Heatwave and health impact research: A global review

Environmental health science research: opportunities and challenges for some developing countries in Africa

Due to ongoing developmental projects, there is a need for regular monitoring of the impact of pollutants on the environment. This review documented the challenges and opportunities in the field of environmental health sciences in some African countries. A systematic review was used to investigate opportunities and challenges in the field of environmental health science in Africa by examining published work with a specific focus on Africa. The reports showed that funding and infrastructure as the major problems. The study also highlighted recruiting study participants, retention, and compensation as a bane in the field in Africa. The absence of modern equipment also hinders research. The review, however, noted research collaboration from the region including studies on emerging pollutants such as pharmaceuticals, per and polyfluoroalkyl substances (PFAS), and microplastic (MPs) as great opportunities. The study concluded that collaboration with other continents, exchange programs and improved governmental interventions may help.

A study on the monitoring of heatwaves and bivariate frequency analysis based on mortality risk assessment in Wuhan, China

The increasingly frequent occurrence of urban heatwaves has become a significant threat to human health. To quantitatively analyze changes in heatwave characteristics and to investigate the return periods of future heatwaves in Wuhan City, China, this study extracted 9 heatwave definitions and divided them into 3 mortality risk levels to identify and analyze historical observations and future projections of heatwaves. The copula functions were employed to derive the joint distribution of heatwave severity and duration and to analyze the co-occurrence return periods. The results demonstrate the following. (1) As the concentration of greenhouse gas emissions increases, the severity of heatwaves intensifies, and the occurrence of heatwaves increases significantly; moreover, a longer duration of heatwaves correlated with higher risk levels in each emission scenario. (2) Increasing concentrations of greenhouse gas emissions result in significantly shorter heatwave co-occurrence return periods at each level of risk. (3) In the 3 risk levels under each emission scenario, the co-occurrence return periods for heatwaves become longer as heatwave severity intensifies and duration increases. Under the influence of climate change, regional-specific early warning systems for heatwaves are necessary and crucial for policymakers to reduce heat-related mortality risks in the population, especially among vulnerable groups.

Estimating the heat-related mortality and morbidity burden in the province of Quebec, Canada

BACKGROUND

As climate change increases the frequency and intensity of extreme heat events, there is an urgent need to quantify the heat-related health burden. However, most past studies have focussed on a single health outcome (mainly mortality) or on specific heatwaves, thus providing limited knowledge of the total pressure heat exerts on health services.

OBJECTIVES

This study aims to quantify the heat-related mortality and morbidity burden for five different health outcomes including all-cause mortality, hospitalizations, emergency department (ED) visits, ambulance transports and calls to a health hotline, using the province of Quebec (Canada) as a case study.

METHODS

A two-step statistical analysis was employed to estimate regional heat-health relationships using Distributed Lag Non-Linear Models (DLNM) and pooled estimates using a multivariate meta-regression. Heat burden was quantified by attributable fraction (AF) and attributable number (AN) for two temperature ranges: all heat (above the minimum mortality/morbidity temperature) and extreme heat (above the 95th percentile of temperature).

RESULTS

Higher temperatures were associated with greater risk ratios for all health outcomes studied, but at different levels. Significant AF ranging from 2 to 3% for the all heat effect and 0.4-1.0% for extreme heat were found for all health outcomes, except for hospitalizations that had an AF of 0.1% for both heat exposures. The estimated burden of all heat (and extreme heat) every summer across the province was 470 (200) deaths, 225 (170) hospitalizations, 36 000 (6 200) ED visits, 7 200 (1 500) ambulance transports and 15 000 (3 300) calls to a health hotline, all figures significant.

DISCUSSION

This new knowledge on the total heat load will help public health authorities to target appropriate actions to reduce its burden now and in the future. The proposed state-of-the-art framework can easily be applied to other regions also experiencing the adverse effects of extreme heat.

Method and process towards developing a Health Vulnerability Index (HVI) for Extreme Weather Events (EWEs) for local residents in South Africa

An increase in incidence and amplitude of extreme weather events (EWEs) linked to climate change, has resulted in greater human exposure and vulnerability to weather-related health effects. Increases in the occurrence of EWEs, including storms, flooding, extreme heat and wildfires, will impact health globally, with poor and vulnerable populations disproportionately affected. Vulnerability to EWEs, and the ability to adapt to these weather shocks, are influenced by existing physical, social and political limitations of a given region. As such, developing context-specific health vulnerability indices to inform planning and decision-making for policy makers and citizens alike, should be prioritized. The existence and development of health vulnerability indices in South Africa are limited, therefore, this study provides a foundation from which future indices can build. Mixed methods approaches including evidence and data analysis/synthesis and focus groups are used to understand the interconnections between extreme weather events and human health, including citizens' understanding of emergent vulnerabilities linked to these events. The methods employed in this study include: •A rapid evidence review (RER) including data extraction identifying health impacts and indicators.•Development of a draft health vulnerability index (HVI) framework.•Focus groups and individual interviews testing the draft HVI for citizen input and framework refinement.

Comprehensive evaluation framework for intervention on health effects of ambient temperature

Despite the existence of many interventions to mitigate or adapt to the health effects of climate change, their effectiveness remains unclear. Here, we introduce the Comprehensive Evaluation Framework for Intervention on Health Effects of Ambient Temperature to evaluate study designs and effects of intervention studies. The framework comprises three types of interventions: proactive, indirect, and direct, and four categories of indicators: classification, methods, scope, and effects. We trialed the framework by an evaluation of existing intervention studies. The evaluation revealed that each intervention has its own applicable characteristics in terms of effectiveness, feasibility, and generalizability scores. We expanded the framework's potential by offering a list of intervention recommendations in different scenarios. Future applications are then explored to establish models of the relationship between study designs and intervention effects, facilitating effective interventions to address the health effects of ambient temperature under climate change.

[Heat and heavy rain prevention measures in daycare centres and care facilities: an evaluation of risk perception, communication and information materials]

BACKGROUND AND AIM

Heat and heavy rain can have negative health impacts for people in Germany. Vulnerable groups in particular, such as children and the elderly, are at increased risk and require special precautions. This paper examines how employers of the municipal administration and facilitating organisations perceive the risk of heat and heavy rain for daycare centres and care facilities, and to what extent an exchange takes place between the municipal level and the facilities. In addition, specially developed information materials with recommendations for action for adapting to heat and heavy rain that are aimed at such facilities were evaluated.

METHODS

In the summer of 2021, we conducted a quantitative survey. A total of 333 respondents from municipal administrations, facilitating organisations and institutions participated. Descriptive analyses and ANOVAs were conducted.

RESULTS

Risk perception and adaptation knowledge concerning heat was perceived higher than concerning heavy rain. The intention to support institutions in finding measures for adaptation was also higher with regard to heat. The majority of interviewees from municipal administrations and institutions communicated with institutions through various channels on different topics including the natural hazards mentioned. The information material was evaluated positively.

DISCUSSION

This article shows that facilities are seen as very affected by heat waves. Awareness towards heavy rainfall needs to be raised. The feedback on the information material clearly shows a high need in this area.

Are hotspots and frequencies of heat waves changing over time? Exploring causes of heat waves in a tropical country

Heat waves significantly impact people's lives and livelihoods and are becoming very alarming and recognized as hot topics worldwide, including in Bangladesh. However, much less is understood regarding recent hotspots, the frequency of heat waves over time, and their underlying causes in Bangladesh. The objective of the study is to explore the current scenario and frequency of heat waves and their possible causes across Bangladesh. The Mann-Kendall and Sen's slope techniques were used to determine seasonal and annual temperature trend patterns of heat wave frequencies. Daily maximum temperature datasets collected from the Bangladesh Meteorological Department (BMD) during 1991-2021 are applied. The frequency of days with Tmax≥ 36°C as the threshold was used to compute different types of heat waves based on the BMD's operational definition. The results show that the mild heat wave (MHW) days followed the subsequent hotspot order: Rajshahi (103) > Chuadanga (79), Ishurdi (60), and Jessore (58), respectively. The frequency of days with Tmax≥36°C was persistence for many days in 2014, especially in the western part of Bangladesh compared to other parts. Similarly, the heat waves condition shown its deadliest event by increasing more days in 2021. The highest increasing trend was identified at the Patuakhali site, with a rate of 0.516 days/year, while the highest decreasing trend was noticed at the Chuadanga site, with a rate of -0.588 days/year. The frequency of days (Tmax≥36°C) is an increasing trend in the south-western part of Bangladesh. The synoptic condition in and around Bangladesh demonstrates that the entrance of heat waves in Bangladesh is due to the advection of higher temperatures from the south/southwest of the Bay of Bengal. The outcomes will guide the national appraisal of heatwave effects, shedding light on the primary causes of definite heatwave phenomena, which are crucial for developing practical adaptation tools.

