Associations between high ambient temperatures and heat waves with mental health outcomes: a systematic review

Emerging concern on air pollution and health: Trade-off between air pollution exposure and physical activity

Air pollution is a major contributor to the global disease burden, especially affecting respiratory and cardiovascular health. However, physical activity is associated with improved lung function, a slower decline in lung function, and lower mortality. The public is more likely to be exposed to air pollution during outdoor physical activity. However, studies on how long-term and short-term exposure to air pollution interacts with physical activity yield inconsistent results, and the thresholds for air pollution and physical activity remain unclear. Thus, more studies are needed to provide sufficient evidence to guide the public to safely engage in outdoor physical activity when exposed to air pollution.

Short-term impact of air pollution, noise and temperature on emergency hospital admissions in Madrid (Spain) due to liver and gallbladder diseases

BACKGROUND

Very few epidemiological studies have explored the environmental and meteorological risk factors that influence liver diseases and gallbladder disorders, and no studies have addressed the specific case of Spain.

METHODS

This is a retrospective ecological study conducted during 2013-2018. We analysed emergency admissions in the central area of the Region of Madrid for the following causes: Liver and gallbladder diseases (L&GB) (ICD-10: K70-K81); disorders of gallbladder (DGB) (ICD 10: K80-K81); liver disease (LD) (ICD 10: K70-K77); alcoholic liver disease (ALD) (ICD-10: K70); viral hepatitis (VH) (ICD10:B15-B19); and hepatic failure, not elsewhere classified (HFNS) (ICD-10: K72). Independent variables used: meteorological (maximum daily temperature (Tmax in ⁰C), minimum daily temperature (Tmin in ⁰C), and relative humidity (RH in %)); chemical air pollution (8-hO3, NO2, PM10, PM2.5 in μg/m3); and noise pollution (equivalent level of daily noise (Ld in dB(A)). Transformed variables: extreme heat in degrees (Theat); wet cold (WC); and high ozone. We fitted Poisson models, negative binomials and zero-inflated Poisson controlled for seasonality, day of the week, holidays, trend, and autoregressive trend. Based on these models, the percentage of cases attributable to statistically significant risk factors was then estimated.

RESULTS

In L&GB emergency admissions daily noise is related to 4.4% (CI95%: 0.8 7.9) of admissions; NO2 to 2.9% (CI95%: 0.1 5.7) and wet cold to 0.2% (CI95%: 0.8 7.9). Heat wave temperature was only related to ALD. In addition, the wet cold association with L&GB is also related to HFNS attributing 1.0% (CI95%: 0.3 1.8) of admissions for this cause.

CONCLUSIONS

Daily noise and NO2 are associated with more than 7% of urgent L&GB admissions. Both pollutants, are mainly emitted by road traffic. A reduction of traffic in cities would result in a reduction of emergency admissions due to this cause.

Integrating the Physical Environment Within a Population Neuroscience Perspective

Population neuroscience recognises the role of the environment in shaping brain, behaviour, and mental health. An overview of current evidence from neuroscientific and epidemiological studies highlights the protective effects of nature on cognitive function and stress reduction, the detrimental effects of urban living on mental health, and emerging concerns relating to extreme weather events and eco-anxiety. Despite the growing body of evidence in this area, knowledge gaps remain due to inconsistent measures of exposure and a reliance on small samples. In this chapter, attention is given to the physical environment and population-level studies as a necessary starting point for exploring the long-term impacts of environmental exposures on mental health, and for informing future research that may capture immediate emotional and neural responses to the environment. Key data sources, including remote sensing imagery, administrative, sensor, and social media data, are outlined. Appropriate measures of exposure are advocated for, recognising the value of area-level measures for estimating exposure over large study samples and spatial and temporal scales. Although integrating data from multiple sources requires consideration for data quality and completeness, deep learning and the increasing availability of high-resolution data present opportunities to build a more complete picture of physical environments. Advances in leveraging detailed locational data are discussed as a subsequent approach for building upon initial observations from population studies and improving understanding of the mechanisms underlying behaviour and human-environment interactions.

The potential of urban trees to reduce heat-related mortality in London

Increasing temperatures and more frequent heatwave events pose threats to population health, particularly in urban environments due to the urban heat island (UHI) effect. Greening, in particular planting trees, is widely discussed as a means of reducing heat exposure and associated mortality in cities. This study aims to use data from personal weather stations (PWS) across the Greater London Authority to understand how urban temperatures vary according to tree canopy coverage and estimate the heat-health impacts of London's urban trees. Data from Netatmo PWS from 2015-2022 were cleaned, combined with official Met Office temperatures, and spatially linked to tree canopy coverage and built environment data. A generalized additive model was used to predict daily average urban temperatures under different tree canopy coverage scenarios for historical and projected future summers, and subsequent health impacts estimated. Results show areas of London with higher canopy coverage have lower urban temperatures, with average maximum daytime temperatures 0.8 °C and minimum temperatures 2.0 °C lower in the top decile versus bottom decile canopy coverage during the 2022 heatwaves. We estimate that London's urban forest helped avoid 153 heat attributable deaths from 2015-2022 (including 16 excess deaths during the 2022 heatwaves), representing around 16% of UHI-related mortality. Increasing tree coverage 10% in-line with the London strategy would have reduced UHI-related mortality by a further 10%, while a maximal tree coverage would have reduced it 55%. By 2061-2080, under RCP8.5, we estimate that London's current tree planting strategy can help avoid an additional 23 heat-attributable deaths a year, with maximal coverage increasing this to 131. Substantial benefits would also be seen for carbon storage and sequestration. Results of this study support increasing urban tree coverage as part of a wider public health effort to mitigate high urban temperatures.

Short-term changes in mental health help-seeking behaviors following exposure to multiple social stressors and a natural disaster

In 2020, unprecedented circumstances led to significant mental health consequences. Individuals faced mental health stressors that extended beyond the devastating impact of the COVID-19 pandemic, including widespread social unrest following the murder of George Floyd, an intense hurricane season in the Atlantic, and the politically divisive 2020 election. The objective of this analysis was to consider changes in help-seeking behavior following exposure to multiple social stressors and a natural disaster. Data from Crisis Text Line (CTL), a national text-based mental health crisis counseling service, was used to determine how help-seeking behavior changed in the wake of each event. Wilcoxon rank sum tests assessed changes in help-seeking behavior for each event in 2020 as compared to the same period in 2019. AutoRegressive Integrated Moving Average (ARIMA) models examined if changes in crisis conversation volumes following each event differed. Higher median conversation volumes noted for the COVID-19 pandemic (+1 to +5 conversations), Hurricane Laura (+1 to +7 conversations) and the 2020 Election (+1 to +26 conversations). ARIMA models show substantial increases in help-seeking behavior following the declaration of a national emergency for the COVID-19 pandemic (+4.3 to +38.2%) and following the 2020 election (+3 to +24.44%). Our analysis found that the mental health response following social stressors may be distinct from natural events, especially when natural disasters occur in the context of multiple social stressors. This analysis adds to the growing body of literature considering the mental health impact of exposure to multiple co-occurring societal stressors, like police violence and a global pandemic.

Global climate change: Effects of future temperatures on emergency department visits for mental disorders in Beijing, China

Rising temperatures can increase the risk of mental disorders. As climate change intensifies, the future disease burden due to mental disorders may be underestimated. Using data on the number of daily emergency department visits for mental disorders at 30 hospitals in Beijing, China during 2016-2018, the relationship between daily mean temperature and such visits was assessed using a quasi-Poisson model integrated with a distributed lag nonlinear model. Emergency department visits for mental disorders attributed to temperature changes were projected using 26 general circulation models under four climate change scenarios. Stratification analyses were then conducted by disease subtype, sex, and age. The results indicate that the temperature-related health burden from mental disorders was projected to increase consistently throughout the 21st century, mainly driven by high temperatures. The future temperature-related health burden was higher for patients with mental disorders due to the use of psychoactive substances and schizophrenia as well as for women and those aged <65 years. These findings enhance our knowledge of how climate change could affect mental well-being and can be used to advance and refine targeted approaches to mitigating and adapting to climate change with a view on addressing mental disorders.

