The temporal variation in the effects of extreme temperature on respiratory mortality: Evidence from 136 cities in China, 2006–2019

Background: In the context of climate change and urbanization, the temporal variation of the adverse health effect of extreme temperature has attracted increasing attention. Methods: The meteorological data and the daily death records of mortality from respiratory diseases of 136 Chinese cities were from 2006 to 2019. Heat wave and cold spell were selected as the indicator events of extreme high temperature and extreme low temperature, respectively. The generalized linear model and time-varying distributed lag model were used to perform a two-stage time-series analysis to evaluate the temporal variation of the mortality risk associated with extreme temperature in the total population, sub-populations (sex- and age- specific) and different regions (climatic zone and relative humidity level). Results: During the study period, relative risk (RR) of respiratory mortality associated with heat wave decreased from 1.22 (95 %CI: 1.07–1.39) to 1.13 (95 %CI: 1.01–1.26) in the total population, and RR of respiratory mortality associated with cold spell decreased from 1.30 (95 %CI: 1.14–1.49) to 1.17 (95 %CI: 1.08–1.26). The impact of heat wave reduced in the males (P = 0.044) and in the females as with cold spell (P