Heatwaves increase road traffic injury morbidity risk and burden in China and its provinces

Previous studies have demonstrated health impacts of climate change, but evidence on heatwaves' associations with road traffic injury (RTI) is limited. In this study, individual information of RTI cases in May-September during 2006-2021 in China were obtained from the National Injury Surveillance System. Daily maximum temperatures (TMmax) during 2006-2021 were collected from the ERA-5 reanalysis, and the projected daily TMmax during 2020-2099 were obtained from the latest Coupled Model Intercomparison Project Phase 6 Shared Socioeconomic Pathways scenarios (SSPs). We used a time-stratified case-crossover analysis to investigate the association between short-term exposure (lag01 days) to heatwaves (exceeding the 92.5th percentile of daily TMmax for ≥ three consecutive days) and RTI, and to project heatwave-related RTI until 2099 across China. Finally, a total of 1 031 082 RTI cases were included in the analyses. Compared with non-heatwaves, the risks of RTI increased by 3.61 % during heatwaves. Greater associations were found in people aged 15-64 years, in people with transportation occupation, for non-motor traffic vehicle injuries, for severe RTI cases, and in Western China particularly in Qinghai province. We projected substantial increases in attributable fraction (AF) of heatwave-related RTI in the future, particularly in Western and Southwest China. The national average increase in AF (per decade) during 2020s-2090s was 0.036 % for SSP1-2.6 scenario, and 0.267 % for SSP5-8.5 scenario. This study provided evidence on the associations of heatwaves with RTI, and the heatwave-related RTI will substantially increase in the future.

Extreme Heat and Occupational Health Risks

Climate change poses a significant occupational health hazard. Rising temperatures and more frequent heat waves are expected to cause increasing heat-related morbidity and mortality for workers across the globe. Agricultural, construction, military, firefighting, mining, and manufacturing workers are at particularly high risk for heat-related illness (HRI). Various factors, including ambient temperatures, personal protective equipment, work arrangements, physical exertion, and work with heavy equipment may put workers at higher risk for HRI. While extreme heat will impact workers across the world, workers in low- and middle-income countries will be disproportionately affected. Tracking occupational HRI will be critical to informing prevention and mitigation strategies. Renewed investment in these strategies, including workplace heat prevention programs and regulatory standards for indoor and outdoor workers, will be needed. Additional research is needed to evaluate the effectiveness of interventions in order to successfully reduce the risk of HRI in the workplace.

Heat and Cardiovascular Mortality: An Epidemiological Perspective

As global temperatures rise, extreme heat events are projected to become more frequent and intense. Extreme heat causes a wide range of health effects, including an overall increase in morbidity and mortality. It is important to note that while there is sufficient epidemiological evidence for heat-related increases in all-cause mortality, evidence on the association between heat and cause-specific deaths such as cardiovascular disease (CVD) mortality (and its more specific causes) is limited, with inconsistent findings. Existing systematic reviews and meta-analyses of epidemiological studies on heat and CVD mortality have summarized the available evidence. However, the target audience of such reviews is mainly limited to the specific field of environmental epidemiology. This overarching perspective aims to provide health professionals with a comprehensive overview of recent epidemiological evidence of how extreme heat is associated with CVD mortality. The rationale behind this broad perspective is that a better understanding of the effect of extreme heat on CVD mortality will help CVD health professionals optimize their plans to adapt to the changes brought about by climate change and heat events. To policymakers, this perspective would help formulate targeted mitigation, strengthen early warning systems, and develop better adaptation strategies. Despite the heterogeneity in evidence worldwide, due in part to different climatic conditions and population dynamics, there is a clear link between heat and CVD mortality. The risk has often been found to be higher in vulnerable subgroups, including older people, people with preexisting conditions, and the socioeconomically deprived. This perspective also highlights the lack of evidence from low- and middle-income countries and focuses on cause-specific CVD deaths. In addition, the perspective highlights the temporal changes in heat-related CVD deaths as well as the interactive effect of heat with other environmental factors and the potential biological pathways. Importantly, these various aspects of epidemiological studies have never been fully investigated and, therefore, the true extent of the impact of heat on CVD deaths remains largely unknown. Furthermore, this perspective also highlights the research gaps in epidemiological studies and the potential solutions to generate more robust evidence on the future consequences of heat on CVD deaths.

How to communicate with older adults about climate change: a systematic review

Introduction

Although older adults are particularly vulnerable to the effects of climate change, they seem to be overall less concerned about it, and less inclined to support climate policies. The study aims to identify the communication strategies that have been evaluated in promoting awareness and/or climate friendly behaviors in older adults.

Methods

We searched multiple electronic databases for studies that evaluated the effects of any interventions aimed at communicating climate change to older persons (over 65 years) and assessed the results as awareness and /or behavioral changes. We selected quantitative, qualitative and mixed methods studies, and we also included systematic reviews for cross-referencing. Risk of bias of included studies was evaluated using different tools according to the study design.

Results

From a total of 5,486 articles, only 3 studies were included. One mixed-method study engaged older adults to assess the community vulnerability to climate change and to develop adaptation recommendations based on their perspectives; one qualitative study conducted focus groups to identify the more effective language, values and themes based on participants' responses to narratives; one quantitative study utilized a 360-degree audio-visual platform allowing users to engage with immersive visualizations of sea-level rise scenarios.

Discussion

Despite the paucity of literature, this review demonstrates the potential for different strategies to increase the awareness of older persons about climate change. The involvement of older adults in the communication process, the identification of their priorities, and the integration of technology in their daily lives are promising approaches but more research, including both quantitative and qualitative studies is recommended on this topic.

Systematic review registeration

For further details about the protocol, this systematic review has been registered on PROSPERO on July 1, 2023 (https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42023438256).

The 2023 report of the MJA-Lancet Countdown on health and climate change: sustainability needed in Australia's health care sector

The MJA-Lancet Countdown on health and climate change in Australia was established in 2017 and produced its first national assessment in 2018 and annual updates in 2019, 2020, 2021 and 2022. It examines five broad domains: health hazards, exposures and impacts; adaptation, planning and resilience for health; mitigation actions and health co-benefits; economics and finance; and public and political engagement. In this, the sixth report of the MJA-Lancet Countdown, we track progress on an extensive suite of indicators across these five domains, accessing and presenting the latest data and further refining and developing our analyses. Our results highlight the health and economic costs of inaction on health and climate change. A series of major flood events across the four eastern states of Australia in 2022 was the main contributor to insured losses from climate-related catastrophes of $7.168 billion - the highest amount on record. The floods also directly caused 23 deaths and resulted in the displacement of tens of thousands of people. High red meat and processed meat consumption and insufficient consumption of fruit and vegetables accounted for about half of the 87 166 diet-related deaths in Australia in 2021. Correction of this imbalance would both save lives and reduce the heavy carbon footprint associated with meat production. We find signs of progress on health and climate change. Importantly, the Australian Government released Australia's first National Health and Climate Strategy, and the Government of Western Australia is preparing a Health Sector Adaptation Plan. We also find increasing action on, and engagement with, health and climate change at a community level, with the number of electric vehicle sales almost doubling in 2022 compared with 2021, and with a 65% increase in coverage of health and climate change in the media in 2022 compared with 2021. Overall, the urgency of substantial enhancements in Australia's mitigation and adaptation responses to the enormous health and climate change challenge cannot be overstated. Australia's energy system, and its health care sector, currently emit an unreasonable and unjust proportion of greenhouse gases into the atmosphere. As the Lancet Countdown enters its second and most critical phase in the leadup to 2030, the depth and breadth of our assessment of health and climate change will be augmented to increasingly examine Australia in its regional context, and to better measure and track key issues in Australia such as mental health and Aboriginal and Torres Strait Islander health and wellbeing.

Social-economic transitions and vulnerability to extreme temperature events from 1960 to 2020 in Chinese cities

Climate change leads to more frequent and intense extreme temperature events, causing a significant number of excess deaths. Using an epidemiological approach, we analyze all-cause deaths related to heatwaves and cold spells in 2,852 Chinese counties from 1960 to 2020. Economic losses associated with these events are determined through the value of statistical life. Findings reveal that cold-related cumulative excess deaths (1,133 thousand) are approximately 2.5 times higher than heat-related deaths, despite an increase in heat-related fatalities in recent decades. Monetized mortality due to heat-related events is estimated at 1,284 billion CNY, while cold-related economic loss is 1,510 billion CNY. Notably, cities located in colder regions experience more heat-related excess deaths, and vice versa. Economic development does not significantly reduce mortality risks to heatwaves across China. This study provides insights into the spatial-temporal heterogeneity of heatwaves and cold spells mortality, essential for policymakers ensuring long-term climate adaptation and sustainability.