Exploring the relationship between nursing students' knowledge and attitudes towards climate change and their psychological distress: a cross-national investigation

BACKGROUND

Climate change poses a worldwide challenge with anticipated exacerbation in the future, resulting in irreversible consequences. Nursing students may be vulnerable to experiencing psychological effects associated with climate change.

AIM

The current study aimed to investigate the relationship between nursing students' knowledge and attitudes toward climate change and their psychological distress.

METHOD

This descriptive cross-sectional study recruited 377 nursing students from three universities located in Saudi Arabia, Jordan, and Egypt in the Middle East. Data collection was conducted using scales for assessing nursing students' knowledge and attitudes towards climate change and their psychological distress. Correlations were assessed and multiple regression analysis was conducted to explore the predictors of students' psychological distress.

RESULTS

The current study showed that knowledge regarding climate change significantly and positively correlated to the attitude toward climate change (r = 0.213), then again, the score of psychological distress significantly and negatively correlated to the score of students' knowledge and attitude regarding climate change (r = - 0.182 and - 0.110 respectively). Regression analyses showed that academic achievement had the strongest positive impact on students' psychological distress, while knowledge regarding climate change and attitude toward climate change had negative impacts (β = 0.381, β=-0.205, and β=-0.045 respectively). Moreover, knowledge and attitude regarding climate change were found to be significant predictors of students' psychological distress, collectively accounting for 18.2% of the observed variance.

CONCLUSIONS/IMPLICATION FOR FUTURE PRACTICE

The findings highlight the importance of incorporating climate change into nursing education programs. By enhancing nursing students' knowledge and attitudes towards climate change, there is potential to reduce their psychological distress. This study underscores the need for curriculum reforms that integrate climate change topics, aiming to foster a well-informed and resilient future nursing workforce.

How does the macroenvironment influence brain and behaviour-a review of current status and future perspectives

The environment influences brain and mental health, both detrimentally and beneficially. Existing research has emphasised the individual psychosocial 'microenvironment'. Less attention has been paid to 'macroenvironmental' challenges, including climate change, pollution, urbanicity, and socioeconomic disparity. Notably, the implications of climate and pollution on brain and mental health have only recently gained prominence. With the advent of large-scale big-data cohorts and an increasingly dense mapping of macroenvironmental parameters, we are now in a position to characterise the relation between macroenvironment, brain, and behaviour across different geographic and cultural locations globally. This review synthesises findings from recent epidemiological and neuroimaging studies, aiming to provide a comprehensive overview of the existing evidence between the macroenvironment and the structure and functions of the brain, with a particular emphasis on its implications for mental illness. We discuss putative underlying mechanisms and address the most common exposures of the macroenvironment. Finally, we identify critical areas for future research to enhance our understanding of the aetiology of mental illness and to inform effective interventions for healthier environments and mental health promotion.

Global burden of self-harm and interpersonal violence and influencing factors study 1990-2019: analysis of the global burden of disease study

INTRODUCTION

Widespread concern exists in today's world regarding self-harm and interpersonal violence. This study to analyze the changes in temporal trends and spatial patterns of risk factors and burdens of self-harm and interpersonal violence using the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2019.

METHODS

Temporal trends in self-harm and interpersonal violence were initially summarized using the estimated annual percentage change (EAPC). Data were compiled and visualized to delineate changes in disease burden and factors influencing self-harm and interpersonal violence from 1990 to 2019, stratified by gender, age and GBD region.

RESULTS

In 2019, the DALY rates of self-harm were 424.7(95% UI 383.25, 466.93). Over the period from 1999 to 2019, self-harm exhibited an overall decreasing trend, with the EAPC of -1.5351 (95% CI -1.6194, -1.4507), -2.0205 (95% CI -2.166, -1.8740) and -2.0605 (95% CI -2.2089, -1.9119), respectively. In contrast, the incidence rate of interpersonal violence was significantly higher than self-harm, with a rate of 413.44 (95% UI 329.88, 502.37) per 100,000 population. Mortality and DALYs of interpersonal violence were lower than those of self-harm, at 5.22 (95% UI 4.87, 5.63) and 342.43 (95% UI 316.61, 371.55). Disease burden of self-harm and interpersonal violence varied by gender, age groups and region. Specific risk factors showed that alcohol use, high temperature and drug use were the main risk factors for self-harm, while alcohol use, intimate partner violence and high temperature were associated with interpersonal violence. Low temperature was a common protective factor for both self-harm and interpersonal violence. The burden of self-harm and interpersonal violence was attributed to different factors influences in different SDI regions.

CONCLUSIONS

The study explored temporal trends and spatial distribution of the global disease burden of self-harm and interpersonal violence, emphasizing the significant impact of factors such as alcohol use, temperature, and drug use on disease burden. Further research and policy actions are needed to interpret recent changes of disease burden of self-harm and interpersonal violence, and dedicated efforts should be implemented to devise evidence-based interventions and policies to curtail risk factors and protect high-risk groups.

The relationship between hot temperatures and hospital admissions for psychosis in adults diagnosed with schizophrenia: A case-crossover study in Quebec, Canada

INTRODUCTION

Some studies have found hot temperatures to be associated with exacerbations of schizophrenia, namely psychoses. As climate changes faster in Northern countries, our understanding of the association between temperature and hospital admissions (HA) for psychosis needs to be deepened.

OBJECTIVES

1) Among adults diagnosed with schizophrenia, measure the relationship between mean temperatures and HAs for psychosis during summer. 2) Determine the influence of individual and ecological characteristics on this relationship.

METHODS

A cohort of adults diagnosed with schizophrenia (n = 30,649) was assembled using Quebec's Integrated Chronic Disease Surveillance System (QICDSS). The follow-up spanned summers from 2001 to 2019, using hospital data from the QICDSS and meteorological data from the National Aeronautics and Space Administration's (NASA) Daymet database. In four geographic regions of the province of Quebec, a conditional logistic regression was used for the case-crossover analysis of the relationship between mean temperatures (at lags up to 6 days) and HAs for psychosis using a distributed lag non-linear model (DLNM). The analyses were adjusted for relative humidity, stratified according to individual (age, sex, and comorbidities) and ecological (material and social deprivation index and exposure to green space) factors, and then pooled through a meta-regression.

RESULTS

The statistical analyses revealed a statistically significant increase in HAs three days (lag 3) after elevated mean temperatures corresponding to the 90th percentile relative to a minimum morbidity temperature (MMT) (OR 1.040; 95% CI 1.008-1.074), while the cumulative effect over six days was not statistically significant (OR 1.052; 95% IC 0.993-1.114). Stratified analyses revealed non statistically significant gradients of increasing HAs relative to increasing material deprivation and decreasing green space levels.

CONCLUSIONS

The statistical analyses conducted in this project showed the pattern of admissions for psychosis after hot days. This finding could be useful to better plan health services in a rapidly changing climate.

Exposure to heat wave risks across time and places: Seasonal variations and predictors of feelings of threat across heat wave geographical susceptibility locations

Vulnerability to heat waves and their negative effects on health vary not only due to individual factors but also due to situational factors, such as time and geography. Hence, we explored seasonal variations and predictors of heat wave feelings of threat across different heat wave geographical susceptibility locations in Portugal. A total of 238 Portuguese residents responded to a web-based longitudinal survey: before the summer, during a heat wave in the summer, during the summer, and after the summer. Geographical location was used as an indicator of risk exposure, operationalized as heat wave occurrence susceptibility (low, moderate, high). Heat wave demands and resources perceptions were assessed to compute an indicator of heat wave feelings of threat. During the heat wave, feelings of threat were higher among participants in high-susceptibility locations, with demands outweighing resources perceptions, suggesting greater distress and coping difficulty. Regression analysis suggested that older participants and female participants living in moderate-high-susceptibility locations had greater difficulty in recovering. Heat wave risk perception and positive affect about heat were identified as the most consistent predictors of heat wave feelings of threat, with risk perception increasing and positive affect decreasing such feelings. Participants with (individual and geographical) vulnerability profiles, who had greater difficulty in coping and recovering from heat waves, could benefit from resource-building/enhancing interventions. In a climatic crisis context, monitoring psychological responses to heat waves (e.g., threat) may enable anticipated action to build resilience before, rather than after, the effects become damaging to physical and psychological health.

