Is there an association between hot weather and poor mental health outcomes? A systematic review and meta-analysis

Exploring perceived relationships between weather, climate and mental health: biometeorological perspectives of healthcare practitioners

Over the last decade, there has been an increase in research examining the influence of weather and climate in mental health caseloads. Variations in temperature, sunshine hours, cloud cover, precipitation and extreme weather events have been statistically linked to diagnoses and increases in hospital admissions for several mental health conditions. This study aimed to explore whether mental health practitioners perceive there to be a link between mental health and daily, seasonal, or inter-annual shifts in various climate variables in South Africa, and the timing and causal mechanisms thereof. Semi-structured interviews were conducted with 50 practicing healthcare practitioners, and the data was analysed using thematic analysis. The findings of this research show that all 50 participants were aware of the link between weather, climate and mental health, primarily through their awareness of seasonal affective disorder. Of the 50 participants, 38 participants could explain the aetiology of seasonal affective disorder. Participants perceived sunlight and temperature to exert an influence on mental health. All 50 participants perceived exposure to sunlight to exert a positive influence on several mental health conditions. Of the 50 participants, 36 participants perceived increases in temperature to exert an adverse effect on mental health symptomology. A minority of 11 participants perceived precipitation to influence mental health conditions such as seasonal affective disorder, bipolar disorder, and substance abuse disorder. Participants' perceptions of the influence of precipitation on mental health provided a unique potential explanation of this relationship, which, at the time of writing, has not been discussed in formal research.

Urban green space, human heat perception and sleep quality: a repeated cross-sectional study

Urban heat poses significant challenges to public health, as exposure to high temperatures is associated to heat stress, resulting in heat strain, sleep deprivation, and cardiovascular morbidity and mortality. As the frequency of heat waves is increasing due to global warming, urban green spaces are often proposed as a nature-based solution to mitigate urban heat stress. This study investigated the impact of urban green space on perceived heat stress and sleep quality, using questionnaires and detailed land cover data. We surveyed 584 respondents during four heat and four control events in the summers of 2021 and 2022, assessing perceived heat stress, sleep quality, and mental health. Using structural equation models, this study analysed the influence of both tree cover and grass and shrub cover on perceived heat stress and sleep quality, while controlling for risk and vulnerability factors. The outcomes revealed that during heat events, enhanced tree cover was associated with reduced heat stress (B = -0.484, 95% CI [-0.693, -0.275], p = 0.001), while increased grass and shrub cover was associated with both reduced heat stress (B = -0. 361 [-0.529, -0.193], p = 0.000) and improved sleep quality (B = -0. 241 [-0.399, -0.083], p = 0.003). Conversely, during control events, stress indicators were more strongly associated with individual vulnerability factors rather than surrounding green space. These results emphasize the importance of combining trees with lower vegetation in urban planning to mitigate heat-related stress and enhance sleep quality, thereby improving overall well-being during heat events.

Exceptional heatwaves and mortality in Europe: Greater impacts since the coronavirus disease 2019 outbreak

Record-breaking hot weather (exceptional heatwaves) has been increasingly common worldwide, posing a significant threat to human health. However, little is known about the effect of these exceptional heatwaves on mortality in Europe, especially since the coronavirus disease 2019 (COVID-19) outbreak, which converges with climate change to affect healthcare systems and human lives. We collected mortality data of 967 regions in 30 European countries over the last decade (2014-2023) from the Eurostat. A standard time-series analysis was used to estimate the effect of exceptional heatwaves by quasi-Poisson regression model, including the main effect (effect from heatwave intensity) and the added effect (effect from heatwave duration), on mortality for each region during two periods (before and since the COVID-19 outbreak). We used random effects meta-analysis to pool the mortality risk (i.e., relative risk [RR]) and burden (i.e., attributable fraction [AF]) associated with exceptional heatwaves, at the country level and for Europe as a whole. In Europe, the mortality burden attributable to main and added effects increased from 0.492% (95% CI: 0.488%-0.496%) to 1.276% (95% CI: 1.266%-1.285%) and from 0.307% (95% CI: 0.294%-0.318%) to 0.428% (95% CI: 0.407%-0.448%), respectively. Furthermore, substantial variations across countries were observed, with some countries such as France and Spain experiencing a large increase in the mortality burden attributable to exceptional heatwaves since the COVID-19 outbreak. Our findings underscore the urgent need for heat-health actions to consider the multi-effects of exceptional heatwaves amidst a warming climate.

Association Between Extreme Heat and Outpatient Visits for Mental Disorders: A Time-Series Analysis in Guangzhou, China

Previous evidence on heatwaves' impact on mental health outpatient visits is limited, especially uncertainty on how different heatwave definitions affect this relationship. In this time-series study, we assessed the association between heatwaves and outpatient visits for mental disorders in Guangzhou, China. Daily outpatient visits for mental disorders and its specific categories (schizophrenia, mood, and neurotic disorders) were sourced from the Urban Resident-based Basic Medical Insurance (URBMI) and the Urban Employee-based Basic Medical Insurance (UEBMI) claims databases in Guangzhou from 2010 to 2014. The study employed nine heatwave definitions, based on combinations of three daily mean temperature thresholds (90th, 92.5th, and 95th percentiles) and durations (2, 3, and 4 days). Using quasi-Poisson generalized linear models (GLMs), we estimated the risks (at lag 0 day) and cumulative effects (lag 0-10 days) of heatwaves on mental disorder outpatient visits. Age, gender, types of medical insurance were considered as potential effect modifiers. We observed a positive association between heatwaves and increased total outpatient visits for mental disorders, both at lag 0 day and during lag 0-10 days. The impact of heatwave was significant at lag 0 day for schizophrenia, mood and neurotic disorders visits, it remained significant for neurotic and mood disorders visits during lag 0-10 days. Heatwave durations lasting more than 4 days were associated with higher relative risks of mental disorders at lag 0 day. Older adults had relatively higher effect estimations than younger individuals. This research highlights the effects of extreme heat on mental health.

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.

["Is there a Link Between Heat Waves and Mental Health Emergencies in the Emergency Department?"]

OBJECTIVE

There is evidence suggesting that climate change, coupled with an increase in the frequency and severity of heatwaves, affects mental health. The aim of this study was to investigate potential associations between high temperature and the utilization of an emergency department (ED) by individuals with psychiatric disorders.

METHODS

A retrospective analysis of all psychiatric emergency patients from 2015 to 2022 (N=15478) was conducted and compared with local temperature data.

RESULTS

Particularly during heatwaves, more psychiatric emergency patients presented to the ED.

CONCLUSION

Beyond the results identified during heatwaves, our extensive analysis of the examined ED revealed no additional significant effects of heat on psychiatric emergencies. This contradicts findings from other studies. Other systemic influences, such as the utilization of the ED during the Covid-19 pandemic, could have modified the results.

Livelihood vulnerability to climate change health impacts among Amhara Sayint district community, northeastern Ethiopia: A composite index approach

Climate change significantly impacts public health, affecting nearly everyone across the globe and contributing to approximately 10% of global mortality. Ethiopia is particularly vulnerable to the changing climate attributed impacts due to economic, and social determinants. While research on climate change is expanding, it often prioritizes its effects on agriculture. The impacts from public health perspective are frequently overlooked. We address this shortcoming by evaluating the vulnerability of the community in the district of Amhara Sayint, Amhara, northeastern Ethiopia, to the health impacts of climate change, and identifying factors involved. Data was collected using a community-based cross-sectional approach, involving 605 randomly selected households between July Twenty and September Five, 2022. The data collection process utilized a validated and pilot-tested questionnaire, which was administered through face-to-face interview with the aid of Kobo Collect toolbox. The community's vulnerability was assessed using the IPCC's framework of vulnerability. Household's Vulnerability status was then classified into three levels according to their Livelihood Vulnerability Index (LVI) score. A partial proportional oddsapproach of ordinal logistic regression model was used to identify factors associated with vulnerability to climate change attributed health impacts. Among the 605 respondents, 48% (95% CI: 44.1, 52.1) were identified as vulnerable, and about 4.6 % (95% CI: 3, 6.6) were classified as highly vulnerable. Wealth status (AOR1 = 1.8; 95 % CI: 1.2, 2.8), educational status (AOR1 = 2.8; 95% CI: 1.1, 7.3), marital status (AOR2 = 4.7, 95% CI: 1.6, 13.4), and home crowdedness (AOR2 = 2.9, 95% CI: 1.1, 8.1) significantly associated with vulnerability. Over half of the residents in the district wereeither being vulnerable or highly vulnerable to climate change attributed health impacts. Therefore, prioritizing prevention and preparedness along with conducting spatial analysis to identify high-risk areas for timely intervention, is essential.

