Association between temperature and mortality: a multi-city time series study in Sichuan Basin, southwest China

BACKGROUND@#There are few multi-city studies on the association between temperature and mortality in basin climates. This study was based on the Sichuan Basin in southwest China to assess the association of basin temperature with non-accidental mortality in the population and with the temperature-related mortality burden.@*METHODS@#Daily mortality data, meteorological and air pollution data were collected for four cities in the Sichuan Basin of southwest China. We used a two-stage time-series analysis to quantify the association between temperature and non-accidental mortality in each city, and a multivariate meta-analysis was performed to obtain the overall cumulative risk. The attributable fractions (AFs) were calculated to access the mortality burden attributable to non-optimal temperature. Additionally, we performed a stratified analyses by gender, age group, education level, and marital status.@*RESULTS@#A total of 751,930 non-accidental deaths were collected in our study. Overall, 10.16% of non-accidental deaths could be attributed to non-optimal temperatures. A majority of temperature-related non-accidental deaths were caused by low temperature, accounting for 9.10% (95% eCI: 5.50%, 12.19%), and heat effects accounted for only 1.06% (95% eCI: 0.76%, 1.33%). The mortality burden attributable to non-optimal temperatures was higher among those under 65 years old, females, those with a low education level, and those with an alternative marriage status.@*CONCLUSIONS@#Our study suggested that a significant association between non-optimal temperature and non-accidental mortality. Those under 65 years old, females, and those with a low educational level or alternative marriage status had the highest attributable burden.

A time-series study on the impact of air pollution on the death of permanent residents in Yancheng City / 公共卫生与预防医学

Objective To investigate the effects of air pollution on non-accidental death of residents in Yancheng City. Methods Data of daily air pollutions (PM2.5, PM10, NO2, SO2 and O3), average temperature, average relative humidity, and daily death information during 2014-2019 were collected. The time series semi parametric generalized additive model was used to analyze the impact of short-term exposure of air pollutants on non-accidental death in Yancheng City. Results The average daily non-accidental deaths of the entire population, respiratory system, and circulatory system were 154, 25, and 51, respectively. With the increase of 10 µg/m3 SO2, the risk of the estimated non-accidental death and respiratory death was increased by 1.19% (95%CI: 0.26%-2.12%) and 2.37% (95%CI: 0.65%-4.12 %), respectively. With the increase of 10 µ g/m3 NO2, the risk of the estimated non-accidental death, circulatory system death and respiratory death was increased by 1.50%（95%CI:0.94%-2.05%）, 1.11%（95%CI:0.08%-2.16%）, and 1.53%（95%CI:0.71%-2.36%）, respectively. With the increase of 10 µg/m3 O3, the risk of the estimated non-accidental death, circulatory system death and respiratory death was increased by 0.64%（95%CI: 0.25%-1.04%）, 0.81%（95%CI: 0.04%-1.58%）, and 0.78%（95%CI: 0.18%-1.37%）, respectively. Conclusion The short-term exposure of air pollutants affects the non-accidental death of the residents in Yancheng, and there are lag effects, of which NO2, SO2 and O3 have a greater impact.

Lagged effect of temperature on non-accidental mortality and years of life lost in Wuxi: a time-series study / 中华疾病控制杂志

Objective To evaluate the effect of air temperature on non-accidental mortality (A00-R99) and years of life lost in Wuxi city. Methods Data on daily non-accidental mortality and meteorology index were collected from 2012 to 2017. Distributed lag non-linear model (DLNM) was used to assess the effect of temperature on non-accidental death and YLL and the cumulative effects between cold and hot temperature on non-accidental mortality and years of life lost with different lag days. Results A V-shaped relationship was noticed between temperature and mortality. Cold effects were delayed by 3 days and persisted for 14 days. Hot effects appeared acute and reached the peak at the same day. Low temperature had stronger gross effect than high temperature had. There were differences of temperature effects between different age and gender groups. Conclusions Low and high temperature were associated with elevated mortality risk. Cold effect had lagged effect and persisted for long time, however, hot effects appeared acute and the impact of low temperature was greater.

Estimating and projecting the acute effect of cold spells on excess mortality under climate change in Guangzhou / 中华预防医学杂志

Objective@#To estimate future excess mortality attributable to cold spells in Guangzhou, China.@*Methods@#We collected the mortality data and metrological data from 2009-2013 of Guangzhou to calculated the association between cold spell days and non-accidental mortality with GLM model. Then we projected future daily average temperatures (2020-2039 (2020s) , 2050-2069 (2050s) , 2080-2099 (2080s) ) with 5 GCMs models and 2 RCPs (RCP4.5 and RCP8.5) to identify cold spell days. The baseline period was the 1980s (1980-1999). Finally, calculated the yearly cold spells related excess death of 1980s, 2020s, 2050s, and 2080s with average daily death count of non-cold spell days, exposure-response relationship, and yearly number of cold spell days.@*Results@#The average of daily non-accidental mortality in Guangzhou from 2009 to 2013 was 96, and the average of daily average was 22.0 ℃. Cold spell days were associated with 3.3% (95%CI: 0.4%-6.2%) increase in non-accidental mortality. In 1980s, yearly cold spells related deaths were 34 (95%CI: 4-64). In 2020s, the number will increase by 0-10; in 2050s, the number will increase by 1-9; and in 2080s, will increase by 1-9 under the RCP4.5 scenario. In 2020s, the number will increase by 0-9; in 2050s, the number will increase by 1-6; and in 2080s, will increase by 0-11 under the RCP8.5 scenario.@*Conclusion@#The cold spells related non-accidental deaths in Guangzhou will increase in future under climate change.

PM10 Exposure and Non-accidental Mortality in Asian Populations: A Meta-analysis of Time-series and Case-crossover Studies / 예방의학회지

OBJECTIVES: We investigated the association between particulate matter less than 10 microm in aerodynamic diameter (PM10) exposure and non-accidental mortality in Asian populations by meta-analysis, using both time-series and case-crossover analysis. METHODS: Among the 819 published studies searched from PubMed and EMBASE using key words related to PM10 exposure and non-accidental mortality in Asian countries, 8 time-series and 4 case-crossover studies were selected for meta-analysis after exclusion by selection criteria. We obtained the relative risk (RR) and 95% confidence intervals (CI) of non-accidental mortality per 10 microg/m3 increase of daily PM10 from each study. We used Q statistics to test the heterogeneity of the results among the different studies and evaluated for publication bias using Begg funnel plot and Egger test. RESULTS: Testing for heterogeneity showed significance (p<0.001); thus, we applied a random-effects model. RR (95% CI) per 10 microg/m3 increase of daily PM10 for both the time-series and case-crossover studies combined, time-series studies relative risk only, and case-crossover studies only, were 1.0047 (1.0033 to 1.0062), 1.0057 (1.0029 to 1.0086), and 1.0027 (1.0010 to 1.0043), respectively. The non-significant Egger test suggested that this analysis was not likely to have a publication bias. CONCLUSIONS: We found a significant positive association between PM10 exposure and non-accidental mortality among Asian populations. Continued investigations are encouraged to contribute to the health impact assessment and public health management of air pollution in Asian countries.