prevalence of asthma and atopic disease has been reported to be low in low income countries, however helminth infections are likely to be high among these communities. The question of whether helminth infections play a role in allergic diseases can best be addressed by intervention studies. None of the studies so far have been based on a large scale placebo-controlled trial.

Method/Design

This study was designed to assess how intestinal helminth infections can influence the immune response and atopic and allergic disorders in children in Indonesia. The relations between allergic outcomes and infection and lifestyle factors will be addressed. This study was set up among school-age children in semi urban and rural areas, located in Ende District of Flores Island, Indonesia. A randomized placebo-controlled anthelmintic treatment trial to elucidate the impact of helminth infections on the prevalence of skin prick test (SPT) reactivity and symptoms of allergic diseases will be performed. The children living in these semi-urban and rural areas will be assessed for SPT to allergens before and after 1 and 2 years of treatment as the primary outcome of the study; the secondary outcome is symptoms (asthma and atopic dermatitis); while the tertiary outcome is immune responses (both antibody levels to allergens and cellular immune responses).

Discussion

The study will provide information on the influence of helminth infections and anthelmintic treatment on immune response, atopy and allergic disorders.

Trial registration

Current Controlled Trials ISRCTN: ISRCTN83830814

Housing environments and child health conditions among recent Mexican immigrant families: a population-based study

The influx of immigrants to urban areas throughout the United States has raised concerns about accessibility of safe, affordable housing and the health consequences of poor-quality housing, particularly among immigrant children. We conducted a population-based study of home environmental conditions among recently immigrated Mexican families (weighted n = 473), generally of low socioeconomic status, and the health conditions of their children, in an urban industrial area north of Denver, Colorado. The majority of recent immigrants had low socioeconomic status; virtually all had household incomes below the Colorado median ($50,841). Approximately one quarter of homes were overcrowded. Adverse environmental conditions were present across recent immigrant homes. These conditions include dampness or mold (44%), pests (28%), and minimal to no ventilation potential (26%), all of which are associated with asthma and atopic diseases. At least one of these three environmental hazards was found in 67% of homes; multiple hazards were present in 27% of homes. Children of recent immigrant families had active symptoms within the past 12 months suggestive of asthma (4%) and atopic disorders (10%); however, fewer than 2% had been diagnosed with these conditions. The prevalence of asthma and atopic symptoms among Mexican immigrant children, albeit lower than in other low income and minority communities, is partially explained by housing conditions. Many of the conditions identified (e.g., pest infestation, mold resulting from plumbing leaks, and lack of exhaust fans) are amenable to low cost interventions. Solutions to address unhealthy housing conditions among recent immigrants must be multi-faceted and include strategies that target household-level improvements and access to health care.

Calculating the prevalence of atopy in children

BACKGROUND

Atopy is an important risk factor for asthma, rhinitis, atopic eczema and urticaria. For this reason, several studies have been done to determine the prevalence of atopy in the paediatric population. The important differences among these studies do not allow the extrapolating of results. In this study, we calculate the prevalence of atopy and atopy-related diseases in a paediatric population using a different methodology.

METHODS

Retrospective study among children referred for drug allergy in which the latter was discarded. We evaluated the prevalence of atopy (measured by allergen sensitisation), asthma, rhinitis, urticaria, atopic eczema and their characteristics.

RESULTS

Three hundred and forty-two patients were studied for adverse drug reaction. This was discarded in 325/342 patients. 20 % of the children in the sample were atopic. Atopy prevalence increased with age. Some atopy related disease was observed in 83/325 (25.5 %) children. Among these children allergen sensitisation increased from 42.3 % in the 0-3 years age group to 93.3 % in the 7-14 age group (p < 0.0001). Prevalence of asthma was 11.5 %, 10.2 % and 7 % in the 0-3, 4-6 and 7-14 age groups, respectively. Prevalence of rhinoconjunctivitis increased through age groups with a prevalence of 20 % among the 7 to 14-year old children.

CONCLUSION

The use of this type of methodology seems to be correct to estimate the prevalence of atopy. Prevalence of allergen sensitisation is very high among 7 to 14-year old children with asthma and/or rhinoconjunctivitis.

The relation between age and time to maximal bronchoconstriction following exercise in children

BACKGROUND

The exercise challenge test (ECT) is a common tool for assessment of asthma in children. Many studies suggest that the "time to maximal bronchoconstriction" (Nadir-t) after exercise challenge in asthmatic children may be age-dependent, although this has never been systematically studied. Such findings may influence epidemiological surveys where the schedule of post-exercise measurements is trimmed. This study systematically assesses the relation between age and time to maximal bronchoconstriction post-ECT.

METHODS

Data were collected retrospectively from 131 subjects (87 male; 3-18 years) who were referred for ECT. The routine ECT was performed according to ATS recommendation of a 6-min run. Spirometry was measured at 1, 3, 5, 10, 15, and 20 min post-exercise. The post-exercise nadir of FEV1 (%baseline) (FEV1-nadir) and the time to maximal fall in Nadir-t (minutes) were sought and values were related to age.

RESULTS

Baseline FEV1 values (mean+/-SD) were 90.5+/-13.8% predicted. FEV1-nadir was -23.6+/-11.7% from baseline values. The Nadir-t was reached at 5.1+/-2.6 min (range 2-12 min). A positive correlation between children's age and Nadir-t was observed (r2=0.542; SD of residuals=1.79; p<0.001), regardless of FEV1-nadir, whether the cutoff of point was -10% or -15% of baseline FEV1. Children <10 years of age showed Nadir-t at 3.4+/-1.7 min post-exercise and older children at 6.6+/-2.5 min post-exercise (p<0.0001).

