Early childhood respiratory symptoms and the subsequent diagnosis of asthma

Background: Respiratory symptoms are frequent in very young children, and the relation of these symptoms to later asthma in some of these children is unknown. Objective: The aim of the study was to describe the natural history of respiratory symptoms in a community-based sample of young children who were prospectively observed for as long as 11 years. Methods: Subjects were participants in the Tucson Epidemiologic Study of Airways Obstructive Disease. They were under 5 years of age at enrollment and were studied by means of a parent-administered mail survey instrument every 1 to 2 years for 3 to 11 years. Results: Among subjects younger than 1 year of age, no single respiratory symptom, such as cough or wheeze only with colds, significantly increased the risk of a subsequent diagnosis of asthma. Among 1- and 2-year-olds, however, those with wheeze only with colds and those with attacks of shortness of breath with wheeze were more likely to be diagnosed with asthma later when compared with children without those symptoms (odds ratio = 2.1; p < 0.05 for wheeze only with colds). At ages 3 to 4 years, symptoms were even more strongly associated with subsequent asthma (odds ratio = 7.2; p < 0.0001 for attacks of shortness of breath with wheeze). Conclusion: Although respiratory symptoms reported by parents very early in life are not significantly associated with future asthma, those symptoms that begin at or persist through ages 3 to 4 years are.