The importance of teaching climate-health literacy in psychotherapeutic training and continuing education

Climate-health literacy is the ability to find, access, understand, interpret, evaluate, and communicate information about the impact of climate change on human health and to make decisions and act accordingly to that information. Climate change affects people's health in numerous ways, both directly and indirectly, e.g., by increasing the risks of cardiovascular disease, infections, depression, anxiety disorders, and trauma. It is important for health professionals to understand the complex interaction between climate change and health. A teaching concept is presented that incorporates the core elements of climate-health literacy. On a first level, physical and climatological basics are taught, direct and indirect impacts of climate change on human health, climate protective measures, the psychological background of climate-protective behavior, and professional ethics. Furthermore, via self-awareness and self-reflection, the impact of climate change on the student's mental health should be evaluated. In an advanced level, the direct and indirect impacts of climate change on mental health are taught, coping strategies, resilience, and vulnerability, as well as the role of health-care professionals in the climate crisis. In expert-level lectures, the knowledge can be deepened, and special content like activist burnout can be addressed.

A systematic review of ambient heat and sleep in a warming climate

Climate change is elevating nighttime and daytime temperatures worldwide, affecting a broad continuum of behavioral and health outcomes. Disturbed sleep is a plausible pathway linking rising ambient temperatures with several observed adverse human responses shown to increase during hot weather. This systematic review aims to provide a comprehensive overview of the literature investigating the relationship between ambient temperature and valid sleep outcomes measured in real-world settings, globally. We show that higher outdoor or indoor temperatures are generally associated with degraded sleep quality and quantity worldwide. The negative effect of heat persists across sleep measures, and is stronger during the hottest months and days, in vulnerable populations, and the warmest regions. Although we identify opportunities to strengthen the state of the science, limited evidence of fast sleep adaptation to heat suggests rising temperatures induced by climate change and urbanization pose a planetary threat to human sleep, and therefore health, performance, and wellbeing.

Shifting focus: Time to look beyond the classic physiological adaptations associated with human heat acclimation

Planet Earth is warming at an unprecedented rate and our future is now assured to be shaped by the consequences of more frequent hot days and extreme heat. Humans will need to adapt both behaviorally and physiologically to thrive in a hotter climate. From a physiological perspective, countless studies have shown that human heat acclimation increases thermoeffector output (i.e., sweating and skin blood flow) and lowers cardiovascular strain (i.e., heart rate) during heat stress. However, the mechanisms mediating these adaptations remain understudied. Furthermore, several possible benefits of heat acclimation for other systems and functions involved in maintaining health and performance during heat stress remain to be elucidated. This review summarizes recent advances in human heat acclimation, with emphasis on recent studies that (1) advanced our understanding of the mechanisms mediating improved thermoeffector output and (2) investigated adaptations that go beyond those classically associated with heat acclimation. We highlight that these studies have contributed to a better understanding of the integrated physiological responses underlying human heat acclimation while leaving key unanswered questions that will need to be addressed in the future.

Maternal health outcomes associated with ambient air pollution: An umbrella review of systematic reviews and meta-analyses

A growing body of literature demonstrated an association between exposure to ambient air pollution and maternal health outcomes with mixed findings. The objective of this umbrella review was to systematically summarize the global evidence on the effects of air pollutants on maternal health outcomes. We adopted the Joanna Briggs Institute (JBI) methodology and Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) reporting standards for this umbrella review. We conducted a comprehensive search across six major electronic databases and other sources to identify relevant systematic reviews and meta-analyses (SRMAs) published from the inception of these databases up to June 30, 2023. Out of 2399 records, 20 citations matched all pre-determined eligibility criteria that include SRMAs focusing on exposure to air pollution and its impact on maternal health, reported quantitative measures or summary effects, and published in peer-reviewed journals in the English language. The risk of bias of included SRMAs was evaluated based on the JBI critical appraisal checklist. All SRMAs reported significant positive associations between ambient air pollution and several maternal health outcomes. Specifically, particulate matter (PM), SO2, and NO demonstrated positive associations with gestational diabetes mellitus (GDM). Moreover, PM and NO2 showed a consistent positive relationship with hypertensive disorder of pregnancy (HDP) and preeclampsia (PE). Although limited, available evidence highlighted a positive correlation between PM and gestational hypertension (GH) and spontaneous abortion (SAB). Only one meta-analysis reported the effects of air pollution on maternal postpartum depression (PPD) where only PM10 showed a significant positive relationship. Limited studies were identified from low- and middle-income countries (LMICs), suggesting evidence gap from the global south. This review necessitates further research on underrepresented regions and communities to strengthen evidence on this critical issue. Lastly, interdisciplinary policymaking and multilevel interventions are needed to alleviate ambient air pollution and associated maternal health disparities.

Self-harm and interpersonal violence due to high temperature from the global burden of disease study 2019: A 30-year assessment

BACKGROUND

The impact of global warming on health due to climate change is increasingly studied, but the global burden of self-harm and interpersonal violence attributable to high temperature is still limited. This study aimed to systematically assess the burden of self-harm and interpersonal violence attributable to high temperature globally or by region and climate zone from 1990 to 2019.

METHODS

We obtained the global, regional, and national deaths, disability-adjusted life years (DALYs), age-standardized mortality rates (ASMR), and age-standardized disability-adjusted life year rates (ASDR) of self-harm and interpersonal violence due to high temperature from 1990 to 2019 through the Global Burden of Disease Study (GBD) 2019. The burden of self-harm and interpersonal violence due to high temperature was estimated by age, sex, climate zone, the socio-demographic index (SDI), and the healthcare access and quality index (HAQ). Average annual percentage changes (AAPCs) in ASMR and ASDR were calculated for 1990-2019 using the Joinpoint model.

RESULTS

From 1990 to 2019, the global deaths and DALYs related to self-harm and interpersonal violence due to high temperature increased from 20,002 (95% UI, 9243 to 41,928) and 1,107,216 (95% UI, 512,062 to 2,319,477) to 26,459 (95% UI, 13,574 to 47,265) and 1,382,487 (95% UI, 722,060 to 2,474,441), respectively. However, the ASMR and ASDR showed varying degrees of decreasing trends, with decreases of 13.36% and 12.66%, respectively. The ASMR was high and declining in low and low-middle SDI regions, particularly in tropical and subtropical regions. In addition, SDI and HAQ index were negatively correlated with ASMR in 204 countries and regions.

CONCLUSIONS

The global burden of self-harm and interpersonal violence attributed to high temperature has decreased over the past 30 years, but the number of deaths and DALYs continues to rise. Climate change continues to make heat stress a significant risk factor for self-harm and interpersonal violence worldwide.

Assessing the Human Health Benefits of Climate Mitigation, Pollution Prevention, and Biodiversity Preservation

Background

Since the Industrial Revolution, humanity has amassed great wealth and achieved unprecedented material prosperity. These advances have come, however, at great cost to the planet. They are guided by an economic model that focuses almost exclusively on short-term gain, while ignoring natural capital and human capital. They have relied on the combustion of vast quantities of fossil fuels, massive consumption of the earth's resources, and production and environmental release of enormous quantities of chemicals, pesticides, fertilizers, and plastics. They have caused climate change, pollution, and biodiversity loss, the "Triple Planetary Crisis". They are responsible for more than 9 million premature deaths per year and for widespread disease - impacts that fall disproportionately upon the poor and the vulnerable.

Goals

To map the human health impacts of climate change, pollution, and biodiversity loss. To outline a framework for assessing the health benefits of interventions against these threats.

Findings

Actions taken by national governments and international agencies to mitigate climate change, pollution, and biodiversity loss can improve health, prevent disease, save lives, and enhance human well-being. Yet assessment of health benefits is largely absent from evaluations of environmental remediation programs. This represents a lost opportunity to quantify the full benefits of environmental remediation and to educate policy makers and the public.

Recommendations

We recommend that national governments and international agencies implementing interventions against climate change, pollution, and biodiversity loss develop metrics and strategies for quantifying the health benefits of these interventions. We recommend that they deploy these tools in parallel with assessments of ecologic and economic benefits. Health metrics developed by the Global Burden of Disease (GBD) study may provide a useful starting point.Incorporation of health metrics into assessments of environmental restoration will require building transdisciplinary collaborations. Environmental scientists and engineers will need to work with health scientists to establish evaluation systems that link environmental and economic data with health data. Such systems will assist international agencies as well as national and local governments in prioritizing environmental interventions.