CONCLUSION

Our results indicate that the time to maximal bronchoconstriction is age-dependent in children and adolescents, and imply that the schedule of post-exercise FEV(1) measurements should be cautiously trimmed.

Wheezing due to rhinovirus infection in infancy: Bronchial hyperresponsiveness at school age

BACKGROUND

Characteristics related to decreased lung function and increased bronchial responsiveness after early childhood wheezing requiring hospitalization are not fully established.

METHODS

Seventy-nine children with wheezing requiring hospitalization at age <2 years were prospectively followed up and re-investigated at age 5.6-8.8 years when the measurements of baseline lung function and bronchial responsiveness to exercise were performed.

RESULTS

At early school age, 23% of children had decreased lung function, and 13% had increased bronchial responsiveness to exercise. Predictors of decreased lung function were maternal history of smoking during pregnancy (odds ratio [OR], 12.8; 95% confidence interval [CI]: 1.2-139.6), parental history of asthma (OR, 4.3; 95%CI: 1.1-17.1), and female gender (OR, 4.0; 95%CI: 1.2-13.7). Increased bronchial responsiveness was associated with rhinovirus infection-induced wheezing in infancy (OR, 6.5; 95%CI: 1.2-36.3), and early cat or dog exposure leading to sensitization (OR, 26.6; 95%CI: 1.3-525.2). Inhaled anti-inflammatory therapy was common in children with rhinovirus infection-induced wheezing in infancy (n = 13/19; P = 0.001 vs children with other/no confirmed virus infection etiology for wheezing in infancy, n = 16/60), which may have improved lung function and attenuated bronchial responsiveness in them.

CONCLUSIONS

After early childhood wheezing requiring hospitalization, one-fourth of children will have decreased lung function and one-eighth of children will show increased bronchial responsiveness at school age. Gender, heredity of asthma, and antenatal exposure to tobacco smoke are predictors of decreased lung function, whereas rhinovirus infection etiology of wheeze and early animal exposure leading to sensitization are associated with increased bronchial responsiveness later in childhood.

Classifying asthma severity: objective versus subjective measures

National guidelines recommend the use of clinical history and spirometry to determine asthma severity. We examined the usefulness of the six guideline-recommended clinical questions in determining asthma severity and then compared guideline-determined severity to clinician-reported and spirometry-determined severity in a cross-sectional study of 201 children with asthma who were not receiving controller therapy. Four guideline-recommended questions (daytime and nocturnal symptoms, school absenteeism, and exercise impairment) determined asthma severity. Concordance between clinician-reported and spirometry-determined asthma severity was poor (kappa = 0.02). Clinical history alone underestimated spirometry-determined disease severity in 27% of children while spirometry results alone underestimated clinician-determined severity in 40% of children.

[Geographic variation in the prevalence of asthma symptoms in Spanish children and adolescents. International Study of Asthma and Allergies in Childhood (ISAAC) Phase 3, Spain]

OBJECTIVE

To analyze geographic variations in the prevalence of symptoms related to asthma in Spanish children and adolescents.

POPULATION AND METHODS

In 2001 and 2002, the Spanish arm of the International Study of Asthma and Allergies in Childhood (ISAAC) Phase 3 collected information on 28 445 children in the age bracket of 6-7 years in 10 metropolitan areas (A Coruña, Asturias, Barcelona, Bilbao, Cartagena, Castellón, Madrid, Pamplona, San Sebastián, and Valencia) and on 31 257 adolescents in the bracket 13-14 years in 11 areas (the previously named areas plus Valladolid). An asthma symptom questionnaire was filled in by parents or the adolescents themselves. Differences in symptoms between geographic areas were analyzed by fitting a logistic regression model. The relationship between symptoms and age was analyzed by linear correlation.

RESULTS

The prevalence of recent wheezing (last 12 months) ranged from 7.1% to 12.9% among 6-7-year-olds and from 7.1% to 15.3% among the 13-14-year-olds. The greatest risk of recent wheezing was observed for children in A Coruña (odds ratio [OR] =1.96 in comparison with the area of lowest prevalence; 95% confidence interval [CI], 1.65-2.33) and Bilbao (OR=1.83; 95% CI, 1.54-2.18) and for adolescents in A Coruña (OR=2.38; 95% CI, 2.04-2.79) and Asturias (OR=2.37; 95% CI, 2.03-2.77). A strong correlation (r=0.72) was observed between the prevalence of recent wheezing and age in each of the geographic areas.

CONCLUSIONS

Considerable geographic variation in the prevalence of asthma symptoms can be seen in Spain even among young children. Symptoms are more frequent in children and adolescents who live on the Spain s northern Atlantic coast.

[Prevalence of current asthma in Majorca. Value of a bronchial hyperresponsiveness test in combination with a questionnaire]

BACKGROUND

The prevalence of asthma shows marked variability and consequently it should be determined in different geographical areas. Standardized questionnaires are reliable for identifying and comparing the prevalences of asthma among areas. However, asthma prevalence based on the use of questionnaires alone could overestimate the true prevalence of this illness. Therefore, the use of other methods such as determination of bronchial hyperresponsiveness is useful as an adjunct to questionnaires in asthma screening and epidemiological studies.

OBJECTIVE

To assess the prevalence of current asthma among schoolchildren in Majorca.

PATIENTS AND METHODS

A total of 608 schoolchildren aged 8-15 years in the island of Majorca were studied. Participants answered a questionnaire on symptoms and performed a free running test for measuring bronchial responsiveness.