Coenzyme Q10 and Vitamin E Alleviate Heat Stress-Induced Mood Disturbances in Male Mice: Modulation of Inflammatory Pathways and the HPA Axis

Heat stress, as an environmental stressor, can lead to temperature dysregulation and neuroinflammation, causing depression and anxiety by disrupting brain physiology and functional connectivity. This study looked at how co-enzyme Q10 (Q10) and vitamin E (Vit E), alone and together, affected heat stress-caused anxiety and depression symptoms and inflammation in male mice. Five groups were utilized in the study: control, heat stress (NS), Q10, Vit E, and the combination group (Q10+Vit E). The mice were subjected for 15min/day to a temperature of 43°C for 14 consecutive days, followed by daily treatments for two weeks with either normal saline, Q10 (500mg/kg), Vit E (250mg/kg), or their combination. The forced swimming test (FST) and tail suspension test (TST) were employed to evaluate despair behavior, whereas the elevated plus maze (EPM) and open field test (OFT) were used to assess anxious behaviors. Subsequently, the animals were sacrificed, and serum corticosterone levels, protein expression of inflammasome-related proteins, and hsp70 gene expression were evaluated in the prefrontal cortex (PFC). The study revealed that treatment with Vit E and Q10, alone or together, provided anxiolytic and antidepressant effects in the heat-stress-subjected animals. Also, giving Vit E and Q10 alone or together greatly lowered serum corticosterone levels. In the PFC, they also lowered the levels of hsp70 mRNA and NF-κB, caspase 1, NLRP3, and IL-1β proteins. It is speculated that treatment with Q10 and Vit E can attenuate heat stress-associated anxious and depressive responses by inhibiting the inflammatory pathways and modulating the hypothalamus-pituitary-adrenal axis.

Association between window ventilation frequency and depressive symptoms among older Chinese adults

OBJECTIVES

Indoor air pollution exposure is harmful to people's physical and mental health, especially in the elderly population. Depressive symptoms are the most common mental health issue among elderly individuals. However, evidence linking the frequency of indoor natural ventilation to depressive symptoms in the elderly population is limited.

METHODS

This study included 7887 individuals 65 years and older from 2017 to 2018 the China Longitudinal Healthy Longevity Survey (CLHLS). The frequency of indoor window ventilation was measured as the self-reported times of ventilation of indoor window per week in each season, and the four seasons' scores were added up to calculate the annual ventilation frequency. Depressive symptoms were measured by the 10-item Center for Epidemiologic Studies Short Depression Scale (CESD). Using three models adjusted for demographic, socio-economic, health status, and environmental factors successively, the correlation between indoor window ventilation frequency and depressive symptoms was verified through logistic regression.

RESULTS

Among the 7887 elderly people included in this study, 1952 (24.7 %) had depressive symptoms. In the fully adjusted model, compared with the lower indoor annual ventilation frequency group, high indoor annual ventilation frequency group was significantly associated with a 33 % (OR: 0.67, 95%CI: 0.51-0.88) lower probability of depressive symptoms. Subgroup analysis and sensitivity analysis yielded similar results.

CONCLUSIONS

High frequency of window ventilation is significantly associated with the lower risk of depressive symptoms in Chinese individuals aged 65 and older. This result provides strong evidence for health intervention and policy formulation.

Changes in meteorological conditions as near-term risk factors for suicide attempts

To evaluate the impact of acute meteorological changes (i.e., maximum temperature, humidity, wind speed, atmospheric pressure, cloud coverage, visibility, precipitation) as situational risk factors proximal (i.e., present in the hours directly preceding) to suicide attempts. Participants were 578 adult patients who were hospitalized within 24 h of a suicide attempt at the only Level 1 trauma hospital in the state of Mississippi. Participants completed a semi-structured interview to determine home address and exact timing of their suicide attempt. A within-person, case-crossover design was used with each patient serving as their own control. Meteorological variables were generated for the 6-hours preceding each patient's suicide attempt (case period) and corresponding hours the day prior (control period). Conditional logistic regression analyses were used to examine predictors of suicide attempts, and biological sex and season were evaluated as potential moderators. The presence of precipitation was associated with reduced odds of suicide attempts. Wind speed was marginally positively associated with suicide attempts among males, and visibility was positively associated with suicide attempts among females. Maximum temperature was positively associated with suicide attempts in the spring. Wind speed, visibility, maximum temperature, and precipitation (absence of) may represent situational risk factors for suicide attempts. Future studies should evaluate additional near-term situational risk factors and determine how to leverage this information to improve suicide risk management efforts to ultimately ameliorate the burden of suicide.

Daily temperature variability and mental health-related hospital visits in New York State

BACKGROUND

Despite plausible behavioral and physiological pathways, limited evidence exists on how daily temperature variability is associated with acute mental health-related episodes.

OBJECTIVES

We aimed to explore associations between daily temperature range (DTR) and mental health-related hospital visits using data of all hospital records in New York State during 1995-2014. We further examined factors that may modify these associations, including age, sex, hospital visit type and season.

METHODS

Using a case-crossover design with distributed lag non-linear DTR terms (0-6 days), we estimated associations between ZIP Code-level DTR and hospital visits for mood (4.6 million hospital visits), anxiety (2.4 million), adjustment (∼368,000), and schizophrenia disorders (∼211,000), controlling for daily mean temperature, via conditional logistic regression models. We assessed potential heterogeneity by age, sex, hospital visit type (in-patient vs. out-patient), and season (summer, winter, and transition seasons).

RESULTS

For all included outcomes, we observed positive associations from period minimum DTR (0.1 °C) until 25th percentile (5.2 °C) and between mean DTR (7.7 °C) and 90th percentile (12.2 °C), beyond which we observed negative associations. For mood disorders, an increase in DTR from 0.1 °C to 12.2 °C was associated with a cumulative 16.0% increase (95% confidence interval [CI]: 12.8, 19.2%) in hospital visit rates. This increase was highest during transition seasons (32.5%; 95%CI: 26.4, 39.0%) compared with summer (10.7%; 95%CI: 4.8, 16.8%) and winter (-1.6%; 95%CI: -7.6, 4.7%). For adjustment and schizophrenia disorders, the strongest associations were seen among the youngest group (0-24 years) with almost no association in the oldest group (65+ years). We observed no evidence for modification by sex and hospital visit type.

DISCUSSION

Daily temperature variability was positively associated with mental health-related hospital visits within specific DTR ranges in New York State, after controlling for daily mean temperature. Given uncertainty on how climate change modifies temperature variability, additional research is crucial to comprehend the implications of these findings, particularly under different scenarios of future temperature variability.

