Non-optimal Temperatures Research Articles

Global analyses on health effects of temperature and climate change: the contribution of the MCC Network

Multi-location analyses have proven to be useful settings for assessing the health impact of environmental hazards at regional and global scales. This study design is being widely applied in climate epidemiology since it allows the quantification of health impacts across highly heterogeneous populations and the identification of vulnerability patterns using a common method. Since 2014, the MCC consortium has developed and applied advanced methodologies to provide robust estimations of mortality impacts of non-optimal temperatures at different spatiotemporal scales in the present time and future climate change scenarios. This was possible thanks to the wide geographical coverage and high statistical power of the data collected. In this work, we aimed to review and summarize findings from published global studies on temperature-related mortality impacts using the MCC dataset. We collected published articles until March 2022 by the MCC Network on health impact assessments of non-optimal temperature and mortality. We included global historical assessments and health impact projections in which heat, cold or both were considered and then combined the estimates by topic and geographical region. Findings from the 20 publications showed good agreement in terms of both spatial and temporal patterns. We found that heat and cold-related risks have decreased over time, and higher vulnerabilities are mostly found in Southeastern regions of Europe and Asia, and in large and highly urbanized cities. Results from the projection studies suggest that heat-related mortality would steeply increase in all regions, and in most of them, this increase would counteract the decrease in cold-related risks leading to a net increase in temperature-mortality under the most pessimistic scenarios. The MCC collaborative research network has greatly contributed to advancing knowledge on the impacts of climate change on health by providing valuable and unique epidemiological evidence on the mortality impacts of non-optimal temperatures. Keywords: climate change, mortality, heat, cold

Projection of combined vulnerability to air pollution and heat stress

Background: Climate change caused by anthropogenic emissions is associated with increase in the frequency and intensity of climate extremes. Exposure to non-optimal temperature is related with 2-5 million deaths per year globally. In addition, air pollution has become a key concern for public health. Particulate matter less than 2.5 µm in diameter (PM2.5) is the largest environmental risk factor globally and is expected to worsen with projected increase in anthropogenic emissions. However, little is studied on vulnerability of combined exposure to these two environmental hazards under a changing climate. Methods: We use outputs from three CMIP6 models to project PM2.5 and Wet Bulb Global Temperature (WBGT) till end of the century under SSP126, 370 and 585 scenarios. We assessed the combined vulnerability of the exposed population, represented by vulnerability index(VI), to these two risk factors by factoring in the distribution of projected gross domestic product and education attainment (together termed socioeconomic indicator). Results: We find currently, 7% of the population (8% of the population above 65years) reside in regions with the highest vulnerability (mostly in Asia), which is projected to increase to 25% (and 32%) in 2050 under the SSP370 scenario. Globally, under all the three scenarios, percentage of population exposed to the most extreme VI was projected to increase till 2050, and decrease thereafter under SSP126, but under SSP585 and SSP370 scenarios, we found a significant increase in the population exposed to the most extreme VI. Conclusions: To the best of our knowledge, we present the first results on projections of combined vulnerability from exposure to two of the most hazardous environmental risk factors,by identifying their collocational hotspots across the globe. Our results may be used to assist decision making targeted towards averting exposure and excess deaths from heat stress and air pollution in the future decades.

Climate change and cardiovascular disease mortality: exploring the association in Puducherry, India

