Abstract
OBJECTIVE: Although exposure to air pollution and pollen is associated with asthma exacerbation and increased health care use, longitudinal effects of fine particulate matter 2.5 (PM(2.5)), ozone (O(3)), and pollen exposure on asthma control status in pediatric patients are understudied. This study investigated effects of exposure to PM(2.5), O(3), and pollen on asthma control status among pediatric patients with asthma. METHODS: A total of 229 dyads of pediatric patients with asthma and their parents were followed for 15 months. The Asthma Control and Communication Instrument was used to measure asthma control, which was reported weekly by parents during a 26-week period. PM(2.5) and O(3) data were collected from the US Environmental Protection Agency Air Quality System. Pollen data were obtained from Intercontinental Marketing Services Health. Mean air pollutant and pollen exposures within 7 days before the reporting of asthma control were used to estimate weekly exposures for each participant. Linear mixed-effects models were performed to test associations of PM(2.5), O(3), and pollen exposure with asthma control status. Sensitivity analyses were performed to evaluate the robustness of findings by different exposure monitoring days per week and distances between monitoring sites and participants' residences. RESULTS: Elevated PM(2.5) concentration and pollen severity were associated with poorer asthma control status (P < .05), yet elevated O(3) concentration was marginally associated with better asthma control (P < .1). CONCLUSIONS: Poorer asthma control status was associated with elevated PM(2.5) and pollen severity. Reducing harmful outdoor environmental ambient exposure may improve asthma outcomes in children and adolescents.