Mortality risk attributable to high and low ambient temperature: a multicountry observational study

Gasparrini, Antonio,Guo, Yuming,Hashizume, Masahiro,Lavigne, Eric,Zanobetti, Antonella,Schwartz, Joel,Tobias, Aurelio,Tong, Shilu,Rocklö,v, Joacim,Forsberg, Bertil,Leone, Michela,De Sario, Manuela Elsevier 2015 The Lancet Vol.386 No.9991

<P><B>Summary</B></P><P><B>Background</B></P><P>Although studies have provided estimates of premature deaths attributable to either heat or cold in selected countries, none has so far offered a systematic assessment across the whole temperature range in populations exposed to different climates. We aimed to quantify the total mortality burden attributable to non-optimum ambient temperature, and the relative contributions from heat and cold and from moderate and extreme temperatures.</P><P><B>Methods</B></P><P>We collected data for 384 locations in Australia, Brazil, Canada, China, Italy, Japan, South Korea, Spain, Sweden, Taiwan, Thailand, UK, and USA. We fitted a standard time-series Poisson model for each location, controlling for trends and day of the week. We estimated temperature–mortality associations with a distributed lag non-linear model with 21 days of lag, and then pooled them in a multivariate metaregression that included country indicators and temperature average and range. We calculated attributable deaths for heat and cold, defined as temperatures above and below the optimum temperature, which corresponded to the point of minimum mortality, and for moderate and extreme temperatures, defined using cutoffs at the 2·5th and 97·5th temperature percentiles.</P><P><B>Findings</B></P><P>We analysed 74 225 200 deaths in various periods between 1985 and 2012. In total, 7·71% (95% empirical CI 7·43–7·91) of mortality was attributable to non-optimum temperature in the selected countries within the study period, with substantial differences between countries, ranging from 3·37% (3·06 to 3·63) in Thailand to 11·00% (9·29 to 12·47) in China. The temperature percentile of minimum mortality varied from roughly the 60th percentile in tropical areas to about the 80–90th percentile in temperate regions. More temperature-attributable deaths were caused by cold (7·29%, 7·02–7·49) than by heat (0·42%, 0·39–0·44). Extreme cold and hot temperatures were responsible for 0·86% (0·84–0·87) of total mortality.</P><P><B>Interpretation</B></P><P>Most of the temperature-related mortality burden was attributable to the contribution of cold. The effect of days of extreme temperature was substantially less than that attributable to milder but non-optimum weather. This evidence has important implications for the planning of public-health interventions to minimise the health consequences of adverse temperatures, and for predictions of future effect in climate-change scenarios.</P><P><B>Funding</B></P><P>UK Medical Research Council.</P>

Heat Wave and Mortality: A Multicountry, Multicommunity Study

Guo, Yuming,Gasparrini, Antonio,Armstrong, Ben G.,Tawatsupa, Benjawan,Tobias, Aurelio,Lavigne, Eric,Coelho, Micheline de Sousa Zanotti Stagliorio,Pan, Xiaochuan,Kim, Ho,Hashizume, Masahiro,Honda, Yasu Environmental Health Perspectives 2017 Environmental health perspectives Vol.125 No.8

<P><B>Background:</B></P><P>Few studies have examined variation in the associations between heat waves and mortality in an international context.</P><P><B>Objectives:</B></P><P>We aimed to systematically examine the impacts of heat waves on mortality with lag effects internationally.</P><P><B>Methods:</B></P><P>We collected daily data of temperature and mortality from 400 communities in 18 countries/regions and defined 12 types of heat waves by combining community-specific daily mean temperature [FORMULA OMISSION], 92.5th, 95th, and 97.5th percentiles of temperature with duration [FORMULA OMISSION], 3, and 4 d. We used time-series analyses to estimate the community-specific heat wave–mortality relation over lags of 0–10 d. Then, we applied meta-analysis to pool heat wave effects at the country level for cumulative and lag effects for each type of heat wave definition.</P><P><B>Results:</B></P><P>Heat waves of all definitions had significant cumulative associations with mortality in all countries, but varied by community. The higher the temperature threshold used to define heat waves, the higher heat wave associations on mortality. However, heat wave duration did not modify the impacts. The association between heat waves and mortality appeared acutely and lasted for 3 and 4 d. Heat waves had higher associations with mortality in moderate cold and moderate hot areas than cold and hot areas. There were no added effects of heat waves on mortality in all countries/regions, except for Brazil, Moldova, and Taiwan. Heat waves defined by daily mean and maximum temperatures produced similar heat wave–mortality associations, but not daily minimum temperature.</P><P><B>Conclusions:</B></P><P>Results indicate that high temperatures create a substantial health burden, and effects of high temperatures over consecutive days are similar to what would be experienced if high temperature days occurred independently. People living in moderate cold and moderate hot areas are more sensitive to heat waves than those living in cold and hot areas. Daily mean and maximum temperatures had similar ability to define heat waves rather than minimum temperature. https://doi.org/10.1289/EHP1026</P>

Changing Susceptibility to Non-Optimum Temperatures in Japan, 1972–2012: The Role of Climate, Demographic, and Socioeconomic Factors

Chung, Yeonseung,Yang, Daewon,Gasparrini, Antonio,Vicedo-Cabrera, Ana M.,Fook Sheng Ng, Chris,Kim, Yoonhee,Honda, Yasushi,Hashizume, Masahiro Environmental Health Perspectives 2018 Environmental health perspectives Vol.126 No.5