Background and Aim: Climate change has far reaching consequences on all aspects of life, including health. Cardiovascular diseases (CVDs), the global leading cause of death, have also been found to be climate sensitive, mainly to temperature. However, the associations between CVDs and temperature are region-specific with relatively few studies on the topic from low-and-middle-income countries (LMICs). This study explores these associations in Puducherry, a coastal district in Eastern India. Methods: We analyzed the association between apparent temperature (Tapp) and CVD mortalities to estimate the burden of in-hospital CVD mortalities attributable to non-optimal temperatures between 2010-2020. We used a binomial regression model to analyze the temperature-mortality association along with a distributed lag non-linear model to capture the delayed and non-linear trends. Results: We found that the optimal temperature range for Puducherry is between 33⁰C and 35⁰C with respect to CVDs. Temperatures both above and below the optimal temperature range were associated with an increased risk of overall in-hospital CVD mortalities, resulting in a U-shaped association curve. Up to 20% of the CVD deaths could be attributable to non-optimal temperatures, with a slightly higher burden attributable to cold (11.2%) than heat (9.12%). We also found that males below 50 years of age were more vulnerable to colder temperatures while females above 50 years were more vulnerable to the heat. Mortality with cerebrovascular accidents was associated more with heat compared to cold, while ischemic heart diseases did not seem to be affected by temperature. Conclusions: This study analyses the temperature-CVD mortality association for the first time in the Puducherry district. It also identified the age and gender differences in temperature attributable CVD mortalities, which can be socio-cultural. Further studies from India could identify the regional associations and enhance the development of regional and contextual climate-health action plans. Keywords: climate-change, cardiovascular diseases,temperature, health, LMIC

Temperature and cardiovascular hospitalization in persons with and without disabilities: Invisible population in climate change discourse

BACKGROUND AND AIM: The adverse health effects of non-optimal temperatures are disproportionately distributed in the population due to differential susceptibility and adaptive capacity to heat and cold. Although persons with disabilities (PwD) can be one of the susceptible populations, they have been neglected in the climate change discourse. This study aimed to investigate the association of ambient temperature with cardiovascular hospitalization in persons with and without disabilities. METHODS: This study used the National Health Insurance Service-National Sample Cohort established by South Korea. Using nationwide data from 2003 to 2013, we conducted a space-time-stratified case-crossover study using a conditional Poisson regression with a distributed lag nonlinear model to investigate the association between daily mean temperature and cardiovascular hospitalization. The extreme and moderate heat (99th and 95th temperature percentile, respectively) and cold (1st and 5th temperature percentile, respectively) effects on hospitalization over ten days were estimated using the minimum hospitalization temperature (MHT) as a reference. All analyses were conducted separately by the existence of a disability. RESULTS: A J-shaped association between temperature and cardiovascular hospitalization was found with the MHT at 22.2°C and 15.9°C in persons with and without disabilities, respectively. In persons without disabilities, the effects of hot temperatures were acute and lasted several days, while the effects of cold temperatures appeared after 2-3 days. In PwD, the effects of hot temperatures lasted up to 10 days, while the effects of cold temperatures appeared immediately with the following deficit in hospitalizations. The cumulative cold effects over ten days were higher in PwD than their non-disabled counterparts, although the cumulative heat effects did not show a significant difference. CONCLUSIONS: PwD were more susceptible to cold-related hospitalizations compared to their non-disabled counterpart. Precision adaptation strategies to heat and cold that considers susceptibility in PwD are needed. KEYWORDS: Temperature; Climate change; Health equity; Disability

High, low, and non-optimum temperatures exposure on road injuries in a changing climate: a secondary analysis based on the Global Burden of Disease Study 2019.

Global warming in the twenty-first century has gradually made high temperatures a major threat to the global population. Health problems associated with extreme temperatures have become a growing public health concern worldwide. This study aimed to estimate road injuries stratified by sex, age, geographic location, and sociodemographic status attribute to high, low, and non-optimal temperatures in 21 regional and global. We used the Global Burden of Disease (GBD) Study Results Tool to examine the age-standardized death rates (ASDR) and disability-adjusted life years (DALYs) due to road injuries in 2019 by Joinpoint regression. In addition, we reported high, low, and non-optimal temperature exposures for road injuries across different groups by gender, age, region, and disease. Moreover, we examined temporal trends in the burden of road disease caused by high, low, and non-optimum temperatures from 1990 to 2019. Trend analyzes were conducted for five sociodemographic index (SDI) regions. Globally, both ASDR and DALY declined from 1990 to 2019, with average annual percent change (AAPC) values of - 1.3% and - 1.2%, respectively. In 2019, the indicators (death and DALYs) steadily declined, while SDI quintile increased in most regions. Road injuries related to death and DALYs rate attributed to high temperatures were 0.17 and 8.50, respectively, in 2019. From 1990 to 2019, DALYs for road injuries caused by low temperatures showed the most significant upward trend in most regions, especially in low-latitude countries. This study provides a comprehensive understanding of the road injury burden caused by high, low, and non-optimum temperatures, which remains high in regions with low SDI. Therefore, special attention should be paid to road injuries in poor countries or in areas with extreme temperatures.

