College of Atmospheric Sciences, Chengdu University of Information Technology, Chengdu, 610000, Sichuan, China.
Key Laboratory for Semi-Arid Climate Change of the Ministry of Education, College of Atmospheric Sciences, Lanzhou University, Lanzhou, 730000, China.
Environ Sci Pollut Res Int. 2020 Jul;27(21):26211-26220. doi: 10.1007/s11356-020-08960-5. Epub 2020 May 2.
Ambient air temperature is a key factor affecting human health. Adverse effects of extreme weather on mortality have been well explored and expounded in numerous epidemiological studies. The relationship between moderate temperature and mortality is, however, underexplored. This study quantitatively investigated the temperature-dependent mortality burden in China. Data on daily average temperature and mortality in 15 Chinese cities during 2010-2016 were collected for this study. The association between temperature and city-specific mortality was investigated with a quasi-Poisson regression combined with a distributed lag nonlinear model across lag 0-21 days. The results were then included in a multivariate meta-analysis to derive the pooled estimates of the effect of temperature on mortality at the multi-city level. Mortality fractions attributable to cold and heat (i.e., at temperatures below and above the minimum mortality temperature (MMT)) were calculated. Additionally, temperature ranges were further divided into 1 °C intervals of ambient temperature, and the attributable fractions were calculated for each range. The MMT varied from the 71th to 93th percentiles of temperature in the 15 Chinese cities, centering at the 78th percentile at the multi-city level. In total, 12.65% of non-accidental mortality was attributable to non-optimum temperature, of which cold and hot temperatures corresponded to attributable fractions of 11.38% and 1.27%, respectively. The results of temperature stratifications suggested that moderately cold temperatures provided the highest contribution to mortality caused by temperature. Specifically, the highest attributable fractions were at 7 °C, 7 °C, 8 °C, 8 °C, 4 °C, 4 °C, 5 °C, 7 °C, 7 °C, 4 °C, 5 °C, 5 °C, 6 °C, 11 °C, and 12 °C, for Harbin, Changchun, Shenyang, Urumqi, Beijing, Tianjin, Shijiazhuang, Xining, Lanzhou, Nanjing, Shanghai, Hefei, Chengdu, Kunming, and Guangzhou, respectively. Cold temperature was responsible for a higher proportion of deaths than heat. Moderate cold temperature contributed to most of the total health burden. Finally, the cumulative total counts of deaths caused by moderate cold were the largest. Although moderate cold conferred a slightly lower relative risk than extreme cold, it was more common than extreme cold. Taken together, our results show that the effects of moderate cold temperature on health should receive more attention. Furthermore, our findings could help improve the prediction of climate change effects on human health and support the development of response strategies for the changing climate.
环境空气温度是影响人类健康的关键因素。大量流行病学研究已经充分探讨和阐述了极端天气对死亡率的不利影响。然而，适中温度与死亡率之间的关系尚未得到充分探索。本研究定量调查了中国因温度变化导致的死亡负担。本研究收集了 2010-2016 年中国 15 个城市的每日平均温度和死亡率数据。采用准泊松回归结合分布式滞后非线性模型，研究了温度与城市特异性死亡率之间的关系，滞后 0-21 天。然后将结果纳入多城市水平的死亡率与温度的多变量荟萃分析中，得出温度对死亡率影响的综合估计。计算了归因于寒冷和炎热（即温度低于和高于最低死亡率温度（MMT））的死亡率分数。此外，进一步将温度范围分为 1°C 的环境温度间隔，并计算每个范围的归因分数。15 个中国城市的 MMT 从第 71 到 93 百分位数的温度变化，多城市水平的中位数为第 78 百分位数。总的来说，非意外死亡率的 12.65%归因于非最佳温度，其中寒冷和炎热温度对应的归因分数分别为 11.38%和 1.27%。温度分层的结果表明，适中的寒冷温度对温度引起的死亡率有最高的贡献。具体来说，最高的归因分数分别为 7°C、7°C、8°C、8°C、4°C、4°C、5°C、7°C、7°C、4°C、5°C、5°C、6°C、11°C 和 12°C，分别对应哈尔滨、长春、沈阳、乌鲁木齐、北京、天津、石家庄、西宁、兰州、南京、上海、合肥、成都、昆明和广州。寒冷温度导致的死亡比例高于炎热温度。中度寒冷导致了大部分的总健康负担。最后，中度寒冷导致的死亡总累计数最大。虽然中度寒冷的相对风险略低于极端寒冷，但它比极端寒冷更常见。综上所述，我们的研究结果表明，适中温度对健康的影响应引起更多关注。此外，我们的研究结果可以帮助改善对气候变化对人类健康影响的预测，并为应对气候变化提供支持。
