Association of ambient temperature with mortality of residents in Yancheng, China: a study based on the distributed lag non-linear model

Objective To investigate the health effect of temperature on the mortality of residents in Yancheng, China.

Methods Daily mortality data (total non-accidental mortality, respiratory disease mortality, and circulatory disease mortality), meteorological data, and air pollution data of Yancheng from 2015 to 2019 were collected from local disease control and prevention departments, meteorological bureau, and environmental monitoring centers, respectively. A distributed lag non-linear model was established to evaluate the association between temperature and mortality of residents.

Results The association curves of temperature with total non-accidental mortality, respiratory disease mortality, and circulatory disease mortality were U-shaped. The association of extreme low temperature with total non-accidental mortality, respiratory disease mortality, and circulatory disease mortality showed a lag effect, and the highest value of relative risk (RR) was observed on day 3 of exposure, with RR values of 1.03 (95% confidence interval CI: 1.02-1.04), 1.06 (95% CI: 1.04-1.09), and 1.02 (95% CI: 1.00-1.04), respectively. The association of extreme high temperature with total non-accidental mortality, respiratory disease mortality, and circulatory disease mortality showed an acute effect, and the highest value of RR was observed on the day of exposure, with RR values of 1.19 (95% CI: 1.14-1.24), 1.20 (95% CI: 1.10-1.30), and 1.25 (95% CI: 1.17-1.33), respectively. The highest RR value was observed for the cumulative health effect of extreme low temperature on total non-accidental mortality, respiratory disease mortality, and circulatory disease mortality on day 14 of exposure, and the cumulative health effect of extreme high temperature on total non-accidental mortality reached the maximum value on day 3 of exposure, while the cumulative health effect of extreme high temperature on respiratory disease mortality and circulatory disease mortality reached the maximum value on day 7 of exposure. The death risk of men was higher than that of women at extreme low temperature and was lower than that of women at extreme high temperature, and the population aged ≥65 years had higher risks of total non-accidental mortality and circulatory disease mortality in extreme high temperature than the population aged < 65 years.

Conclusion Unsuitable temperature can increase the mortality and health risk of residents in Yancheng, and the lag effect of low temperature is longer than that of high temperature.