Low ambient temperature might trigger the symptom onset of pulmonary embolism: A nationwide case-crossover study at hourly level in China

BackgroundPulmonary embolism (PE) is an important cause of death and its seasonality has long been observed. Very few epidemiological studies have explored the potential role of ambient temperature in PE symptom onset, especially at the hourly level. MethodsWe conducted a time-stratified case-crossover study among 17,903 PE patients with hourly onset of symptom from 1590 hospitals across China between January 2015 and September 2020. Conditional logistic regression model combined with distributed lag non-linear models were used to explore the associations between hourly ambient temperature and PE symptom onset. The attributable fractions due to non-optimum temperature were calculated. ResultsThe exposure-response relationship curve was inverse and almost linear. Lower temperature was significantly associated with higher risk of PE symptom onset when temperature was below 18 °C. This risk occurred immediately at the same hour, attenuated thereafter, and became nonsignificant at approximately 72 h after exposure. Compared with the referent temperature (P99, 34.1 °C), the odds ratio of PE symptom onset associated with extremely low temperature (P1, −16.1 °C) over lag 0–72 h was 1.63 (95%CI: 1.23, 2.16). Low temperature may account for 16.19 % of the symptom onset nationally with higher proportion in the south of China. The effects were stronger in older adults, males, and cold seasons. ConclusionsWe provided the first-hand robust evidence that transient exposure (at the hourly level) to low temperature might trigger the symptom onset of PE and constitute a considerable burden for PE patients. Targeted protections and health education are needed for susceptible populations.

Relationship of Water Temperature and Air Humidity with Aedes Sp. Manggarai Tebet Village South Jakarta in 2022

Environmental-based diseases are still a health problem for the people of Indonesia. One of the diseases caused by environmental sanitation conditions that do not meet health requirements is dengue hemorrhagic fever. Several environmental factors such as temperature, air, and the intensity of lighting that enter the house are thought to strengthen the occurrence of dengue fever. The presence of mosquito larvae is an indicator that will greatly affect the presence of mosquito populations in a place. This study aims to determine the relationship between water temperature and air humidity with the presence of Aedes sp . in RW. 03 Kelurahan Manggarai, Kecamatan Tebet, South Jakarta in 2022. This research is a descriptive analytic study with a cross sectional study design . The research location in RW 03 is located in Manggarai Village. The total population in this study amounted to 298 houses, while the sample in this study amounted to 75 houses. The sampling technique that the writer uses is cluster random sampling . The results of the study were statistically tested with the chi-square test at a 95% confidence level. The result is that there are 8 houses that found larvae (10.70%) and larvae were found in 19 containers (10.74%). The type of landfill that found the most larvae was buckets totaling 16 (9.04%). With the larva-free rate (ABJ) in RW 03 Manggarai Village, Tebet District, South Jakarta of 89.33%, House Index (HI) of 10.67%, Container Index (CI) of 9.73%, and Breteau Index (BI) by 24. Most of the houses found Aedes sp . In containers with non-optimal temperature (>27 o C) as many as 64 houses (85.30%) and optimal humidity (70-80%) for the growth of Aedes sp . A total of 67 houses (10.70%). Statistical analysis showed that there was a relationship between water temperature and the presence of Aedes sp. ( p-value = 0.000) and there is no relationship between air humidity and the presence of Aedes sp larvae . ( p-value = 0.301). To reduce the presence of Aedes sp . It is suggested that every family member must work together to prevent Aedes sp. where people can live a clean and healthy life, by regulating the air circulation in the house and eliminating the Aedes aegypti mosquito breading place .

Global, regional, and national trends of dementia incidence and risk factors, 1990-2019: A Global Burden of Disease study.