RESULTS

The prevalence of wheezing during the previous 12 months was 18.1% (11.5% for the group aged 12-15 years). A fall in forced expiratory volume in one second (FEV1) greater than 15% after exercise testing was found in 61 children (10.5%). An association between bronchial responsiveness and the results of the written questionnaire referring to wheezing was found, but not between bronchial responsiveness and nocturnal coughing. The prevalence of "current asthma" (recent wheezing and bronchial responsiveness) was 3.4%.

CONCLUSION

The prevalence of current asthma in our area is lower than that reported for other Spanish areas. The use of questionnaires and a free running test can be useful in identifying children at greatest risk.

Construction and validation of a risk-screening questionnaire for the investigation of recurrent airway obstruction in epidemiological studies of horse populations in Great Britain

Recurrent airway obstruction (RAO) is an environmental respiratory disease affecting horses. A risk-screening questionnaire (RSQ) for RAO would provide a useful tool to investigate the epidemiology of the disease in horses; our aim in this study was to construct and validate such an instrument. Guidance for what questions to include in the RSQ came from three processes: a review of the scientific literature, a survey of equine practitioners in the UK and a consultation with 19 experts using a modified Delphi technique. The latter consultation consisted of two rounds; agreement amongst the experts increased between the rounds. The quantitative outputs provided estimates of the probabilities of a horse having RAO for each particular piece of historical information or clinical sign. The RSQ for RAO was a short questionnaire for completion by horse owners regarding the horse, its health and its management. The likelihood of a horse having RAO (the RAO score) was calculated from a completed RSQ by combining the relevant estimated probabilities. The RSQ was validated against a reference standard of a veterinary diagnosis including respiratory cytology. This was achieved by inviting veterinary surgeons (residing in Great Britain who had taken part in the practitioner survey, and who had indicated that they used respiratory cytology in the diagnosis of respiratory cases) to participate. During 2003 and 2004 these veterinary surgeons returned RSQs for 40 cases that underwent investigation of the respiratory tract and 40 controls; 18 of the cases were given a final diagnosis of RAO. A receiver-operating characteristic (ROC) curve was used to select a positive cut-off of 0.87 for the RSQ for RAO. This suggested that the RSQ had a sensitivity of 0.83 (95% confidence interval=0.59-0.96) and specificity of 0.85 (0.74-0.93) for the diagnosis of apparent RAO (compared to all other diagnoses).

Validation of questions on asthma and wheeze in farming and anthroposophic children

BACKGROUND

In most epidemiological surveys the estimated prevalence of asthma is based on questionnaire responses, which may depend on the individual's perception as well as medical consulting habits in a given population. Therefore, measurement of bronchial hyper-responsiveness as a key feature of asthma has been suggested as an objective parameter for asthma.

OBJECTIVE

The aim of the present study was to validate questionnaire responses on asthma and wheeze against bronchial response to hypertonic saline (HS) (4.5%) in populations previously shown to have a lower prevalence of asthma and allergies: farmers' children and children from anthroposophic families.

METHODS

Children whose parents had completed a written questionnaire in the cross-sectional PARSIFAL-study were drawn from the following four subgroups: 'farm children' (n=183), 'farm reference children' (n=173), 'Steiner schoolchildren' (n=243) and 'Steiner reference children' (n=179). Overall, 319 children with wheeze in the last 12 months and 459 children without wheeze in the last 12 months performed an HS challenge.

RESULTS

Odds ratios, sensitivity, specificity, likelihood ratios and measures of association did not differ significantly between the four subgroups. The correlation between the bronchial response to HS and wheeze and asthma questions was moderate and similar for farm children, farm reference children, Steiner schoolchildren and Steiner reference children (kappa for 'wheeze': 0.25, 0.33, 0.31, 0.35, respectively, P=0.754, kappa for 'doctor's diagnosis of asthma': 0.33, 0.19, 0.33, 032, respectively, P=0.499).

CONCLUSION

The findings from this study suggest that the reliabilitiy of questionnaire responses on asthma and wheeze is comparable between farmers' children, children raised in families with anthroposophic lifestyle and their respective peers.

Sleep disturbance and daytime symptoms in wheezing school-aged children

The aim of the study was to investigate whether wheezing is associated with disturbed sleep and increased daytime symptoms in school-aged children. A random sample of 1234 children, aged 6-14 years, participated in a respiratory health study in the region of Antwerp. The International Study of Asthma and Allergies in Childhood questionnaire and a separate sleep questionnaire were completed. In the children who wheezed in the last 12 months, sleep quality was more frequently disturbed due to nocturnal awakenings and restless sleep compared with children who did not wheeze. Daytime sleepiness and tiredness were more common in wheezing than in non-wheezing children. After adjusting for possible confounders a positive association was found between wheeze and: difficulties falling asleep [odds ratio (OR) = 2.0], restless sleep (OR = 5.0), daytime sleepiness (OR = 3.8) and daytime tiredness (OR = 5.1). Chronic cough (OR = 2.4), snoring (OR = 2.0), chronic rhinitis (OR = 2.6) and eczema (OR = 3.3) were associated with disturbed sleep. Chronic cough (OR = 2.5) and rhinitis (OR = 4.1) were related to daytime tiredness. Chronic rhinitis was an important risk factor for snoring (OR = 1.9). In wheezing school-aged children, decreased quality of sleep and increased daytime tiredness and sleepiness were more often reported. Upper airway symptoms were related to the sleep disturbances.

A comparative study of bronchodilator reversibility with albuterol, between asthma symptomatic and asymptomatic children according to ISAAC questionnaire in Mexico City

BACKGROUND

Asthma is an important childhood disease. Recent surveys of the International Study of Asthma and Allergies in Childhood (ISAAC) suggest that the prevalence of asthma is increasing but these surveys do not include any pulmonary tests to confirm the possible diagnosis of asthma.

