Evaluation of associations between asthma exacerbations and distance to roadways using geocoded electronic health records data

Abstract

Background: Asthma exacerbations in children often require medications, urgent care, and hospitalization. Multiple environmental triggers have been associated with asthma exacerbations, including particulate matter 2.5 (PM2.5) and carbon monoxide (CO), which are primarily generated by motor vehicle exhaust. There is mixed evidence as to whether proximity to highways increases risk of asthma exacerbations. Methods: To test this hypothesis, we assessed the association between asthma exacerbations and the distance to two types of roadways in Durham County, accounting for other patient-level factors. We abstracted data from the Duke University Health System electronic health record (EHR), identifying 6,208 children with asthma between 2014 – 2019. We geocoded each child’s distance to roadways (both 35 MPH+ and 55 MPH+). We classified asthma exacerbation severity into four tiers and fitted a recurrent event survival model to account for multiple exacerbations. Results: There was a consistent weak effect of residential distance from 55+ MPH highway and any asthma exacerbation (Hazard Ratio: 0.98 (95% confidence interval: 0.94, 1.01)), but there was no effect from distance to 35+ MPH roadway (Hazard Ratio: 0.98 (95% confidence interval: 0.83, 1.15)). Conclusions: While the results were negative, characteristics of a study sample – namely farther distance to roadways and generally good ambient environmental pollution may contribute to this. Compared to previous work which often relied on self-report measures, we are able to obtain a more objective assessment of outcomes. Overall, this work highlights the opportunity to use EHR data to study environmental impacts of disease.