Abstract
BACKGROUND: Characteristics related to decreased lung function and increased bronchial responsiveness after early childhood wheezing requiring hospitalization are not fully established. METHODS: Seventy-nine children with wheezing requiring hospitalization at age <2 years were prospectively followed up and re-investigated at age 5.6-8.8 years when the measurements of baseline lung function and bronchial responsiveness to exercise were performed. RESULTS: At early school age, 23% of children had decreased lung function, and 13% had increased bronchial responsiveness to exercise. Predictors of decreased lung function were maternal history of smoking during pregnancy (odds ratio [OR], 12.8; 95% confidence interval [CI]: 1.2-139.6), parental history of asthma (OR, 4.3; 95%CI: 1.1-17.1), and female gender (OR, 4.0; 95%CI: 1.2-13.7). Increased bronchial responsiveness was associated with rhinovirus infection-induced wheezing in infancy (OR, 6.5; 95%CI: 1.2-36.3), and early cat or dog exposure leading to sensitization (OR, 26.6; 95%CI: 1.3-525.2). Inhaled anti-inflammatory therapy was common in children with rhinovirus infection-induced wheezing in infancy (n = 13/19; P = 0.001 vs children with other/no confirmed virus infection etiology for wheezing in infancy, n = 16/60), which may have improved lung function and attenuated bronchial responsiveness in them. CONCLUSIONS: After early childhood wheezing requiring hospitalization, one-fourth of children will have decreased lung function and one-eighth of children will show increased bronchial responsiveness at school age. Gender, heredity of asthma, and antenatal exposure to tobacco smoke are predictors of decreased lung function, whereas rhinovirus infection etiology of wheeze and early animal exposure leading to sensitization are associated with increased bronchial responsiveness later in childhood.