3194.0 Assessing associations between long-term CO, NO2, O3, PM2.5, and so2 exposure and annual ischemic stroke hospitalization in the United States at the national level
Environments and Aging in Place
Session: Environments and Aging in Place
Program: Aging & Public Health
Time: 2:30 - 3:30 PM
Presenters:
Joshua Warren, PhD
Erica Leifheit, PhD
Judith Litchtman, PhD, MPH
Abstract
Objective: Nationwide data reflecting the association between the most common US air pollutants (CO, NO2, O3, PM2.5, SO2) and the risk of ischemic stroke (IS) are limited. We analyzed the relationship between average annual levels of these pollutants and IS hospitalizations across the US during 2014-2015 in fee-for-service Medicare beneficiaries >65 years.
Methods: We identified patients hospitalized for IS from Medicare records based on discharge ICD-9 codes. We obtained long-term air pollutant exposure data from the Environmental Protection Agency and National Aeronautics and Space Administration and temperature data from the Parameter-elevation Regressions on Independent Slopes Model Climate Group. Patient-level sociodemographics and comorbidities were collected from Medicare files. Mixed models with state-specific random intercepts were used to obtain estimates of the association between long-term air pollutant exposure and IS hospitalizations adjusted for patient-level factors and average annual temperature.
Results: The study population included 475,177 patients hospitalized with IS. Following adjustment, only PM2.5 and CO were associated with IS hospitalizations. Each one standard deviation increase in PM2.5 and CO corresponded with a 6.7% (95% CI: 4.3%-9.1%) increase and a 2.2% (95% CI: 0.7%-3.7%) decrease in IS hospitalization, respectively.
Conclusion: Long-term PM2.5 exposure was associated with a modest increase in IS hospitalization in Medicare beneficiaries at pollutant levels within national air standards. The smaller inverse association between long-term CO exposure warrants additional consideration as it has otherwise only been reported in animal models. Additionally, whether air quality improvements such as lowering PM2.5 exposure leads to reductions in IS hospitalizations requires further research.