Associations Between Anthropogenic Factors, Meteorological Factors, and Cause-Specific Emergency Department Admissions

Unpredictable emergency department (ED) admissions challenge healthcare systems, causing resource allocation inefficiencies. This study analyses associations between air pollutants, meteorological factors, and 2,655,861 cause-specific ED admissions from 2014 to 2018 across 12 categories. Generalized additive models were used to assess non-linear associations for each exposure, yielding Incidence Rate Ratios (IRR), while the population attributable fraction (PAF) calculated each exposure's contribution to cause-specific ED admissions. IRRs revealed increased risks of ED admissions for respiratory infections (IRR: 1.06, 95% CI: 1.01-1.11) and infectious and parasitic diseases (IRR: 1.09, 95% CI: 1.03-1.15) during increased rainfall (13.21-16.97 mm). Wind speeds >12.73 km/hr corresponded to increased risks of ED admissions for respiratory infections (IRR: 1.12, 95% CI: 1.03-1.21) and oral diseases (IRR: 1.58, 95% CI: 1.31-1.91). Higher concentrations of air pollutants were associated with elevated risks of cardiovascular disease (IRR: 1.16, 95% CI: 1.05-1.27 for PM10) and respiratory infection-related ED admissions (IRR: 2.78, 95% CI: 1.69-4.56 for CO). Wind speeds >12.5 km/hr were predicted to contribute toward 10% of respiratory infection ED admissions, while mean temperatures >28°C corresponded to increases in the PAF up to 5% for genitourinary disorders and digestive diseases. PM10 concentrations >60 μg/m3 were highly attributable toward cardiovascular disease (PAF: 10%), digestive disease (PAF: 15%) and musculoskeletal disease (PAF: 10%) ED admissions. CO concentrations >0.6 ppm were highly attributable to respiratory infections (PAF: 20%) and diabetes mellitus (PAF: 20%) ED admissions. This study underscores protective effects of meteorological variables and deleterious impacts of air pollutant exposures across the ED admission categories considered.

Dynamic prediction of lung cancer suicide risk based on meteorological factors and clinical characteristics：A landmarking analysis approach

Suicide is a severe public health issue globally. Accurately identifying high-risk lung cancer patients for suicidal behavior and taking timely intervention measures has become a focus of current research. This study intended to construct dynamic prediction models for identifying suicide risk among lung cancer patients. Patients were sourced from the Surveillance, Epidemiology, and End Results database, while meteorological data was acquired from the Centers for Disease Control and Prevention. This cohort comprised 455, 708 eligible lung cancer patients from January 1979 to December 2011. A Cox proportional hazard regression model based on landmarking approach was employed to explore the impact of meteorological factors and clinical characteristics on suicide among lung cancer patients, and to build dynamic prediction models for the suicide risk of these patients. Additionally, subgroup analyses were conducted by age and sex. The model's performance was evaluated using the C-index, Brier score, area under curve (AUC) and calibration plot. During the study period, there were 666 deaths by suicide among lung cancer patients. Multivariable Cox results from the dynamic prediction model indicated that age, marital status, race, sex, primary site, stage, monthly average daily sunlight, and monthly average temperature were significant predictors of suicide. The dynamic prediction model demonstrated well consistency and discrimination capabilities. Subgroup analyses revealed that the association of monthly average daily sunlight and monthly average temperature with suicide remained significant among female and younger lung cancer patients. The dynamic prediction model can effectively incorporate covariates with time-varying to predict lung cancer patients' suicide death. The results of this study have significant implications for assessing lung cancer individuals' suicide risk.

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.

Commercial determinants of mental ill health: An umbrella review

Mental ill health has complex and interrelated underlying causes, with wider determinants of health often overlooked as risk factors. The 'commercial determinants of health' are gradually receiving more attention and recognition but there is a relative lack of awareness of the commercial determinants of mental health. This aim of this umbrella review was to synthesise systematic review level evidence for the association between commercial determinants and mental health outcomes. This umbrella review included evidence from high, middle, and low-income countries. We included terms related to broader commercial activities and terms focused on six key unhealthy commodities (tobacco, alcohol, ultra-processed foods, gambling, social media, fossil fuels) and the impacts of fossil fuel consumption (climate change, air pollution, wider pollution). We included 65 reviews and found evidence from high quality reviews for associations between alcohol, tobacco, gambling, social media, ultra-processed foods and air pollution and depression; alcohol, tobacco, gambling, social media, climate change and air pollution with suicide; climate change and air pollution with anxiety; and social media with self-harm. There was a lack of evidence examining wider practices of commercial industries. Our umbrella review demonstrates that by broadening the focus on commercial determinants, the influence of commercial products and activities on mental ill health can be better understood. The lack of research examining broader commercial practices on mental ill health is an area that should be addressed. Our review highlights the existing base of high-quality evidence for many of these unhealthy commodities' impacts on mental ill health and indicates that commercial determinants is a valuable framework for understanding the drivers of mental ill health.

[Climate crisis and psychiatry]

BACKGROUND

The climate crisis is increasingly leading to negative consequences for mental health and is of growing importance for psychiatric and psychotherapeutic care.

OBJECTIVE

The effects of the climate crisis on mental health and its significance for psychiatric and psychotherapeutic care are presented. Recommendations for sustainability in psychiatric and psychotherapeutic practice are provided.

MATERIAL AND METHODS

A narrative review of the literature was conducted for this article.

RESULTS

The climate crisis has direct, indirect and intersectional negative effects on mental health. Sustainable and preventive recommendations for the practice include promoting health literacy, faster access to psychotherapy and online counselling, supporting social networks, promoting employment and reducing poverty, homelessness and social isolation. It is recommended to increase the proportion of outpatient care and to streamline administrative processes. The use of disposable products should be minimized and the application of instrumental diagnostics and materials should be optimized according to guidelines. Digital interventions should be considered more frequently in the clinical practice and sustainable facility management should be improved. Access to green spaces for the general population and patients should be facilitated.

CONCLUSION

Due to the negative impact of the climate crisis on mental health, sustainability should be promoted in psychiatric and psychotherapeutic care.

Seasonal variations in psychiatry outpatient service utilization in a tertiary health care center in subtropical arid regions of northwestern India

Background

Research on climatic parameters contributing to psychiatric disorder seasonality is limited, particularly in subtropical, arid climates like Rajasthan, necessitating investigation into seasonal variations in psychiatric disorder incidence in the region. This study investigates seasonal variations in psychiatric disorder prevalence over 2 years at a Rajasthan tertiary healthcare center, aiming to uncover links with climatic factors.

Aims

To investigate seasonal variations in the utilization of outpatient psychiatry services and elucidate potential determinants contributing to these temporal variations.

Settings and Design

This is a hospital-based study. A retrospective chart review of all new patients who utilized psychiatry outpatient services from July 2021 to July 2023 was conducted.

Methods and Material

Data were gathered from psychiatric outpatient records of adults (July 2021 to July 2023), diagnosed using ICD-10. Seasons were categorized: winter (November-January), spring (February-April), summer (May-July), and rainy (August-October). Meteorological data, temperature, and day length were obtained. Statistical analyses, including Pearson correlation and Chi-square fitness, assessed seasonal associations with psychiatric disorders.

Results

A total of 29,164 patient records were observed. Depression correlated with temperature and photoperiod. Mania peaked in August, linked to day length. Schizophrenia showed seasonal variation without environmental correlation. Anxiety peaked in March with no statistical significance. Obsessive compulsive disorder cases spiked in June, moderately correlated with temperature and photoperiod. Alcohol-related disorders peaked in December, while opioid dependence remained steady. Cannabis-induced psychosis peaked in summer, strongly correlated with temperature and day length. Headaches surged in August, positively correlated with temperature and day length.

Conclusions

This study reveals complex relationships between seasonality, environmental factors, and psychiatric disorders, emphasizing their importance in mental health research and practice.

Systemic inequalities in heat risk for greater London

The temperature rise and increases in extreme heat events related to global climate change is a growing public health threat. Populations in temperate climates, including the UK, must urgently adapt to increased hot weather as current infrastructure primarily focusses on resilience to cold. As we adapt, care should be taken to ensure existing health inequalities are reduced. Lessons can be learned from regions that experience warmer climates and applied to adaptation in the UK. We identified known indicators of heat-health risk and explored their distribution across area level income for London. Understanding these indicators and their distributions across populations can support the development of interventions that have the dual aim of improving health and reducing inequalities. An exploratory analysis was conducted for each indicator at neighbourhood level to assess existence of disparities in their distributions across London. A systems-thinking approach was employed to deduce if these amount to systemic inequalities in heat risk, whereby those most exposed to heat are more susceptible and less able to adapt. Using this information, we proposed interventions and made recommendations for their implementation. We find inequalities across indicators relating to exposure, vulnerability, and adaptive capacity. Including inequalities in urban greening and access to greenspace, physical and mental health and access to communication and support. Through a system diagram we demonstrate how these indicators interact and suggest that systemic inequalities in risk exist and will become more evident as exposure increases with rising temperatures, depending on how we adapt. We use this information to identify barriers to the effective implementation of adaptation strategies and make recommendations on the implementation of interventions. This includes effective and wide-reaching communication considering the various channels and accessibility requirements of the population and consideration of all dwelling tenures when implementing policies relating to home improvements in the context of heat.

