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Asymptomatic bronchial hyperreactivity and the development of asthma and other respiratory tract illnesses in
1Department of General Practice, University of Wales College of Medicine, Cardiff, UK.
Insights
Asymptomatic bronchial hyperresponsiveness (BHR) in children predicts future asthma development. This finding highlights BHR as a key indicator for early asthma risk assessment in pediatric populations.
Area of Science:
- Pediatric Pulmonology
- Allergy and Immunology
- Epidemiology
Background:
- The link between asymptomatic bronchial hyperresponsiveness (BHR) and the future development of asthma in children remains unclear.
- A longitudinal study was designed to investigate the predictive value of BHR in a primary care setting.
Purpose of the Study:
- To determine if asymptomatic bronchial hyperresponsiveness (BHR) in children is a risk factor for developing asthma.
- To assess the predictive value of BHR for asthma development in a pediatric population.
Main Methods:
- A standard free running asthma screening test (FRAST) was administered to 956 schoolchildren (ages 4-11) in 1985.
- Peak expiratory flow (PEF) was measured before and after a six-minute exercise challenge.
- Children with a >15% fall in PEF (positive FRAST) were identified as having BHR and followed for six years.
Main Results:
- Of 60 children with asymptomatic BHR, 32 (58%) developed asthma by 1991.
- The positive FRAST demonstrated 58% sensitivity and 97% specificity for predicting asthma.
- Associated conditions like hay fever, eczema, and otitis media were more common in the BHR group.
Conclusions:
- Asymptomatic bronchial hyperresponsiveness (BHR), identified via exercise challenge, is a significant predictor of clinical asthma development in children.
- A relationship was observed between BHR, asthma, and other airway diseases, including upper respiratory infections and otitis media.
Background:
It is not clear whether asymptomatic bronchial hyperresponsiveness (BHR) in children is a risk factor for the subsequent development of asthma. A longitudinal study was conducted to determine the predictive value of BHR for the development of asthma in a primary care patient population.
Methods:
A standard free running asthma screening test (FRAST) was applied to 956 schoolchildren aged between 4 and 11 years in 1985. Peak expiratory flow (PEF) rates were measured before hard running for six minutes and following a three minute rest period. Children with a fall in PEF of more than 15% were labelled as having a positive FRAST. Clinical data from the patients' notes and from symptom questionnaires were compared with age and sex matched controls for children known to have asthma, and for those with a positive FRAST but no asthma (BHR group). Over the ensuing six years to 1991 further clinical data were gathered to compare the development of asthma and other diseases of the airways in both the BHR groups and their controls.
Results:
Of the 956 children exercised in 1985, 60 who were not known to have asthma had an abnormal test. Of the 55 of these studied in 1991, 32 (58%) had developed asthma. The sensitivity of a positive FRAST for the development of asthma was 58%, its specificity 97%, and positive predictive value 72%. Hay fever, eczema, otitis media, "bronchitis," and family history of atopy also occurred more commonly in this group.
Conclusions:
Asymptomatic BHR, as shown by exercise challenge, can predict the development of clinical asthma. This study has also shown a relation between BHR, asthma, and other diseases of the airways, notably upper respiratory tract infection, "bronchitis," and otitis media.