Impacts of compounding drought and heatwave events on child mental health: insights from a spatial clustering analysis

BACKGROUND

Concurrent heatwave and drought events may have larger health impacts than each event separately; however, no US-based studies have examined differential mental health impacts of compound drought and heatwave events in pediatric populations.

OBJECTIVE

To examine the spatial patterns of mood disorders and suicide-related emergency department (ED) visits in children during heatwave, drought, and compound heatwave and drought events. We tested whether the occurrence of compound heatwave and drought events have a synergistic (multiplicative) effect on the risk of mental health related outcomes in children as compared to the additive effect of each individual climate hazard. Lastly, we identified household and community-level determinants of geographic variability of high psychiatric burden.

METHODS

Daily counts of psychiatric ED visits in North Carolina from 2016 to 2019 (May to Sept) for pediatric populations were aggregated at the county scale. Bernoulli cluster analyses identified high-risk spatial clusters of psychiatric morbidity during heatwave, drought, or compound heatwave and drought periods. Multivariate adaptive regression models examined the individual importance of household and community-level determinants in predicting high-risk clustering of mood disorders or suicidality across the three climate threats.

RESULTS

Results showed significant spatial clustering of suicide and mood disorder risks in children during heatwave, drought, and compound event periods. Periods of drought were associated with the highest likelihood of spatial clustering for suicide and mood disorders, where the risk of an ED visit was 4.48 and 6.32 times higher, respectively, compared to non-drought periods. Compounding events were associated with a threefold increase in both suicide and mood disorder-related ED visits. Community and household vulnerability factors that most contributed to spatial clustering varied across climate hazards, but consistent determinants included residential segregation, green space availability, low English proficiency, overcrowding, no broadband access, no vehicle access, housing vacancy, and availability of housing units.

CONCLUSION

Findings advance understanding on the locations of vulnerable pediatric populations who are disproportionately exposed to compounding climate stressors and identify community resilience factors to target in public health adaptation strategies.

Residential greenness for mitigating impacts of extreme heat events on depression and supporting mental health

Background

Residential green spaces (RGS) are a crucial aspect of urban life, which provide residents with a positive living environment both for mental and physical well-being. However, extreme heat events caused by global warming and local urban heat island effects are threatening the public health of rapidly growing populations. This is especially true for mental health. Depression is a mental illness that can be impacted by extreme heat events, i.e., heatwaves.

Objective

This study aimed to investigate the potential for residential green spaces (RGS) to alleviate depression by reducing heat stress sensitivity during extreme heat events.

Methods

We conducted a literature review using scientometric analysis with CiteSpace to summarize existing research on the relationships between RGS, depression, and heatwaves. We proposed a conceptual framework for the relationship between RGS and depression, and that extreme heat events may be an important contributor to depression.

Results

Our review found that RGS can provide ecosystem services that lower ambient temperatures through evaporative cooling, radiation reflection, humidity regulation, and shading. Different types of RGS, i.e., small green spaces, green roofs, green walls, and street trees, have varying cooling capacities. The mechanisms by which RGS alleviate depression during heatwaves involve green space composition, exposure, physical activity, social contacts, and cohesion. And we proposed a conceptual framework for the relationship between RGS and depression, and that extreme heat events may be an important contributor to depression.

Conclusion

We present a multidimensional RGS evaluation roadmap to inform green space design for reducing depression during heatwaves. Establishing RGS multidimensional evaluation can guide future research on leveraging RGS to build resilience against extreme heat and improve public mental health.

Spatio-temporal interpolation and delineation of extreme heat events in California between 2017 and 2021

Robust spatio-temporal delineation of extreme climate events and accurate identification of areas that are impacted by an event is a prerequisite for identifying population-level and health-related risks. In prior research, attributes such as temperature and humidity have often been linearly assigned to the population of the study unit from the closest weather station. This could result in inaccurate event delineation and biased assessment of extreme heat exposure. We have developed a spatio-temporal model to dynamically delineate boundaries for Extreme Heat Events (EHE) across space and over time, using a relative measure of Apparent Temperature (AT). Our surface interpolation approach offers a higher spatio-temporal resolution compared to the standard nearest-station (NS) assignment method. We show that the proposed approach can provide at least 80.8 percent improvement in identification of areas and populations impacted by EHEs. This improvement in average adjusts the misclassification of about one million Californians per day of an extreme event, who would be either unidentified or misidentified under EHEs between 2017 and 2021.

Climate attribution of interpersonal violence: International evidence

Anthropogenic climate change is increasingly threatening interpersonal violence, yet global evidence for related impacts and potential transmission mechanisms remains limited. We examine whether and how climate change, particularly climate extremes, affects interpersonal violence. Using the panel data of 140 countries and regions from 2000 to 2019, we find that hot and wet extremes precipitated increase in homicide rates globally. Economic level, inequality, and resources scarcity were important intermediaries through which climate extremes affected homicide, while the direct effects still dominated the total effects. We then reveal the heterogeneous effects of climate extremes, further suggesting that poor countries and regions with relatively small contributions to climate change were particularly sensitive to climate extremes. These findings elucidate a strong climate-violence link, helping explain implications of facilitating violence prevention and mitigating climate change.

[Climate change, biodiversity loss and pollution: consequences for psychiatry]

The climate crisis, loss of biodiversity and increasing global pollution are a threat to mental health. Comprehensive transformations are needed to overcome these crises, which will also affect the mental healthcare system. If done correctly these change processes can seize the chance to improve mental health while at the same time addressing the crises. This includes avoiding the need for psychiatric treatment by strengthening the focus on mental health promotion and prevention, and also considering environmental aspects when targetting therapy procedures. In addition, by focusing on nutrition, mobility and the effects of nature, patients can be empowered to increase their mental resilience whilst reducing the negative effects on the environment. At the same time, the mental healthcare system must adapt to changing environmental conditions: increasing heat waves make protective measures necessary, especially for people with mental illnesses and increasing extreme weather events can lead to shifts in the spectrum of illnesses. Appropriate funding mechanisms will have to be established to support mental healthcare throughout this transformation.

The influence of climate change on mental health in populations of the western Pacific region: An umbrella scoping review

The Western Pacific Region (WPR) is on the front line of climate change challenges. Understanding how these challenges affect the WPR populations' mental health is essential to design effective prevention and care policies. Thus, the present study conducted an umbrella scoping review that examined the influence of climate change on mental health in the WPR, using review articles as a source of information. Ten review articles were selected according to eligibility criteria, and the findings were synthesized according to the socio-economic status of the countries identified: Australia, the Republic of Korea, the Philippines, Vietnam, the Pacific Islands (broadly), and China. The findings revealed that each country and sub-region has its own unique profile of climate change-related challenges and vulnerable populations, highlighting the need for specific approaches to mental health care. Specifically, the influence of climate-related challenges differed according to populations' region (e.g., rural populations), demographic characteristics (e.g., age and gender), culture (e.g., traditional tights to land), and employment (e.g., farmers and fishers). The most frequently reported mental health outcomes in response to climate change-related challenges such as droughts, floods, storms, tornadoes, typhoons, and climate-related migration were the decline in mental well-being and the increase in post-traumatic stress disorder symptoms. In addition, using the GRADE framework for assessing the certainty of the findings, we identified that the number of articles discussing associations between a given climate change challenge and a mental health outcome was overall limited. Based on our findings and findings on a global scale, we identified several key research gaps in WPR and provided recommendations for future research and policy strategies.

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.

Estimating climate change and mental health impacts in Canada: A cross-sectional survey protocol

Climate change has severe and sweeping impacts on mental health. Although research is burgeoning on mental health impacts following climate and weather extremes, less is known about how common these impacts are outside of extreme events. Existing research exploring the prevalence of psychosocial responses to climate change primarily examines university students and uses non-random sampling methods. Herein, our protocol outlines an approach to data collection, processing, and analysis to estimate the population prevalence, magnitude, and distribution of mental health responses to climate change in Canada. A cross-sectional survey of youth and adults aged 13 years and older in Canada will be administered over the course of one year. The questionnaire will take approximately 10 minutes to complete orally and will be administered in English, French, and Inuktitut. The survey will consist of six sections: (1) self-reported past experiences of climate change; (2) self-reported climate-related emotions; (3) self-reported past and current impacts, anticipatory impacts, and vicarious experiences; (4) self-reported subclinical outcomes; (5) self-reported behavioural responses; and (6) demographics. A multi-stage, multi-stratified random probability sampling method will be used to obtain a sample representative of the Canadian population. We will use two different modes of recruitment: an addressed letter sent by postal mail or a telephone call (landlines and cellular). Population-weighted descriptive statistics, principal component analysis, and weighted multivariable regression will be used to analyse the data. The results of this survey will provide the first national prevalence estimates of subclinical mental health responses to climate change outcomes of people living in Canada.