Time to death and its determinants of under-five children in rural Ethiopia by using shared frailty

Under-five (U5M) is one of the most significant and sensitive measures of the community's health. Children who live in rural areas are more likely than those who live in urban areas to die before the age of five. Therefore, the study aimed to assess the Survival status of under-five mortality and its determinants in rural Ethiopia. The 2019 Ethiopia Mini Demographic and Health Survey was used in this study as a secondary source (EMDHS). A total of 4426 weighted under-five children were included in the study. To determine survival time and identify predictors of death among children under the age of five, the Cox's gamma shared frailty model and the Kaplan Meier model, respectively, were used. An adjusted Hazard Ratio (AHR) along with a 95% Confidence Interval (CI) were used to measure the size and direction of the association. The Study showed that in rural Ethiopia, 6.03% of children died before celebrating their first birthday. The median age of under-five mortality in rural Ethiopia was estimated to be 29 Months. The hazard of death among under-five children and those who had given birth to two children in the last five years was 4.99 times less likely to be at risk of dying than those who had given birth to one Child in the previous five years (AHR 4.99, 95% CI 2.97, 8.83). The Study Concluded that under-five mortality remained high in rural Ethiopia. In the final model, the Age of Mothers, Sex of Household, Breastfeeding, Types of Birth, Sex of Child, Educational Level of Mothers, Wealth Index, Child ever born, Marital Status, and Water Source were significant predictors of under-five mortality. Twins and children who are not breastfed should receive additional attention, along with improving water resources for households and mothers income.

Urban heat mitigation by green and blue infrastructure: Drivers, effectiveness, and future needs

The combination of urbanization and global warming leads to urban overheating and compounds the frequency and intensity of extreme heat events due to climate change. Yet, the risk of urban overheating can be mitigated by urban green-blue-grey infrastructure (GBGI), such as parks, wetlands, and engineered greening, which have the potential to effectively reduce summer air temperatures. Despite many reviews, the evidence bases on quantified GBGI cooling benefits remains partial and the practical recommendations for implementation are unclear. This systematic literature review synthesizes the evidence base for heat mitigation and related co-benefits, identifies knowledge gaps, and proposes recommendations for their implementation to maximize their benefits. After screening 27,486 papers, 202 were reviewed, based on 51 GBGI types categorized under 10 main divisions. Certain GBGI (green walls, parks, street trees) have been well researched for their urban cooling capabilities. However, several other GBGI have received negligible (zoological garden, golf course, estuary) or minimal (private garden, allotment) attention. The most efficient air cooling was observed in botanical gardens (5.0 ± 3.5°C), wetlands (4.9 ± 3.2°C), green walls (4.1 ± 4.2°C), street trees (3.8 ± 3.1°C), and vegetated balconies (3.8 ± 2.7°C). Under changing climate conditions (2070-2100) with consideration of RCP8.5, there is a shift in climate subtypes, either within the same climate zone (e.g., Dfa to Dfb and Cfb to Cfa) or across other climate zones (e.g., Dfb [continental warm-summer humid] to BSk [dry, cold semi-arid] and Cwa [temperate] to Am [tropical]). These shifts may result in lower efficiency for the current GBGI in the future. Given the importance of multiple services, it is crucial to balance their functionality, cooling performance, and other related co-benefits when planning for the future GBGI. This global GBGI heat mitigation inventory can assist policymakers and urban planners in prioritizing effective interventions to reduce the risk of urban overheating, filling research gaps, and promoting community resilience.

Individual heat adaptation: Analyzing risk communication, warnings, heat risk perception, and protective behavior in three German cities

Extreme heat poses severe health threats, as the increased numbers of hospitalizations and fatalities during heat waves show, though little is known about adaptive behavior toward heat. We conducted a household survey on individual perceptions of heat stress and individual heat protection in the summer and autumn of 2019. In total, 1417 people from three medium-sized German cities participated via telephone or online. Based on the Protective Action Decision Model (PADM), which we adapted to heat stress, we analyzed links between risk perception, environmental and demographic factors, perceptions of stakeholders, different heat warning messages, as well as actual and intended adaptive behavior. Overall, the PADM constructs explained around 16% of the variance in protection motivation, 19% in protective response, and 23% in emotion-focused coping. Context factors (i.e., temperature, risk communication, gender, age, and homeownership) were significant predictors of the addressed outcome variables as were psychological factors (i.e., perceived personal vulnerability, response efficacy, response costs, preparedness, and perceived external responsibility). We further explored the effect of different warning messages on situational knowledge and intended behavioral adaptation in an experimental setting. Results showed that respondents felt significantly better informed after receiving a warning with action recommendations and reported more intended specific behaviors. Our research gives insights into individual protective action decision-making processes. Based on our findings, we recommend tailoring risk communication strategies and combining heat warnings with action recommendations whenever possible to increase understanding and individual adaptation.

Identifying heat thresholds for South Africa towards the development of a heat-health warning system

Exposure to heatwaves may result in adverse human health impacts. Heat alerts in South Africa are currently based on defined temperature-fixed threshold values for large towns and cities. However, heat-health warning systems (HHWS) should incorporate metrics that have been shown to be effective predictors of negative heat-related health outcomes. This study contributes to the development of a HHWS for South Africa that can potentially minimize heat-related mortality. Distributed lag nonlinear models (DLNM) were used to assess the association between maximum and minimum temperature and diurnal temperature range (DTR) and population-adjusted mortality during summer months, and the effects were presented as incidence rate ratios (IRR). District-level thresholds for the best predictor from these three metrics were estimated with threshold regression. The mortality dataset contained records of daily registered deaths (n = 8,476,532) from 1997 to 2013 and data for the temperature indices were for the same period. Maximum temperature appeared to be the most statistically significant predictor of all-cause mortality with strong associations observed in 40 out of 52 districts. Maximum temperature was associated with increased risk of mortality in all but three of the districts. Our results also found that heat-related mortality was influenced by regional climate because the spatial distribution of the thresholds varied according to the climate zones across the country. On average, districts located in the hot, arid interior provinces of the Northern Cape and North West experienced some of the highest thresholds compared to districts located in temperate interior or coastal provinces. As the effects of climate change become more significant, population exposure to heat is increasing. Therefore, evidence-based HHWS are required to reduce heat-related mortality and morbidity. The exceedance of the maximum temperature thresholds provided in this study could be used to issue heat alerts as part of effective heat health action plans.

Preparing for a hotter climate: A systematic review and meta-analysis of heatwaves and ambulance callouts in Australia

OBJECTIVE

The objective of this study was to quantify the impact of heatwaves on likelihood of ambulance callouts for Australia.

METHODS

A systematic review and meta-analysis was conducted to retrieve and synthesise evidence published from 1 January 2011 to 31 May 2023 about the association between heatwaves and the likelihood of ambulance callouts in Australia. Different heatwave definitions were used ranging from excess heat factor to heatwave defined as a continuous period with temperatures above certain defined thresholds (which varied based on study locations).

RESULTS

We included nine papers which met the inclusion criteria for the review. Eight were eligible for the meta-analyses. The multilevel meta-analyses revealed that the likelihood of ambulance callouts for all causes and for cardiovascular diseases increased by 10% (95% confidence interval: 8%, 13%) and 5% (95% confidence interval: 1%, 3%), respectively, during heatwave days.

CONCLUSIONS

Exposure to heatwaves is associated with an increased likelihood of ambulance callouts, and there is a dose-response association between heatwave severity and the likelihood of ambulance callouts.

IMPLICATIONS FOR PUBLIC HEALTH

The number of heatwave days are going to increase, and this will mean an increase in the likelihood of ambulance callouts, thereby, spotlighting the real burden that heatwaves place on our already stressed healthcare system. The findings of this study underscore the critical need for proactive measures, including the establishment of research initiatives and holistic heat health awareness campaigns, spanning from the individual and community levels to the healthcare system, in order to create a more resilient Australia in the face of heatwave-related challenges.

