Exposure to air pollution and its effect on ischemic strokes (EP-PARTICLES study)

It is well known that exceeded levels of particulate matter in the air and other air pollutants harmfully affect the cardiovascular system. Empirical analyses of the effects of these factors on stroke incidence and mortality are still limited. The main objective of our analyses was to determine the association between short-term exposure to air pollutants and stroke incidence in non-industrial areas, more specifically in north-eastern Poland. To achieve this aim, we used data from the National Health Fund on patients hospitalized for stroke between 2011 and 2020 in the largest city of the region described as the Green Lungs of Poland. The pollution levels and atmospheric conditions data were obtained from the Provincial Inspectorate for Environmental Protection and the Institute of Meteorology and Water Management. Using daily data on hospitalizations, atmospheric conditions, and pollution, as well as ordered logistic regression models the hypotheses on the impact of weather and air pollution conditions on ischemic strokes were tested. The study group included 4838 patients, 45.6% of whom were male; the average patient age was approximately 74 years. The average concentrations of PM(2.5) were 19.09 µg/m(3), PM(10) 26.66 µg/m(3) and CO 0.35 µg/m(3). Analyses showed that an increase in PM(2.5) and PM(10) concentrations by 10 µg/m(3) was associated with an increase in the incidence of stroke on the day of exposure (OR = 1.075, 95% CI 0.999–1.157, P = 0.053; OR = 1.056, 95% CI 1.004–1.110, P = 0.035) and the effect was even several times greater on the occurrence of a stroke event in general (PM(2.5): OR = 1.120, 95% CI 1.013–1.237, P = 0.026; PM(10): OR = 1.103, 95% CI 1.028–1.182, P = 0.006). Furthermore, a short-term (up to 3 days) effect of CO on stroke incidence was observed in the study area. An increase of 1 μg/m(3) CO was associated with a lower incidence of stroke 2 days after the exposure (OR = 0.976, 95% CI 0.953–0.998, P = 0.037) and a higher incidence 3 days after the exposure (OR = 1.026, 95% CI 1.004–1.049, P = 0.022).