How does the macroenvironment influence brain and behaviour - a review of current status and future perspectives

The environment influences mental health, both detrimentally and beneficially. Current research has emphasized the individual psychosocial 'microenvironment'. Less attention has been paid to 'macro-environmental' challenges including climate change, pollution, urbanicity and socioeconomic disparity. With the advent of large-scale big-data cohorts and an increasingly dense mapping of macroenvironmental parameters, we are now in a position to characterise the relation between macroenvironment, brain, and behaviour across different geographic and cultural locations globally. This review synthesises findings from recent epidemiological and neuroimaging studies, aiming to provide a comprehensive overview of the existing evidence between the macroenvironment and the structure and functions of the brain, with a particular emphasis on its implications for mental illness. We discuss putative underlying mechanisms and address the most common exposures of the macroenvironment. Finally, we identify critical areas for future research to enhance our understanding of the aetiology of mental illness and to inform effective interventions for healthier environments and mental health promotion.

The complex impacts of economic growth pressure on carbon emission intensity: an empirical evidence from city data in China

Excessive carbon emissions are the major challenge to global sustainable development. In the context of the coronavirus pandemic, pressure on global economic growth is gradually rising, threatening established carbon reduction targets. However, the relationship between economic growth pressures and carbon emission intensity has yet to be clearly discussed. Thus, this study quantitatively discusses the impacts of economic growth pressures from central (EGPN) and provincial (EGPP) governments on city carbon intensity. The study is based on data from China's city panels from 2005 to 2019. This study finds that (1) there is a U-shaped correlation between economic growth pressure and a city's carbon emission intensity, whether the economic growth pressure comes from the central government or the provincial government; (2) carbon emission intensity is more sensitive to economic growth pressure from the provincial government than it is to economic growth pressure from the central government. The findings of this study will help enhance the understanding of the relationship between economic growth pressure and carbon emission intensity, and can also provide a reference for global sustainable development that balances economic growth and environmental protection.

Effect Modifications of Overhead-View and Eye-Level Urban Greenery on Heat-Mortality Associations: Small-Area Analyses Using Case Time Series Design and Different Greenery Measurements

BACKGROUND

The protective effect of urban greenery from adverse heat impacts remains inconclusive. Existing inconsistent findings could be attributed to the different estimation techniques used.

OBJECTIVES

We investigated how effect modifications of urban greenery on heat-mortality associations vary when using different greenery measurements reflecting overhead-view and eye-level urban greenery.

METHODS

We collected meteorological and daily mortality data for 286 territory planning units between 2005 and 2018 in Hong Kong. Three greenery measurements were extracted for each unit: a) the normalized difference vegetation index (NDVI) from Landsat remote sensing images, b) the percentage of greenspace based on land use data, and c) eye-level street greenery from street view images via a deep learning technique. Time-series analyses were performed using the case time series design with a linear interaction between the temperature term and each of the three greenery measurements. Effect modifications were also estimated for different age groups, sex categories, and cause-specific diseases.

RESULTS

Higher mortality risks were associated with both moderate and extreme heat, with relative risks (RRs) of 1.022 (95% CI: 1.000, 1.044) and 1.045 (95% CI: 1.013, 1.079) at the 90th and 99th percentiles of temperatures relative to the minimum mortality temperature (MMT). Lower RRs were observed in greener areas whichever of the three greenery measurements was used, but the disparity of RRs between areas with low and high levels of urban greenery was more apparent when using eye-level street greenery as the index at high temperatures (99th percentile relative to MMT), with RRs for low and high levels of greenery, respectively, of 1.096 (95% CI: 1.035, 1.161) and 0.985 (95% CI: 0.920, 1.055) for NDVI (p = 0.0193 ), 1.068 (95% CI: 1.021, 1.117) and 0.990 (95% CI: 0.906, 1.081) for the percentage of greenspace (p = 0.1338 ), and 1.103 (95% CI: 1.034, 1.177) and 0.943 (95% CI: 0.841, 1.057) for eye-level street greenery (p = 0.0186 ). Health discrepancies remained for nonaccidental mortality and cardiorespiratory diseases and were more apparent for older adults (≥ 65 years of age) and females.

DISCUSSION

This study provides new evidence that eye-level street greenery shows stronger associations with reduced heat-mortality risks compared with overhead-view greenery based on NDVI and percentage of greenspace. The effect modification of urban greenery tends to be amplified as temperatures rise and are more apparent in older adults and females. Heat mitigation strategies and health interventions, in particular with regard to accessible and visible greenery, are needed for helping heat-sensitive subpopulation groups in coping with extreme heat. https://doi.org/10.1289/EHP12589.

Predicting climate-change induced heat-related illness risk in Grand Canyon National Park visitors

BACKGROUND

The climate crisis is the greatest public health threat of the 21st century. Excessive heat is responsible for more deaths than any other extreme weather event, and the frequency, intensity, and duration of extreme heat events are increasing globally due to climate change. Exposure to excessive heat can result in heat related illnesses (HRIs) and long-term poor health outcomes. Physical exertion, sudden exposure to excessive heat, and the lack of physical or behavioral adaptation resources are all associated with greater HRI risk, which is expected to increase for visitors to Grand Canyon National Park (GCNP) and other public lands as climate change worsens.

OBJECTIVES

Our objectives were to understand 1) the relationship between weather and HRI in GCNP visitors, 2) how future HRI rates may change, and 3) how land management agencies can update risk mitigation strategies to match changing risk and better manage an increased HRI burden.

METHODS

We utilized previously published data on HRI in GCNP visitors, and records of daily visitation, temperatures, and maximum and minimum daily humidity from the same study period to develop a model estimate for HRI risk. We then used future climate projections from the World Climate Research Programme's Coupled Model Intercomparison Project phase 5 multi-model dataset to model future HRI risk under different climate scenarios.

RESULTS

The incidence of HRI was significantly associated with maximum daily temperature and minimum relative humidity, and was more common in the shoulder season months. We estimated that HRI will increase 29%-137% over 2004-2009 levels through 2100, assuming no change in visitation.

DISCUSSION

Climate change will continue to increase HRI risk for GCNP visitors and poses risks to public land managers' mission to provide for safe recreation experiences for the benefit of this and future generations in places like GCNP. Excessive risk during the shoulder season months presents an opportunity to increase preventative search and rescue and education efforts to mitigate increased risk.

Climatic and Economic Background Determine the Disparities in Urbanites' Expressed Happiness during the Summer Heat

Climate-change-induced extreme weather events increase heat-related mortality and health risks for urbanites, which may also affect urbanites' expressed happiness (EH) and well-being. However, the links among EH, climate, and socioeconomic factors remain unclear. Here we collected ∼6 million geotagged tweets from 44 Chinese prefecture-level cities based on Sina Weibo and performed a quadratic regression model to explore the relationships between summer heat and EH. A three-stage analysis was developed to examine spatiotemporal heterogeneity and identify factors contributing to disparities in urbanites' EH. Results show that all cities exhibited a similar hump-shaped relationship, with an overall optimal temperature (OT) of 22.8 °C. The estimated OT varied geographically, with 25.3, 23.8, and 20.0 °C from north to south. Moreover, a 1 standard deviation increase in heatwave intensity was associated with a 0.813 (95% CI: 0.177, 1.449) standard deviation decrease in EH. Notably, within the geographic scope of this study, it was observed that urbanites in northern China and economically underdeveloped cities faced significantly lower heat risks during the summer heat. This research provides insight for future studies and practical applications concerning extreme weather events, urbanites' mental health, and sustainable urban development goal.

