Ambient Air Pollution and Risk for Stroke Hospitalization: Impact on Susceptible Groups

Stroke is a leading cause of death, and air pollution is associated with stroke hospitaliza-tion. However, the susceptibility factors are unclear. Retrospective studies from 2014 to 2018 in Kaohsiung, Taiwan, were analyzed. Adult patients (>17 years) admitted to a medical center with stroke diagnosis were enrolled and patient characteristics and comorbidities were recorded. Air pollutant measurements, including those of particulate matter (PM) with aerodynamic diameters < 10 μm (PM₁₀) and < 2.5 μm (PM_2.5), nitrogen dioxide (NO₂), and ozone (O₃), were collected from air quality monitoring stations. During the study period, interquartile range (IQR) increments in PM_2.5 on lag3 and lag4 were 12.3% (95% CI, 1.1–24.7%) and 11.5% (95% CI, 0.3–23.9%) concerning the risk of stroke hospitalization, respectively. Subgroup analysis revealed that the risk of stroke hospitalization after exposure to PM_2.5 was greater for those with advanced age (≥80 years, interaction p = 0.045) and hypertension (interaction p = 0.034), after adjusting for temperature and humid-ity. A dose-dependent effect of PM2.5 on stroke hospitalization was evident. This is one of few studies focusing on the health effects of PM_2.5 for patients with risk factors of stroke. We found that patients with risk factors, such as advanced age and hypertension, are more susceptible to PM_2.5 impacts on stroke hospitalization.