Association between exposure to air pollution and increased ischemic stroke incidence: a retrospective population-based cohort study (EP-PARTICLES study)

Aims: Short-term effects of Polish smog, particularly benzo(alpha)pyrene (B(a)P), are unclear. We aimed to examine the association between short-term exposure to air pollution and ischemic stroke (IS) incidence.

Methods: We conducted a retrospective population-based cohort study including an EP-PARTICLES cohort of 8 million inhabitants in the years 2011-2020 (80 million person-years of observation). Individual clinical data on emergency hospitalizations due to IS - ICD-10: I63.X was analyzed. We used quasi-Poisson models to examine municipality-specific associations between air pollutants and IS, considering various covariates.

Results: We recorded 146,262 cases of IS with a dominance of females (51.8%) and people over 65 years old (77.6%). In the overall population, exposure to PM2.5, NO2, B(a)P and SO2 increased the risk of IS onset on the day of exposure by 2.4%, 1%, 0.8%, and 0.6%, respectively. Age and sex were modifying variables for PM2.5, NO2 and B(a)P exposure with more pronounced effects in non-elderly individuals and women (all pinteraction< 0.001). Residents of regions with high tobacco and alcohol consumption were more sensitive to the effects of PM2.5 and SO2. The slopes of response-effect curves were non-linear and steeper at lower concentrations.

Conclusions: Exposure to air pollution may be associated with higher IS incidence, particularly posing a higher risk to non-elderly women. Harmful lifestyle habits might exacerbate its impact. Exposure to even low levels of air pollutants had negative effects.