Extreme Heat and Suicide Watch Incidents Among Incarcerated Men

Importance

Extreme heat poses a distinct risk to the 2.1 million incarcerated people in the United States, who have disparately high rates of behavioral health conditions. Suicide is a leading cause of death among people in prisons.

Objective

To examine associations of extreme heat, solitary confinement, and an indicator of suicidal behaviors among incarcerated men in a Deep South US prison system.

Design, Setting, and Participants

This longitudinal case series panel study included adult men in prisons in Louisiana, a state with one of the largest prison systems in the United States that has been engaged in litigation due to lack of air conditioning and extreme heat. The unit of analysis was prison facility-days. A facility-level data set was created by merging administrative data files, which included demographic characteristics, health classification, housing location and movement, disciplinary records, and involvement in suicide-watch incidents for all incarcerated men in Louisiana during the observation period. Individual-level variables were aggregated to facility-days to merge in daily maximum heat index data from the US Local Climatological Data, which were linked to the zip codes of prisons. The observation period was January 1, 2015, to December 31, 2017. Data set construction occurred from August 2020 to September 2022, and analysis was conducted from December 2022 to February 2023.

Exposure

The focal exposure was extreme heat days. Daily maximum heat index data were categorized into 6 bins (<30 °F, 30-39 °F, 40-49 °F, 50-59 °F, 70-79 °F, and ≥80 °F) and as an indicator for any facility-day where the maximum heat index exceeded the 90th percentile of heat indices for total days in observation period. Conditional fixed-effects negative binomial regression models were used to calculate incident rate ratios to test associations between extreme heat and suicide watch incidents, while controlling for covariates.

Main Outcomes and Measures

The focal outcome was daily count of suicide watch incidents that were recorded in a carceral system database. Covariates included daily percentages of incarcerated persons at each prison with serious mental illness diagnosis, daily rate of solitary confinement, and total facility population.

Results

The sample of 6 state-operated prisons provided 6576 facility-days for the analysis. Results suggest a dose-responsive association between extreme heat and daily counts of suicide-watch incidents; compared with days with temperatures between 60 and 69 °F, the rate of daily suicide incidents increased by 29% when the heat index reached the level of caution (ie, 80-89 °F) and by 36% when reaching extreme caution (90-103 °F) (80-89 °F: incidence rate ratio [IRR], 1.29; 95% CI, 1.17-1.43; P < .001; 90-103 °F: IRR, 1.36; 95% CI, 1.15-1.61; P < .001). Compared with other days, those with the extreme heat indicator were significantly associated with a 30% increase in the incident rate of daily suicide-watch incidents (IRR, 1.30; 95% CI, 1.18-1.45; P < .001).

Conclusions and Relevance

Findings suggest an association between extreme heat and an indicator of suicidality among an incarcerated sample, contribute to an emerging literature exploring linkages between climatological events and health outcomes in prisons, and may have implications for legal interventions and advocacy seeking to abate heat-induced morbidity and mortality in carceral contexts.

How ambient temperature affects mood: an ecological momentary assessment study in Switzerland

BACKGROUND

Recent research has suggested that an increase in temperature can negatively affect mental health and increase hospitalization for mental illness. It is not clear, however, what factors or mechanisms mediate this association. We aimed to (1) investigate the associations between ambient temperatures and bad daily mood, and (2) identify variables affecting the strength of these associations (modifiers) including the time, the day of the week and the year of the mood rating, socio-demographic characteristics, sleep quality, psychiatric disorders and the personality trait neuroticism in the community.

METHODS

Data stemmed from the second follow-up evaluation of CoLaus|PsyCoLaus, a prospective cohort study conducted in the general population of Lausanne (Switzerland). The 906 participants rated their mood level four times a day during seven days using a cell phone app. Mixed-effects logistic regression was used to determine the association between daily maximum temperature and mood level. Participant ID was inserted as a random effect in the model, whereas the time of the day, the day of the week and the year were inserted as fixed effects. Models were controlled for several confounders (socio-demographic characteristics, sleep quality, weather parameters and air pollutants). Stratified analyses were conducted based on socio-demographic characteristics, sleep quality, presence of psychiatric disorders or a high neuroticism.

RESULTS

Overall, the probability of having a bad mood for the entire day decreased by 7.0% (OR: 0.93: 95% CI 0.88, 0.99) for each 5 °C increase in maximum temperature. A smaller and less precise effect (-3%; OR: 0.97: 95% CI 0.91, 1.03) was found when controlling for sunshine duration. A higher association was found in participants with bipolar disorder (-23%; OR: 0.77: 95% CI 0.51, 1.17) and in participants with a high neuroticism (-13%; OR: 0.87 95% CI 0.80, 0.95), whereas the association was reversed for participants with anxiety (20%; OR: 1.20: 95% CI 0.90, 1.59), depression (18%; OR: 1.18 95% CI 0.94, 1.48) and schizophrenia (193%; OR: 2.93 95% CI 1.17, 7.73).

CONCLUSIONS

According to our findings, rising temperatures may positively affect mood in the general population. However, individuals with certain psychiatric disorders, such as anxiety, depression, and schizophrenia, may exhibit altered responses to heat, which may explain their increased morbidity when exposed to high temperatures. This suggests that tailored public health policies are required to protect this vulnerable population.

Ambient temperature and mental health: a systematic review and meta-analysis

BACKGROUND

Increasing evidence indicates that ambient outdoor temperature could affect mental health, which is especially concerning in the context of climate change. We aimed to comprehensively analyse the current evidence regarding the associations between ambient temperature and mental health outcomes.

METHODS

We did a systematic review and meta-analysis of the evidence regarding associations between ambient outdoor temperature and changes in mental health outcomes. We searched WebOfScience, Embase, PsychINFO, and PubMed for articles published from database origin up to April 7, 2022. Eligible articles were epidemiological, observational studies in humans of all ages, which evaluated real-world responses to ambient outdoor temperature, and had mental health as a documented outcome; studies of manipulated or controlled temperature or those with only physical health outcomes were excluded. All eligible studies were synthesised qualitatively. If three or more studies reported the same or equivalent effect statistics and if they had equivalent exposure, outcome, and metrics, the studies were pooled in a random-effects meta-analysis. The risk of bias for individual studies was assessed using the Newcastle-Ottawa Scale. The quality of evidence across studies was assessed using the Office of Health Assessment and Translation (OHAT) approach.

FINDINGS

114 studies were included in the systematic review, of which 19 were suitable for meta-analysis. Three meta-analyses were conducted for suicide outcomes: a 1°C increase in mean monthly temperature was associated with an increase in incidence of 1·5% (95% CI 0·8-2·2, p<0·001; n=1 563 109, seven effects pooled from three studies); a 1°C increase in mean daily temperature was associated with an increase in incidence of 1·7% (0·3-3·0, p=0·014; n=113 523, five effects pooled from five studies); and a 1°C increase in mean monthly temperature was associated with a risk ratio of 1·01 (95% CI 1·00-1·01, p<0·001; n=111 794, six effects pooled from three studies). Three meta-analyses were conducted for hospital attendance or admission for mental illness: heatwaves versus non-heatwave periods were associated with an increase in incidence of 9·7% (95% CI 7·6-11·9, p<0·001; n=362 086, three studies); the risk ratio at the 99th percentile of daily mean temperature compared with the 50th percentile was 1·02 (95% CI 1·01-1·03, p=0·006; n=532 296, three studies); and no significant association was found between a 10°C increase in daily mean temperature and hospital attendance. In a qualitative narrative synthesis, we found that ambient outdoor temperature (including absolute temperatures, temperature variability, and heatwaves) was positively associated with attempted and completed suicides (86 studies), hospital attendance or admission for mental illness (43 studies), and worse outcomes for community mental health and wellbeing (19 studies), but much of the evidence was of low certainty with high heterogeneity.

INTERPRETATION

Increased temperature and temperature variability could be associated with increased cases of suicide and suicidal behaviour, hospital attendance or admission for mental illness, and poor community health and wellbeing. Climate change is likely to increase temperature anomalies, variability, and heatwaves as well as average temperatures; as such, health system leaders and policy makers must be adequately prepared and should develop adaptation strategies. More high-quality, standardised research is required to improve our understanding of these effects.

FUNDING

None.

