The combined effects of heatwaves, air pollution and greenery on the risk of frailty: a national cohort study.

The associations between heatwaves and frailty, as well as the joint effects of heatwaves with air pollution and greenery, are currently unknown. This study leverages data from the China Health and Retirement Longitudinal Study (CHARLS), which collected information from 6,400 older adults between 2011 and 2018. Our outcome variable was frailty, as measured by the frailty index (FI > 0.21). Heatwaves were defined based on maximum temperature, incorporating four thresholds (≥ 97.5%, 97.5%, 92.5%, and 90%) and three durations (≥ 2, 3, and 4 days). These variables were considered as time-varying variables, representing the one-year exposure preceding survival events. Fine particulate matter (PM2.5) and greenery (normalized difference vegetation index (NDVI)) were utilized as indicators of air pollution and greenery exposure, respectively, and were treated as time-varying indicators concurrent with heatwaves.Time-varying Cox proportional hazards models were employed to assess the independent effects, as well as the multiplicative and additive interactions of heatwaves, air pollution, and greenery on the risk of frailty. These effects were quantified using hazard ratios (HRs), a traditional product term representing the ratio of HRs, and the relative excess risk due to interaction (RERI). Our findings indicate that heatwaves are associated with an increased risk of frailty, with HRs ranging from 1.035 (95% CI: 1.006-1.064) to 1.063 (95% CI: 1.028-1.101). We observed both a positive multiplicative interaction (HRs > 1) and an additive interaction (RERI > 0) between high level PM2.5 concentration, lack of greenery, and heatwaves. This study reveals that the combined effects exacerbate the adverse impact of heatwaves on the risk of frailty. Moreover, the combined effects of heatwaves, air pollution, and greenery exposure on frailty risk vary across age, gender, and educational attainment.

Impact of zinc oxide nanoparticles on the behavior and stress indicators of African catfish (Clarias gariepinus) exposed to heat stress.

This study was designed to assess the role of nano-zinc oxide in mitigating the deleterious effects of heat stress in African catfish (Clarias gariepinus) by evaluating parameters such as aggressive behavior (biting frequency and chasing duration), hematological indicators, and stress-related biochemical markers. A total of 96 catfish were divided into four distinct groups (24 fish/group): The first group (CON) served as the control group, receiving a diet free of nano-zinc oxide. The second group (HS) was exposed to heat stress at 35 °C ± 1 °C. The third group (ZN) was fed a diet containing nano-zinc oxide at 30 mg/kg of the diet, and the fourth group (ZHN) was exposed to heat stress (35 °C ± 1 °C) and fed a diet containing nano-zinc oxide at 30 mg/kg of the diet. The results clarified that the aggressive behavior and cortisol levels were significantly higher (P < 0.05) in the HS group compared to the CON and ZHN groups. Additionally, the level of acetylcholinesterase (AChE) was significantly lower (P < 0.05) in the HS group compared to the CON and ZHN groups. Meanwhile, a significant (P < 0.05) decrease in red blood cells, hemoglobin, packed cell volume, white blood cells, alkaline phosphatase, and lymphocytes, was observed in fish belonging to the HS group, while the levels of alanine aminotransferase, aspartate aminotransferase, neutrophils, and monocytes showed a significant increase (P < 0.05). Supplementation with nano-zinc oxide significantly recovered most hematological and biochemical parameters. In conclusion, nano-zinc oxide contributed significantly to the regulation of the negative impacts of heat stress on fish by reducing aggressive behavior and cortisol levels. Additionally, it improved the levels of AChE and certain hematological and biochemical parameters.

Can switching from cigarettes to heated tobacco products reduce consequences of pulmonary infection?

