Summer heatwave, ozone pollution and ischemic stroke mortality: An individual-level case-crossover study by Zhen Wang ISBN 101016/JENVRES2025120818 instant download

Summer heatwave, ozone pollution and ischemic stroke mortality: An individual-level case-crossover study by Zhen Wang ISBN 101016/JENVRES2025120818 instant download

Background: Although the association of short-term ozone and heatwave exposure with cerebrovascular diseasehas been well documented, it remains largely unknown whether their co-exposure could synergistically triggerischemic stroke (IS) mortality.Methods: We performed an individual-level, time-stratified case-crossover analysis utilizing province-wide ISdeaths (n = 59079) in warm seasons (May–September) during 2016–2019, across Jiangsu, eastern China.Heatwave was defined according to a combination of multiple temperature thresholds (90–97.5th percentiles)and durations (2–4 days). Daily estimates of ozone concentration (0.01◦ × 0.01◦) and heatwave (0.1◦ × 0.1◦)were extracted from spatiotemporal grid dataset at subject’s residential address. Conditional logistic regressionmodels were utilized to evaluate the associations of short-term ozone and heatwave exposure with IS mortality.Multiplicative and additive interaction effects of ozone and heatwave were assessed using stratified analyses viadividing cases into low and high exposure groups.Results: Ozone exposure was associated with an increased odds of IS mortality, exhibiting an approximately lineartrend across the broad concentration range of 59–227 μg/m3. Under various heatwave definitions, the odds of ISmortality associated with heatwave ranged from 1.167 (95% confidential interval [CI]: 1.135, 1.199) to 1.497(95% CI: 1.431, 1.565) in the total population. Stratified analyses suggested intensified ozone-related IS risk onheatwave days than non-heatwave days, and intensified heatwave-related risk on high-ozone days than lowozone days. We observed significant synergistic effects of heatwave and ozone on IS mortality, with relativeexcess odds due to interaction ranging from 0.15 (95% CI: 0.08, 0.22) to 0.26 (95% CI: 0.13, 0.39). For heatwavewith stricter definition, the heatwave and joint ozone-heatwave effects on IS mortality tended to becomestronger. We estimated that 3.66% (95% CI: 1.87%, 5.39%) to 4.19% (95% CI: 2.57%, 5.76%) of IS deaths couldbe attributable to heatwave and ozone exposure. The elderly aged 85+ years were at higher vulnerability toheatwave and co-exposure event of extreme heat and ozone pollution.Conclusions: Compound ozone and heatwave exposure may synergistically trigger IS deaths, and old adults wereat higher vulnerability to exposure-related excess risk. Coordinated governance of climate change and airpollution may potentially bring substantial cerebrovascular health benefi