An ample literature documents the growing prevalence of dementia and associated costs. Less attention has been paid to decreased dementia incidence in some countries. We analyzed trends in age-standardized dementia, stroke, and ischemic heart disease (the triple threat) incidence rates and population attributable fraction of death and disability attributable to 12 risk factors in 204 countries and territories and 51 regions using Global Burden of Disease 2019 data. During 1990 to 2019, dementia incidence declined in 71 countries; 18 showed statistically significant declines, ranging from -12.1% (95% uncertainty intervals -16.9 to -6.8) to -2.4% (-4.6 to -0.5). During 2010 to 2019, 16 countries showed non-significant declines. Globally, the burden of the triple threat attributable to air pollution, dietary risks, non-optimal temperature, lead exposure, and tobacco use decreased from 1990 to 2019. The declining incidence of dementia in some countries, despite growing prevalence, is encouraging and urges further investigation.

Asthma mortality attributable to ambient temperatures: A case-crossover study in China

BackgroundWhether ambient temperature exposure contributes to death from asthma remains unknown to date. We therefore conducted a case-crossover study in China to quantitatively evaluate the association and burden of ambient temperature exposure on asthma mortality. MethodsUsing data from the National Mortality Surveillance System in China, we conducted a time-stratified case-crossover study of 15 888 individuals who lived in Hubei and Jiangsu province, China and died from asthma as the underlying cause in 2015–2019. Individual-level exposures to air temperature and apparent temperature on the date of death and 21 days prior were assessed based on each subject's residential address. Distributed lag nonlinear models based on conditional logistic regression were used to quantify exposure-response associations and calculate fraction and number of deaths attributable to non-optimum ambient temperatures. ResultsWe observed a reverse J-shaped association between air temperature and risk of asthma mortality, with a minimum mortality temperature of 21.3 °C. Non-optimum ambient temperature is responsible for substantial excess mortality from asthma. In total, 26.3% of asthma mortality were attributable to non-optimum temperatures, with moderate cold, moderate hot, extreme cold and extreme hot responsible for 21.7%, 2.4%, 2.1% and 0.9% of asthma mortality, respectively. The total attributable fraction and number was significantly higher among adults aged less than 80 years in hot temperature. ConclusionsExposure to non-optimum ambient temperature, especially moderate cold temperature, was responsible for substantial excess mortality from asthma. These findings have important implications for planning of public-health interventions to minimize the adverse respiratory damage from non-optimum ambient temperature.

Associations of ambient temperature with mortality for ischemic and hemorrhagic stroke and the modification effects of greenness in Shandong Province, China

BackgroundEvidence is scant on the relative and attributable contributions of ambient temperature on stroke subtypes mortality. Few studies have examined modification effects of multiple greenness indicators on such contributions, especially in China. We quantified the associations between ambient temperature and overall, ischemic, and hemorrhagic stroke mortality; further examined whether the associations were modified by greenness. MethodsWe conducted a multicenter time-series analysis from January 1, 2013 to December 31, 2019. we adopted a distributed lag non-linear model to evaluate county-specific temperature-stroke mortality associations. We then applied a random-effects meta-analysis to pool county-specific effects. Attributable mortality was calculated for cold and heat, defined as temperatures below and above the minimum mortality temperature (MMT). Finally, We conducted a multivariate meta-regression to determine associations between greenness and stroke mortality risks for cold and heat, using normalized difference vegetation index (NDVI), soil adjusted vegetation index (SAVI), and enhanced vegetation index (EVI) as quantitative indicators of greenness exposure. ResultsIn the study period, 138,749 deaths from total stroke were reported: 86,873 ischemic and 51,876 hemorrhagic stroke. We observed significant W-shaped relationships between temperature and stroke mortality, with substantial differences among counties and regions. With MMT as the temperature threshold, 17.16 % (95 % empirical CI, 13.38 %–19.75 %) of overall, 20.05 % (95 % eCI, 16.46 %–22.70 %) of ischemic, and 12.55 % (95 % eCI, 5.59 %–16.24 %) of hemorrhagic stroke mortality were attributable to non-optimum temperature (combining cold and heat), more mortality was caused by cold (14.94 %; 95 % eCI, 11.57 %–17.34 %) than by heat (2.22 %; 95 % eCI, 1.54 %–2.72 %). Higher levels of NDVI, SAVI and EVI were related to mitigated effects of non-optimum temperatures—especially heat. ConclusionsExposure to non-optimum temperatures aggravated stroke mortality risks; increasing greenness could alleviate that risks. This evidence has important implications for local communities in developing adaptive strategies to minimize the health consequences of adverse temperatures.