RATIONALE: While tobacco industry data suggests that switching from combustible cigarettes to heated tobacco products (HTPs), like IQOS, may reduce the users' exposure to respiratory toxicants, it is not known if using HTPs impacts the outcomes of acute respiratory infections. OBJECTIVES: Does switching from cigarettes to HTPs improve responses to pulmonary infection. METHODS: We conducted experiments in which 3 groups of mice were pre-exposed to cigarette smoke for 8 weeks, followed by 8-week exposure to (1) HTPs (tobacco product switching), (2) air (smoking cessation), or (3) continued exposure to cigarette smoke. Pulmonary bacterial clearance and surrogate markers of lung damage were assessed as study outcomes. MAIN RESULTS: Significantly compromised clearance of bacteria from the lungs post-acute challenge occurred in both the switching group and in mice continuously exposed to cigarette smoke. Bacterial clearance, inflammatory T-cell infiltration into the lungs, and albumin leak improved at 12 h post-acute challenge in the switching group compared to mice continuously exposed to cigarette smoke. Bacterial clearance, total lung immune-cell infiltration, inflammatory T-cell infiltration into the lungs, the content of total proteins in the BAL, and albumin leak measured post-acute challenge were compromised in the switching group compared to mice in the cessation group. Switching from cigarettes to HTPs did not improve lung myeloperoxidase and neutrophil elastase levels (markers for lung inflammation and damage), which, however, were significantly reduced in the cessation group. CONCLUSIONS: This study reveals only a modest improvement in respiratory infection outcomes after switching exposure from cigarettes to HTPs and significantly compromised outcomes compared to a complete cessation of exposure to all tobacco products.

Heatwave and upper urinary tract stones morbidity: effect modification by heatwave definitions, disease subtypes, and vulnerable populations.

As heatwave occurs with increased frequency and intensity, the disease burden for urolithiasis, a heat-specific disease, will increase. However, heatwave effect on urolithiasis subtypes morbidity and optimal heatwave definition for urolithiasis remain unclear. Distributed lagged linear models were used to assess the associations between 32 defined heatwave and upper urinary tract stones morbidity. Relative risk (RR) and attributable fraction (AF) of upper urinary tract stone morbidity associated with heatwave of different intensities (low, middle, and high) were pooled by meta-analysis. Optimal heatwave definition was selected based on the combined score of AF, RR, and quasi-Akaike Information Criterion (QAIC) value. Stratified analyses were conducted to investigate the modification effects of gender, age, and disease subtypes. Association between heatwave and upper urinary tract stones morbidity was mainly for ureteral calculus, and AF was highest for low-intensity heatwave. This study's optimal heatwave was defined as average temperature > 93rd percentile for ≥ 2 consecutive days, with AF of 7.40% (95% CI: 2.02%, 11.27%). Heatwave was associated with ureteral calculus morbidity in males and middle-aged adults. While heatwave effect was statistically insignificant in females and other age groups. Managers should develop appropriate definitions to address heatwave based on regional characteristics and focus on heatwave effects on urolithiasis.

Association between use of heated tobacco products and long-term respiratory effects considering smoking history: internet-based cross-sectional study in Japan.

BACKGROUND: With the use of heated tobacco products (HTPs) becoming more widespread in Japan, interest in the health effects of HTP has grown. Since the majority of HTP users are former smokers, information about the user's smoking history and health status before HTP use is needed when assessing the health effects of HTP use. The limited epidemiological studies available did not consistently consider this information adequately, therefore we conducted a cross-sectional study investigating the association between HTP use and respiratory chronic diseases and symptoms. METHODS: The questionnaires were sent to a research panel members in Japan via the Internet, and individuals who met the study criteria and were either current exclusive HTP users, current exclusive cigarette users or those had never used tobacco products were selected. Information about the participants' smoking history and health status before they used HTPs was obtained. The effects of participant smoking history before HTP use and the impacts on outcomes upon switching to HTP were assessed using a logistic regression model. The odds ratio (OR) for current exclusive HTP users relative to never tobacco users was calculated. The OR was calculated under two scenarios, one in which the smoking history was ignored or one in which the smoking history was considered. RESULTS: Of the participants from whom responses to the questionnaires were obtained, 17,406 participants were included in the analysis. Almost all participating current exclusive HTP users had a history of long-term smoking (mean: 30.8 years), and the occurrence of outcomes both before and after the start using HTP was reported. The ORs, without adjustment and with adjustment for smoking history before HTP use were, 3.23 (95% CI: 1.37-7.61) and 1.85 (95% CI: 0.70-4.89) respectively in COPD, same as other outcomes. CONCLUSIONS: These results suggest that smoking history before HTP using affects the occurrence of outcomes, and underscore the importance of considering smoking history when assessing the health effect of HTP use. Since the duration of HTP use is considerably shorter than that of cigarette use at present, further research, such as follow-up surveys assessing the long-term respiratory effects of HTP use, will be necessary.

