Particulate Air Pollution Exposure and Stroke among Adults in Israel

Abstract

Stroke is the second most common cause of death and disability in the world. Many studies have found fine particulate matter (PM_2.5) exposure to be associated with an increased risk of atherosclerotic cardiovascular disease, mostly focusing on ischemic heart disease and acute myocardial infarction. In a national analysis conducted in Israel-an area with unique climate conditions and high air pollution levels, we estimated the association between short-term PM_2.5 exposure and ischemic stroke, intracerebral hemorrhage (ICH), or transient ischemic attacks (TIA). Using the Israeli National Stroke Registry, we obtained information on all stroke cases across Israel in 2014-2018. We obtained daily PM_2.5 exposures from spatiotemporally resolved exposure models. We restricted the analytical data to days in which PM_2.5 levels did not exceed the Israeli 24 h standard (37.5 µg/m³). We repeated the analysis with a stratification by sociodemographic characteristics and comorbidities. For all outcomes, the exposure-response curves were nonlinear. PM_2.5 exposure was associated with a higher ischemic stroke risk, with larger effect estimates at higher exposure levels. Although nonsignificant, the exposure-response curve for TIA was similar. The associations with ICH were nonsignificant throughout the PM_2.5 exposure distribution. The associations with ischemic stroke/TIA were larger among women, non-Jewish individuals, older adults, and individuals with diabetes, hypertension, and ischemic heart disease. In conclusion, short-term PM_2.5 exposure is associated with a higher risk for ischemic stroke and possibly TIA, even when PM_2.5 concentrations do not exceed the Israeli air quality guideline threshold. Vulnerability to the air pollution effects differed by age, sex, ethnicity, and comorbidities.

Keywords: PM2.5; air pollution; stroke.

Figure 1

The association between PM_2.5 exposure on the event day and types of strokes. Figure 1 shows the associations between PM_2.5 exposure on the event day and intracerebral hemorrhage (ICH), ischemic stroke, or transient ischemic attack (TIA). Results were obtained from conditional logistic regressions, in which control days were selected within the same month and year as the case day and matched by the weekday. Models were adjusted for a spline function of daily mean temperature.

Figure 2

The association between PM_2.5 exposure on the event day and ischemic stroke/TIA stratified by age, sex, ethnicity, and SES. Figure 2 shows the associations between PM_2.5 exposure on the event day and ischemic stroke/transient ischemic attack (TIA), stratified by ethnicity (Jewish versus non-Jewish), median age (<73 years versus 73 years and older), sex (male versus female), and neighborhood socioeconomic status (SES) (lower than the median score versus median score or higher). Results were obtained from conditional logistic regressions, in which control days were selected within the same month and year as the case day and matched by the weekday. Models were adjusted for a spline function of daily mean temperature.

Figure 3

The association between PM_2.5 exposure on the event day and ischemic stroke/TIA stratified by cardiometabolic chronic conditions. Figure 3 shows the associations between PM_2.5 exposure on the event day and ischemic stroke/transient ischemic attack (TIA), stratified by diabetes, hypertension, hyperlipidemia, and ischemic heart disease (IHD).