OBJECTIVE

To compare bronchodilator reversibility with the albuterol test in symptomatic and asymptomatic 6-7-year-old children with asthma participating in the ISAAC survey and living in Mexico City.

PATIENTS AND METHODS

We performed an observational, descriptive, comparative, cross sectional study in children participating in phase 3b of the ISAAC study. According to the ISAAC questionnaire children were classified as asthma symptomatic or asymptomatic. Both groups had bronchodilator reversibility with the albuterol test, using the guidelines of the American Thoracic Society to confirm or rule out the diagnosis of asthma.

RESULTS

The asymptomatic group had a baseline FEV1 of 1.70 +/- 0.34 l/sec (mean +/- SD) and an endpoint FEV1 of 1.76 +/- 0.42 l/sec; in the symptomatic group the respective values were 1.51 +/- 0.41 l/sec and 1.57 +/- 0.44 l/sec (p < 0.05). A positive reversibility test was found in 13/136 (9.6 %) children in the asymptomatic group and in 22/112 (19.6 %) children in the symptomatic group (p < 0.05).

CONCLUSION

Because of its low sensitivity, bronchodilator reversibility cannot be considered a diagnostic tool to confirm diagnosis of asthma.

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.

The bedding environment, sleep position, and frequent wheeze in childhood

OBJECTIVE

Synthetic quilt use has been associated with increased childhood wheeze in previous studies. Our aim was to examine whether the adverse effect of synthetic quilt use on frequent wheeze differed by usual sleep position.

DESIGN, SETTING, AND PARTICIPANTS

A population-based cross-sectional study of 6378 (92% of those eligible) 7-year-olds in Tasmania, Australia, was conducted in 1995. Exercise-challenge lung function was obtained on a subset of 414 children from randomly selected schools.

EXPOSURE MEASURES

Child bedding including pillow and overbedding composition and usual sleep position by parental questionnaire.

OUTCOME MEASURES

Frequent wheeze (>12 wheeze episodes over the past year), using the International Study of Asthma and Allergies in Childhood parental questionnaire, and baseline and postexercise forced expiratory volume in 1 second lung-function measures.

RESULTS

Frequent wheeze (n = 117) was positively associated with synthetic quilts, synthetic pillows, electric blankets, and sleeping in a bottom bunk bed but did not vary by sleep position. In a nested case-control analysis, the association between synthetic quilt use and frequent wheeze differed by sleep position. Among children who slept supine, synthetic (versus feather) quilt use was associated with frequent wheeze (adjusted odds ratio: 2.37 [1.08, 5.23]). However, among nonsupine sleepers, overlying synthetic quilt use was not associated with frequent wheeze (adjusted odds ratio: 1.06 [0.60, 1.88]). This difference in quilt effect by sleep position was highly significant. Similarly, synthetic quilt use was associated with lower postexercise forced expiratory volume in 1 second measures among supine but not nonsupine sleeping children.

CONCLUSION

An increasing focus on the bedding environment immediately adjacent to the nose and mouth is required for respiratory disorders provoked by bedding, such as child asthma characterized by frequent wheeze.

A school-based case identification process for identifying inner city children with asthma: the Breathmobile program

BACKGROUND

Striking increases in the prevalence and morbidity of asthma among inner city children have been documented.

OBJECTIVE

To establish and evaluate a large-scale, school-based case-detection process designed to efficiently and reliably identify inner city children with asthma.

METHODS

A bilingual, seven-question, self-administered, parental asthma screening survey was developed. Clinical validation was achieved in a sample of 675 consecutive parents bringing a child to the school-based Breathmobile Program for initial evaluation, using a comprehensive evaluation by a physician specialist (ie, allergist) as the standard. Survey response patterns were used to construct a novel seven-model, tiered scoring algorithm and an abbreviated algorithm that predict the probability of a child being clinically classified as "yes asthma" or "no asthma." A systematic survey distribution process administered by a single coordinator was developed, and the impact of a classroom-oriented incentive offering a 25 dollars school supply gift certificate for survey return rates of >or= 80% was evaluated.

RESULTS

A total of 636 parents provided one or more survey responses and information sufficient for clinical classification. The scoring algorithm correctly identified children with asthma (>or= 80% probability) with a sensitivity of 86.5%, a specificity of 83.6%, and a misclassification rate of 14.3% (91 of 636 children). The sensitivity for identifying persistent asthma was 91.3%. Asthma prevalence estimates derived using survey results from a larger sampling of the general population were similar to rates previously reported for comparable populations. The inclusion of an inexpensive incentive increased the median survey return rates from 35.3 to 65% (z= -11.9; p <.001). The screening process has been used to conduct 27,526 surveys at inner city schools.

CONCLUSIONS

The Breathmobile case-detection process offers a validated, comprehensive, large-scale method with which to identify children with asthma at their school sites.

Elevated asthma and indoor environmental exposures among Puerto Rican children of East Harlem

OBJECTIVE

East Harlem in New York City, a community with a large Puerto Rican population, has among the highest rates of asthma hospitalizations and mortality in the United States, but it is not known if the high rates are related to the ethnic composition, environmental or community factors, or if the higher rates reflect differentials in access to appropriate asthma care. A survey was conducted to: (a) estimate the prevalence of current asthma by ethnicity among school-age children, (b) assess indoor environmental risk factors for childhood asthma, and (c) assess health care utilization and school absences associated with childhood asthma.

DESIGN

A cross-sectional survey of parents of elementary school children, using a self-administered questionnaire with a 12-month recall on asthma symptoms based on the International Study of Asthma and Allergies in Childhood.