Low temperature and temperature decline increase acute aortic dissection risk and burden: A nationwide case crossover analysis at hourly level among 40,270 patients

SummaryBackgroundAcute aortic dissection (AAD) is a life-threatening cardiovascular emergency with high mortality, so identifying modifiable risk factors of AAD is of great public health significance. The associations of non-optimal temperature and temperature variability with AAD onset and the disease burden have not been fully understood.MethodsWe conducted a time-stratified case-crossover study using a nationwide registry dataset from 1,868 hospitals in 313 Chinese cities. Conditional logistic regression and distributed lag models were used to investigate associations of temperature and temperature changes between neighboring days (TCN) with the hourly AAD onset and calculate the attributable fractions. We also evaluated the heterogeneity of the associations.FindingsA total of 40,270 eligible AAD cases were included. The exposure-response curves for temperature and TCN with AAD onset risk were both inverse and approximately linear. The risks were present on the concurrent hour (for temperature) or day (for TCN) and lasted for almost 1 day. The cumulative relative risks of AAD were 1.027 and 1.026 per 1°C lower temperature and temperature decline between neighboring days, respectively. The associations were significant during the non-heating period, but were not present during the heating period in cities with central heating. 23.13% of AAD cases nationwide were attributable to low temperature and 1.58% were attributable to temperature decline from the previous day.InterpretationThis is the largest nationwide study demonstrating robust associations of low temperature and temperature decline with AAD onset. We, for the first time, calculated the corresponding disease burden and further showed that central heating may be a modifier for temperature-related AAD risk and burden.FundingThis work was supported by the National Natural Science Foundation of China (92043301 and 92143301), Shanghai International Science and Technology Partnership Project (No. 21230780200), the Medical Research Council-UK (MR/R013349/1), and the Natural Environment Research Council UK (NE/R009384/1).

Global spatiotemporal trends of cardiovascular diseases due to temperature in different climates and socio-demographic index regions from 1990 to 2019.

With the rapidly changing climate, assessing the global trends of cardiovascular diseases (CVDs) attributed to high and low temperatures in different climate zones and under varying socio-demographic levels is crucial for regulations, preparation, intervention, and clinical practice for CVD. Our study included 204 countries with global CVD data ranging from 1990 to 2019. We obtained the age-standardized mortality rate (ASMR); disability-adjusted life rate of CVD attributed to high, low, and non-optimal temperatures; and socio-demographic index (SDI) data from the Global Health Data Exchange. We also downloaded the temperature data from the Climatic Research Unit. These 204 countries were divided into five climate zones and five SDI levels according to the annual average temperature data and SDI in 2019. The temporal trends of CVD burden attributed to high, low, and non-optimal temperatures were estimated by using the cubic regression spline and the generalized additive mixed model (GAMM). The total burden of temperature-related CVD has been declining in the last 30years. However, the burden of CVD attributed to high temperature showed an increasing trend. Among different climate regions, the ASMRs of CVD attributed to high temperature were the highest in the tropical regions, followed by subtropical regions, and the lowest in the boreal regions. In the past 30years, the burden of CVD attributed to high temperatures has shown a significant increasing trend, while declining trends are observed for non-optimal and low temperatures. The CVD burden attributed to high temperatures is particularly pronounced in warmer and low-SDI regions with an increasing trend of CVD burden due to high temperature.

Standing Genetic Diversity and Transmission Bottleneck Size Drive Adaptation in Bacteriophage Qβ.