Twenty-first-century demographic and social inequalities of heat-related deaths in Brazilian urban areas

Population exposure to heat waves (HWs) is increasing worldwide due to climate change, significantly affecting society, including public health. Despite its significant vulnerabilities and limited adaptation resources to rising temperatures, South America, particularly Brazil, lacks research on the health impacts of temperature extremes, especially on the role played by socioeconomic factors in the risk of heat-related illness. Here, we present a comprehensive analysis of the effects of HWs on mortality rates in the 14 most populous urban areas, comprising approximately 35% of the country's population. Excess mortality during HWs was estimated through the observed-to-expected ratio (O/E) for total deaths during the events identified. Moreover, the interplay of intersectionality and vulnerability to heat considering demographics and socioeconomic heterogeneities, using gender, age, race, and educational level as proxies, as well as the leading causes of heat-related excess death, were assessed. A significant increase in the frequency was observed from the 1970s (0-3 HWs year-1) to the 2010s (3-11 HWs year-1), with higher tendencies in the northern, northeastern, and central-western regions. Over the 2000-2018 period, 48,075 (40,448-55,279) excessive deaths were attributed to the growing number of HWs (>20 times the number of landslides-related deaths for the same period). Nevertheless, our event-based surveillance analysis did not detect the HW-mortality nexus, reinforcing that extreme heat events are a neglected disaster in Brazil. Among the leading causes of death, diseases of the circulatory and respiratory systems and neoplasms were the most frequent. Critical regional differences were observed, which can be linked to the sharp North-South inequalities in terms of socioeconomic and health indicators, such as life expectancy. Higher heat-related excess mortality was observed for low-educational level people, blacks and browns, older adults, and females. Such findings highlight that the strengthening of primary health care combined with reducing socioeconomic, racial, and gender inequalities represents a crucial step to reducing heat-related deaths.

Heat wave exposure and increased heat-related hospitalizations in young children in South Korea: A time-series study

BACKGROUND

Numerous studies have investigated the association between heat wave exposure increased heat-related hospitalizations in the general population. However, little is known about heat-related morbidity in young children who are more vulnerable than the general population. Therefore, we aimed to evaluate the association between hospitalization for heat-related illness in children and heat wave exposure in South Korea.

METHODS

We used the National Health Insurance Service (NHIS) database, which provides medical records from 2015 to 2019 in South Korea. We defined daily hospitalizations for heat-related illness of children younger than five years during the summer period (June to August). We considered the definition of heat waves considering the absolute temperature and percentile. A total of 12 different heat waves were used. A time-series analysis was used to investigate the association between heat wave exposure and heat-related hospitalization among children younger than five years. We used a two-stage design involving a meta-analysis after modeling by each region.

RESULTS

We included 16,879 daily heat-related hospitalizations among children younger than five years. Overall, heat wave exposure within two days was most related for heat-related hospitalizations in young children. The relative risk (RR) due to heat wave exposure within two days (lag2) (12 definitions: 70th to 90th percentile of maximum temperature) ranged from 1.038 (95% confidence interval (CI): 0.971, 1.110) to 1.083 (95% CI: 1.036, 1.133). We found that boys were more vulnerable to heat exposure than girls. In addition, we found that urban areas were more vulnerable to heat exposure than rural areas.

CONCLUSIONS

In our study, heat wave exposure during summer was found to be associated with an increased risk of hospitalization for heat-related illness among children younger than five years. Our findings suggest the need for summer heat wave management and prevention for children.

Heat stress reduces brown adipose tissue activity by exacerbating mitochondrial damage in type 2 diabetic mice

Epidemiological evidence shows that diabetic patients are susceptible to high temperature weather, and brown adipose tissue (BAT) activity is closely related to type 2 diabetes (T2DM). Activation of BAT under cold stress helps improve T2DM. However, the impact of high temperature on the activity of BAT is still unclear. The study aimed to investigate the impact of heat stress on glucose and lipid metabolism in T2DM mice by influencing BAT activity. High-fat feeding and injecting streptozotocin (STZ) induced model of T2DM mice. All mice were randomly divided into three groups: a normal(N) group, a diabetes (DM) group and a heat stress diabetes (DMHS) group. The DMHS group received heat stress intervention for 3 days. Fasting blood glucose, fasting serum insulin and blood lipids were measured in all three groups. The activity of BAT was assessed by using quantitative real-time PCR (qRT-PCR), electron microscopy, and PET CT. Furthermore, the UHPLC-Q-TOF MS technique was employed to perform metabolomics analysis of BAT on both DM group and DMHS group. The results of this study indicated that heat stress aggravated the dysregulation of glucose and lipid metabolism, exacerbated mitochondrial dysfunction in BAT and reduced the activity of BAT in T2DM mice. This may be related to the abnormal accumulation of branched-chain amino acids (BCAAs) in the mitochondria of BAT.

Heat impacts on human health in the Western Pacific Region: an umbrella review

Background

High temperatures and heatwaves are occurring more frequently and lasting longer because of climate change. A synthesis of existing evidence of heat-related health impacts in the Western Pacific Region (WPR) is lacking. This review addresses this gap.

Methods

The Scopus and PubMed databases were searched for reviews about heat impacts on mortality, cardiovascular morbidity, respiratory morbidity, dehydration and heat stroke, adverse birth outcomes, and sleep disturbance. The last search was conducted in February 2023 and only publications written in English were included. Primary studies and reviews that did not include specific WPR data were excluded. Data were extracted from 29 reviews.

Findings

There is strong evidence of heat-related mortality in the WPR, with the evidence concentrating on high-income countries and China. Associations between heat and cardiovascular or respiratory morbidity are not robust. There is evidence of heat-related dehydration and stroke, and preterm and still births in high-income countries in the WPR. Some evidence of sleep disturbance from heat is found for Australia, Japan and China.

Interpretation

Mortality is by far the most studied and robust health outcome of heat. Future research should focus on morbidity, and lower income countries in continental Asia and Pacific Island States, where there is little review-level evidence.

Funding

Funded by the World Health Organization WPR Office.

Factors causing emergency medical care overload during heatwaves: A Delphi study

Heatwaves pose an important risk for population health and are associated with an increased demand for emergency care. To find factors causing such overload, an online Delphi study included 15 experts in emergency medicine, disaster medicine, or public health. One open-ended question was delivered in the first round. After content analysis, the obtained statements were sent to the experts in two rounds to be rated on a 7-point linear scale. Consensus was defined as a standard deviation ≤ 1.0. Thirty-one statements were obtained after content analysis. The experts agreed on 18 statements, mostly focusing on the input section of patient processing and identifying stakeholders, the population, and primary care as targets of potential interventions. Additional dedicated resources and bed capacity were deemed important as per throughput and output sections, respectively. These findings could be used in the future to implement and test solutions to increase emergency healthcare resilience during heatwaves and reduce disaster risk due to climatic change.

Atmospheric pathway of marine heatwaves over the Northwestern Pacific

This study analyzes the influence of the Pacific-Japan (PJ) atmospheric teleconnection pattern and its interaction with oceanic processes on sea surface warming over the Northwestern Pacific. The PJ pattern is a thermally driven Rossby wave that originates over the tropical western Pacific through deep convection and propagates toward high latitudes. It plays a significant role in sea surface warming by inducing anticyclonic circulation and the corresponding northwestward extension of the subtropical high over the Northwestern Pacific. This study revealed that the key processes responsible for sea surface warming were an increase in insolation and a decrease in the ocean-to-atmosphere latent heat flux under the anticyclonic conditions driven by the PJ. This finding provides valuable insights into the role of atmospheric processes, we refer to it as the "atmospheric pathway", in the development of East Asian marine heatwaves (MHWs). A detailed understanding of this process will contribute to the prediction and mitigation of MHWs in East Asian countries.

Summer heat waves and their mortality risk over a 14-year period in a western region of Iran

Compared to previous decade, impact of heat waves (HWs) on mortality in recent years needs to be discussed in Iran. We investigated temporal change in added impact of summer HWs on mortality in eight cities of Iran. The pooled length of HWs was compared between 2015-2022 and 2008-2014 using random and fixed-effects of meta-analysis regression model. The temporal change in impact of HWs was evaluated through interaction effect between crossbasis function of HW and year in a two-stage time varying model. In order to pool the reduced coefficients of each period, multivariate meta-regression model, including city-specific temperature and temperature range as heterogenicity factors, was used. In addition to relative risk (RR), attributable fraction (AF) of HW in the two periods was also estimated in each city. In the last years, the frequency of all HWs was higher and the weak HWs were significantly longer. The only significant RR was related to the lowest and low severe HWs which was observed in the second period. In terms of AF, compared to the strong HWs, all weak HWs caused a considerable excess mortality in all cities and second period. The subgroup analysis revealed that the significant impact in the second period was mainly related to females and elderlies. The increased risk and AF due to more frequent and longer HWs (weak HWs) in the last years highlights the need for mitigation strategies in the region. Because of uncertainty in the results of severe HWs, further elaborately investigation of the HWs is need.