SETTING

Two public elementary schools in East Harlem (n = 1615 students 5-12 years of age).

RESULTS

Among the 1319 respondents (response rate 82%), the prevalence for current asthma (doctor or nurse diagnosis at any time plus wheezing in the past 12 months) was 23%. Puerto Rican children had a prevalence of 35%. Puerto Rican children reported both higher symptomatic frequencies and higher rates of physician diagnosis. Living in a home where cockroaches, rats, or mice had been seen in the past month and with a dust-enhancing heating system also was associated with having asthma, regardless of ethnicity. Compared with other children with asthma, Puerto Rican children with asthma were more likely to live in homes where rats or mice had been seen in the past month. Regardless of ethnicity, children with more frequent, more severe asthma symptoms and incomplete asthma action plans were more likely to have visited the emergency department in the past year. Puerto Rican children were more likely to have missed school because of their asthma in the past year.

CONCLUSION

The prevalence of current asthma was significantly higher among Puerto Ricans, who had higher symptomatic frequency and greater diagnosis rates. Although all children with asthma in the East Harlem study appear to be sensitive to selected indoor environmental risk factors, only Puerto Rican children with asthma appear to be sensitive to the presence of rodents in their buildings. However, their higher school absence rate suggests problems with routine asthma management that could be addressed by improved medical management, programs to help parents manage their children's asthma, or school staff assistance with medications.

Exercise-induced bronchospasm in children: comparison of FEV1 and FEF25-75% responses

The response of asthmatic children to exercise has usually been evaluated by forced expiratory volume in 1 sec (FEV(1)). We reasoned that other respiratory indexes derived from the forced vital capacity maneuver such as forced expiratory flow between 25-75% of vital capacity (FEF(25-75%)) would add significant information in the evaluation of the relationship between asthma severity and response to exercise. We studied 164 children with intermittent (n = 63), mild persistent (n = 30), moderate persistent (n = 40), and severe persistent asthma (n = 31). Subjects exercised for 6 min on a cycle ergometer at 80% of their maximum heart rate, and spirometry was performed before and 5, 10, and 20 min after exercise. There was good correlation between changes in FEV(1) and FEF(25-75%) after exercise (r = 0.60, P < 0.001 for intermittent asthma and r = 0.80, P < 0.001 for severe persistent asthma). The presence of a fall in both FEV(1) (>/=10%) and in FEF(25-75%) (>/=26%) when compared to a decrease in only one of these two indexes was significantly greater in children with more severe asthma (60.0% for intermittent asthma and 94.4% for severe persistent asthma, P = 0.022). FEF(25-75%) can decrease in response to exercise without changes in FEV(1), mainly in children with mild asthma. In the evaluation of the response to exercise in children with different asthma severities, more than one maximum expiratory flow-volume parameter should be used.

Results of an inner-city school-based asthma and allergy screening pilot study: a combined approach using written questionnaires and step testing

BACKGROUND

A questionnaire alone may not be an adequate screening tool for asthma.

OBJECTIVE

To determine whether an asthma questionnaire used in combination with an exercise step test is better than a questionnaire alone in screening for asthma in children and to evaluate the validity of a rhinitis questionnaire in determining atopy.

METHODS

The International Study of Asthma and Allergies in Childhood (ISAAC) asthma core questionnaire was used to screen for asthma in 307 inner-city first through third graders. All children who had scores consistent with a diagnosis of asthma underwent step testing, as did a subset of children who had negative overall scores. All children who had inconsistent asthma scores and step test results underwent methacholine challenge testing. The same 307 children underwent rhinitis screening and children who had one or more positive responses on the ISAAC rhinitis questionnaire underwent skin testing as did a subset of children who had all negative responses.

RESULTS

Three hundred of 307 asthma and rhinitis questionnaires were returned. Twenty-eight children (9%) had global asthma scores that were considered to be positive (5 or above). Twenty-four of these children underwent step testing as did 34 randomly selected children who had negative global asthma scores. Thirty-one (91%) of the 34 children who had negative global asthma scores had negative step tests. Similarly, 20 of 24 children (83%) of the children who had positive global asthma scores had negative step tests. Only 4 children who had positive global asthma scores were step test-positive or had reversible airway obstruction at baseline. Using a positive methacholine challenge as the gold standard for establishing bronchial hyperresponsiveness, the global asthma score derived from the eight-item ISAAC asthma questionnaire yielded a sensitivity of 64%, a specificity of 11%, a positive predictive value of 47%, and a negative predictive value of 20%. Comparing the six-item ISAAC rhinitis questionnaire results to the gold standard, skin test reactivity, the questionnaire yielded a sensitivity of 76%, a specificity of 21%, a positive predictive value of 56%, and a negative predictive value of 40%.

CONCLUSIONS

Step testing was not useful as a screening tool for asthma. In addition, the ISAAC asthma questionnaire may not be a good asthma screening tool for inner-city pediatric populations, especially if the form is self-administered. Investigators should first validate both the ISAAC asthma and rhinitis screening questionnaires in the particular population to be studied before widespread asthma and allergy screening efforts are initiated using these tools.