Association of heat and cold waves with cause-specific mortality in Iran: a systematic review and meta-analysis.

Despite the frequent occurrence of heat waves in the Middle East, there is a lack of evidence regarding the overall estimates for the effect of heat waves on mortality in this region. This study aimed to review the effect of exposure to heat and cold waves and daily cause-specific mortality. Four electronic databases were searched. The titles, abstracts, and full-texts of the articles were carefully reviewed by two researchers. Once eligible studies were identified, the required data were extracted. Separate meta-analyses were conducted based on gender, age group, and health endpoint combinations. According to the meta-analysis, heat waves had a statistically significant effect on all-cause mortality with an RR of 1.23 (CI 95%: 1.08, 1.39). Cardiovascular mortality significantly increased in heat waves with an RR of 1.08 (CI 95%: 1.05, 1.10). However, the increase in respiratory mortality was not statistically significant. Compared to young people (age < 65 years old) and women, elderly and men were more vulnerable to heat waves with RRs of 1.31 (95% CI: 1.05, 1.57) and 1.33 (95% CI: 1.08, 1.58), respectively. This study can be beneficial in developing response or adaptation plans for heat waves. Future studies should focus on other specific health endpoints like ischemic heart disease, chronic obstructive pulmonary diseases, etc., and other outcomes such as hospitalization and emergency visits.

What causes cardiac mitochondrial failure at high environmental temperatures?

Although a mechanism accounting for hyperthermic death at critical temperatures remains elusive, the mitochondria of crucial active excitable tissues (i.e. heart and brain) may well be key to this process. Mitochondria produce ∼90% of the ATP required by cells to maintain cellular integrity and function. They also integrate into biosynthetic pathways that support metabolism as a whole, allow communication within the cell, and regulate cellular health and death pathways. We have previously shown that cardiac and brain mitochondria demonstrate decreases in the efficiency of, and absolute capacity for ATP synthesis as temperatures rise, until ultimately there is too little ATP to support cellular demands, and organ failure follows. Importantly, substantial decreases in ATP synthesis occur at temperatures immediately below the temperature of heart failure, and this suggests a causal role of mitochondria in hyperthermic death. However, what causes mitochondria to fail? Here, we consider the answers to this question. Mitochondrial dysfunction at high temperature has classically been attributed to elevated leak respiration suspected to result from increased movement of protons (H+) through the inner mitochondrial membrane (IMM), thereby bypassing the ATP synthases. In this Commentary, we introduce some alternative explanations for elevated leak respiration. We first consider respiratory complex I and then propose that a loss of IMM structure occurs as temperatures rise. The loss of the cristae folds of the IMM may affect the efficiency of H+ transport, increasing H+ conductance either through the IMM or into the bulk water phases of mitochondria. In either case, O2 consumption increases while ATP synthesis decreases.

Cardiovascular responses to heat and cold exposure are altered by preterm birth in guinea pigs.

Adversity early in life can modify the trajectory for disease risk extending decades beyond the event. Preterm birth produces persistent cardiovascular alterations that may appear maladaptive in adulthood. We have previously hypothesized that those born preterm may exhibit cardiovascular vulnerability in the climate change context. Further, this vulnerability may be present as early as childhood. We aimed to identify the early signs of cardiovascular dysfunction at childhood-equivalent age using our animal model of preterm birth. Using a whole-body thermal stress test, guinea pigs aged 35-d and 38-d (equivalent to 8-10-year-old children) and born at term or preterm gestations were exposed to progressive hyper- (TC = 41.5°C) and hypo-thermia (TC = 34°C; normothermia TC = 39°C). Comprehensive cardiovascular monitoring included ECG, blood pressure, microvascular perfusion, blood gas, and catecholamine profile, as well as skin and core body temperature. Preterm-born animals exhibited attenuated vascular responses to hyperthermic stress, and a significant elevation in systolic blood pressure in response to hypothermic stress. Such responses are similar to those observed in elderly populations and indicate the presence of cardiovascular dysfunction. This is the first study to demonstrate the impact of preterm birth on the cardiovascular response to both heat and cold stress. Further, this dysfunction has been observed at an earlier age than that achievable using traditional stress testing techniques. The present findings warrant further investigation.

