There is increasing evidence that a sizable number of children who are not diagnosed with asthma report asthma-like symptoms. The purpose of this study by the North Carolina Department of Epidemiology was to determine the prevalence and health consequences of asthma-like symptoms (wheezing and cough) among children without a physician diagnosis of asthma. A standardized 30-minute questionnaire adapted from the International Study of Asthma and Allergies in Childhood (ISAAC) was administered to 128,568 children aged 12 to 14 years (7th and 8th grade) in 499 North Carolina public middle schools between December 1999 and June 2002. The survey included written symptom questions related to consequences of wheezing or breathing problems (school absences, sleep disturbances, activity limitations), health care use (admissions, emergency department [ED] visits, physician visits), physician diagnosis, and environmental exposures, as well as 5 video scenes of adolescents with asthma-like symptoms. The scenes showed wheezing at rest during the day, wheezing after exercise, waking at night by wheezing or by cough, and severe wheezing with intercostal retractions. For purposes of comparison, children were placed in 1 of 3 groups: children reporting current asthma-like symptoms and no physician diagnosis, children with physician diagnoses of asthma and current asthma-like symptoms, and children who reported never having any asthma-like symptoms and no diagnosis of asthma. There were no significant demographic differences between schools that participated (88%) and those that did not participate (12%). Sixty-seven percent of children returned 128,568 questionnaires. Approximately 5,700 questionnaires were excluded because of missing data, leaving 122,829 questionnaires for analysis.
Seventeen percent (21,184) of the children reported current asthma-like symptoms but no diagnosis of asthma during the previous 12 months. Combining this group with children with diagnosed asthma resulted in a population-based prevalence of 33% ever having asthma or asthma-like symptoms. Health consequences among children with asthma-like symptoms but no diagnosis were substantial: 20% missed at least a half-day of school per month, 25% had limited activities once or twice per month, and 32% suffered sleep disturbances in the previous 4 weeks because of wheezing. Nine percent of these children reported inhaler use more than once per month in the preceding year despite having no diagnosis of asthma, 7% reported 1 or more ED visits for asthma-like symptoms, and 6% reported wheeze-related hospitalizations in the preceding year. In comparison, 47% of children with physician-reported asthma and current asthma-like symptoms reported missing a half-day or more of school in the preceding month and 30% reported 1 or more ED visits in the preceding year for asthma-like symptoms.
When compared to the gold standard of bronchial hyperresponsiveness, the ISAAC questionnaire has been validated as more reliable for diagnosing asthma than physician diagnosis.1 The ISAAC survey has previously been used to identify asthma prevalence rates among adolescents.2
A potential limitation of the current study is that the data was based on adolescents’...