Examining the non-linear association between ambient temperature and mental health of elderly adults in the community: evidence from Guangzhou, China

The association between ambient temperature and mental health has been explored previously. However, research on the psychological effect of temperature in vulnerable groups and neighborhood scales have been scarce. Based on the survey and temperature data collected from 20 neighborhoods in Guangzhou, China, this study estimated the association between ambient temperature and community mental health among the elderly, adopting a fixed-effects methodology. According to this empirical analysis, compared to a comfortable temperature range of 20℃-25℃, measures of worse mental health among elderly were significant in high and low temperatures with increases in negative outcomes observable at both ends of the temperature range, leading to the U-shaped relationship. Second, the association between ambient temperature and worse mental health was found in the subcategories of gender, income, and symptom events. Specifically, from the hot temperature aspect, elderly males were more sensitive than elderly females. The effect on the low was far more than on the middle-high income group, and the probability of each symptom of the elderly's mental health significantly increased. From the cool temperature aspect, the temperature in the range of 5ºC-10ºC was significantly associated with the probability of some symptoms (feeling down, not calm, downheartedness, and unhappiness) and the middle-high income group. Our research enriches the empirical research on ambient temperature and mental health from a multidisciplinary perspective and suggests the need for healthy aging and age-friendly planning in Chinese settings.

Effect of wildfire on the prevalence of opioid misuse through anxiety among young adults in the United States: a modeling study

BACKGROUND

Exposure to climate change events like wildfires can lead to health and mental health problems. While conceptual frameworks have been hypothesized describing the potential relationship between disaster exposure and substance use, the association remains under-researched and unquantified.

METHODS

We constructed a quantitative portrayal of one proposed conceptual framework that focuses on the intermediary role of anxiety. We used the Monte Carlo simulation to estimate the impact of wildfire exposure on opioid misuse outcomes through increased anxiety. We searched for and extracted prior empirical evidence on the associations between wildfire anxiety and anxiety-opioid misuse. Three scenarios were devised: in S1 the impact of wildfire on opioid misuse was limited to increasing anxiety incidence; in S2 we also considered the additive role of altered anxiety phenotype; and in S3 we further considered the role of increased opioid-related consequences of pre-existing anxiety due to wildfire exposure.

RESULTS

Models show that the prevalence of opioid misuse post-wildfire may rise to 6.0%-7.2% from a baseline of 5.3%. In S1, the opioid misuse prevalence ratio was 1.12 (95% uncertainty interval [UI]: 1.00 - 1.27). The two exploratory scenarios, with less stringent assumptions, yielded prevalence ratios of 1.23 (95% UI: 1.00 - 1.51) and 1.34 (95% UI: 1.11 - 1.63).

CONCLUSIONS

Our modeling study suggests that exposure to wildfires may elevate opioid misuse through increasing anxiety incidence and severity. This can lead to substantial health burdens, possibly beyond the duration of the wildfire event, which may offset recent gains in opioid misuse prevention.

Heat exposure impacts on urban health: A meta-analysis

The escalating health risks posed by warm weather in urban areas have become a pressing global public health issue. This study undertakes a meta-analysis to evaluate the impact of warm weather on health in urban settings. We comprehensively searched PubMed, Embase, Scopus, and Web of Science for literature published before September 6, 2023, evaluating evidence quality using the Navigation Guide Criteria. We included original studies utilizing high temperatures or heatwaves as exposure metrics and employing observational designs. A meta-analysis was carried out to assess the relative risk (RR) of the association between high temperatures (or heatwaves) and disease outcomes. Out of 12,893 studies identified, 188 met the inclusion criteria for meta-analysis. Results demonstrate a statistically significant association between a 1 °C temperature increase and a 2.1 % elevation in disease-related mortality (RR 1.021 [95 % CI 1.018-1.023]), alongside a 1.1 % increase in morbidity (RR 1.011 [95 % CI 1.007-1.016]). Heatwaves also showed associations with increased total mortality (RR 1.224 [95 % CI 1.186-1.264]) and morbidity (RR 1.038 [95 % CI 1.010-1.066]). Subgroup analyses for diseases, sex, age, climatic zones, countries, and time periods consistently indicated heightened disease-related mortality and morbidity linked to high temperatures. Notably, China's urban population faced an elevated mortality risk (RR 1.027 [95 % CI 1.018-1.036]) compared to other countries (RR 1.021 [95 % CI 1.019-1.024]). Mortality associated with high temperatures after 2007 (RR 1.022 [95 % CI 1.015-1.029]) was higher than before 2007 (RR 1.017 [95 % CI 1.013-1.021]), reflecting increased health risks as the global warming accelerates. Our findings underscore the positive association between rising temperatures and/or heatwaves and adverse health outcomes in urban populations. The widespread exposure to high temperatures amplifies health risks across various diseases, demographics, climates, and countries, with potential exacerbation under ongoing global warming. Further research is imperative to delineate factors influencing altered heat exposure impacts.

Humid heat environment causes anxiety-like disorder via impairing gut microbiota and bile acid metabolism in mice

Climate and environmental changes threaten human mental health, but the impacts of specific environmental conditions on neuropsychiatric disorders remain largely unclear. Here, we show the impact of a humid heat environment on the brain and the gut microbiota using a conditioned housing male mouse model. We demonstrate that a humid heat environment can cause anxiety-like behaviour in male mice. Microbial 16 S rRNA sequencing analysis reveals that a humid heat environment caused gut microbiota dysbiosis (e.g., decreased abundance of Lactobacillus murinus), and metabolomics reveals an increase in serum levels of secondary bile acids (e.g., lithocholic acid). Moreover, increased neuroinflammation is indicated by the elevated expression of proinflammatory cytokines in the serum and cortex, activated PI3K/AKT/NF-κB signalling and a microglial response in the cortex. Strikingly, transplantation of the microbiota from mice reared in a humid heat environment readily recapitulates these abnormalities in germ-free mice, and these abnormalities are markedly reversed by Lactobacillus murinus administration. Human samples collected during the humid heat season also show a decrease in Lactobacillus murinus abundance and an increase in the serum lithocholic acid concentration. In conclusion, gut microbiota dysbiosis induced by a humid heat environment drives the progression of anxiety disorders by impairing bile acid metabolism and enhancing neuroinflammation, and probiotic administration is a potential therapeutic strategy for these disorders.

Combination of Dasatinib and Quercetin alleviates heat stress-induced cognitive deficits in aged and young adult male mice

OBJECTIVE

Dasatinib and quercetin (D & Q) have demonstrated promise in improving aged-related pathophysiological dysfunctions in humans and mice. Herein we aimed to ascertain whether the heat stress (HS)-induced cognitive deficits in aged or even young adult male mice can be reduced by D & Q therapy.

METHODS

Before the onset of HS, animals were pre-treated with D & Q or placebo for 3 consecutive days every 2 weeks over a 10-week period. Cognitive function, intestinal barrier permeability, and blood-brain barrier permeability were assessed.

RESULTS

Compared to the non-HS young adult male mice, the HS young adult male mice or the aged male mice had significantly lesser extents of the exacerbated stress reactions, intestinal barrier disruption, endotoxemia, systemic inflammation and oxidative stress, blood-brain barrier disruption, hippocampal inflammation and oxidative stress, and cognitive deficits evaluated at 7 days post-HS. All the cognitive deficits and other syndromes that occurred in young adult HS mice or in aged HS mice were significantly attenuated by D & Q therapy (P < 0.01). Compared to the young adult HS mice, the aged HS mice had significantly (P < 0.01) higher severity of cognitive deficits and other related syndromes.

CONCLUSIONS

First, our data show that aged male mice are more vulnerable to HS-induced cognitive deficits than those of the young adult male mice. Second, we demonstrate that a combination of D and Q therapy attenuates cognitive deficits in heat stressed aged or young adult male mice via broad normalization of the brain-gut-endotoxin axis function.

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.