Analysis of heatwaves based on the universal thermal climate index and apparent temperature over mainland Southeast Asia

Heatwaves have caused significant damage to human health, infrastructure, and economies in recent decades, and the occurrences of heatwaves are becoming more frequent and severe across the globe under climate change. The previous studies on heatwaves have primarily focused on air temperature, neglecting other variables like wind speed, relative humidity, and radiation, which could lead to a serious underestimation of the adverse effects of heatwaves. To address this issue, this study proposed to the use of more sophisticated thermal indices, such as universal thermal climate index (UTCI) and apparent temperature (AT), to define heatwaves and carry out a comprehensive heatwave assessment over mainland southeast Asia (MSEA) from 1961 to 2020. The traditional temperature-based method was also compared. The results of the study demonstrate that the annual maximum temperature in heatwave days (HWA) and the annual average temperature in heatwave days (HWM) are significantly underestimated if only air temperature is considered. However, UTCI and AT tend to predict a lower frequency of yearly heatwave occurrences and shorter durations. Trend analysis indicates a general increase in heatwave occurrences across MSEA under all thermal indices in the past six decades, particularly in the last 30 years. This study's approach and findings provide a holistic view of heatwave characteristics based on thermal indices and highlight the risk of intensified heat stress during heatwaves in MSEA.

Review article: Scoping review of the characteristics and outcomes of adults presenting to the emergency department during heatwaves

As a result of climate change heatwaves are expected to increase in frequency and intensity and will have detrimental impacts on human health globally. EDs are often the critical point of care for acute heat illnesses and other conditions associated with heat exposure. Existing literature has focused on heatwave-related hospitalisation and mortality. This scoping review aimed to identify, evaluate and summarise current literature regarding patient characteristics and outcomes of ED admissions from heatwaves. A scoping review of the literature was conducted using six databases: Medline, EMBASE, EMCARE, CINAHL, PsycINFO, and Scopus, using MeSH terms and keywords related to 'heatwave' and 'Emergency Department'. Articles were included if they were: published in English from January 2000 to August 2021, related to ED, and examined high temperature periods consistent with heatwave criteria. Articles were appraised using the Mixed Methods Appraisal Tool (MMAT). Thirty-one studies were included, mostly from the United States, Australia, and France. The study designs include retrospective case analysis, case-control, and time-series analysis. Eight studies examined known heatwaves, 21 used different criteria to identify heatwave occurrence, and two focused on heat-related illness. The selected articles display a moderate-high quality on MMAT. ED admissions for both heat-related illnesses and other conditions increased during heatwaves, with up to 18.5 times risk increase. The risk was elevated for all population groups, and substantially in the elderly, male patients with certain comorbidities, medications, or lower socioeconomic status. Outcomes including hospitalisation and mortality rates after ED admissions showed positive associations with heatwaves. The heatwaves resulting from climate change will place increasing demands on EDs providing care for increasingly susceptible populations. Significant public heatwave planning across multiple sectors is required to reduce the risk of overwhelming EDs with these patients.

Population vulnerability to heat: A case-crossover analysis of heat health alerts and hospital morbidity data in Victoria, Australia

OBJECTIVE

From 2010 to 2022, the Victorian Department of Health operated a heat health alert system. We explored whether changes to morbidity occurred during or directly after these alerts, and how this differed for certain population groups.

METHODS

We used a space-time-stratified case-crossover design and conditional logistic regression to examine the associations between heat health alerts and heat-related and all-cause emergency department (ED) presentations and hospital admissions at the state-wide level, with models created for the whole population and subgroups. Data were included for the warm season (November-March) from 2014 to 2021.

RESULTS

Increases occurred in heat-related ED presentations (OR 1.73, 95% CI: 1.53-1.96) and heat-related hospital admissions (OR 1.23, 95% CI: 1.16-1.30) on days on or after heat health alerts. Effect sizes were largest for those 65 years and older, Aboriginal and Torres Strait Islander people, and those living in the most disadvantaged areas.

CONCLUSIONS

We confirm that increases in morbidity occurred in Victoria during heat health alerts and describe which population groups are more likely to require healthcare in a hospital.

IMPLICATIONS FOR PUBLIC HEALTH

These findings can inform responses before and during periods of extreme heat, data-driven adaptation strategies, and the development of heat health surveillance systems.

Vulnerability assessment of urban agglomerations to the risk of heat waves in China since the 21st century

In the context of global warming, frequent heat wave disasters have seriously threatened the safety of human life and property. The urban agglomeration, as the main region with a high concentration of population and economy, is susceptible to heat weaves due to the existing urban heat island effect. In this study, we investigated the temporal and spatial characteristics of heat waves (heat index, HI) in China from 2000 to 2020 and assess the vulnerability of 19 urban agglomerations to heat waves from the perspective of exposure, sensitivity and adaptability. The results show that: (1) In the past 20 years, the frequency and intensity of HI (greater than 26.67 °C) both showed an upward trend. (2) Shandong Peninsula, Central Henan, Yangtze River Delta, Middle Reaches of Yangtze River, and Mid-southern Liaoning urban agglomerations always maintain a high vulnerability. (3) From 2000 to 2020, the vulnerability of Beijing-Tianjin-Hebei, Yangtze River Delta, Chengdu-Chongqing, Middle reaches of Yangtze River, Guangdong-Fujian-Zhejiang, Harbin-Changchun and Mid-southern Liaoning urban agglomerations were always dominated by exposure. The vulnerability of Shandong Peninsula, Beibu Gulf and Central Henan urban agglomeration has always been dominated by sensitivity. The vulnerability of North Tianshan Mountain, Lanzhou-Xining, Guanzhong and Hu-Bao-E-Yu urban agglomeration has always been dominated by inadequate adaptability. (4) Recently, the factors that contributed most to exposure, sensitivity and adaptability were population density, the proportion of outdoor workers and water supply, with contribution rates of 38%, 55% and 26%, respectively. This study can provide a scientific basis for the rational allocation of resources among urban agglomerations, effectively formulating policies and guiding population migration from high temperature disasters.

The Impact of Heat Waves on Health Care Services in Low- or Middle-Income Countries: Protocol for a Systematic Review

BACKGROUND

Heat waves significantly impact ecosystems and human health, especially that of vulnerable populations, and are associated with increased morbidity and mortality. Besides being directly related to climate-sensitive health outcomes, heat waves have indirectly increased the burden on our health care systems. Although the existing literature examines the impact of heat waves and morbidity, past research has mostly been conducted in high-income countries (HICs), and studies on the impact of heat waves on morbidity in low- or middle-income countries (LMICs) are still scarce.

OBJECTIVE

This paper presents the protocol for a systematic review that aims to provide evidence of the impact of heat waves on health care services in LMICs.

METHODS

We will identify peer-reviewed studies from 3 online databases, including the Web of Science, PubMed, and SCOPUS, published from January 2002 to April 2023, using the PRISMA (Preferred Reporting Items for Systematic reviews and Meta-Analyses) guidelines. Quality assessment will be conducted using the Navigation Guide checklist. Key search terms include heatwaves, extreme heat, hospitalization, outpatient visit, burden, health services, and morbidity.

RESULTS

This systematic review will provide insight into the impact of heat waves on health care services in LMICs, especially on emergency department visits, ambulance call-outs, hospital admissions, outpatient department visits, in-hospital mortality, and health care operational costs.

CONCLUSIONS

The results of this review are anticipated to help policymakers and key stakeholders obtain a better understanding of the impact of heat waves on health care services and prioritize investments to mitigate the effects of heat waves in LMICs. This entails creating a comprehensive heat wave plan and ensuring that adequate infrastructure, capacity, and human resources are allocated in the health care sector. These measures will undoubtedly contribute to the development of resilience in health care systems and hence protect the health and well-being of individuals and communities.

TRIAL REGISTRATION

PROSPERO CRD42022365471; https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=365471.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/44702.

Methods of Assessing Health Care Costs in a Changing Climate: A Case Study of Heatwaves and Ambulance Dispatches in Tasmania, Australia

Anthropogenic climate change is causing a rise in global temperatures, with this trend projected to increase into the future. Rising temperatures result in an increase in the frequency and severity of heatwave events, with an associated increase in poor health outcomes for vulnerable individuals. This places an increasing strain on health care services. However, methods calculating future health care costs associated with this trend are poorly understood. We calculated health care costs attributable to heatwave events in Tasmania 2009-2019, using ambulance dispatches as a case study. We also modeled the expected health and economic burden for projected heatwave frequencies between 2010 and 2089. We developed our models based on two possible approaches to describing population adaptation to heatwaves-an adapted population calculated by determining heatwave episodes using a rolling baseline, and a non-adapted population calculated by determining heatwave episodes using a static baseline. Using a rolling baseline calculation for 2010 to 2089, we estimated additional ambulance costs averaging AUD$57,147 per year and totaling AUD$4,571,788. For the same period using a static baseline, we estimated additional ambulance costs averaging AUD$517,342 per year and totaling AUD$41,387,349. While this method is suitable for estimating the health care costs associated with heatwaves, it could be utilized for estimating health care costs related to other climate-related extreme events. Different methods of estimating heatwaves, modeling an adapted versus non-adapted population, provide substantial differences in projected costs. There is potential for considerable health system cost savings when a population is supported to adapt to extreme heat.

