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Prevalence and predictors of bronchial hyperresponsiveness in children aged 7-16 years
V Backer1, N Bach-Mortensen, A Dirksen
1Dept. of Medicine B, Laboratory of Respiratory Physiology, State University Hospital, Copenhagen, Denmark.
Insights
Bronchial hyperresponsiveness (BH) affects 16% of children, with atopic symptoms like asthma, rhinitis, and eczema being key predictors. Asthma severity is independent of IgE or skin tests, unlike other atopic conditions.
Area of Science:
- Pediatric Pulmonology
- Allergy and Immunology
- Epidemiology
Background:
- Bronchial hyperresponsiveness (BH) is a common finding in children.
- Understanding its prevalence and predictors is crucial for early diagnosis and management.
- Atopy is frequently associated with respiratory conditions in childhood.
Purpose of the Study:
- To determine the prevalence of bronchial hyperresponsiveness in a pediatric population.
- To identify potential predictors of bronchial hyperresponsiveness, including atopic symptoms and family history.
- To differentiate the degree of bronchial responsiveness based on specific atopic conditions.
Main Methods:
- A cross-sectional study of 527 children aged 7-16 years in Copenhagen.
- Data collection included interviews, skin prick tests for common allergens, and serum IgE measurements.
- Bronchial responsiveness was assessed using a histamine inhalation test to determine the provocative concentration (PC20).
Main Results:
- 16% (79/527) of children exhibited bronchial hyperresponsiveness (PC20 ≤ 8 mg/ml).
- Atopic symptoms (asthma, rhinitis, eczema) showed a significant correlation (P < 0.001) with BH prevalence and severity.
- Family history of atopy significantly influenced bronchial responsiveness (P < 0.001); no correlation was found with passive smoking or elevated IgE in non-atopic children.
Conclusions:
- Bronchial hyperresponsiveness is most severe in children with asthma, irrespective of elevated IgE or positive skin prick tests.
- Children with rhinitis, dermatitis, or asymptomatic BH exhibit similar degrees of responsiveness, distinct from those with asthma.
- Atopic status is a primary determinant of bronchial hyperresponsiveness severity in children.
Abstract:
To study the prevalence and possible predictors of bronchial responsiveness we examined a cross-section of 527 children aged 7-16 years from Copenhagen. The method used included an interview with the child and the parents, skin prick test with common allergens and se-IgE. Bronchial responsiveness was measured by a histamine inhalation test. We found that 79 (16%) of the children had bronchial hyperresponsiveness (BH), defined as a 20% fall in FEV1 with a provoking concentration of histamine (PC20) at 8 mg/ml or less. Atopic symptoms defined as asthma, rhinitis or eczema were significantly (P less than 0.001) correlated to BH both in prevalence and degree of BH. None of the children with urticaria had BH. The degree of bronchial responsiveness was also significantly influenced (P less than 0.001) by family disposition to atopy, whereas we found no correlation between BH and "passive" smoking, specific skin test in unselected children, or elevation of IgE in children without atopic symptoms. We conclude that BH is severest in children with asthma, independent of elevated IgE or positive skin prick test. Children with rhinitis, dermatitis, or asymptomatic BH have the same degree of BH; this differed from that in children with asthma.