Climate change and women's mental health in two vulnerable communities of Bangladesh: An ethnographic study

Climate change is one of the most significant challenges humanity faces in the 21st century, with its health impacts being profoundly felt in the most vulnerable countries. However, the mental health impacts of climate change, particularly concerning social inequality and gender dynamics, are less documented in the Global South. This paper focuses on the impact of climate change on women's mental health in two vulnerable communities in Bangladesh. This study employed qualitative methods, including, in-depth interviews, and focus group discussions (FGDs). The communities were selected based on their vulnerability to climate change. A total of 80 participants were selected using snowball sampling, and 55 interviews and 6 FGDs were conducted. Women are particularly vulnerable to climate change impacts on mental health due to their gender roles and responsibilities. Responsible for taking care of their families, they have to face additional challenges due to climate change impacts, such as increased workload, food insecurity, and social insecurity when their husband migrates to the cities for jobs. Women also face social and cultural barriers, which exacerbate their vulnerability to climate change impacts on mental health. Socioeconomic and environmental determinants appear to be embedded and lead to psychological suffering in relation to social roles and gender norms. Interventions should be designed to address the specific needs and challenges faced by women in these communities. Policymakers should take a gender-sensitive approach to address the mental health impacts of climate change in these communities. This study contributes to the growing body of research on the gendered impacts of climate change with a trajectory approach and provides insights for future research in this area.

Heat Exposure and Dementia-Related Mortality in China

Importance

Although existing research has found daily heat to be associated with dementia-related outcomes, there is still a gap in understanding the differing associations of nighttime and daytime heat with dementia-related deaths.

Objectives

To quantitatively assess the risk and burden of dementia-related deaths associated with short-term nighttime and daytime heat exposure and identify potential effect modifications.

Design, Setting, and Participants

This case-crossover study analyzed individual death records for dementia across all mainland China counties from January 1, 2013, to December 31, 2019, using a time-stratified case-crossover approach. Statistical analysis was conducted from January 1, 2013, to December 31, 2019.

Exposures

Two novel heat metrics: hot night excess (HNE) and hot day excess (HDE), representing nighttime and daytime heat intensity, respectively.

Main Outcomes and Measures

Main outcomes were the relative risk and burden of dementia-related deaths associated with HNE and HDE under different definitions. Analysis was conducted with conditional logistic regression integrated with the distributed lag nonlinear model.

Results

The study involved 132 573 dementia-related deaths (mean [SD] age, 82.5 [22.5] years; 73 086 women [55.1%]). For a 95% threshold, the median hot night threshold was 24.5 °C (IQR, 20.1 °C-26.2 °C) with an HNE of 3.7 °C (IQR, 3.1 °C-4.3 °C), and the median hot day threshold was 33.3 °C (IQR, 29.9 °C-34.7 °C) with an HDE of 0.6 °C (IQR, 0.5 °C-0.8 °C). Both nighttime and daytime heat were associated with increased risk of dementia-related deaths. Hot nights' associations with risk of dementia-related deaths persisted for 6 days, while hot days' associations with risk of dementia-related deaths extended over 10 days. Extreme HDE had a higher relative risk of dementia-related deaths, with a greater burden associated with extreme HNE at more stringent thresholds. At a 97.5% threshold, the odds ratio for dementia-related deaths was 1.38 (95% CI, 1.22-1.55) for extreme HNE and 1.46 (95% CI, 1.27-1.68) for extreme HDE, with an attributable fraction of 1.45% (95% empirical confidence interval [95% eCI], 1.43%-1.47%) for extreme HNE and 1.10% (95% eCI, 1.08%-1.11%) for extreme HDE. Subgroup analyses suggested heightened susceptibility among females, individuals older than 75 years of age, and those with lower educational levels. Regional disparities were observed, with individuals in the south exhibiting greater sensitivity to nighttime heat and those in the north to daytime heat.

Conclusions and Relevance

Results of this nationwide case-crossover study suggest that both nighttime and daytime heat are associated with increased risk of dementia-related deaths, with a greater burden associated with nighttime heat. These findings underscore the necessity of time-specific interventions to mitigate extreme heat risk.

Impact of air pollution and climate change on mental health outcomes: an umbrella review of global evidence

The impact of air pollution and climate change on mental health has recently raised strong concerns. However, a comprehensive overview analyzing the existing evidence while addressing relevant biases is lacking. This umbrella review systematically searched the PubMed/Medline, Scopus and PsycINFO databases (up to June 26, 2023) for any systematic review with meta-analysis investigating the association of air pollution or climate change with mental health outcomes. We used the R metaumbrella package to calculate and stratify the credibility of the evidence according to criteria (i.e., convincing, highly suggestive, suggestive, or weak) that address several biases, complemented by sensitivity analyses. We included 32 systematic reviews with meta-analysis that examined 284 individual studies and 237 associations of exposures to air pollution or climate change hazards and mental health outcomes. Most associations (n=195, 82.3%) involved air pollution, while the rest (n=42, 17.7%) regarded climate change hazards (mostly focusing on temperature: n=35, 14.8%). Mental health outcomes in most associations (n=185, 78.1%) involved mental disorders, followed by suicidal behavior (n=29, 12.4%), access to mental health care services (n=9, 3.7%), mental disorders-related symptomatology (n=8, 3.3%), and multiple categories together (n=6, 2.5%). Twelve associations (5.0%) achieved convincing (class I) or highly suggestive (class II) evidence. Regarding exposures to air pollution, there was convincing (class I) evidence for the association between long-term exposure to solvents and a higher incidence of dementia or cognitive impairment (odds ratio, OR=1.139), and highly suggestive (class II) evidence for the association between long-term exposure to some pollutants and higher risk for cognitive disorders (higher incidence of dementia with high vs. low levels of carbon monoxide, CO: OR=1.587; higher incidence of vascular dementia per 1 μg/m3 increase of nitrogen oxides, NOx: hazard ratio, HR=1.004). There was also highly suggestive (class II) evidence for the association between exposure to airborne particulate matter with diameter ≤10 μm (PM10) during the second trimester of pregnancy and the incidence of post-partum depression (OR=1.023 per 1 μg/m3 increase); and for the association between short-term exposure to sulfur dioxide (SO2) and schizophrenia relapse (risk ratio, RR=1.005 and 1.004 per 1 μg/m3 increase, respectively 5 and 7 days after exposure). Regarding climate change hazards, there was highly suggestive (class II) evidence for the association between short-term exposure to increased temperature and suicide- or mental disorders-related mortality (RR=1.024), suicidal behavior (RR=1.012), and hospital access (i.e., hospitalization or emergency department visits) due to suicidal behavior or mental disorders (RR=1.011) or mental disorders only (RR=1.009) (RR values per 1°C increase). There was also highly suggestive (class II) evidence for the association between short-term exposure to increased apparent temperature (i.e., the temperature equivalent perceived by humans) and suicidal behavior (RR=1.01 per 1°C increase). Finally, there was highly suggestive (class II) evidence for the association between the temporal proximity of cyclone exposure and severity of symptoms of post-traumatic stress disorder (r=0.275). Although most of the above associations were small in magnitude, they extend to the entire world population, and are therefore likely to have a substantial impact. This umbrella review classifies and quantifies for the first time the global negative impacts that air pollution and climate change can exert on mental health, identifying evidence-based targets that can inform future research and population health actions.

Multimorbidity and emergency hospitalisations during hot weather

BACKGROUND

People with chronic diseases are a commonly listed heat-vulnerable group in heat-health action plans. While prior research identifies multiple health conditions that may increase vulnerability to ambient heat, there is minimal evidence regarding the implications of multimorbidity (two or more chronic diseases).

METHODS

From the statewide hospital registry of Queensland, Australia, we identified people aged ≥15 years who had emergency hospitalisation(s) between March 2004 and April 2016 and previously had 0, 1, 2, or ≥3 of five chronic diseases: cardiovascular disease, diabetes, mental disorders, asthma/COPD, and chronic kidney disease. We conducted time-stratified case-crossover analyses to estimate the odds ratio of hospitalisations associated with ambient heat exposure in people with different numbers, types, and combinations of chronic diseases. Ambient heat exposure was defined as a 5 °C increase in daily mean temperature above the median.