Perception of dyspnea during exercise-induced bronchoconstriction

After strenuous physical exercise, many subjects show a significant bronchoconstriction and report dyspnea. Despite this clinical condition being a commonly encountered situation during daily life, which may be responsible for substantial disability there is little information on the relationship between the perception of dyspnea and exercise-induced bronchoconstriction (EIB) after a standardized exercise challenge. For these reasons, we evaluated 200 consecutive outpatients (median age 13 years, ranging from 5 to 56 years) referred to our laboratory to perform an exercise test out of suspicion of EIB. On exercise challenge, perception of dyspnea was rated on a modified bipolar Borg scale immediately before each FEV1 measurement. Sixty-nine (35%) subjects had a positive exercise challenge, defined as a decrease of at least 20% in FEV1 from baseline. Both the onset and the decay of dyspnea preceded those of bronchoconstriction. Overall, the rating of dyspnea in the laboratory was well related with the reports of exercise-related symptoms. Similarly, 36 of 77 (47%) asthmatics with a history of exertional symptoms and 24 of 65 patients (40%) without a history had a positive challenge. Asthmatics reporting exertional symptoms perceived a greater magnitude of dyspnea after exercise independently from the degree of bronchoconstriction. Overall, dyspnea was significantly but loosely correlated to the magnitude of decrease in FEV1, being also influenced by age, gender and BMI.

CONCLUSIONS

We conclude that dyspnea recorded in the laboratory after exercise test is related to exertional symptoms reported during real life, but not completely related to EIB. The rating of dyspnea is a well-suited model to study naturally occurring exercise-induced dyspnea and a useful tool to enlarge the results of an exercise challenge.

In search of childhood asthma: questionnaire, tests of bronchial hyperresponsiveness, and clinical evaluation

BACKGROUND

The definition or diagnosis of asthma is a challenge for both clinicians and epidemiologists. Symptom history is usually supplemented with tests of bronchial hyperresponsiveness (BHR) in spite of their uncertainty in improving diagnostic accuracy.

METHODS

To assess the interrelationship between respiratory symptoms, BHR, and clinical diagnosis of asthma, the respiratory symptoms of 1633 schoolchildren were screened using a questionnaire (response rate 81.2%) and a clinical study was conducted in a subsample of 247 children. Data from a free running test and a methacholine inhalation challenge test were available in 218 children. The diagnosis of asthma was confirmed by a paediatric allergist.

RESULTS

Despite their high specificity (>0.97), BHR tests did not significantly improve the diagnostic accuracy after the symptom history: area under the receiver operator characteristic (ROC) curve was 0.90 for a logistic regression model with four symptoms and 0.94 for the symptoms with free running test and methacholine inhalation challenge results. On the other hand, BHR tests had low sensitivity (0.35-0.47), whereas several symptoms had both high specificity (>0.97) and sensitivity (>0.7) in relation to clinical asthma, which makes them a better tool for asthma epidemiology than BHR.

CONCLUSIONS

Symptom history still forms the basis for defining asthma in both clinical and epidemiological settings. BHR tests only marginally increased the diagnostic accuracy after symptom history had been taken into account. The diagnosis of childhood asthma should not therefore be overlooked in symptomatic cases with no objective evidence of BHR. Moreover, BHR should not be required for defining asthma in epidemiological studies.

Which clinical subgroups within the spectrum of child asthma are attributable to atopy?

STUDY OBJECTIVES

The contribution of atopy to childhood asthma has been debated. We aimed to examine the relationship between atopy and asthma, taking into account differences in respiratory symptoms and disease severity.

DESIGN

A cross-sectional asthma survey involving the following: (1) a population sample of 758 (81% of eligible) school children aged 8 to 10 years from randomly selected schools in the Australian Capital Territory in 1999, and (2) a hospital-based sample of 78 (70% of eligible) children attending the hospital for asthma. Skin-prick test results to 10 common aeroallergens were available on 722 children and 77 children, respectively. Baseline spirometry was obtained on a subset of school children (n = 515, 78% of eligible).

RESULTS

The association between atopy and wheeze by wheeze frequency over the past year was as follows: no episodes (odds ratio [OR], 1.00 [reference]), 1 to 3 episodes (OR, 3.27; 95% confidence interval [CI], 2.15 to 4.97), 4 to 12 episodes (OR, 3.44; 95% CI, 1.75 to 6.75), and > 12 episodes (OR, 8.70; 95% CI, 3.07 to 24.55), with a higher population attributable fraction (PAF) for > 12 episodes (75%) than 1 to 3 episodes (49%). Atopy was moderately related to asthma ever (OR, 2.09; 95% CI, 1.52 to 2.85; PAF, 33%) but strongly related to 1999 hospital attendance for asthma (OR, 16.95; 95% CI, 6.76 to 42.48; PAF, 89%). Adjustment for child age, gas heater use, and maternal smoking near the child did not materially alter these findings.

CONCLUSIONS

The clinical features of frequent wheeze or hospital asthma attendance are largely attributable to atopy, but infrequent wheeze or a history of asthma ever are not. Atopic children are overrepresented in the severe range of the asthma spectrum.

Diagnosing pediatric asthma: validating the Easy Breathing Survey

OBJECTIVE

To determine the sensitivity, specificity, and predictive value of a simple, self-administered questionnaire for the diagnosis of asthma in children.

STUDY DESIGN

A questionnaire specifically designed to assist primary care providers in making a diagnosis of asthma in children was developed and administered in 4 different primary care and subspecialty clinics, validated, and then used as part of an asthma management program called Easy Breathing. Asthma diagnoses were made according to recommended National Asthma Expert Panel Guidelines.

RESULTS

Four questions on the survey were shown to be sensitive and specific for asthma. The sensitivity was greater for all levels (mild, moderate, and severe) of persistent asthma than for mild, intermittent asthma. A positive response to any 1 of the 4 questions was over 94% sensitive for asthma; a negative response to all 4 questions was 55% specific for ruling out asthma.

CONCLUSIONS

Patient responses to 4 specific respiratory symptom questions can assist primary care providers in diagnosing asthma in children. Primary care providers serving pediatric populations at high risk for asthma should consider asking patients or their parents these 4 questions regarding asthma symptoms on a regular basis.

