- Siersted H,
- Boldsen J,
- Hansesn H,
- Mostgaard G,
- Hyldebrandt N
Purpose of the Study
To describe factors related to the underdiagnosis of asthma in adolescence.
A total of 495 schoolchildren aged 12 to 15 years were selected from a cohort of 1369 children investigated 3 years earlier. Selection was conducted by randomization (n = 292) and by a history indicating allergy or asthma-like symptoms in the subject or family (n = 203).
Subjects completed a comprehensive questionnaire and monitored peak expiratory flow bid for 2 weeks. Laboratory examinations included anthropometric measurements, puberty staging, spirometry, treadmill exercise testing, and methacholine challenge. Subjects discontinued bronchodilators but not inhaled steroids before testing. Current asthma symptoms were determined by questionnaire. Physician-diagnosed asthma was identified by asking the subject if they had been diagnosed with asthma, were on asthma medication, or both. Subjects without a previous diagnosis but with asthma-like symptoms by objective evaluation (one or more obstructive airway abnormalities: low ratio of forced expiratory volume in 1 second (FEV1) to forced vital capacity, positive response to methacholine or exercise, or peak flow variability) were labeled as undiagnosed asthma.
Undiagnosed asthma comprised one third of all identified asthmatics. Underdiagnosis was independently associated with low physical activity, high body mass, family problems, passive smoking, and absence of rhinitis. Girls comprised 69% of undiagnosed patients (P = .007 compared with diagnosed). The major symptom of undiagnosed asthma was cough (58%). Wheezing (35%) or breathing difficulty (50%) were reported less frequently than those with diagnosed asthma. Less than one third of the undiagnosed patients reported symptoms to their physician.
Asthma, as defined by symptoms and objective measures, was seriously underdiagnosed among adolescents. The problem was more common in girls and was associated with decreased tendency to report symptoms.
The results from this study suggest that asthma continues to be significantly underdiagnosed in some populations. It is important that histories regarding asthma symptoms be taken during well child and sick visits, that cough be recognized as a potential manifestation of asthma, and that objective measures of lung function be obtained whenever there is a suspicious history.