A Dirt(y) World in a Changing Climate: Importance of Heat Stress in the Risk Assessment of Pesticides for Soil Arthropods.

The rise in global temperatures and increasing severity of heat waves pose significant threats to soil organisms, disrupting ecological balances in soil communities. Additionally, the implications of environmental pollution are exacerbated in a warmer world, as changes in temperature affect the uptake, transformation and elimination of toxicants, thereby increasing the vulnerability of organisms. Nevertheless, our understanding of such processes remains largely unexplored. The present study examines the impact of high temperatures on the uptake and effects of the fungicide fluazinam on the springtail Folsomia candida (Collembola, Isotomidae). Conducted under non-optimum but realistic high temperatures, the experiments revealed that increased temperature hampered detoxification processes in F. candida, enhancing the toxic effects of fluazinam. High temperatures and the fungicide exerted synergistic interactions, reducing F. candida's reproduction and increasing adult mortality beyond what would be predicted by simple addition of the heat and chemical effects. These findings highlight the need to reevaluate the current ecological risk assessment and the regulatory framework in response to climate changes. This research enhances our understanding of how global warming affects the toxicokinetics and toxicodynamics (TK-TD) of chemicals in terrestrial invertebrates. In conclusion, our results suggest that adjustments to regulatory threshold values are necessary to address the impact of a changing climate.

When the Going Gets Tough, the Females Get Going: Sex-Specific Physiological Responses to Simultaneous Exposure to Hypoxia and Marine Heatwave Events in a Ubiquitous Copepod.

The existence of sex-specific differences in phenotypic traits is widely recognized. Yet they are often ignored in studies looking at the impact of global changes on marine organisms, particularly within the context of combined drivers that are known to elicit complex interactions. We tested sex-specific physiological responses of the cosmopolitan and ecologically important marine copepod Acartia tonsa exposed to combined hypoxia and marine heatwave (MHW) conditions, both of which individually strongly affect marine ectotherms. Females and males were acutely exposed for 5 days to a combination of either control (18°C) or a high temperature mimicking a MHW (25°C), and normoxia (100% O2 sat.) or mild hypoxia (35% O2 sat.). Life-history traits, as well as sex-specific survival and physiological traits, were measured. Females had overall higher thermal tolerance levels and responded differently than males when exposed to the combined global change drivers investigated. Females also showed lower metabolic thermal sensitivity when compared to males. Additionally, the MHW exerted a dominant effect on the traits investigated, causing a lower survival and higher metabolic rate at 25°C. However, egg production rates appeared unaffected by hypoxia and MHW conditions. Our results showed that MHWs could strongly affect copepods' survival, that combined exposure to hypoxia and MHW exerted an interactive effect only on CTmax, and that sex-specific vulnerability to these global change drivers could have major implications for population dynamics. Our results highlight the importance of considering the differences in the responses of females and males to rapid environmental changes to improve the implementation of climate-smart conservation approaches.

The effect modification of PM2.5 and ozone on the short-term associations between temperature and mortality across the urban areas of Japan.

