O3213: Associations Between Roadway Proximity and Clinical Outcomes in Patients with Poorly Controlled Asthma

Background: The achievement of asthma control can be complicated by disease-related factors such as environmental triggers. Persistent exposure to air pollution at home is one such trigger that has been demonstrated to increase risk of asthma exacerbation.

Methods: A total of 447 children aged 5 through 17 years with poorly controlled asthma despite treatment with an asthma controller medication were evaluated. Participants and their caregivers completed questionnaires pertaining to demographic and clinical information. The Asthma Control Questionnaire (ACQ-6) was administered, and spirometry was performed. The electronic health record was reviewed for asthma visits within the previous 12 months. Addresses were geocoded and spatially joined to census tracts. Air pollution indices were determined for each participant’s census tract from the Environmental Justice Index (EJI) Environmental Burden Module. Residential proximity to a major roadway was estimated with a validated mapping system.

Results: The participants were predominantly black (74.3%) with an average age of 10.8 years (IQR = 8.3, 13.5). Children with an asthma exacerbation necessitating an ED visit in the previous 12 months lived closer to major roadways (Fig 1A). Closer residential proximity to major roadways was also associated with reduced lung function (Fig 1B-D). Children living within 1000 meters of a major roadway, compared to children living 3000 meters or beyond, had lower spirometry measurements (Fig 1E-G). No associations were found between roadway proximity and ACQ-6 scores or hospitalization frequency. Roadway proximity was strongly associated with diesel PM concentrations, modestly associated with PM2.5 days above the regulatory standard, and not significantly associated with ozone days above the regulatory standard (Fig 2A-B).

Conclusion: Residential proximity to a major roadway is associated with ED utilization, reduced lung function on spirometry testing, and air pollution indices in children with poorly controlled asthma. Policy change is needed to reduce outdoor air pollutant exposure and ideally prevent asthma exacerbation.