FINDINGS

There were 2,263,427 emergency hospitalisations recorded (48.7% in males and 51.3% in females). When the mean temperature increased, hospitalisation odds increased with chronic disease number, particularly in older persons (≥65 years), males, and non-indigenous people. For instance, in older persons with 0, 1, 2, or ≥3 chronic diseases, the odds ratios associated with ambient heat exposure were 1.00 (95% confidence interval: 0.96, 1.04), 1.06 (1.02, 1.09), 1.08 (1.02, 1.14), and 1.13 (1.07, 1.19), respectively. Among the chronic diseases, chronic kidney disease, and asthma/COPD, either existing alone, together, or in combination with other diseases, were associated with the highest odds of hospitalisations under ambient heat exposure.

INTERPRETATION

While individuals with multimorbidity are considered in heat-health action plans, this study suggests the need to consider specifically examining them as a distinct and vulnerable subgroup.

FUNDING

Wellcome.

[Pathophysiology and management of heat illness]

BACKGROUND

The frequency and intensity of heat waves are currently increasing due to climate change. Hence more cases of heat illness are being observed, a potentially life-threatening disease, which requires rapid and expert management.

OBJECTIVES

An overview of the pathophysiology and acute management of heat illness is presented.

MATERIALS AND METHODS

Analysis and evaluation of important, recently published contributions, studies, and reviews regarding heat illness without claim for completeness or fulfilling the criteria for a 'systematic meta-analysis'. Presentation of a recommended clinical-practical classification and management of heat illness in emergency departments or intensive care units.

RESULTS

The manifestation of heat illness arising from prolonged exposure to heat prevaries (heat cramps, heat edema, heat exhaustion, heat stroke). The main pathophysiologic mechanisms are disruption of thermoregulation, peripheral vasodilation of the skin surface, hypoperfusion of visceral organs, and brain, and cardiac stress. Uncompensated heat stress can result in multiorgan dysfunction/failure syndrome due to the initiation of cytokine pathways, specifically in at-risk and/or chronically ill patients. The manifestation of uncompensated heat stroke is associated with a hospital mortality > 50%. Rapid identification, classification and targeted management are crucial for the outcome, in particular the initiation of adequate cooling measures.

CONCLUSION

In the future, increasing numbers of patients suffering from prolonged heat exposure will require treatment in emergency departments and intensive care units. Sufficient professional knowledge regarding pathophysiology and management are decisive for successful therapy. Hence, the topic heat illness should be implemented in training and education.

The effects of extreme heat on human health in tropical Africa

This review examines high-quality research evidence that synthesises the effects of extreme heat on human health in tropical Africa. Web of Science (WoS) was used to identify research articles on the effects extreme heat, humidity, Wet-bulb Globe Temperature (WBGT), apparent temperature, wind, Heat Index, Humidex, Universal Thermal Climate Index (UTCI), heatwave, high temperature and hot climate on human health, human comfort, heat stress, heat rashes, and heat-related morbidity and mortality. A total of 5, 735 articles were initially identified, which were reduced to 100 based on a set of inclusion and exclusion criteria. The review discovered that temperatures up to 60°C have been recorded in the region and that extreme heat has many adverse effects on human health, such as worsening mental health in low-income adults, increasing the likelihood of miscarriage, and adverse effects on well-being and safety, psychological behaviour, efficiency, and social comfort of outdoor workers who spend long hours performing manual labour. Extreme heat raises the risk of death from heat-related disease, necessitating preventative measures such as adaptation methods to mitigate the adverse effects on vulnerable populations during hot weather. This study highlights the social inequalities in heat exposure and adverse health outcomes.

Effects of expanded adverse childhood experiences including school bullying, childhood poverty, and natural disasters on mental health in adulthood

The study aimed to examine the association of expanded adverse childhood experiences (ACEs) with psychological distress in adulthood. The data from nation-wide online cohort was used for analysis. Community dwelling adults in Japan were included. The ACEs was assessed by 15 items of ACE-J, including childhood poverty and school bullying. Severe psychological distress was determined as the score of Kessler 6 over 13. Multivariable logistic regression analysis was conducted, by using sample weighting. A total of 28,617 participants were analyzed. About 75% of Japanese people had one or more ACEs. The prevalence of those with ACEs over 4 was 14.7%. Those with ACEs over 4 showed adjusted odds ratio = 8.18 [95% CI 7.14-9.38] for severe psychological distress. The prevalence of childhood poverty was 29% for 50-64 year old participants and 40% of 65 or older participants. The impact of childhood poverty on psychological distress was less than other ACEs in these age cohorts. Bullying was experienced 21-27% in young generations, but 10% in 65 or older participants. However, the impact on psychological distress in adulthood was relatively high in all age groups. ACEs have impacted mental health for a long time. Future research and practice to reduce ACEs are encouraged.

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.

The interplay between climate change and ageing: A systematic review of health indicators

Climate change and rapid population ageing pose challenges for communities and public policies. This systematic review aims to gather data from studies that present health indicators establishing the connection between climate change and the physical and mental health of the older population (≥ 65 years), who experience a heightened vulnerability to the impacts of climate change when compared to other age cohorts. This review was conducted according to the PICO strategy and following Cochrane and PRISMA guidelines. Three databases (PubMed, Scopus and Greenfile) were searched for articles from 2015 to 2022. After applying inclusion and exclusion criteria,nineteen studies were included. The findings indicated that various climate change phenomena are associated with an elevated risk of mortality and morbidity outcomes in older adults. These included cardiovascular, respiratory, renal, and mental diseases, along with physical injuries. Notably, the impact of climate change was influenced by gender, socioeconomic status, education level, and age-vulnerability factors. Climate change directly affected the health of older adults through ambient temperature variability, extreme and abnormal temperatures, strong winds, sea temperature variability, extreme El Niño-southern Oscillation (ENSO) conditions and droughts, and indirectly by air pollution resulting from wildfires. This review presents further evidence confirming that climate change significantly impacts the health and well-being of older adults. It highlights the urgency for implementing effective strategies to facilitate adaptation and mitigation, enhancing the overall quality of life for all individuals.

The impact of climate change and related extreme weather on people with limb loss

The human health consequences of climate change and extreme weather events are well documented. Published literature details the unique effects and necessary adaptation planning for people with physical disabilities in general; however, the specific impacts and plans for people with limb loss have yet to be explored. In this article, we discuss the impacts related to threats due to heat, cold, severe storms, and power outages. We describe how climate change uniquely affects people with limb loss and underscore the need for rehabilitation care providers and researchers to: (1) study the health impacts of climate change on people with lower limb loss; (2) educate themselves and patients on the climate crisis and climate preparedness; (3) co-develop resiliency strategies with patients, governments, and community organizations to improve adaptive capacity; and (4) advocate for policy changes that will enact protections for this at-risk population.

Heat stroke-induced cerebral cortex nerve injury by mitochondrial dysfunction: A comprehensive multi-omics profiling analysis

In recent years, global warming has led to frequent instances of extremely high temperatures during summer, arousing significant concern about the adverse effects of high temperature. Among these, heat stroke is the most serious, which has detrimental effects on the all organs of human body, especially on brain. However, the comprehensive pathogenesis leading to brain damage remains unclear. In this study, we constructed a mouse model of heat stroke and conducted multi-omics profiling to identify relevant pathogenesis induced by heat stroke. The mice were placed in a constant temperature chamber at 42 °C with a humidity of 50 %, and the criteria for success in modeling were that the rectal temperature reached 42 °C and that the mice were trembling. Then the mice were immediately taken out for further experiments. Firstly, we conducted cFos protein localization and identified the cerebral cortex, especially the anterior cingulate cortex as the region exhibiting the most pronounced damage. Secondly, we performed metabolomics, transcriptomics, and proteomics analysis on cerebral cortex. This multi-omics investigation unveiled noteworthy alterations in proteins and metabolites within pathways associated with neurotransmitter systems, heatstroke-induced mitochondrial dysfunction, encompassing histidine and pentose phosphate metabolic pathways, as well as oxidative stress. In addition, the cerebral cortex exhibited pronounced Reactive Oxygen Species (ROS) production, alongside significant downregulation of the mitochondrial outer membrane protein Tomm40 and mitochondrial permeability transition pore, implicating cerebral cortex mitochondrial dysfunction as the primary instigator of neural impairment. This study marks a significant milestone as the first to employ multi-omics analysis in exploring the molecular mechanisms underlying heat stroke-induced damage in cerebral cortex neurons. It comprehensively identifies all potentially impacted pathways by heat stroke, laying a solid foundation for ensuing research endeavors. Consequently, this study introduces a fresh angle to clinical approaches in heatstroke prevention and treatment, as well as establishes an innovative groundwork for shaping future-forward environmental policies.

