Acute lower respiratory illness in childhood as a predictor of lung function and chronic respiratory symptoms.

This study investigated the relationship of acute lower respiratory illness (LRI) to level and change in level of forced expiratory volumes in a cohort of 801 children, followed longitudinally for a maximum of 13 yr. The co-occurrence of respiratory illness before 2 yr of age and two or more LRI during a single surveillance year was associated with a 20.3% lower mean cross-sectional level of FEF25-75, and with reduced longitudinal change in level of FEF25-75. The effect of LRI on lung function was uniformly stronger for boys than for girls. Of the children with illness before 2 yr of age and two or more LRI, six of 14 were male asthmatics with mean levels of FEF25-75 that were lower than those of other asthmatic children. Pneumonia and/or hospitalization for respiratory illness prior to the onset of study were associated with lower cross-sectional levels of forced expiratory volumes at entry to the study, even when asthmatics/persistent wheezers were eliminated from the analysis (6.1% lower level of FEV1 for a nonasthmatic boy with previous hospitalization versus a nonasthmatic boy without hospitalization). In the longitudinal analysis, pneumonia and/or hospitalization were associated with slower increase in level of forced expiratory volumes, even after adjusting for "ever diagnosis of asthma/current any wheeze" (starting at the same leve, after eight years a boy with hospitalization would develop a 5.0% lower FEV1 than a boy without hospitalization). Acute LRI also was evaluated as a predictor of chronic respiratory symptoms.(ABSTRACT TRUNCATED AT 250 WORDS)