<P><B>Background:</B></P><P>Previous studies have shown that population susceptibility to non-optimum temperatures has changed over time, but little is known about the related time-varying factors that underlie the changes.</P><P><B>Objective:</B></P><P>Our objective was to investigate the changing population susceptibility to non-optimum temperatures in 47 prefectures of Japan over four decades from 1972 to 2012, addressing three aspects: minimum mortality temperature (MMT) and heat- and cold-related mortality risks. In addition, we aimed to examine how these aspects of susceptibility were associated with climate, demographic, and socioeconomic variables.</P><P><B>Methods:</B></P><P>We first used a two-stage time-series design with a time-varying distributed lag nonlinear model and multivariate meta-analysis to estimate the time-varying MMT, heat- and cold-related mortality risks. We then applied linear mixed effects models to investigate the association between each of the three time-varying aspects of susceptibility and various time-varying factors.</P><P><B>Results:</B></P><P>MMT increased from 23.2 [95% confidence interval (CI): 23, 23.6] to 28.7 (27.0, 29.7) °C. Heat-related mortality risk [relative risk (RR) for the 99th percentile of temperature vs. the MMT] decreased from 1.18 (1.15, 1.21) to 1.01 (0.98, 1.04). Cold-related mortality risk (RR for the first percentile vs. the MMT) generally decreased from 1.48 (1.41, 1.54) to 1.35 (1.32, 1.40), with the exception of a few eastern prefectures that showed increased risk. The changing patterns in all three aspects differed by region, sex, and causes of death. Higher mean temperature was associated ([FORMULA OMISSION]) with lower heat risk, whereas higher humidity was associated with higher cold risk. A higher percentage of elderly people was associated with a higher cold risk, whereas higher economic strength of the prefecture was related to lower cold risk.</P><P><B>Conclusions:</B></P><P>Population susceptibility to heat has decreased over the last four decades in Japan. Susceptibility to cold has decreased overall except for several eastern prefectures where it has either increased or remained unchanged. Certain climate, demographic, and socioeconomic factors explored in the current study might underlie this changing susceptibility. https://doi.org/10.1289/EHP2546</P>

Mortality burden of diurnal temperature range and its temporal changes: A multi-country study

Lee, Whanhee,Bell, Michelle L.,Gasparrini, Antonio,Armstrong, Ben G.,Sera, Francesco,Hwang, Sunghee,Lavigne, Eric,Zanobetti, Antonella,Coelho, Micheline de Sousa Zanotti Stagliorio,Saldiva, Paulo Hila Elsevier 2018 Environment international Vol.110 No.-

<P><B>Abstract</B></P> <P>Although diurnal temperature range (DTR) is a key index of climate change, few studies have reported the health burden of DTR and its temporal changes at a multi-country scale. Therefore, we assessed the attributable risk fraction of DTR on mortality and its temporal variations in a multi-country data set. We collected time-series data covering mortality and weather variables from 308 cities in 10 countries from 1972 to 2013. The temporal change in DTR-related mortality was estimated for each city with a time-varying distributed lag model. Estimates for each city were pooled using a multivariate meta-analysis. The results showed that the attributable fraction of total mortality to DTR was 2.5% (95% eCI: 2.3–2.7%) over the entire study period. In all countries, the attributable fraction increased from 2.4% (2.1–2.7%) to 2.7% (2.4–2.9%) between the first and last study years. This study found that DTR has significantly contributed to mortality in all the countries studied, and this attributable fraction has significantly increased over time in the USA, the UK, Spain, and South Korea. Therefore, because the health burden of DTR is not likely to reduce in the near future, countermeasures are needed to alleviate its impact on human health.</P> <P><B>Highlights</B></P> <P> <UL> <LI> We analyzed the health burden of diurnal temperature range (DTR) for 10 countries. </LI> <LI> In addition, we estimated the temporal changes in the mortality burden of DTR. </LI> <LI> The excessive risk and attributable risk of DTR was significant in most countries. </LI> <LI> The mortality burden due to DTR has been increased during decades (1972–2013). </LI> <LI> We conclude that the effect of DTR will not decrease in the near future. </LI> </UL> </P>

Predicted temperature-increase-induced global health burden and its regional variability

Lee, Jae Young,Kim, Ho,Gasparrini, Antonio,Armstrong, Ben,Bell, Michelle L.,Sera, Francesco,Lavigne, Eric,Abrutzky, Rosana,Tong, Shilu,Coelho, Micheline de Sousa Zanotti Stagliorio,Saldiva, Paulo Hila Elsevier 2019 Environment international Vol.131 No.-

<P><B>Abstract</B></P> <P>An increase in the global health burden of temperature was projected for 459 locations in 28 countries worldwide under four representative concentration pathway scenarios until 2099. We determined that the amount of temperature increase for each 100 ppm increase in global CO<SUB>2</SUB> concentrations is nearly constant, regardless of climate scenarios. The overall average temperature increase during 2010–2099 is largest in Canada (1.16 °C/100 ppm) and Finland (1.14 °C/100 ppm), while it is smallest in Ireland (0.62 °C/100 ppm) and Argentina (0.63 °C/100 ppm). In addition, for each 1 °C temperature increase, the amount of excess mortality is increased largely in tropical countries such as Vietnam (10.34%p/°C) and the Philippines (8.18%p/°C), while it is decreased in Ireland (−0.92%p/°C) and Australia (−0.32%p/°C). To understand the regional variability in temperature increase and mortality, we performed a regression-based modeling. We observed that the projected temperature increase is highly correlated with daily temperature range at the location and vulnerability to temperature increase is affected by health expenditure, and proportions of obese and elderly population.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Future health burden with respect to CO<SUB>2</SUB> increase was projected in 28 countries. </LI> <LI> Future temperature and mortality were compared across locations. </LI> <LI> Daily temperature range determines the rate of temperature increase. </LI> <LI> Amount of health expenditure determines the vulnerability to temperature change. </LI> </UL> </P>