Efficacy assessment of green-blue nature-based solutions against environmental heat mitigation

Nature-based solutions (NBS) such as green (vegetation) and blue (waterbodies) infrastructure are being promoted as cost-effective and sustainable strategies for managing the heatwaves risks, but long-term monitoring evidence is needed to support their implementation. This work aims to conduct a comparative assessment of the cooling efficiency of green (woodland and grassland) and blue (waterbody) NBS in contrast to a built-up area. Over a year of continuous fixed monitoring showed that the average daily maximum temperatures at NBS locations were 2-3 °C (up-to 15%) lower than the built-up area. Woodland showed the maximum temperature reduction in almost all seasons, followed by waterbody and grassland. NBS performed the best during the summers, peak sunshine, and heatwave hours (up to ∼ 6 °C cooler than built-up area). Using an e-bike for mobile monitoring, the areas where green-blue NBS were combined showed the highest spatial cooling extent, followed by waterbody, woodland, and grassland areas. The database generated can validate city-scale environmental models and assist city planners to incorporate NBS into urban dwellings based on the opportunity, need and scope, aligning with Sustainable Development Goals 11 (sustainable cities and communities) and 13 (climate action).

Heatwaves: does global research reflect the growing threat in the light of climate change?

BACKGROUND

With the increasing impacts of climate change, heatwaves are placing an enormous burden on health and social systems and threatening ecological diversity around the world. Heatwaves are increasing not only in frequency but also in severity and magnitude. They are causing the deaths of thousands of people. Research is needed on a multidisciplinary, supra-regional, and regional level.

METHODS

A detailed evaluation of the research conducted is not yet available. Therefore, this study provides a detailed insight into the publication landscape to identify key players, incentives, and requirements for future scientific efforts that are useful not only for scientists but also to stakeholders and project funders.

RESULTS

The number of publications on heatwaves is increasing, outpacing the trend of research indexed by the Science Citation Index Expanded. However, funding is lagging behind comparatively. Looking at absolute numbers, the USA, Australia, China, and some European countries have been identified as major players in heatwave research. If socio-economic numbers are included, Switzerland and Portugal lead the way. Australia and the UK dominate if the change in heatwave-exposed people is included. Nevertheless, exposure and economic strength of publishing countries were identified as the main drivers of national research interests. Previous heatwaves, in particular, have driven research efforts primarily at the national level.

CONCLUSION

For an efficient monitoring or early detection system that also includes the economically weak regions, internationally networked efforts are necessary to enable preventive measures and damage limitation against heatwaves. Regardless of previous regional extreme heat events, research approaches should be focused to the global level.

Preterm-born individuals: a vulnerable population at risk of cardiovascular morbidity and mortality during thermal extremes?

NEW FINDINGS

What is the topic of this review? Thermal extremes disproportionately affect populations with cardiovascular conditions. Preterm birth, across all gestational age ranges below 37 weeks, has been identified as a non-modifiable risk factor for cardiovascular disease. The hypothesis is presented that individuals born preterm are at an increased risk of cardiovascular morbidity and mortality during thermal extremes. What advances does it highlight? Cardiovascular stress tests performed in preterm-born populations, from infancy through adulthood, highlight a progression of cardiovascular dysfunction accelerating through adolescence and adulthood. This dysfunction has many similarities with populations known to be at risk in thermal extremes.

ABSTRACT

Preterm-born individuals are a uniquely vulnerable population. Preterm exposure to the extrauterine environment and the (mal)adaptations that occur during the transitional period can result in alterations to their macro- and micro-physiological state. The physiological adaptations that increase survival in the short term may place those born preterm on a trajectory of lifelong dysfunction and later-life decompensation. Cardiovascular compensation in children and adolescents, which masks this trajectory of dysfunction, is overcome under stress, such that the functional cardiovascular capacity is reduced and recovery impaired following physiological stress. This has implications for their response to thermal stress. As the Anthropocene introduces greater changes in our environment, thermal extremes will impact vulnerable populations as yet unidentified in the climate change context. Here, we present the hypothesis that individuals born preterm are a vulnerable population at an increased risk of cardiovascular morbidity and mortality during thermal extremes.

The Association between Drought Exposure and Respiratory-Related Mortality in the United States from 2000 to 2018

Climate change has brought increasing attention to the assessment of health risks associated with climate and extreme events. Drought is a complex climate phenomenon that has been increasing in frequency and severity both locally and globally due to climate change. However, the health risks of drought are often overlooked, especially in places such as the United States, as the pathways to health impacts are complex and indirect. This study aims to conduct a comprehensive assessment of the effects of monthly drought exposure on respiratory mortality for NOAA climate regions in the United States from 2000 to 2018. A two-stage model was applied to estimate the location-specific and overall effects of respiratory risk associated with two different drought indices over two timescales (the US Drought Monitor and the 6-month and 12-month Evaporative Demand Drought Index). During moderate and severe drought exposure, respiratory mortality risk ratio in the general population increased up to 6.0% (95% Cr: 4.8 to 7.2) in the Northeast, 9.0% (95% Cr: 4.9 to 13.3) in the Northern Rockies and Plains, 5.2% (95% Cr: 3.9 to 6.5) in the Ohio Valley, 3.5% (95% Cr: 1.9 to 5.0) in the Southeast, and 15.9% (95% Cr: 10.8 to 20.4) in the Upper Midwest. Our results showed that age, ethnicity, sex (both male and female), and urbanicity (both metro and non-metro) resulted in more affected population subgroups in certain climate regions. The magnitude and direction of respiratory risk ratio differed across NOAA climate regions. These results demonstrate a need for policymakers and communities to develop more effective strategies to mitigate the effects of drought across regions.

Health effects of climate change in Africa: A call for an improved implementation of prevention measures

The world's climate, particularly in Africa, has changed substantially during the past few decades, contributed by several human activities. Africa is one of the continents that is most vulnerable to climate change globally. Since the beginning of 2022, extreme weather events in Africa have affected about 19 million people and killed at least 4,000 individuals. Cyclones, floods, heatwaves, wildfires, droughts, and famine were among the severe weather occurrences. Natural disasters and extreme weather events brought on by climate change may compromise access to clean water, sanitation systems, and healthcare facilities, making people more vulnerable to a number of illnesses. Floods and drought can lead to both communicable and non-communicable diseases. The African population is more likely to experience more mental health disorders than before because of natural disasters, which result in the loss of property and sometimes loss of lives more frequently. We, therefore, call for an improved implementation of strategies to prevent the health effects of climate change so that the health of the people in Africa can be maintained.

Effects of heatwave features on machine-learning-based heat-related ambulance calls prediction models in Japan

Researchers agree that there is substantial evidence of an increasing trend in both the frequency and duration of extreme temperature events. Increasing extreme temperature events will place more pressure on public health and emergency medical resources, and societies will need to find effective and reliable solutions to adapt to hotter summers. This study developed an effective method to predict the number of daily heat-related ambulance calls. Both national- and regional-level models were developed to evaluate the performance of machine-learning-based methods on heat-related ambulance call prediction. The national model showed a high prediction accuracy and can be applied over most regions, while the regional model showed extremely high prediction accuracy in each corresponding region and reliable accuracy in special cases. We found that the introduction of heatwave features, including accumulated heat stress, heat acclimatization, and optimal temperature, significantly improved prediction accuracy. The adjusted coefficient of determination (adjusted R²) of the national model improved from 0.9061 to 0.9659 by including these features, and the adjusted R² of the regional model also improved from 0.9102 to 0.9860. Furthermore, we used five bias-corrected global climate models (GCMs) to forecast the total number of summer heat-related ambulance calls under three different future climate scenarios nationally and regionally. Our analysis demonstrated that, at the end of the 21st century, the total number of heat-related ambulance calls in Japan will reach approximately 250,000 per year (nearly four times the current amount) under SSP-5.85. Our results suggest that disaster management agencies can use this highly accurate model to forecast potential high emergency medical resource burden caused by extreme heat events, allowing them to raise and improve public awareness and prepare countermeasures in advance. The method proposed in Japan in this paper can be applied to other countries that have relevant data and weather information systems.