BACKGROUND: The acute effects of temperature and air pollution on mortality are well-known environmental factors that have been receiving more recognition lately. However, the health effects resulting from the interaction of air pollution and temperature remain uncertain, particularly in cities with low levels of pollution. This study aims to examine the modification effects of particulate matter with a diameter of 2.5 µm or less (PM2.5) and ozone (O3) on the association between temperature and mortality. METHODS: We collected the daily number of all-cause, cardiovascular, and respiratory mortality from 20 major cities in Japan from 2012-2018. We obtained meteorological data from the Japan Meteorological Agency and air pollution data from the National Institute for Environmental Studies. We conducted analyses using a quasi-Poisson regression model with a distributed lag non-linear model for temperature in each city and subsequently performed a random-effects meta-analysis to derive average estimates. RESULTS: We found that high levels of O3 might positively modify the mortality risk of heat exposure, especially for cardiovascular diseases. Subgroups such as the elderly and females were susceptible. We did not observe consistent evidence of effect modification by PM2.5, including effect modification on cold by both pollutants. CONCLUSION: PM2.5 and O3 may positively modify the short-term association between heat and mortality in the urban areas of Japan. These results highlight the need for public health policies and interventions to address the collective impacts of both temperature and air pollution.

Vulnerability to heat-related mortality and the effect of prevention measures: a time-stratified case-crossover study in Switzerland.

BACKGROUND: Swiss climate scenarios predict increases in the frequency and intensity of extreme heat episodes in the future. For the effective prevention of heat-related mortality, several aspects of the population's vulnerability to heat must be understood on a local level. METHODS: A nationwide analysis of individual death records was conducted, enabling a more comprehensive understanding than typical heat studies based on aggregated data. A total of 320,306 individual death records from the Swiss National Cohort with precise address information during the warm season (May to September) from 2003-2016 were linked to indoor and outdoor high-resolution daily temperature estimates. A time-stratified case-crossover study combined with distributed lag non-linear models was then performed to assess the temperature-mortality associations for various causes of death and to estimate the potential effect modification of individual characteristics. Additionally, it was explored whether the effect of extreme heat changed over time in regions with and without cantonal heat-health action plans (HHAPs). RESULTS: Using the temperature with the lowest cause-specific mortality risk (minimum mortality temperature) as the reference temperature, extreme heat (defined as ambient daily maximum temperature reaching 33 °C) was associated with a strong increase in all-cause mortality (odds ratio (OR): 1.21, 95% CI: 1.17-1.25) and disease-specific mortality from Alzheimer's disease and dementia (OR: 1.67, 95% CI: 1.48-1.88), COPD (OR: 1.37, 95% CI: 1.12-1.67), diabetes (OR: 1.34, 95% CI: 1.06-1.70), and myocardial infarction (OR: 1.26, 95% CI: 1.10-1.44). Indoor temperatures above 24 °C were found to be critical for mortality. The population most vulnerable to heat included older adults (≥75 years), unmarried individuals, people with a low education level, older women with low neighbourhood socioeconomic position, and men under 75 years old with low socioeconomic position. Overall, the risk of heat-related all-cause mortality in 2009-2016 was lower than that in 2003-2008. The decrease was significantly stronger in the region where cantonal HHAPs were implemented. CONCLUSIONS: This study provides important information for planning targeted and effective measures to reduce heat-related health risks in Switzerland. It demonstrates that HHAPs contribute to reducing heat-related mortality, although they may not reach the high-risk population of individuals with low socioeconomic position. Future prevention efforts should also target the less privileged population, including people younger than 75 years.

Effect of Heating and Massaging of Meibomian Glands on Their Imaging.

Background and Objectives: Infrared light is used to image the Meibomian glands through their thermal profile. This study aimed to investigate the effects of a combination of heating and an eyelid massage on Meibomian gland visibility and tear film parameters. Materials and Methods: Twenty-four participants (26 ± 6.9 years) were enrolled in this prospective study, which involved imaging the Meibomian glands of both the lower and upper eyelid and assessing the non-invasive breakup time (NIBUT), tear meniscus height (TMH), and blink rate (using the CA-800, Topcon) at baseline after five minutes of eyelid warming followed by a five-minute eyelid massage. The second session, which was randomised in sequence, repeated the same measurements but without the inclusion of any eyelid warming or massage as the control condition. Results: While there was no change in lower lid Meibomian gland appearance as a result of eyelid heating, eyelid massage, or multiple lid eversion (median 2.0, range 0.0 to 4.0; p = 0.782), there was a change in upper lid appearance 5 min after heating and lid massage (p = 0.025), but again, multiple lid eversion had no effect (p > 0.05). The NIBUT decreased on second lid eversion (p = 0.049), although this was not evident on the third lid eversion (p = 0.090). The effect on NIBUT was also apparent with heating (p = 0.034 immediately after) but was sustained with 5 min of eyelid massage (p = 0.031). The TMH increased with heating (p < 0.001), and this effect was sustained with 5 min of eyelid massage (p = 0.011), but there was no lid eversion effect (p > 0.05). The blink rate was unaffected by heating, eyelid massage, or multiple eversions of the eyelids (median 24 blinks/min, range 8 to 59 blinks/min; p = 0.61). Conclusions: Eyelid warming can increase the visibility of the Meibomian glands, although this effect was only observed with upper lid imaging and the effect dissipated after 5 min of eyelid massage. Warming and massage also disrupt the tear film, as does multiple lid eversion, emphasising the need to use the least invasive tear film assessment techniques first.

