Estimating the prevalence of undiagnosed asthma and associated morbidity in inner-city children.

Abstract

The prevalence of asthma among urban black children in the United States is twice that of suburban whites. The extent to which urban children endure the symptoms and consequences of asthma without benefit of physician diagnosis and treatment is unknown. A population-based study, consisting of a parental survey and a pulmonary function test, was conducted in two urban schools to estimate the prevalence of undiagnosed asthma and related morbidity among children, grades 3-5. Undiagnosed asthma was defined as the following in the absence of a physician diagnosis: Three or more reported symptoms indicative of asthma and/or a $\ge$15% drop in baseline FEV$\sb1$ post-exercise challenge (BHR). Children meeting the above criteria for were further classified as "probable" (symptoms and BHR) or "possible" (symptoms only or BHR only). A total of 230 children (61% of those eligible) took part in both phases of the study. Parent-reported prevalence of physician-diagnosed asthma was 17.4% (95% Confidence Interval = 12.4%-22.3%). One child, 0.4% (95%CI = 0-1.3%) met criteria for "probable" undiagnosed asthma. Another 11.7% (95%CI = 7.6%-15.9%) met study criteria for possible undiagnosed asthma. "Probable" and "possible" undiagnosed asthmatics were combined for further analyses. In a logistic regression including demographics and SES, undiagnosed asthma was associated with sleep disturbance, Odds Ratio = 2.8 (95%CI = 1.1-7.1); limited participation in school gym, OR = 6.8 (95%CI = 2.5-18.5); and school absenteeism, OR = 1.7 (95%CI = 0.7-4.0). Results suggest a high prevalence of possible undiagnosed asthma and related morbidity in this population.