Productivity-adjusted life years lost due to non-optimum temperatures in Brazil: A nationwide time-series study

Non-optimal temperatures are associated with premature deaths globally. However, the evidence is limited in low- and middle-income countries, and the productivity losses due to non-optimal temperatures have not been quantified. We aimed to estimate the work-related impacts and economic losses attributable to non-optimal temperatures in Brazil. We collected daily mortality data from 510 immediate regions in Brazil during 2000 and 2019. A two-stage time-series analysis was applied to evaluate the association between non-optimum temperatures and the Productivity-Adjusted Life-Years (PALYs) lost. The temperature-PALYs association was fitted for each location in the first stage and then we applied meta-analyses to obtain the national estimations. The attributable fraction (AF) of PALY lost due to ambient temperatures and the corresponding economic costs were calculated for different subgroups of the working-age population. A total of 3,629,661 of PALYs lost were attributed to non-optimal temperatures during 2000-2019 in Brazil, corresponding to 2.90 % (95 % CI: 1.82 %, 3.95 %) of the total PALYs lost. Non-optimal temperatures have led to US$104.86 billion (95 % CI: 65.95, 142.70) of economic costs related to PALYs lost and the economic burden was more substantial in males and the population aged 15-44 years. Higher risks of extreme cold temperatures were observed in the South region in Brazil while extreme hot temperatures were observed in the Central West and Northeast regions. In conclusion, non-optimal temperatures are associated with considerable labour losses as well as economic costs in Brazil. Tailored policies and adaptation strategies should be proposed to mitigate the impacts of non-optimal temperatures on the labour supply in a changing climate.

Historic evolution of population exposure to heatwaves in Xinjiang Uygur Autonomous Region, China

Heatwaves have pronounced impacts on human health and the environment on a global scale. Although the characteristics of heatwaves has been well documented, there still remains a lack of dynamic studies of population exposure to heatwaves (PEH), particularly in the arid regions. In this study, we analyzed the spatio-temporal evolution characteristics of heatwaves and PEH in Xinjiang using the daily maximum temperature (Tmax), relative humidity (RH), and high-resolution gridded population datasets. The results revealed that the heatwaves in Xinjiang occur more continually and intensely from 1961 to 2020. Furthermore, there is substantial spatial heterogeneity of heatwaves with eastern part of the Tarim Basin, Turpan, and Hami been the most prone areas. The PEH in Xinjiang showed an increasing trend with high areas mainly in Kashgar, Aksu, Turpan, and Hotan. The increase in PEH is mainly contributed from population growth, climate change and their interaction. From 2001 to 2020, the climate effect contribution decreased by 8.5%, the contribution rate of population and interaction effects increased by 3.3% and 5.2%, respectively. This work provides a scientific basis for the development of policies to improve the resilience against hazards in arid regions.

Combined effects of heatwaves and air pollution, green space and blue space on the incidence of hypertension: A national cohort study

Extreme heat exposure has been associated with hypertension. However, its interactive influences with air pollution, green and blue spaces are unclear. This study aimed to explore the interaction between heatwaves, air pollution, green and blue spaces on hypertension. Cohort data enrolled 6448 Chinese older adults aged 65 years and over were derived from the Chinese Longitudinal Healthy Longevity Survey (CLHLS) between 2008 and 2018. Nine heatwave definitions, combining three heat thresholds (92.5th, 95th, and 97.5th percentiles of daily maximum temperature) and three durations (≥2, 3 and 4 days) were used as time-varying variables in the analysis and were the one-year exposure before survival events. Fine particulate matter (PM ≤2.5 μm in aerodynamic diameter (PM_2.5)), the Normalized Difference Vegetation Index (NDVI) and the average proportion of open water bodies were used to reflect the air pollution, green and blue space exposures, respectively. PM_2.5, green and blue space exposures were time-varying indicators and contemporaneous with heatwaves. Mixed Cox models with time-varying variables were fitted to assess the multiplicative and additive interaction of heatwaves, PM_2.5, and green and blue spaces on hypertension, measured by a traditional product term with the ratio of hazard ratio (HR) and relative risk due to interaction (RERI), respectively. A positive multiplicative (HRs >1) and additive interaction (RERIs >0) between heatwaves and higher PM_2.5 levels was observed. There was a synergistic effect between heatwaves and decreasing greenness levels on hypertension incidence on additive and multiplicative scales. No significant interaction between heatwaves and blue space was observed in the analysis. The combined effects of heatwaves, air pollution, green and blue space exposures on the risk of hypertension varied with age, gender, and educational attainment. This study's findings complemented the existing evidence and revealed synergistic harmful impacts for heatwaves with air pollution and lack of green space on hypertension incidence.

Determining the Impact of Heatwaves on Emergency Ambulance Calls in Queensland: A Retrospective Population-Based Study

Heatwaves are a significant and growing threat to the health and well-being of the residents of Queensland, Australia. This threat is increasing due to climate change. Excess heat increases the demand for health services, including ambulance calls, and the purpose of this study was to explore this impact across Queensland. A state-wide retrospective analysis of heatwaves and emergency 'Triple Zero' (000) calls to Queensland Ambulance (QAS) from 2010-2019 was undertaken. Call data from the QAS and heatwave data from the Bureau of Meteorology were analysed using a case-crossover approach at the postcode level. Ambulance calls increased by 12.68% during heatwaves. The effect was greatest during low-severity heatwaves (22.16%), followed by severe (14.32%) and extreme heatwaves (1.16%). The impact varied by rurality, with those living in very remote areas and major cities most impacted, along with those of low and middle socioeconomic status during low and severe intensity heat events. Lag effects post-heatwave continued for at least 10 days. Heatwaves significantly increase ambulance call centre workload, so ambulance services must actively prepare resources and personnel to address increases in heatwave frequency, duration, and severity. Communities must be informed of the risks of heatwaves at all severities, particularly low severity, and the sustained risks in the days following a heat event.

Heatwaves and mortality in Queensland 2010-2019: implications for a homogenous state-wide approach

Heatwaves are a significant cause of adverse health outcomes and mortality in Australia, worsening with climate change. In Queensland, the northeastern-most state, little is known about the impact of heatwaves outside of the capital city of Brisbane. This study aims to explore the impact of heatwaves on mortality across various demographic and environmental conditions within Queensland from 2010 to 2019. The Excess Heat Factor was used to indicate heatwave periods at the Statistical Area 2 (SA2) level. Registered deaths data from the Australian Bureau of Statistics and heatwave data from the Bureau of Meteorology were matched using a case-crossover approach. Relative risk and 95% confidence intervals were calculated across years, regions, age, sex, rurality, socioeconomic status, and cause of death. Heatwaves were associated with a 5% increase in all-cause mortality compared to deaths on non-heatwave days, with variability across the state. The risk of death on a heatwave day versus a non-heatwave day varied by heatwave severity. Individuals living in urban centers, the elderly, and those living in regions of lower socioeconomic status were most impacted by heatwave mortality. The relative risk of dying from neoplasms, nervous system conditions, respiratory conditions, and mental and behavioral conditions increased during heatwaves. As heatwaves increase in Queensland due to climate change, understanding the impact of heatwaves on mortality across Queensland is important to tailor public health messages. There is considerable variability across communities, demographic groups, and medical conditions, and as such messages need to be tailored to risk.

The Association Between High Ambient Temperature and Mortality in the Mediterranean Basin: a Systematic Review and Meta-analysis

PURPOSE OF REVIEW

The Mediterranean basin is highly vulnerable to climate change. This study is aimed at quantifying the risk of mortality associated with exposure to high ambient temperature in the Mediterranean basin in the general population and in vulnerable sub-populations.

RECENT FINDINGS

We retrieved effect estimates from studies linking temperature and mortality in the Mediterranean basin, between 2000 and 2021. In a meta-analysis of 16 studies, we found an increased risk of all-cause mortality due to ambient heat/high temperature exposure in the Mediterranean basin, with a pooled RR of 1.035 (95%CI 1.028-1.041) per 1 °C increase in temperature above local thresholds (I² = 79%). Risk was highest for respiratory mortality (RR = 1.063, 95% CI 1.052-1.074) and cardiovascular mortality (RR = 1.046, 95% CI 1.036-1.057). Hot ambient temperatures increase the mortality risk across the Mediterranean basin. Further studies, especially in North African, Asian Mediterranean, and eastern European countries, are needed to bolster regional preparedness against future heat-related health burdens.

Heat waves and mortality in the Brazilian Amazon: Effect modification by heat wave characteristics, population subgroup, and cause of death

BACKGROUND

The Brazilian Amazon faces overlapping socio-environmental, sanitary, and climate challenges, and is a hotspot of concern due to projected increases in temperature and in the frequency of heat waves. Understanding the effects of extreme events on health is a central issue for developing climate policies focused on the population's health.

OBJECTIVES

We investigated the effects of heat waves on mortality in the Brazilian Amazon, examining effect modification according to various heat wave definitions, population subgroups, and causes of death.