The impact of increasing temperatures due to climate change on infectious diseases.

Global temperatures will continue to rise due to climate change, with high temperature periods expected to increase in intensity, frequency, and duration. Infectious diseases, including vector-borne diseases such as dengue fever and malaria, waterborne diseases such as cholera, and foodborne diseases such as salmonellosis are influenced by temperature and other climatic variables, thus contributing to higher disease burden and associated healthcare costs, particularly in socioeconomically disadvantaged regions. Targeted efforts and investments are therefore needed to support low and middle income countries to prepare for and respond to the increasing infectious disease threats posed by rising temperatures. This can be facilitated by the development and refinement of robust disease and entomological surveillance and early warning systems with integration of climatic information that promote enhanced understanding of the geographic distribution of disease risk. To enhance healthcare workforce capacity and capability to respond to these public health threats, medical curricula and continuing professional education programmes for healthcare providers must include evidence based components on the impacts of climate change on infectious diseases.

Role of vitamin E on bovine skeletal-muscle-derived cells from Korean native cattle under heat treatment.

Our study aimed to evaluate the dualistic effect of heat stress on muscle differentiation at different temperatures, and whether vitamin E, a powerful antioxidant, could offset any negative effects, using bovine skeletal-muscle-derived cells (BSMCs) with myogenic properties. The BSMCs were extracted from the skeletal muscle of 30-mo-old Korean native cattle and subjected to myogenic differentiation under 3 heat exposure conditions: 37 °C (control; CON), 39 °C (mild heat stress; MHS), and 41 °C (severe heat stress; SHS) for 24 h with or without vitamin E treatment (NE or VE). After 24 h treatments, the cells were returned to 37 °C incubators and differentiated until day 6. On day 1, because of the heat exposure, the gene expression of MYOG was the highest in MHS (P = 0.047), suggesting a promotive effect of mild heat stress on myogenic differentiation, while on day 6, compared with CON and MHS, MYOD (P = 0.013) and MYOG (P = 0.029) were the lowest in SHS. Vitamin E treatment also lowered MYOG (P = 0.097), regardless of heat exposure. On day 1, HSPB1 (P = 0.001) and HSP70 (P < 0.001) were the highest in SHS, and an interaction between heat exposure and vitamin E treatment was found on day 6 (P < 0.027). BCL-2 was also the highest on day 1 in SHS (P = 0.05), and an interaction of heat exposure and vitamin E treatment was found on day 1 on BAX expression (P = 0.038). For antioxidant genes, SOD1 (P = 0.002) and GPX1 (P < 0.001) were affected by heat exposure, with the highest levels being observed in SHS, and on day 6, GPX1 was still the highest in SHS (P = 0.027). The fusion index was also affected by heat exposure, showing a decrease in SHS and an increase in MHS compared with CON (P < 0.001). Significant effects were noted from heat exposure (P < 0.001), vitamin E treatment (P < 0.001), and the interaction of heat exposure and vitamin E treatment (P = 0.002) on the protein content. Taken together, our findings provide evidence that vitamin E could ameliorate the harmful effects of heat exposure by modulating heat shock proteins and apoptosis regulators, improving the protein synthesis of BSMCs during myogenic differentiation. These results suggest that vitamin E supplementation could potentially protect muscle development in beef cattle under summer heat stress.