A critical issue to understanding how populations adapt to new selective pressures is the relative contribution of the initial standing genetic diversity versus that generated de novo. RNA viruses are an excellent model to study this question, as they form highly heterogeneous populations whose genetic diversity can be modulated by factors such as the number of generations, the size of population bottlenecks, or exposure to new environment conditions. In this work, we propagated at nonoptimal temperature (43 °C) two bacteriophage Qβ populations differing in their degree of heterogeneity. Deep sequencing analysis showed that, prior to the temperature change, the most heterogeneous population contained some low-frequency mutations that had previously been detected in the consensus sequences of other Qβ populations adapted to 43 °C. Evolved populations with origin in this ancestor reached similar growth rates, but the adaptive pathways depended on the frequency of these standing mutations and the transmission bottleneck size. In contrast, the growth rate achieved by populations with origin in the less heterogeneous ancestor did depend on the transmission bottleneck size. The conclusion is that viral diversification in a particular environment may lead to the emergence of mutants capable of accelerating adaptation when the environment changes.

Temperature-related chest pain presentations and future projections with climate change

BackgroundClimate change has led to increased interest in studying adverse health effects relating to ambient temperatures. It is unclear whether incident chest pain is associated with non-optimal temperatures and how chest pain presentation rates might be affected by climate change. MethodsThe study included ambulance data of chest pain presentations in Melbourne, Australia from 1/1/2015 to 30/6/2019 with linkage to hospital and emergency discharge diagnosis data. A time series quasi-Poisson regression with a distributed lag nonlinear model was fitted to assess the temperature-chest pain presentation associations overall and according to age, sex, socioeconomic status, and event location subgroups, with adjustment for season, day of the week and long-term trend. Future excess chest pain presentations associated with cold and heat were projected under six general circulation models under medium and high emission scenarios. ResultsIn 206,789 chest pain presentations, mean (SD) age was 61.2 (18.9) years and 50.3 % were female. Significant heat- and cold-related increased risk of chest pain presentations were observed for mean air temperatures above and below 20.8 °C, respectively. Excess chest pain presentations related to heat were observed in all subgroups, but appeared to be attenuated for older patients (≥70 years), patients of higher socioeconomic status (SES), and patients developing chest pain at home. We projected increases in heat-related chest pain presentations with climate change under both medium- and high-emission scenarios, which are offset by decreases in chest pain presentations related to cold temperatures. ConclusionsHeat- and cold- exposure appear to increase the risk of chest pain presentations, especially among younger patients and patients of lower SES. This will have important implications with climate change modelling of chest pain, in particular highlighting the importance of risk mitigation strategies to minimise adverse health impacts on hotter days.

The cell wall and the response and tolerance to stresses of biotechnological relevance in yeasts.

In industrial settings and processes, yeasts may face multiple adverse environmental conditions. These include exposure to non-optimal temperatures or pH, osmotic stress, and deleterious concentrations of diverse inhibitory compounds. These toxic chemicals may result from the desired accumulation of added-value bio-products, yeast metabolism, or be present or derive from the pre-treatment of feedstocks, as in lignocellulosic biomass hydrolysates. Adaptation and tolerance to industrially relevant stress factors involve highly complex and coordinated molecular mechanisms occurring in the yeast cell with repercussions on the performance and economy of bioprocesses, or on the microbiological stability and conservation of foods, beverages, and other goods. To sense, survive, and adapt to different stresses, yeasts rely on a network of signaling pathways to modulate the global transcriptional response and elicit coordinated changes in the cell. These pathways cooperate and tightly regulate the composition, organization and biophysical properties of the cell wall. The intricacy of the underlying regulatory networks reflects the major role of the cell wall as the first line of defense against a wide range of environmental stresses. However, the involvement of cell wall in the adaptation and tolerance of yeasts to multiple stresses of biotechnological relevance has not received the deserved attention. This article provides an overview of the molecular mechanisms involved in fine-tuning cell wall physicochemical properties during the stress response of Saccharomyces cerevisiae and their implication in stress tolerance. The available information for non-conventional yeast species is also included. These non-Saccharomyces species have recently been on the focus of very active research to better explore or control their biotechnological potential envisaging the transition to a sustainable circular bioeconomy.

