Global impact of climate variability and air pollution on age-standardized stroke mortality rates from 2000 to 2020: a country-level analysis

Background Climate variability and air pollution adversely affect stroke, yet comprehensive global assessments are lacking. This study investigates their impact on age-standardized stroke mortality rates (ASMR) from 2000–2020.Methods We analyzed 179 countries using the Global Burden of Disease Study 2021 (GBD 2021) data for stroke ASMR, European Center for Medium-Range Weather Forecasts Reanalysis v5 (ERA5) climate data, and air pollution data (nitrogen dioxide [NO2], fine particulate matter [PM2.5], ground-level ozone [O3]). Climate variability indicators included temperature and humidity deviance percentages, extreme weather events, and variability measures. Linear mixed-effects models examined associations between stroke ASMR and climate variability indicators, air pollution, Socio-Demographic Index (SDI), smoking, and alcohol consumption.Results Global stroke ASMR substantially decreased from 2000–2020, driven by increased SDI and reduced smoking. Each 2.34% decrease in negative humidity deviance increased ASMR by 0.98/100,000 (95% CI: 0.21–1.76; p < 0.05). Each 13.16-day increase in extreme hot days raised ASMR by 0.59/100,000 (95% CI: 0.14–1.04; p < 0.05). Each 14.01-day increase in extreme cold days elevated ASMR by 0.67/100,000 (95% CI: 0.24–1.11; p < 0.05). Each 9.7 ppb ozone increase statistically significantly raised ASMR by 7.41/100,000 (95% CI: 6.02–8.80; p < 0.05).Conclusion These associations suggest potential benefits from addressing climate variability mitigation, air pollution control, and stroke prevention to reduce global stroke mortality burden.