METHODS

We included all 32 Amazonian municipalities with more than 100,000 inhabitants. The study period was from 2000 to 2018. We obtained mortality data from the Information Technology Department of the Brazilian Public Healthcare System, and meteorological data were derived from the ERA5-Land reanalysis dataset. Heat waves were defined according to their intensity (90th; 92.5th; 95th; 97.5th and 99th temperature percentiles) and duration (≥2, ≥3, and ≥4 days). In each city, we used a time-stratified case-crossover study to estimate the effects of each heat wave definition on mortality, according to population subgroup and cause of death. The lagged effects of heat waves were estimated using conditional Poisson regression combined with distributed lag non-linear models. Models were adjusted for specific humidity and public holidays. Risk ratios were pooled for the Brazilian Amazon using a univariate random-effects meta-analysis.

RESULTS

The pooled relative risks (RR) for mortality from total non-external causes varied between 1.03 (95% CI: 1.01-1.06), for the less stringent heat wave definition, and 1.18 (95% CI: 1.04-1.33) for the more stringent definition. The mortality risk rose as the heat wave intensity increased, although the increase from 2 to 3, and 3-4 days was small. Although not statistically different, our results suggest a higher mortality risk for the elderly, this was also higher for women than men, and for cardiovascular causes than for non-external or respiratory ones.

CONCLUSIONS

Heat waves were associated with a higher risk of mortality from non-external causes and cardiovascular diseases. Heat wave intensity played a more important role than duration in determining this risk. Suggestive evidence indicated that the elderly and women were more vulnerable to the effects of heat waves on mortality.

Effects of Heatwaves on Hospital Admissions for Cardiovascular and Respiratory Diseases, in Southern Vietnam, 2010-2018: Time Series Analysis

This study investigated the associations between heatwaves and daily hospital admissions for cardiovascular and respiratory diseases in two provinces in Viet Nam known to be vulnerable to droughts during 2010-2018. This study applied a time series analysis with data extracted from the electronic database of provincial hospitals and meteorological stations from the corresponding province. To eliminate over-dispersion, this time series analysis used Quasi-Poisson regression. The models were controlled for the day of the week, holiday, time trend, and relative humidity. Heatwaves were defined as the maximum temperature exceeding P90th over the period from 2010 to 2018 during at least three consecutive days. Data from 31,191 hospital admissions for respiratory diseases and 29,056 hospitalizations for cardiovascular diseases were investigated in the two provinces. Associations between hospital admissions for respiratory diseases and heatwaves in Ninh Thuan were observed at lag 2, with excess risk (ER = 8.31%, 95% confidence interval: 0.64-16.55%). However, heatwaves were negatively associated with cardiovascular diseases in Ca Mau, which was determined amongst the elderly (age above 60), ER = -7.28%, 95%CI: -13.97--0.08%. Heatwaves can be a risk factor for hospital admission due to respiratory diseases in Vietnam. Further studies need to be conducted to assert the link between heat waves and cardiovascular diseases.

Mortality Risk Related to Heatwaves in Dezful City, Southwest of Iran

BACKGROUND

We aimed to evaluate the impact of heatwaves on daily deaths due to non-accidental, cardiovascular and respiratory causes in the city of Dezful in Iran from 2013 to 2019.

METHOD

We collected daily ambient temperature and mortality and defined 2 types of heatwaves by combining daily temperature ⩾90th in each month of the study period or since 30 years with duration ⩾2 and 3 days. We used a distributed lag non-linear model to study the association between each type of heatwave definition, and deaths due to non-accidental, cardiovascular and respiratory causes with lags up to 13 days.

RESULTS

There was no discernible correlation in this area, despite the fact that heatwaves raised the risk of death from cardiovascular causes and lowered the risk from respiratory causes. On the other hand, the risk of total non-accidental mortality on days with the heatwaves is significantly higher than normal days. In main effects, the heatwaves have a significant relationship with the risk of total non-accidental mortality (in the first heatwave definition, Cumulative Excess Risk (CER) in lag_0-2 was 10.4 and in second heatwave definition, CER values in lag_{0, 0-2, and 0-6} were 12.4, 29.2, and 38.8 respectively). Also, in added effects, heatwaves have a significant relationship with the risk of total non-accidental mortality (in the first heatwave definition, CER in lag_{0 and 0-2} were 1.79 and 4.11 and in the second heatwave definition, CER values in lag_{0, 0-2, and 0-6} were 7.76, 18.35 and 24.87 respectively). In addition, heatwaves appeared to contribute to a cumulative excess risk of non-accidental death among the male group as well as the older adults.

CONCLUSION

However, the results showed that heatwaves could have detrimental effects on health, even in populations accustomed to the extreme heat. Therefore, early warning systems which monitor heatwaves should provide the necessary warnings to the population, especially the most vulnerable groups.

The extreme heat wave of July-August 2021 in the Athens urban area (Greece): Atmospheric and human-biometeorological analysis exploiting ultra-high resolution numerical modeling and the local climate zone framework

Greece was affected by a prolonged and extreme heat wave (HW) event (July 28-August 05) during the abnormally hot summer of 2021, with the maximum temperature in Athens, the capital of the country, reaching up to 43.9 °C in the city center. This observation corresponds to the second highest maximum temperature recorded since 1900, based on the historical temperature time series of the National Observatory of Athens weather station at Thissio. In the present study, a multi-scale numerical modeling system is used to analyze the urban climate and thermal bioclimate in the Athens urban area (AUA) in the course of the HW event, as well as during 3 days prior to the heat wave and 3 days after the episode. The system consists of the Weather Research and Forecasting model, the advanced urban scheme BEP/BEM (Building Energy Parameterization/Building Energy Model) and the human-biometeorological model RayMan Pro, and incorporates the local climate zone (LCZ) classification scheme. The system's validation results demonstrated a robust modeling set-up, characterized by high capability in capturing the observed magnitude and diurnal variation of the urban meteorological and heat stress conditions. The analysis of two- and three-dimensional fields of near-surface air temperature, humidity and wind unraveled the interplay of geographical factors (surface relief and proximity to the sea), background atmospheric circulations (Etesians and sea breeze) and HW-related synoptic forcing with the AUA's urban form. These interactions had a significant impact on the LCZs heat stress responsiveness, expressed using the modified physiologically equivalent temperature (mPET), between different regions of the study area, as well as at inter- and intra-LCZ level (statistically significant differences at 95 % confidence interval), providing thus, urban design and health-related implications that can be exploited in human thermal discomfort mitigation strategies in AUA.

How Antimicrobial Resistance Is Linked to Climate Change: An Overview of Two Intertwined Global Challenges

Globally, antimicrobial resistance (AMR) and climate change (CC) are two of the top health emergencies, and can be considered as two interlinked public health priorities. The complex commonalities between AMR and CC should be deeply investigated in a One Health perspective. Here, we provided an overview of the current knowledge about the relationship between AMR and CC. Overall, the studies included pointed out the need for applying a systemic approach to planetary health. Firstly, CC increasingly brings humans and animals into contact, leading to outbreaks of zoonotic and vector-borne diseases with pandemic potential. Although it is well-established that antimicrobial use in human, animal and environmental sectors is one of the main drivers of AMR, the COVID-19 pandemic is exacerbating the current scenario, by influencing the use of antibiotics, personal protective equipment, and biocides. This also results in higher concentrations of contaminants (e.g., microplastics) in natural water bodies, which cannot be completely removed from wastewater treatment plants, and which could sustain the AMR spread. Our overview underlined the lack of studies on the direct relationship between AMR and CC, and encouraged further research to investigate the multiple aspects involved, and its effect on human health.

Analysis and intervention of heatwave related economic loss: Comprehensive insights from supply, demand, and public expenditure into the relationship between the influencing factors

Increasing extreme temperatures are producing a serious impact on the economies of cities. However, the importance of social factors is typically neglected by the existing research. In this work, we first establish a supply-demand-public expenditure (SDP) framework for assessing and forecasting heat-related economic loss. Compared with the previous framework, SDP possesses a more comprehensive index system and functions that apply to all types of cities. We selected different economic development and geographical locations (Nanjing, Suzhou, and Yancheng) as case studies to verify the wide applicability of the SDP framework. A qualitative analysis and quantitative prediction of heatwaves and socioeconomic factors on losses were conducted for different cities. The results showed that different loss types displayed obvious regional heterogeneity among the cities. The labor value loss was the most significant type, and health loss was the most vulnerable type. In addition, public expenditure played a neglected critical regulatory role. Apart from these, the current level of public expenditure for heat prevention and control remains insufficient. Based on an assessment of the effects of interventions, policymakers need to make more efforts to increase the proportion of heat-related public spending and ensure stable socio-economic development by utilizing pathways with positive intervention potentials.