Impacts of extremely high temperature and heatwave on heatstroke in Chongqing, China

Abstract

Few studies have reported the quantitative association between heat and heatstroke (HS) occurrence, particularly in China. The aim of this study was to quantitatively assess the association between high temperature/heatwave and HS occurrence in Chongqing. The daily HS data from 2009 to 2013 of Chongqing were extracted from Chongqing Center for Disease Control and Prevention. A Zero-inflated Poisson regression model (ZIP) with a logistic distribution was used to quantitatively analyze the impacts of the daily maximum temperature (Tmax) over the threshold on HS occurrence by gender, age, and severity of HS, after controlling for covariates including day of the week (DOW), relative humidity, and daily temperature range. Lag effects up to 10 days were analyzed. Heatwave intensity, which was classified into four levels according to the quartile of its values, was calculated by Tmax multiplied the duration of a heatwave. The excess risk of HS during heatwave with different intensity was analyzed. The Tmax threshold for HS was 34 °C in Chongqing. After adjusting for potential confounders, strong associations and age-specific lag effects between Tmax and daily HS occurrence were observed. The impacts of Tmax on total HS lasted for 7 days (lag0-6), with the highest excess risk (ER) value of 30.5% (95% CI 23.6 and 37.8%) on lag0 with each 1 °C increment in Tmax over the threshold. A slightly stronger temperature-HS association was detected in male compared to female. The population over 65 years had the highest ER and the younger adults aged 19-35 and 35-55 years also showed significant heat-HS associations. The number of daily cases increased with the increasing of duration of heatwave and the peak value occurred on the eleventh day of the heatwave. The excess risk of HS during the heatwave with 1 to 4 level of intensity increased by 2.54, 2.97, 5.61, and 11.3 times, respectively, as compared with that of non-heatwave. Extreme heat is becoming a huge threat to public health due to the strong temperature-HS associations in Chongqing. Climate change with increasing temperatures may make the situation worse. Our results can provide reference for developing and improving relevant public health strategies and early extreme weather and health warning system to prevent and reduce the health risks due to extreme weather and climate change in Chongqing.

Expert consensus on the diagnosis and treatment of heat stroke in China

“…Statistical data have shown that the incidences of HS and HSinduced deaths are increasing each year. However, the existing data are limited to some cities or provinces with small sample sizes, and as a result, they have limited reference value [19][20][21][22]. Currently, large-scale HS epidemiology data are still lacking in China.…”

Health impact of climate change in cities of middle-income countries: the case of China

“…The Chinese Centre of Diseases Control and Prevention put in place the Heat-Related Illness Surveillance System in 2007, and the relevant data have been analyzed in several studies conducted in the past few years. Major cities including Chongqing, Wuhan, Shanghai and Ningbo reported the most number of cases, and strong association between maximum temperature and heat-related illness had been consistently found in studies conducted across China, 82 in Chongqing 83 and in Ningbo, 84 with 34°C estimated to be the threshold point for Chongqing.…”

Direct and indirect health impacts of climate change on the vulnerable elderly population in East China

“…Increased human health vulnerability to climate change is associated with many factors including rapid population growth, (as in the case of China) poverty and hunger, poor health, low levels of education, and lack of access to information on climate change (Demirkesen and Evrendilek 2017;Füssel and Klein 2006). It has been shown that the elderly (people who are 65 years or older) are particularly vulnerable to the impacts of heat waves (Li et al 2017b). For example, the 2003 heatwave in Shanghai was reported to have caused a 12 percent increase in total deaths and a 19 percent increase in cardiovascular mortality amongst the elderly .…”

“…It is estimated that the heat waves will cause severe health impacts on the metropolitan areas in the Pearl River Delta as heat waves become more intense and longer in duration (Yao-Dong et al 2013). Many studies that have investigated heat wave related mortality (Li et al 2017b;Luo and Lau 2017;Yin and Wang 2017;Zhou et al 2017) but less attention has been given to the health effects of cold spells (Staddon et al 2014) in the context of global climate change (Zhou et al 2014). It is important to note that climate change may lead to warmer winters but with greater weather variability leading to the counter intuitive effect of more cold spells occurring.…”