Abstracts: ISEE 20th Annual Conference, Pasadena, California, October 12–16, 2008: Symposium Abstracts
Early Diagnosis of Asthma Modifies the Effect of Air Pollution on Lung Development in Children
Children's Health Study cohorts of 2078 fourth (recruited in 1993 and 1996) and 750 seventh (recruited in 1993) graders were evaluated yearly until high school graduation. Based on these longitudinal data, we examined whether the effect of ambient air pollution on children's lung growth was modified by physician diagnosed asthma. A novel spline based multi-level mixed effects model was used to characterize the nonlinear lung growth patterns during the rapid growth period of adolescence and also to allow for proper comparisons at various levels: within-individual (over time), between individuals (within community) and between communities, after adjustments for potential confounders and effect modifiers. Significant deficits in lung growth (as measured by FEV1, FVC and MMEF) were associated with between-community differences in long term levels of NO2, PM10, PM2.5, acid vapor, elemental carbon and organic carbon, but not with ozone. Moreover, children whose asthma was diagnosed before age five had both the largest asthma-associated deficits in lung function and the largest effect of air pollution, compared to those who were never diagnosed with asthma or were diagnosed after age five. These results indicate that current levels of air pollution could lead to chronic impairment in children's lung development, especially in the highly susceptible group of children with early diagnosed asthma.© 2008 Lippincott Williams & Wilkins, Inc.