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

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 ischaemic stroke (IS) incidence.

We conducted a retrospective population-based cohort study including an EP-PARTICLES cohort of 8 million inhabitants in the years 2011–20 (80 million person-years of observation). Individual clinical data on emergency hospitalizations due to IS (ICD-10: I63.X) was analysed. We used quasi-Poisson models to examine municipality-specific associations between air pollutants and IS, considering various covariates. 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 PM_2.5, 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 PM_2.5, NO₂, and B(a)P exposure with more pronounced effects in non-elderly individuals and women (all P_interaction < 0.001). Residents of regions with high tobacco and alcohol consumption were more sensitive to the effects of PM_2.5 and SO₂. The slopes of response–effect curves were non-linear and steeper at lower concentrations.

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.

The study was registered at ClinicalTrials.gov (NCT05198492).