A time series analysis of the impact of extreme temperature on non-accidental 120 emergency visits in Xining, China, 2016—2019

Objective To investigate the association between extreme temperature and non-accidental 120 emergency visits in Xining, China, and to identify vulnerable populations.

Methods The data of daily emergency visits in Xining in 2016—2019 were obtained from Qinghai Provincial Medical Emergency Center, daily meteorological data were obtained from Qinghai Provincial Meteorological Bureau, and air pollution data were collected from Xining Ecology and Environment Bureau. After controlling for the confounding factors such as atmospheric pollutant concentration, humidity, and the day-of-the-week effect, a distributed lag non-linear model was used to fit the association between daily average temperature and emergency visits, including its lag effect, and subgroup analyses were performed based on sex and age.

Results In 2016—2019, Qinghai Provincial Medical Emergency Center handled 48 354 non-accidental emergency visits in Xining, with a median daily number of 29 visits. Both extremely high and low temperature caused an increase in non-accidental emergency visits, and the effect of high temperature appeared on the same day and lasted for 6 days, while the effect of low temperature appeared after a lag of 5 days and lasted for 11 days. The maximum cumulative relative risk (cumRR) (lag 0-19 d) for the total population under extremely low temperature (P_2.5=-10 ℃) was 1.49 (95% confidence interval CI: 1.09-2.04), while the maximum cumRR (lag 0-9 d) under extremely high temperature (P_97.5 = 21 ℃) was 1.15 (95% CI: 1.06-1.25). There was a slight difference in cumulative effect value between different populations, with female individuals showing a higher cumulative effect from cold than male individuals and the < 65 years age group showing a higher cumulative effect from heat than the ≥65 years age group.

Conclusion Both extremely high and low temperature can increase the risk of non-accidental emergency visits among the residents of Xining, with the presence of lag effects. The health hazard effect is rapid but short-lived under extremely high temperature and is slow but long-lasting under extremely low temperature.