Short-term effects of NO2 on the risk of stroke hospitalization and interaction with climatic factors: a medical record-based study

Background Evidence for NO2 as a traffic sign pollutant on the risk of stroke in the population is deficient, and there is no clear evidence of an interaction with extreme meteorological conditions. Methods We used a generalized additive model to assess the independent effect of NO2 on stroke, plotted exposure-response curves to assess the relationship between ambient NO2 concentrations and the risk of hospitalization for stroke in the population, and stratified analyses to assess the presence of interactions between NO2 and temperature and humidity. Findings The single-day lagged and cumulative lagged effects of NO2 on the risk of HS hospitalization had the largest effect values at Lag0 (ER = 3.430, 95%CI: 1.326 ~ 5.577), Lag05 (ER = 4.643, 95%CI: 0.781 ~ 8.652), respectively; and the single-day lagged and cumulative lagged effects of NO2 on the risk of IS hospitalization had the largest effect value at The effect values were largest at Lag1 (ER = 2.076, 95%CI: 0.180 ~ 4.007) and Lag02 (ER = 3.347, 95% CI: 0.827 ~ 5.529).High temperature was synergistic with ambient NO2 on the risk of hospitalization in both HS and IS total populations (RERI = 0.083, 95%CI: 0.004 ~ 0.207), (RERI = 0.074, 95%CI: 0.009 ~ 0.168), and low RH and high RH synergistic with ambient NO2 on the risk of hospitalization in HS (RERI = 0.099, 95% CI: 0.052 to 0.142), (RERI = 0.127, 95% CI: 0.111 to 0.155). Interpretation Exposure to NO2 increases the risk of hospitalization related to hemorrhagic and ischemic strokes. NO2 and temperature or humidity interact with risk of stroke hospitalization with sex and age differences.