Maternal exposure to ambient air temperature and adverse birth outcomes: An umbrella review of systematic reviews and meta-analyses

BACKGROUND

Multiple systematic reviews on prenatal ambient temperature and adverse birth outcomes exist, but the overall epidemiological evidence and the appropriate metric for thermal stress remain unclear. An umbrella review was performed to summarise and appraise the evidence with recommendations.

METHODS

Systematic reviews and meta-analyses on the associations between ambient temperature and adverse birth outcomes (preterm birth, stillbirth, birth weight, low birth weight, and small for gestational age) up to December 20, 2023, were synthesised according to a published protocol. Databases PubMed, CINAHL, Scopus, MEDLINE/Ovid, EMBASE/Ovid, Web of Science Core Collection, systematic reviews repositories, electronic grey literature, and references were searched. Risk of bias was assessed using Joanna Briggs Institute's critical appraisal tool.

RESULTS

Eleven systematic reviews, including two meta-analyses, were included. This comprised 90 distinct observational studies that employed multiple temperature assessment metrics with a very high overlap of primary studies. Primary studies were mostly from the United States while both Africa and South Asia contributed only three studies. A majority (7 out of 11) of the systematic reviews were rated as moderate risk of bias. All systematic reviews indicated that maternal exposures to both extremely high and low temperatures, particularly during late gestation are associated with increased risks of preterm birth, stillbirth, and reduced fetal growth. However, due to great differences in the exposure assessments, high heterogeneity, imprecision, and methodological limitations of the included systematic reviews, the overall epidemiological evidence was classified as probable evidence of causation. No study assessed biothermal metrics for thermal stress.

CONCLUSIONS

Despite the notable methodological differences, prenatal exposure to extreme ambient temperatures, particularly during late pregnancy, was associated with adverse birth outcomes. Adhering to the appropriate systematic review guidelines for environmental health research, incorporating biothermal metrics into exposure assessment, evidence from broader geodemographic settings, and interventions are recommended in future studies.

Effect of wildfire on the prevalence of opioid misuse through anxiety among young adults in the United States: A modeling study

Background

Exposure to climate change events like wildfires can lead to health and mental health problems. While conceptual frameworks have been hypothesized describing the potential relationship between disaster exposure and substance use, the association remains under-researched and unquantified.

Methods

We constructed a quantitative portrayal of one proposed conceptual framework that focuses on the intermediary role of anxiety. We used the Monte Carlo simulation to estimate the impact of wildfire exposure on opioid misuse outcomes through increased anxiety. We searched for and extracted prior empirical evidence on the associations between wildfire anxiety and anxiety-opioid misuse. A base case scenario (S1) was devised in which the impact of wildfire on opioid misuse was limited to increasing anxiety incidence. Two exploratory scenarios investigated the additive roles of altered anxiety phenotype (S2) and increased severity of pre-existing anxiety (S3) due to wildfire exposure.

Results

Models show that the prevalence of opioid misuse post-wildfire may rise to 6.0%-7.2%. In S1 (base case), the opioid misuse prevalence ratio was 1.12 (95% uncertainty interval [UI]: 1.00 - 1.27). The two exploratory scenarios, with less stringent assumptions, yielded prevalence ratios of 1.23 (95% UI: 1.00 - 1.51) and 1.34 (95% UI: 1.11 - 1.63).

Conclusions

Our modeling study suggests that exposure to wildfires may elevate opioid misuse through increasing anxiety incidence and severity. This may lead to substantial health burdens that may persist long after the initial wildfire event, which may offset recent gains in opioid misuse prevention.

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.

The perceived impact of climate change on mental health and suicidality in Kenyan high school students

BACKGROUND

Climate change has psychological impacts but most of the attention has been focused on the physical impact. This study was aimed at determining the association of climate change with adolescent mental health and suicidality as reported by Kenyan high school students.

METHODS

This was a cross sectional study with a sample size of 2,652. The participants were high school students selected from 10 schools in 3 regions of Kenya. A questionnaire was used to assess climate change experiences, mental health problems, and suicidality of the youth. Data were analyzed descriptively and with logistic regression to determine various associations of the different variables and the predictors of the various scores of SDQ and suicidality at 95% CI.

RESULTS

Significant differences were observed between gender and two of the threats of climate change - worry and being afraid as subjectively experienced by the participants. Females were more worried and afraid of climate change than males. On univariate and multivariate logistic regression, we found that various experiences of climate change were significantly associated with various scores of SDQ and much fewer of the experiences predicted SDQ scores. The same pattern was reflected in suicidality.

CONCLUSION

Climate change appears to be associated with mental health concerns and suicidality according to Kenyan high school students' reports with gender differences in some associations.

Mental illness and increased vulnerability to negative health effects from extreme heat events: a systematic review

RATIONALE

Across countries, extreme heat events are projected to increase in frequency and intensity because of climate change. Exposure to extreme heat events can have a substantial negative impact on human health, and extant research suggests that individuals with mental illness are particularly vulnerable. To date, there has been no review of evidence regarding this vulnerability to inform response strategies and future research.

OBJECTIVE

A systematic review was undertaken to investigate mental illness as an effect modifier of the relationship between heat exposure and morbidity or mortality.

METHODS

Six databases (Medline, Embase, Global Health, PsychInfo, CINAHL and Scopus) were searched for studies published between the years 2000 to 2022. Twenty-two observational studies that met the inclusion criteria were investigated through narrative synthesis. The RoBANS tool, ROBIS and GRADE were used to assess the certainty of evidence including the risk of bias.

RESULTS

Individuals with mental illness experience worse morbidity and mortality outcomes compared to their counterparts without mental illness in all studies investigating high temperature over a single day. This did not hold for studies examining heatwaves, which reported mixed findings.

CONCLUSIONS AND IMPLICATIONS

People with diagnosed mental illness should be targeted for policy and service attention during high temperature days. Further research should investigate specific mental illness and adjust for a wider range of confounding factors.

Heatwave characteristics complicate the association between PM2.5 components and schizophrenia hospitalizations in a changing climate: Leveraging of the individual residential environment

BACKGROUND

In the era characterized by global environmental and climatic changes, understanding the effects of PM2.5 components and heatwaves on schizophrenia (SCZ) is essential for implementing environmental interventions at the population level. However, research in this area remains limited, which highlights the need for further research and effort. We aim to assess the association between exposure to PM2.5 components and hospitalizations for SCZ under different heatwave characteristics.

METHODS

We conducted a 16 municipalities-wide, individual exposure-based, time-stratified, case-crossover study from January 1, 2017, to December 31, 2020, encompassing 160736 hospitalizations in Anhui Province, China. Daily concentrations of PM2.5 components were obtained from the Tracking Air Pollution in China dataset. Conditional logistic regression models were used to investigate the association between PM2.5 components and hospitalizations. Additionally, restricted cubic spline models were used to identify protective thresholds of residential environment in response to environmental and climate change.

RESULTS

Our findings indicate a positive correlation between PM2.5 and its components and hospitalizations. Significantly, a 1 μg/m3 increase in black carbon (BC) was associated with the highest risk, at 1.58% (95%CI: 0.95-2.25). Exposure to heatwaves synergistically enhanced the impact of PM2.5 components on hospitalization risks, and the interaction varied with the intensity and duration of heatwaves. Under the 99th percentile heatwave events, the impact of PM2.5 and its components on hospitalizations was most pronounced, which were PM2.5 (2-4d: 4.59%, 5.09%, and 5.09%), sulfate (2-4d: 21.73%, 23.23%, and 25.25%), nitrate (2-4d: 17.51%, 16.93%, and 20.31%), ammonium (2-4d: 27.49%, 31.03%, and 32.41%), organic matter (2-4d: 32.07%, 25.42%, and 24.48%), and BC (2-4d: 259.36%, 288.21%, and 152.52%), respectively. Encouragingly, a protective effect was observed when green and blue spaces comprised more than 17.6% of the residential environment.

