Objective: To examine the impact of heat waves and cold spells on the incidence of hemorrhagic stroke, so as to provide insights into prevention of hemorrhagic stroke. Methods: Data pertaining to the incidence of hemorrhagic stroke in Zibo City from 2015 to 2019 were collected from Shandong Provincial Management Information System for Chronic Diseases and Cause of Death Surveillance, and the meteorological data during the period from 2015 to 2019 were captured from National Meteorological Information Center of China. The air quality index (AQI) was collected from the National Daily Report of Urban Air Quality in China. Heat wave was defined as the highest daily temperature that was no less than the 90th percentile (P90), P92.5, P95 and P97.5 of the highest daily temperature in the warm season for at least 2, 3 or 4 days, and cold spell was defined as the lowest daily temperature that was no more than the P10, P7.5, P5 and P2.5 of the lowest daily temperature in the cold season for at least 2, 3 or 4 days. The effect of heat waves and cold spells on the incidence of hemorrhagic stroke was evaluated using a generalized additive model and described with relative risk (RR) and its 95%CI. Results: A total of 8 844 case with first-onset hemorrhagic stroke were recorded in Zibo City from 2015 to 2019. The lowest daily temperature that was no more than P10, P7.5 or P5 of the lowest daily temperature in the cold season for at least two days, or that was no more than P10 or P7.5 of the lowest daily temperature for at least 3 days resulted a remarkably increased risk of hemorrhagic stroke (lowest RR=1.187, 95%CI: 1.031-1.366; highest RR=1.242, 95%CI: 1.042-1.480), and after adjusting the effect of daily mean temperature, the lowest daily temperature that was no more than P10 or P7.5 of the lowest daily temperature in the cold season for at least two days, or that was no more than P10 of the lowest daily temperature for at least 3 days resulted a remarkably increased risk of hemorrhagic stroke (lowest RR=1.236, 95%CI: 1.009-1.513; highest RR=1.274, 95%CI: 1.023-1.585). However, there was no significant association between heat waves and the risk of hemorrhagic stroke. Conclusion Cold spells may increase the risk of hemorrhagic stroke, while no significant association is examined between heat waves and the risk of hemorrhagic stroke.

Objective: To investigate the impact of temperature changes between neighboring days (TCN) on the mortality risk of respiratory diseases, so as to provide the evidence for the study of deaths from respiratory diseases caused by climate change. Methods: The monitoring data of deaths from respiratory diseases in Zibo City from 2015 to 2019 were collected from Shandong Provincial Management Information System for Chronic Diseases and Cause of Death Surveillance. The meteorological and air pollutant data of the same period were collected from China Meteorological Data Website and ChinaHighAirPollutants dataset. The effect of TCN on the risk of deaths from respiratory diseases was examined using a generalized additive model combined with a distributed lag non-linear model, and subgroup analyses for gender and age were conducted. The disease burden attributed to TCN at different intervals was assessed by calculating attributable fraction. Results: Totally 11 767 deaths from respiratory diseases were reported in Zibo City from 2015 to 2019, including 6 648 males (56.50%) and 5 119 females (43.50%). There were 1 307 deaths aged <65 years (11.11%), and 10 460 deaths aged 65 years and older (88.89%). A monotonically increasing exposure-response relationship was observed between TCN and deaths from respiratory diseases in the general population, females, and the population aged 65 years and older. The 95th percentile of TCN (P95, 3.84 ℃) reached the peak at a cumulative lagged of day 11 (RR=2.063, 95%CI: 1.261-3.376). The results of subgroup analyses showed greater impacts on females and the population aged 65 years and older, with cumulative lagged effects peaking at day 12 (RR=3.119, 95%CI: 1.476-6.589) and day 11 (RR=2.107, 95%CI: 1.260-3.523). The results of attributional risk analysis showed that next-day warming might increase the attributable risk of deaths from respiratory diseases, and next-day cooling might decrease the attributable risk. Conclusion Next-day warming may increase the mortality risk of respiratory diseases, and has greater impacts on females and the population aged 65 years and older.