Hik28-dependent and Hik28-independent ABC transporters were revealed by proteome-wide analysis of ΔHik28 under combined stress

Synechocystis histidine kinase, Sll0474: Hik28, a signal protein in a two-component signal transduction system, plays a critical role in responding to a decrease in growth temperature and is also involved in nitrogen metabolism. In the present study, under combined stress from non-optimal growth temperature and nitrogen depletion, a comparative proteomic analysis of the wild type (WT) and a deletion mutant (MT) of Synechocystis histidine kinase, Sll0474: Hik28, in a two-component signal transduction system identified the specific groups of ABC transporters that were Hik28-dependent, e.g., the iron transporter, and Hik28-independent, e.g., the phosphate transporter. The iron transporter, AfuA, was found to be upregulated only in the WT strain grown under the combined stress of high temperature and nitrogen depletion. Whereas, the expression level of the phosphate transporter, PstS, was increased in both the WT and MT strains. Moreover, the location in the genome of the genes encoding Hik28 and ABC transporters in Synechocystis sp. PCC6803 were analyzed in parallel with the comparative proteomic data. The results suggested the regulation of the ABC transporters by the gene in a two-component system located in an adjacent location in the genome.

Small-area assessment of temperature-related mortality risks in England and Wales: a case time series analysis

Epidemiological literature on the health risks associated with non-optimal temperature has mostly reported average estimates across large areas or specific population groups. However, the heterogeneous distribution of drivers of vulnerability can result in local differences in health risks associated with heat and cold. We aimed to analyse the association between ambient air temperature and all-cause mortality across England and Wales and characterise small scale patterns in temperature-related mortality risks and impacts. We performed a country-wide small-area analysis using data on all-cause mortality and air temperature for 34 753 lower super output areas (LSOAs) within 348 local authority districts (LADs) across England and Wales between Jan 1, 2000, and Dec 31, 2019. We first performed a case time series analysis of LSOA-specific and age-specific mortality series matched with 1 × 1 km gridded temperature data using distributed lag non-linear models, and then a repeated-measure multivariate meta-regression to pool LAD-specific estimates using area-level climatological, socioeconomic, and topographical predictors. The final analysis included 10 716 879 deaths from all causes. The small-area assessment estimated that each year in England and Wales, there was on average 791 excess deaths (empirical 95% CI 611-957) attributable to heat and 60 573 (55 796-65 145) attributable to cold, corresponding to standardised excess mortality rates of 1·57 deaths (empirical 95% CI 1·21-1·90) per 100 000 person-years for heat and 122·34 deaths (112·90-131·52) per 100 000 person-years for cold. The risks increased with age and were highly heterogeneous geographically, with the minimum mortality temperature ranging from 14·9°C to 22·6°C. Heat-related mortality was higher in urban areas, whereas cold-related mortality showed a more nuanced geographical pattern and increased risk in areas with greater socioeconomic deprivation. This study provides a comprehensive assessment of excess mortality related to non-optimal outdoor temperature, with several risk indicators reported by age and multiple geographical levels. The analysis provides detailed risk maps that are useful for designing effective public health and climate policies at both local and national levels. Medical Research Council, Natural Environment Research Council, EU Horizon 2020 Programme, National Institute of Health Research.

The Establishment of a New Air Health Index Integrating the Mortality Risks Due to Ambient Air Pollution and Non-Optimum Temperature

A composite Air Health Index (AHI) is helpful for separately emphasizing the health risks of multiple stimuli and communicating the overall risks of an adverse atmospheric environment to the public. We aimed to establish a new AHI by integrating daily mortality risks due to air pollution with those due to non-optimum temperature in China. Based on the exposure-response (E-R) coefficients obtained from time-series models, the new AHI was constructed as the sum of excess mortality risk associated with air pollutants and non-optimum temperature in 272 Chinese cities from 2013 to 2015. We examined the association between the “total AHI” (based on total mortality) and total mortality, and further compared the ability of the “total AHI” to predict specific cardiopulmonary mortality with that of “specific AHIs” (based on specific mortalities). On average, air pollution and non-optimum temperature were associated with 28.23% of daily excess mortality, of which 23.47% was associated with non-optimum temperature while the remainder was associated with fine particulate matter (PM 2.5 ) (1.12%), NO 2 (2.29%,), and O 3 (2.29%). The new AHI uses a 10-point scale and shows an average across all 272 cities of 6 points. The E-R curve for AHI and mortality is approximately linear, without any thresholds. Each one unit increase in “total AHI” is associated with a 0.84% increase in all-cause mortality and 1.01%, 0.98%, 1.02%, 1.66%, and 1.71% increases in cardiovascular disease, coronary heart disease, stroke, respiratory diseases, and chronic obstructive pulmonary disease mortality, respectively. Cause-specific mortality risk estimates using the “total AHI” are similar to those predicted by “specific AHIs.” In conclusion, the “total AHI” proposed herein could be a promising tool for communicating health risks related to exposure to the ambient environment to the public.