DISCUSSION

PM2.5 components and heatwave exposure were positively associated with an increased risk of hospitalizations, although green and blue spaces provided a mitigating effect.

Too hot to thrive: a qualitative inquiry of community perspectives on the effect of high ambient temperature on postpartum women and neonates in Kilifi, Kenya

OBJECTIVE

To understand community perspectives on the effects of high ambient temperature on the health and wellbeing of neonates, and impacts on post-partum women and infant care in Kilifi.

DESIGN

Qualitative study using key informant interviews, in-depth interviews and focus group discussions with pregnant and postpartum women (n = 22), mothers-in-law (n = 19), male spouses (n = 20), community health volunteers (CHVs) (n = 22) and stakeholders from health and government ministries (n = 16).

SETTINGS

We conducted our research in Kilifi County in Kenya's Coast Province. The area is largely rural and during summer, air temperatures can reach 37˚C and rarely go below 23˚C.

DATA ANALYSIS

Data were analyzed in NVivo 12, using both inductive and deductive approaches.

RESULTS

High ambient temperature is perceived by community members to have direct and indirect health pathways in pregnancy and postpartum periods, including on the neonates. The direct impacts include injuries on the neonate's skin and in the mouth, leading to discomfort and affecting breastfeeding and sleeping. Participants described babies as "having no peace". Heat effects were perceived to be amplified by indoor air pollution and heat from indoor cooking fires. Community members believed that exclusive breastfeeding was not practical in conditions of extreme heat because it lowered breast milk production, which was, in turn, linked to a low scarcity of food and time spend by mothers away from their neonates performing household chores. Kangaroo Mother Care (KMC) was also negatively affected. Participants reported that postpartum women took longer to heal in the heat, were exhausted most of the time and tended not to attend postnatal care.

CONCLUSIONS

High ambient temperatures affect postpartum women and their neonates through direct and indirect pathways. Discomfort makes it difficult for the mother to care for the baby. Multi-sectoral policies and programs are required to mitigate the negative impacts of high ambient temperatures on maternal and neonatal health in rural Kilifi and similar settings.

Impact of heat on mental health emergency visits: a time series study from all public emergency centres, in Curitiba, Brazil

OBJECTIVES

Quantify the risk of mental health (MH)-related emergency department visits (EDVs) due to heat, in the city of Curitiba, Brazil.

DESIGN

Daily time series analysis, using quasi-Poisson combined with distributed lag non-linear model on EDV for MH disorders, from 2017 to 2021.

SETTING

All nine emergency centres from the public health system, in Curitiba.

PARTICIPANTS

101 452 EDVs for MH disorders and suicide attempts over 5 years, from patients residing inside the territory of Curitiba.

MAIN OUTCOME MEASURE

Relative risk of EDV (RREDV) due to extreme mean temperature (24.5°C, 99th percentile) relative to the median (18.02°C), controlling for long-term trends, air pollution and humidity, and measuring effects delayed up to 10 days.

RESULTS

Extreme heat was associated with higher single-lag EDV risk of RREDV 1.03(95% CI 1.01 to 1.05-single-lag 2), and cumulatively of RREDV 1.15 (95% CI 1.05 to 1.26-lag-cumulative 0-6). Strong risk was observed for patients with suicide attempts (RREDV 1.85, 95% CI 1.08 to 3.16) and neurotic disorders (RREDV 1.18, 95% CI 1.06 to 1.31). As to demographic subgroups, females (RREDV 1.20, 95% CI 1.08 to 1.34) and patients aged 18-64 (RREDV 1.18, 95% CI 1.07 to 1.30) were significantly endangered. Extreme heat resulted in lower risks of EDV for patients with organic disorders (RREDV 0.60, 95% CI 0.40 to 0.89), personality disorders (RREDV 0.48, 95% CI 0.26 to 0.91) and MH in general in the elderly ≥65 (RREDV 0.77, 95% CI 0.60 to 0.98). We found no significant RREDV among males and patients aged 0-17.

CONCLUSION

The risk of MH-related EDV due to heat is elevated for the entire study population, but very differentiated by subgroups. This opens avenue for adaptation policies in healthcare: such as monitoring populations at risk and establishing an early warning systems to prevent exacerbation of MH episodes and to reduce suicide attempts. Further studies are welcome, why the reported risk differences occur and what, if any, role healthcare seeking barriers might play.

Meteorological factors, ambient air pollution, and daily hospital admissions for depressive disorder in Harbin: A time-series study

BACKGROUND

The literature has discussed the relationship between environmental factors and depressive disorders; however, the results are inconsistent in different studies and regions, as are the interaction effects between environmental factors. We hypothesized that meteorological factors and ambient air pollution individually affect and interact to affect depressive disorder morbidity.

AIM

To investigate the effects of meteorological factors and air pollution on depressive disorders, including their lagged effects and interactions.

METHODS

The samples were obtained from a class 3 hospital in Harbin, China. Daily hospital admission data for depressive disorders from January 1, 2015 to December 31, 2022 were obtained. Meteorological and air pollution data were also collected during the same period. Generalized additive models with quasi-Poisson regression were used for time-series modeling to measure the non-linear and delayed effects of environmental factors. We further incorporated each pair of environmental factors into a bivariate response surface model to examine the interaction effects on hospital admissions for depressive disorders.

RESULTS

Data for 2922 d were included in the study, with no missing values. The total number of depressive admissions was 83905. Medium to high correlations existed between environmental factors. Air temperature (AT) and wind speed (WS) significantly affected the number of admissions for depression. An extremely low temperature (-29.0 ℃) at lag 0 caused a 53% [relative risk (RR)= 1.53, 95% confidence interval (CI): 1.23-1.89] increase in daily hospital admissions relative to the median temperature. Extremely low WSs (0.4 m/s) at lag 7 increased the number of admissions by 58% (RR = 1.58, 95%CI: 1.07-2.31). In contrast, atmospheric pressure and relative humidity had smaller effects. Among the six air pollutants considered in the time-series model, nitrogen dioxide (NO2) was the only pollutant that showed significant effects over non-cumulative, cumulative, immediate, and lagged conditions. The cumulative effect of NO2 at lag 7 was 0.47% (RR = 1.0047, 95%CI: 1.0024-1.0071). Interaction effects were found between AT and the five air pollutants, atmospheric temperature and the four air pollutants, WS and sulfur dioxide.

CONCLUSION

Meteorological factors and the air pollutant NO2 affect daily hospital admissions for depressive disorders, and interactions exist between meteorological factors and ambient air pollution.

Prevention of suicides associated with global warming: perspectives from early career psychiatrists

Climate change poses significant challenges to global mental health, with potential consequences including increased rates of suicide and mental health disorders. Early Career Psychiatrists (ECPs) play a crucial role in addressing these challenges. The Climate Psychiatry Alliance, a group of psychiatrists dedicated to improving mental health amidst climate change, recognizes the importance of cultivating climate-aware ECPs. Training ECPs to become confident climate-aware clinicians enables them to effectively treat patients experiencing anxiety, depression, and PTSD in the context of climate-related distress. Together with other mental health professionals, ECPs can contribute to efforts by implementing strategies for monitoring and treating mental health problems arising from climate events. Additionally, they can raise awareness about the psychological consequences and risks of suicide associated with climate change. Collaboration among ECPs from various regions is essential in developing community-based approaches and reducing vulnerabilities. ECPs must prioritize supporting vulnerable populations by advocating for increased funding for mental health support and research in affected areas. Long-term solutions to address the mental health impacts of climate change and global warming should be pursued to mitigate future suicidality. Integrating climate considerations into local mental health programs and expanding psychological support services is crucial. By promoting emotional resilience and self-awareness, ECPs can contribute to building a more climate-resilient and mentally healthy society.