Objective: 1). To describe the factors associated with not receiving an asthma diagnosis among children with frequent wheezing symptoms and 2). to determine risk factors for frequent wheezing in the population.
Methods: The North Carolina School Asthma Survey provided self-reported questionnaire data on respiratory health from 122 829 children ages 12 to 18 years enrolled in 499 public middle schools in North Carolina during the 1999-2000 school year. Questions from the International Survey of Allergies and Asthma in Childhood were used to estimate the prevalence of asthma and wheezing-related illness and associated factors.
Results: Factors independently associated with undiagnosed frequent wheezing versus asymptomatic children included female gender (odds ratio [OR]: 1.45; 95% confidence interval [CI]: 1.35-1.54), current smoking (OR: 2.60; 95% CI: 2.43-2.79), exposure to household smoke (OR: 1.59; 95% CI: 1.50-1.70), low socioeconomic status (OR: 1.52; 95% CI: 1.42-1.63), and African American (OR: 1.25; 95% CI: 1.15-1.34), Native American (OR: 1.35; 95% CI: 1.11-1.62), and Mexican American (OR: 1.32; 95% CI: 1.17-1.48) race/ethnicity. Urban residence showed a weak negative association (OR: 0.91; 95% CI: 0.85-0.96). A similar pattern of results was observed for analyses comparing odds of undiagnosed frequent wheeze versus diagnosed asthmatics. Report of allergies was less likely in frequent wheezers (70%) compared with diagnosed asthmatics (86%), but much higher than in asymptomatic children (36%). Thirty-three percent of children with undiagnosed frequent wheezing reported 1 or more physician visits in the last year for wheezing or breathing problems compared with 71% of children with diagnosed asthma, and 4% in asymptomatic children. The prevalence of any inhaler use in the past 12 months was 12% for undiagnosed frequent wheezers versus 78% for diagnosed asthmatics. The proportion of undiagnosed frequent wheezers with fair or poor self-rated health (23%) was slightly higher than diagnosed asthmatics (20%) and much higher than asymptomatic children (4%).
Conclusions: In one of the largest adolescent asthma surveys ever reported in the United States, undiagnosed frequent wheezing was independently associated with female gender, current smoking, exposure to household smoke, low socioeconomic status, allergies, and African American, Native American, and Mexican American race/ethnicity. Children with undiagnosed frequent wheezing were not receiving adequate health care for their asthma-like illness. Clinicians who treat adolescents should consider asking adolescents specifically about wheezing. This information may assist primary care physicians in identifying children with undiagnosed asthma in need of treatment.