Validation of a new questionnaire on asthma, allergic rhinitis, and conjunctivitis in young adults

BACKGROUND

Epidemiologic data on asthma and allergies among adults are mainly based on questionnaires: this study validates the questions on asthma, allergic rhinitis, and conjunctivitis of a new Finnish questionnaire.

METHODS

To validate questions used in a country-wide study among university students aged 18-25 years, we examined 150 subjects who had ever reported asthma or wheezing, and 140 without asthma symptoms. Questions were validated in relation to current diseases including 1) symptoms detected during the preceding year at the physician's interview 2) objective measurements, such as methacholine challenge, skin prick tests, and specific IgE. Data were adjusted for original proportions of "asthmatics" and"nonasthmatics" in the questionnaire study.

RESULTS

Questions on "reported asthma" and "doctor-diagnosed asthma" had good positive predictive value (PPV) and specificity in diagnosing current asthma. The question on "attacks of shortness of breath with wheezing", and especially the question on "cough with wheezing" were most sensitive. Questions on "allergic nasal symptoms" and "allergic eye symptoms" that were "related to pollen or animals" were sensitive, but a further question on doctor's diagnosis yielded higher specificity and PPV.

CONCLUSION

Diagnosis-based questions were found suitable for risk-factor studies, because of their good specificity and PPV, and symptom-based questions for screening, because they were highest in sensitivity.

Asthma, inhaled corticosteroid use, and bone mass in prepubertal children

The aim of this cross-sectional study was to describe the role of asthma, asthma severity, and medication usage in bone mineralization of prepubertal children. Asthma severity, medication usage, and physical activity were assessed by questionnaire and objective measures in 330 children. Bone densitometry and body composition were measured by dual-energy x-ray absorptiometry. Asthma ever was reported by 110 subjects (33%). A diagnosis of asthma was not associated with any deficit in bone mass, whereas usage of inhaled corticosteroids (ICS) in the last year (but not past use) was associated with deficits in bone in the total body (only after adjustment for confounders), particularly for doses of > or =400 microg/day. These observations support current recommendations with regard to ICS usage in children, but require confirmation in longitudinal studies.

The relation between infant indoor environment and subsequent asthma

Our aim was to examine the contribution of an infant's indoor environment to childhood asthma using prospective data. We conducted a cross-sectional asthma survey in 1995 on 92% (6,378/6,911) of 7-year-olds in Tasmania, Australia. We linked these data with data collected in 1988 as part of the Tasmanian Infant Health Survey, which was designed to investigate sudden infant death. We were able to match 863 records out of the 1,111 in the 1988 survey and the 6,378 in the 1995 survey. The former group was interviewed at home at 1 month of age. In homes where at least one adult smoked in 1988, reported infant exposure to smoking in the same room in 1988 was associated with increased asthma by 1995 (relative risk = 1.52; 95% confidence interval = 1.01-2.29) after adjustment for confounders. The associations between infant exposure to environmental tobacco smoke and asthma were not consistent, however. Gas heater use in 1988 was associated with asthma (relative risk = 1.92; 95% confidence interval = 1.33-2.76). Markers of aeroallergen exposure at 1 month of age were not materially associated with asthma or wheeze. In some settings, air circulation practice with regard to bedroom door closure appeared important. Poor indoor air quality may play an important role in the development of childhood asthma.

Community study using a polymerase chain reaction panel to determine the prevalence of common respiratory viruses in asthmatic and nonasthmatic children

We developed a sensitive polymerase chain reaction (PCR) panel, suitable for the detection of seven common respiratory viruses, to study the prevalence of viruses in nasal swabs obtained from clinically stable asthmatic children (n = 21), non-physician diagnosed asthmatic children with exercise-induced bronchoconstriction (EIB) (n = 16), and nonasthmatic, non-EIB controls (n = 33). The PCR panel detected viruses in 43/70 (61.4%) specimens but there were no significant differences in prevalence of these viruses between the three groups of children. These results indicate that clinically stable asthmatic and nonasthmatic children frequently harbor viruses in the upper respiratory tract.

Relationship between early life respiratory illness, family size over time, and the development of asthma and hay fever: a seven year follow up study

BACKGROUND

The timing and mechanism of the inverse association between increasing sibling number and atopic disease are not yet understood. A study was undertaken to examine how family size at birth predicts early respiratory illness, to report the association between infant respiratory illness and childhood atopic disease, and to determine whether the protective effect of large family size operates during infancy or later childhood.

METHODS

A prospective follow up study was carried out on 863 children (78%) of 1111 participants in the Tasmanian Infant Health Survey performed in 1988. In 1988 household size and history of respiratory illness were obtained by parental interview at home (median age 35 days) and later by telephone (median age 85 days). In 1995 asthma, hay fever, and household size were assessed by parental questionnaire in a large cross sectional survey.

RESULTS

In 1988 increasing resident number (per resident) (adjusted odds ratio (AOR) 1.17 (95% CI 1.05 to 1.31)) and resident density (AOR 1.77 (95% CI 1.07 to 2.94)) were related to parental report of an upper respiratory tract infection (URTI) by one month of age. Children with a reported URTI by home interview were more likely to have subsequent asthma (adjusted relative risk (ARR) 1.27 (95% CI 1.05 to 1.53)). The association between lower respiratory tract infection (LRTI) at telephone interview (relative risk (RR) 1.34 (95% CI 1.02 to 1.75) and asthma was reduced after adjustment for family history of asthma (ARR 1.27 (95% CI 0.98 to 1.66)). Antibiotic use by home interview was not associated with subsequent asthma or hay fever. Indicators of family size in 1988 were associated with hay fever but not asthma but, in contrast, resident number in 1995 was inversely associated with asthma (AOR 0.82 (95% CI 0.72 to 0.92) per resident) and hay fever (AOR 0.82 (95% CI 0.71 to 0.96) per resident). Children with no siblings were at risk for current asthma, particularly if symptoms began after the age of four (RR 2.81 (95% CI 1.36 to 5.84)).