Extreme weather events and HIV: development of a conceptual framework through qualitative interviews with people with HIV impacted by the California wildfires and their clinicians

BACKGROUND

People with HIV (PWH) are disproportionately vulnerable to the impacts of wildfires, given the need for frequent access to healthcare systems, higher burden of comorbidities, higher food insecurity, mental and behavioral health challenges, and challenges of living with HIV in a rural area. In this study, we aim to better understand the pathways through which wildfires impact health outcomes among PWH.

METHODS

From October 2021 through February 2022, we conducted individual semi-structured qualitative interviews with PWH impacted by the Northern California wildfires and clinicians of PWH who were impacted by wildfires. The study aims were to explore the influence of wildfires on the health of PWH and to discuss measures at the individual, clinic, and system levels that helped to mitigate these impacts.

RESULTS

We interviewed 15 PWH and 7 clinicians. While some PWH felt that surviving the HIV epidemic added to their resilience against wildfires, many felt that the wildfires compounded the HIV-related traumas that they have experienced. Participants outlined five main routes by which wildfires negatively impacted their health: (1) access to healthcare (medications, clinics, clinic staff), (2) mental health (trauma; anxiety, depression, or stress; sleep disturbances; coping strategies), (3) physical health (cardiopulmonary, other co-morbidities), (4) social/economic impacts (housing, finances, community), and (5) nutrition and exercise. The recommendations for future wildfire preparedness were at the (1) individual-level (what to have during evacuation), (2) pharmacy-level (procedural, staffing), and (3) clinic- or county-level (funds and vouchers; case management; mental health services; emergency response planning; other services such as telehealth, home visits, home laboratory testing).

CONCLUSIONS

Based on our data and prior research, we devised a conceptual framework that acknowledges the impact of wildfires at the community-, household-, and individual-level with implications for physical and mental health outcomes among PWH. These findings and framework can help in developing future interventions, programs, and policies to mitigate the cumulative impacts of extreme weather events on the health of PWH, particularly among individuals living in rural areas. Further studies are needed to examine health system strengthening strategies, innovative methods to improve access to healthcare, and community resilience through disaster preparedness.

TRIAL REGISTRATION

N/A.

Ambient temperature and air pollution associations with suicide and homicide mortality in California: A statewide case-crossover study

BACKGROUND

Higher ambient temperature and air pollution may contribute to increased risk of behaviors harmful to oneself or to others; however, quantitative evidence is limited. We examined the relationship of deaths due to suicide and homicide with temperature and air pollution in California-a state prone to high levels of both exposures.

METHOD

California death certificates from 2014 to 2019 were used to identify deaths due to suicide and homicide. Residential data for decedents were used to assign exposure to daily temperature (maximum[Tmax], minimum[Tmin]) and daily average air pollution concentrations (particulate matter <10 μm[PM10] and < 2.5 μm[PM2.5], nitrogen dioxide[NO2], ozone[O3]). Tmin served as a surrogate for nighttime temperature. A time-stratified case-crossover study design using conditional logistic regression was used to assess the effects of daily exposure to temperature and air pollutants on suicide and homicide mortality, adjusting for relative humidity. Effect modification by sex and age was assessed.

RESULTS

We observed 24,387 deaths due to suicide and 10,767 deaths due to homicide. We found a monotonic temperature association for both outcomes. A 5 °C increase in Tmax at lag-2 and Tmin at lag-0 was associated with 3.1 % (95 % confidence interval [CI]: 1.1 %-5.2 %) and 3.8 % (95%CI: 0.9 %-6.8 %) increased odds of death due to suicide, respectively. The increased odds of homicide mortality per 5 °C increase in Tmax at lag-0 and Tmin at lag-1 were 4.9 % (95%CI: 1.6 %-8.1 %) and 6.2 % (95%CI: 1.6 %-11.0 %), respectively. No air pollutant associations were statistically significant. Temperature associations were robust after adjustment for PM2.5. Some temperature effects were larger among women for suicide and men for homicide mortality, and among those over age 65 years for both outcomes.

CONCLUSION

Risk of suicide and homicide mortality increases with increasing daily ambient temperatures. Findings have public health relevance given anticipated increases in temperatures due to global climate change.

Survey of extreme heat public health preparedness plans and response activities in the most populous jurisdictions in the United States

BACKGROUND

Increasingly frequent and intense extreme heat events (EHEs) are indicative of climate change impacts, and urban areas' social and built environments increase their risk for health consequences. Heat action plans (HAPs) are a strategy to bolster municipal EHE preparedness. The objective of this research is to characterize municipal interventions to EHEs and compare U.S. jurisdictions with and without formal heat action plans.

METHODS

An online survey was sent to 99 U.S. jurisdictions with populations > 200,000 between September 2021 and January 2022. Summary statistics were calculated to describe the proportion of total jurisdictions, as well as jurisdictions with and without HAPs and in different geographies that reported engagement in extreme heat preparedness and response activities.

RESULTS

Thirty-eight (38.4%) jurisdictions responded to the survey. Of those respondents, twenty-three (60.5%) reported the development of a HAP, of which 22 (95.7%) reported plans for opening cooling centers. All respondents reported conducting heat-related risk communications; however, communication approaches focused on passive, technology-dependent mechanisms. While 75.7% of jurisdictions reported having developed a definition for an EHE, less than two-thirds of responding jurisdictions reported any of the following activities: conducting heat-related surveillance (61.1%), implementing provisions for power outages (53.1%), increasing access to fans or air conditioners (48.4%), developing heat vulnerability maps (43.2%), or evaluating activities (34.2%). There were only two statistically significant (p ≥ .05) differences in the prevalence of heat-related activities between jurisdictions with and without a written HAP, possibly attributable to a relatively small sample size: surveillance and having a definition of extreme heat.

CONCLUSIONS

Jurisdictions can strengthen their extreme heat preparedness by expanding their consideration of at-risk populations to include communities of color, conducting formal evaluations of their responses, and by bridging the gap between the populations determined to be most at-risk and the channels of communication designed to reach them.

The Impact of Extreme Heat Exposure on Pregnant People and Neonates: A State of the Science Review

The relationship between heat exposure and perinatal morbidity and mortality is of increasing concern as global temperatures rise and extreme heat events become more frequent and intense. Heat exposure can lead to a multitude of harmful outcomes for pregnant individuals and neonates, including hospitalization and death. This state of the science review explored the evidence on the associations between heat exposure and negative health outcomes during pregnancy and the neonatal period. Findings suggest that improving health care provider and patient awareness of heat-related risks and implementing specific interventions could mitigate adverse outcomes. Furthermore, public health and other policy interventions are needed to increase thermal comfort and reduce societal exposure to extreme heat and related risks. Early warning systems, medical alerts, provider and patient education, and increased access to health care and thermal comfort may improve pregnancy and early life health outcomes.

Association of Temperature Thresholds with Heat Illness- and Cardiorespiratory-Related Emergency Visits during Summer Months in Alaska

BACKGROUND

Recent record-breaking hot temperatures in Alaska have raised concerns about the potential human health implications of heat exposure among this unacclimated population.

OBJECTIVES

We estimated cardiorespiratory morbidity associated with days above summer (June-August) heat index (HI, apparent temperature) thresholds in three major population centers (Anchorage, Fairbanks, and the Matanuska-Susitna Valley) for the years 2015-2019.

METHODS

We implemented time-stratified case-crossover analyses of emergency department (ED) visits for International Classification of Diseases, 10^th Revision codes indicative of heat illness and major cardiorespiratory diagnostic codes using data from the Alaska Health Facilities Data Reporting Program. Using conditional logistic regression models, we tested maximum hourly HI temperature thresholds between 21.1°C (70°F) and 30°C (86°F) for a single day, 2 consecutive days, and the absolute number of previous consecutive days above the threshold, adjusting for the daily average concentration of particulate matter ≤2.5μg.

