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

Abstract 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 ischaemic stroke (IS) incidence. Methods and results 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 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. Conclusion 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. Registration The study was registered at ClinicalTrials.gov (NCT05198492).