CONCLUSIONS

The apparent protective effect of large household size and asthma could not be explained by an increase in reported early respiratory illness. The first year of life may not be the most critical time for the protective effect of large household size to be mediated in relation to asthma, but this effect occurred by the seventh year of life.

Exercise-induced bronchospasm in children: effects of asthma severity

The prevalence of exercise-induced bronchospasm (EIB) in asthmatic individuals has been reported to vary from 40% to 90%. There are, however, few studies addressing the effects of asthma severity on airway responsiveness to exercise. The purpose of the present study was to investigate the effects of asthma severity on EIB in children. We studied 164 children classified as having intermittent (n = 63), mild persistent (n = 30), moderate persistent (n = 40), and severe persistent asthma (n = 31) according to the Global Initiative for Asthma classification. Subjects exercised for 6 min on a cycle ergometer at 80% of their maximum heart rate, and spirometry was performed before and 5, 10, and 20 min after exercise challenge. The prevalence of EIB in children with moderate or severe persistent asthma was significantly greater than in children with intermittent asthma (p < 0.001). EIB-positive children with intermittent asthma exhibited smaller changes in FEV1 than children in the other three groups (p < 0.001). There was no significant relationship between baseline FEV1 and the decline in FEV1 after exercise. We conclude that the prevalence of EIB is greater in children with more severe asthma, and that the intensity of response to exercise is not consistently related to the clinical severity of asthma.

Lung function measures and their relationship to respiratory symptoms in 7- and 8-year-old children

Abnormal pulmonary function in childhood is a well-known risk factor for lung function impairment in adult life. It is therefore of clinical interest to recognize lower pulmonary function in childhood. We investigated the association between asthma-like respiratory symptoms and the lung function parameters FVC, FEV1, and FEF(25-75) in a population-based sample of 402 schoolchildren, aged 7 and 8 years, using linear regression analyses. Without accounting for other respiratory symptoms, wheeze, exercise-induced wheeze, chronic cough, and history of wheezy bronchitis or lower respiratory infections in early childhood were significantly associated with reduced lung function. After stepwise elimination of symptoms from the regression models, only exercise-induced wheeze (FEV1, -15%pred, FEF(25-75), -21%pred) and a history of chronic cough (FEV1, -5%pred; FEF(25-75), -11%pred) remained significant predictors of decreased lung function. After adjustment for different variability, no significant differences were seen between the effects of symptoms on the flow measurements FEV1 and FEF(25-75). We conclude that children who report exercise-induced wheeze and/or chronic cough may have a considerable deficit in lung function at early school age.

Cross sectional study of the relation between sibling number and asthma, hay fever, and eczema

OBJECTIVES

To document the relation between sibling number and atopic disease, and to assess the contribution of possible confounding factors to the protective effect of siblings in relation to asthma and hay fever.

DESIGN AND SUBJECTS

Cross sectional survey by parental questionnaire in Tasmania, Australia, on 6378 children (92% of those eligible) who reached 7 years of age during 1995.

METHODS

Exercise challenge lung function testing was conducted on 428 children. Analyses reported were conducted on singleton births only (n = 6158).

RESULTS

The prevalences of a history of asthma ever, hay fever, and eczema were 27%, 19%, and 22%, respectively. Asthma and hay fever, but not eczema, were inversely related to sibling number, with evidence of a dose-response trend. The mean age at onset for asthma or wheezy breathing decreased as the number of siblings increased. The inverse association between sibling number and asthma or hay fever persisted after adjustment for several confounders, such as parental smoking or breast feeding, but did not persist after adjustment for household size in 1995.

CONCLUSIONS

The protective effect of high sibling number could not be separated from household size at age 7, and it appears to be operating after birth and influences the age at onset of asthma symptoms. Further work to increase knowledge of how the protective effect of the presence of siblings works might have important implications for the understanding of the pathogenesis of asthma.

The prevalence of respiratory symptoms and asthma among school children in three different areas of Norway

The role of exposure to ambient air pollution has been a topic of interest as a potential risk factor for respiratory symptoms and asthma. We expected that the prevalence rates would vary in Norway between the capital, Oslo, the mountainous area Hallingdal and the industrial area Odda. Surveys were conducted in school children, aged 6-16 years, in; Oslo (n = 2577), Hallingdal (n = 1177) and Odda (n = 831). The parent-reported prevalence of wheeze in past year was almost similar in Oslo (13.1 (95% CI 11.7-14.5)) and Upper Hallingdal (14.2 (13.1-15.3)), but lower in Odda (9.0 (7.0-11.0)). The findings for severe respiratory symptoms were almost equal. The age patterns within each area differed. The risk of wheeze ever (p < 0.001) and wheeze in past year (p = 0.04) decreased with increasing age in Odda, while there was an increase in the risk of exercise induced wheeze in Oslo (p = 0.02) and Hallingdal (p < 0.001). The lifetime prevalence of asthma was lowest in Odda (5.4 (3.8-7.0)) compared to Oslo (9.4 (8.2-10.6)) and Hallingdal (8.5 (6.8-10.2)). There was a positive association between physical activity and wheeze in past year. The results do not support the hypothesis that respiratory morbidity is more common in urban than rural areas, age and physical activity can influence the prevalence rates of respiratory symptoms in school children.