Jing Hu1, Ying Wen2, Yanran Duan1, Siyu Yan1, Yi Liao3, Haibin Pan4, Jiahui Zhu2, Ping Yin1, Jinquan Cheng5, Hongwei Jiang6. 1. Department of Epidemiology and Biostatistics, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China. 2. Department of Molecular Epidemiology, Shenzhen Center for Disease Control and Prevention, Shenzhen, China. 3. Department of Public Health Promotion, Shenzhen Center for Disease Control and Prevention, Shenzhen, China. 4. Laboratory of Physical Testing and Chemical Analysis, Shenzhen Center for Disease Control and Prevention, Shenzhen, China. 5. Shenzhen Center for Disease Control and Prevention, Shenzhen, China. 6. Department of Epidemiology and Biostatistics, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China. Electronic address: 2011020088@hust.edu.cn.
Abstract
BACKGROUND: Compared to hospital admissions (HAs), emergency ambulance dispatches (EADs) can be considered a real-time outcome for evaluating the public health impacts of ambient temperature. OBJECTIVES: This study aimed to assess if temperature has a causal effect on cause-specific EADs and its potential main and added effect in Shenzhen from 2013 to 2017. METHODS: A distributed lag nonlinear model (DLNM) with quasi-Poisson distribution was applied to quantify the association between temperature and EADs. Likewise, the fraction of EADs attributable to different temperature ranges was calculated to identify extreme temperature ranges affecting population health. We then explored the main and added wave effects of heatwaves. RESULTS: Ambient temperature showed a U-shaped association with EADs. The minimum risk temperature was 17 °C (16th percentile of the daily mean temperature). Compared with the cold, the relative risk (RR) of heat on EADs presented smaller but the attributable risk larger. The main effects of heatwaves on EADs varied with external causes; and the peak RR of heat on EADs was observed in suicidal behaviors with heatwaves defined as 3 or more days with temperatures above the 75th percentile (RR = 4.53, 95% CI: 1.23-16.68), followed by assault (RR = 2.36, 95% CI: 1.25-4.48) and accidents (RR = 1.72, 95% CI: 1.30-2.28), while the added wave effect was negligible. CONCLUSIONS: Heat was responsible for a higher proportion of EADs than cold. Most of the increase in health risk during warm season can be simply ascribed to the independent effects of daily temperature occurrences whether it is or not on the heat-wave day. And the main effects of heatwaves on cause-specific EADs showed varied change trends, of which the incidence of suicides seems more susceptible, followed by assault and accidents.
BACKGROUND: Compared to hospital admissions (HAs), emergency ambulance dispatches (EADs) can be considered a real-time outcome for evaluating the public health impacts of ambient temperature. OBJECTIVES: This study aimed to assess if temperature has a causal effect on cause-specific EADs and its potential main and added effect in Shenzhen from 2013 to 2017. METHODS: A distributed lag nonlinear model (DLNM) with quasi-Poisson distribution was applied to quantify the association between temperature and EADs. Likewise, the fraction of EADs attributable to different temperature ranges was calculated to identify extreme temperature ranges affecting population health. We then explored the main and added wave effects of heatwaves. RESULTS: Ambient temperature showed a U-shaped association with EADs. The minimum risk temperature was 17 °C (16th percentile of the daily mean temperature). Compared with the cold, the relative risk (RR) of heat on EADs presented smaller but the attributable risk larger. The main effects of heatwaves on EADs varied with external causes; and the peak RR of heat on EADs was observed in suicidal behaviors with heatwaves defined as 3 or more days with temperatures above the 75th percentile (RR = 4.53, 95% CI: 1.23-16.68), followed by assault (RR = 2.36, 95% CI: 1.25-4.48) and accidents (RR = 1.72, 95% CI: 1.30-2.28), while the added wave effect was negligible. CONCLUSIONS: Heat was responsible for a higher proportion of EADs than cold. Most of the increase in health risk during warm season can be simply ascribed to the independent effects of daily temperature occurrences whether it is or not on the heat-wave day. And the main effects of heatwaves on cause-specific EADs showed varied change trends, of which the incidence of suicides seems more susceptible, followed by assault and accidents.