City-level impact of extreme temperatures and mortality in Latin America

Climate change and urbanization are rapidly increasing human exposure to extreme ambient temperatures, yet few studies have examined temperature and mortality in Latin America. We conducted a nonlinear, distributed-lag, longitudinal analysis of daily ambient temperatures and mortality among 326 Latin American cities between 2002 and 2015. We observed 15,431,532 deaths among ≈2.9 billion person-years of risk. The excess death fraction of total deaths was 0.67% (95% confidence interval (CI) 0.58–0.74%) for heat-related deaths and 5.09% (95% CI 4.64–5.47%) for cold-related deaths. The relative risk of death was 1.057 (95% CI 1.046–1.067%) per 1 °C higher temperature during extreme heat and 1.034 (95% CI 1.028–1.040%) per 1 °C lower temperature during extreme cold. In Latin American cities, a substantial proportion of deaths is attributable to nonoptimal ambient temperatures. Marginal increases in observed hot temperatures are associated with steep increases in mortality risk. These risks were strongest among older adults and for cardiovascular and respiratory deaths.

Non-optimum temperature increases risk and burden of acute myocardial infarction onset: A nationwide case-crossover study at hourly level in 324 Chinese cities.

SummaryBackgroundThe associations of ambient temperature with acute myocardial infarction (AMI) have seldom been examined based on the time of symptom onset.MethodsWe conducted a time-stratified case-crossover study among 1,046,773 eligible AMI patients from 2,093 hospitals in 324 Chinese cities from January 1, 2015 to June 30, 2021, after excluding those transferred from other hospitals or having not reported the time of symptom onset. Hourly exposure to ambient temperature was calculated as multiple moving 24-h averages (days) before hourly onset of AMI symptoms. Conditional logistic regression and distributed lag non-linear models with a duration of 0–21 days were used to estimate the cumulative associations of non-optimum temperature with AMI onset and the corresponding disease burden nationally. Subgroup analyses by region and period were conducted. Specifically, cities with and without centralized heating system were classified into heating and non-heating regions, respectively. The whole year in heating region was divided into heating and non-heating periods based on the duration of centralized heating in each city.FindingsAlmost monotonically increasing risks were observed for both overall AMI and its two subtypes when ambient temperature declined. The effects of extremely low temperature occurred immediately on the concurrent day, and lasted up to almost 3 weeks. The excess risks of AMI onset associated with non-optimum ambient temperatures were observed during the whole year in the non-heating region and non-heating period in the heating region, but not during heating period. Specifically, odds ratios of AMI onset associated with extremely low temperature cumulated over 0–21 days were 1.24 (95% CI: 1.13–1.37), 1.46 (95% CI: 1.20–1.76), and 1.62 (95% CI: 1.46–1.81) in the heating region during non-heating period, in the non-heating region during winter and non-winter period, respectively. The heat effects on AMI onset were very modest and transient. Totally, 13.26% of AMI cases could be attributable to non-optimum temperatures nationally. The burden of AMI attributable to non-optimum temperature was much smaller in heating region than in non-heating region. Somewhat stronger effects were observed in females and patients aged older than 65.InterpretationThis nationwide study provided robust evidence that non-optimum ambient temperature may significantly trigger AMI onset, and for the first time estimated the disease burden after accounting for spatial and seasonal heterogeneity. Centralized heating might substantially mitigate AMI burden due to non-optimum temperature.FundingShanghai International Science and Technology Partnership Project, National Natural Science Foundation of China, Talent Training Program of Zhongshan Hospital, Fudan University.