Ambient air pollution and out-of-hospital cardiac arrest. Israel nation wide assessment

Introduction: Previous research suggested that an out-of-hospital cardiac arrest (OHCA) may be triggered by an exposure to ambient pollutants. Objective: We investigated the link between OHCA and a short-term exposure to particulate matter (PM) and other pollutants, within extreme climate conditions in Israel and high PM. Methods: In a case-crossover analysis, we analyzed all adult cases of OHCA in Israel during 2016-2017. The airpollution and meteorology data were retrieved from the 132 monitoring stations. All associations at study were investigated using a lag-distributed regression and adjusted to temperature and humidity. Results: There were 12401 OHCA cases. Patients experiencing OHCA were likely to be exposed to elevated levels of pollutants, specifically, nitrogen dioxide (NO2) and particulate matter of size <= 2.5 mu m (PM2.5) several hours prior to an event, although both at borderline significance, i.e. odds ratio (OR) = 1.20 (95%CI 0.96; 1.51) and OR = 1.15 (95%CI 0.84; 1.60), respectively. An exposure to NO2 was independently associated with OHCA among males (OR = 1.39, 95%CI 0.96; 2.01) and if occurred during the midweek (OR = 1.43, 95%CI 1.03; 1.97). The adverse effect of PM10 was more evident during a weekend (OR = 2.36, 95%CI 0.88; 6.28), as opposed to working days (OR = 0.81, 95%CI 0.45; 1.44). Analysis stratified by regions suggested a spatial variability in pollution associated with OHCA. Conclusions: Short-term exposure to high levels of pollution is adversely associated with OHCA independently of meteorological conditions. The magnitude of the effect is modified by patients' demography. Main finding: Short-term exposure to high levels of pollution is adversely associated with OHCA. This effect is independent of temperature and humidity.