RESULTS

There were increased odds of ED visits for heat illness above a HI threshold as low as 21.1°C (70°F) [odds ratio (OR)=13.84; 95% confidence interval (CI): 4.05, 47.29], and this increased risk continued for up to 4 d (OR=2.43; 95% CI: 1.15, 5.10). Asthma and pneumonia were the only respiratory outcomes positively associated with the HI: ED visits for both were highest the day after a heat event (Asthma: HI>27°C(80°F) OR=1.18; 95% CI: 1.00, 1.39; Pneumonia: HI>28°C(82°F) OR=1.40; 95% CI: 1.06, 1.84). There was a decreased odds of bronchitis-related ED visits when the HI was above thresholds of 21.1-28°C (70-82°F) across all lag days. We found stronger effects for ischemia and myocardial infarction (MI) than for respiratory outcomes. Multiple days of warm weather were associated with an increased risk of health impacts. For each additional preceding day above a HI of 22°C (72°F), the odds of ED visits related to ischemia increased 6% (95% CI: 1%, 12%); for each additional preceding day above a HI of 21.1°C (70°F), the odds of ED visits related to MI increased 7% (95% CI: 1%, 14%).

DISCUSSION

This study demonstrates the importance of planning for extreme heat events and developing local guidance for heat warnings, even in areas with historically mild summertime climates. https://doi.org/10.1289/EHP11363.

Assessing the Burden of Suicide Death Associated With Nonoptimum Temperature in a Changing Climate

Importance

Few studies have projected future suicide burden associated with daily temperatures in a warming climate.

Objectives

To assess the burden of suicide death associated with daily nonoptimal temperature and to project the change of suicide burden associated with nonoptimal temperature in different regions and seasons under various climate change scenarios.

Design, Setting, and Participants

Between January 1, 2013, and December 31, 2019, we conducted a time-stratified, case-control study among more than 430 000 individual suicide decedents from all counties in mainland China.

Exposures

Daily meteorological data were obtained from the European Centre for Medium-Range Weather Forecasts Reanalysis Fifth Generation (ERA5) reanalysis product. Historical and future temperature series were projected under 3 scenarios of greenhouse-gas emissions from 1980 to 2099, with 10 general circulation models.

Main Outcomes and Measures

The relative risk (RR) and burden of suicide death associated with nonoptimal temperature (ie, temperatures greater than or less than minimum-mortality temperature); the change of suicide burden associated with future climate warming in different regions and seasons under various climate change scenarios.

Results

Of 432 008 individuals (mean [SD] age; 57.6 [19.0] years; 253 093 male [58.6%]) who died by suicide, 85.8% (370 577) had a middle school education or less. The temperature-suicide associations were approximately linear, with increasing death risks at higher temperatures. The excess risk was more prominent among older adults (ie, ≥75 years; RR, 1.71; 95% CI, 1.46-1.99) and those with low education level (ie, middle school education or less; RR, 1.46; 95% CI, 1.36-1.57). There were 15.2% suicide deaths (95% estimated CI [eCI], 14.6%-15.6%) associated with nonoptimal temperature nationally. Consistent and drastic increases in excess suicide deaths over this century were predicted under the high-emission scenario, whereas a leveling-off trend after the mid-21st century was predicted under the medium- and low-emission scenarios. Nationally, compared with the historical period (1980-2009), excess suicide deaths were predicted to increase by 8.3% to 11.4% in the 2050s and 8.5% to 21.7% in the 2090s under the 3 scenarios. The projected percentage increments of excess suicide deaths were predicted to be greater in the South (55.0%; 95% eCI, 30.5%-85.6%) and in winter (54.5%; 95% eCI, 30.4%-77.0%) in the 2090s under the high-emission scenario.

Conclusions and Relevance

Findings of this nationwide case-control study suggest that higher temperature may be associated with the risk and burden of suicide death in China. These findings highlight the importance of implementing effective climate policies to reduce greenhouse gas emissions and tailoring public health policies to adapt to global warming.

Unpacking the inter- and intra-urban differences of the association between health and exposure to heat and air quality in Australia using global and local machine learning models

Environmental stressors including high temperature and air pollution cause health problems. However, understanding how the combined exposure to heat and air pollution affects both physical and mental health remains insufficient due to the complexity of such effects mingling with human society, urban and natural environments. Our study roots in the Social Ecological Theory and employs a tri-environmental conceptual framework (i.e., across social, built and natural environment) to examine how the combined exposure to heat and air pollution affect self-reported physical and mental health via, for the first time, the fine-grained nationwide investigation in Australia and highlight how such effects vary across inter- and intra-urban areas. We conducted an ecological study to explore the importance of heat and air quality to physical and mental health by considering 48 tri-environmental confounders through the global and local random forest regression models, as advanced machine learning methods with the advantage of revealing the spatial heterogeneity of variables. Our key findings are threefold. First, the social and built environmental factors are important to physical and mental health in both urban and rural areas, and even more important than exposure to heat and air pollution. Second, the relationship between temperature and air quality and health follows a V-shape, reflecting people's different adaptation and tolerance to temperature and air quality. Third, the important roles that heat and air pollution play in physical and mental health are most obvious in the inner-city and near inner-city areas of the major capital cities, as well as in the industrial zones in peri-urban regions and in Darwin city with a low-latitude. We draw several policy implications to minimise the inter- and intra-urban differences in healthcare access and service distribution to populations with different sensitivity to heat and air quality across urban and rural areas. Our conceptual framework can also be applied to examine the relationship between other environmental problems and health outcomes in the era of a warming climate.

Unequal exposure to heatwaves in Los Angeles: Impact of uneven green spaces

Cities worldwide are experiencing record-breaking summer temperatures. Urban environments exacerbate extreme heat, resulting in not only the urban heat island but also intracity variations in heat exposure. Understanding these disparities is crucial to support equitable climate mitigation and adaptation efforts. We found persistent negative correlations between daytime land surface temperature (LST) and median household income across the Los Angeles metropolitan area based on Ecosystem Spaceborne Thermal Radiometer Experiment on Space Station observations from 2018 to 2021. Lower evapotranspiration resulting from the unequal distribution of vegetation cover is a major factor leading to higher LST in low-income neighborhoods. Disparities worsen with higher regional mean surface temperature, with a $10,000 decrease in income leading to ~0.2°C LST increase at 20°C and up to ~0.7°C at 45°C. With more frequent and intense heat waves projected in the future, equitable mitigation measures, such as increasing surface albedo and tree cover in low-income neighborhoods, are necessary to address these disparities.

Thinking clearly about climate change and mental health

OBJECTIVE

To examine the quality and strength of evidence for an association between temperature increases caused by climate change and suicide used in policy documents to advocate for radical changes to healthcare systems in pursuit of decarbonisation.

METHOD

The designs of articles collected in a systematic review which concluded that there was an association between climate change and increased rates of suicide were analysed for their capacity to support this conclusion. Complete US data covering temperatures and suicide rates between 1968 and 2004 was aggregated and analysed using linear regression to evaluate evidence for an association between temperature and suicide.

RESULTS

None of the articles collected in the review has a design capable of investigating whether there is an association between temperature increases caused by climate change and rates of suicide. At the national level increased annual US temperatures were associated with a decrease in the rate of suicide, and at the state level it was common for high average temperature states to have low rates of suicide and vice versa.

CONCLUSIONS

Policy recommendations for radical changes in healthcare services have been based on misrepresented evidence. Policy makers should beware of recommendations that ignore scientific evidence to pursue faith-based goals.

Short-term exposure to temperature and mental health in North Carolina: a distributed lag nonlinear analysis

Adverse mental health outcomes have been associated with high temperatures in studies worldwide. Few studies explore a broad range of mental health outcomes, and to our knowledge, none are specific to NC, USA. This ecological study explored the relationship between ambient temperature and mental health outcomes (suicide, self-harm and suicide ideation, anxiety and stress, mood disorders, and depression) in six urban counties across the state of NC, USA. We applied a quasi-Poisson generalized linear model combined with a distributed lag nonlinear model (DLNM) to examine the short-term effects of daily ambient temperature on emergency admissions for mental health conditions (2016 to 2018) and violent deaths (2004 to 2018). The results were predominately insignificant, with some key exceptions. The county with the greatest temperature range (Wake) displays higher levels of significance, while counties with the lowest temperature ranges (New Hanover and Pitt) are almost entirely insignificant. Self-harm and suicidal ideation peak in the warm months (July) and generally exhibit a protective effect at lower temperatures and shorter lag intervals. Whereas anxiety, depression, and major depressive disorders peak in the cooler months (May and September). Suicide is the only outcome that favored a 20-day lag period in the sensitivity analysis, although the association with temperature was insignificant. Our findings suggest additional research is needed across a suite of mental health outcomes to fully understand the effects of temperatures on mental health.