Our research explored how heat affects muscle cell development and whether vitamin E could ameliorate any potential adverse effects on beef production. The study used muscle cells derived from 30-mo-old Korean native cattle. We conducted the experiments by exposing these cells to 3 different temperatures, 37 °C (CON), 39 °C (MHS), and 41 °C (SHS), for a day during myogenic differentiation and under different vitamin E treatments (NE or VE). After this heat exposure, all cells were kept under normal conditions for 6 d to observe differentiation and gene expression. Indicated by the increased expression of a myogenic gene (MYOG) and increased protein accumulation, we revealed that MHS helped the development of bovine skeletal-muscle-derived cells. However, SHS appeared to hinder muscle growth, reducing the levels of muscle-specific genes, MYOD and MYOG, compared with CON and MHS. Interestingly, vitamin E seemed to reduce the negative impact of heat by modulating heat-stress proteins (HSPB1 and HSP70) and the genes involved in cell death (BCL-2 and BAX). Additionally, cells under SHS showed the highest expression of antioxidant genes (SOD1 and GPX1). Taken together, these findings suggest that vitamin E could be beneficial in environments where cells are exposed to heat conditions, helping them to maintain better cellular function and growth.

Integrating observational and modelled data to advance the understanding of heat stress effects on pregnant subsistence farmers in the gambia.

Studies on the effect of heat stress on pregnant women are scarce, particularly in highly vulnerable populations. To support the risk assessment of pregnant subsistence farmers in the West Kiang district, The Gambia we conducted a study on the pathophysiological effects of extreme heat stress and assessed the applicability of heat stress indices. From ERA5 climate reanalysis we added location-specific modelled solar radiation to datasets of a previous observational cohort study involving on-site measurements of 92 women working in the heat. Associations between physiological and environmental variables were assessed through Pearson correlation coefficient analysis, mixed effect linear models with random intercepts per participant and confirmatory composite analysis. We found Pearson correlations between r-values of 0 and 0.54, as well as independent effects of environmental variables on skin- and tympanic temperature, but not on heart rate, within a confidence interval of 98%. Pregnant women experienced stronger pathophysiological effects from heat stress in their third rather than in their second trimester. Environmental heat stress significantly altered maternal heat strain, particularly under humid conditions above a 50% relative humidity threshold, demonstrating interactive effects. Based on our results, we recommend including heat stress indices (e.g. UTCI or WBGT) in local heat-health warning systems.

Impact of hot and cold nights on pneumonia hospitalisations in children under five years: Evidence from low-, middle-, and high-income countries.

BACKGROUND: Studies have shown that abnormal temperature at night is a risk factor for respiratory health. However, there is limited evidence on the impact of hot and cold nights on cause-specific diseases such as pneumonia, which is a leading cause of morbidity and mortality in children. METHODS: We collected daily data on pneumonia hospitalisations in children under five years from 2011 to 2017 in three low-, middle- and high-income countries (Bangladesh, China, and Australia). The intensity of hot and cold nights was measured by excess temperature. A space-time-stratified case-crossover analysis was used to estimate the association between hot and cold nights and childhood pneumonia hospitalisations. We further estimated the fraction of childhood pneumonia hospitalisations attributable to hot and cold nights. RESULTS: Both hot and cold nights were associated with an increased risk of hospitalisations for childhood pneumonia in low-, middle-, and high-income countries, with a greater disease burden from hot nights. Specifically, the fraction of childhood pneumonia attributable to hot nights was the largest in Australia [21.2%, 95% confidence interval (CI): 11.8%-28.1%], followed by Bangladesh (15.2%, 95% CI: 4.1%-23.8%) and China (2.7%, 95% CI: 0.4%-4.7%). Additionally, the fraction of childhood pneumonia attributable to cold nights was 1.3% (95% CI: 0.4%-2.0%) in Bangladesh and 0.4% (95% CI: 0.1%-0.7%) in China. CONCLUSION: This multi-country study suggests that hot and cold nights are not only associated with a higher risk of pneumonia hospitalisations in children but also responsible for substantial fraction of hospitalisations, with a greater impact from hot nights.

Health impact of urban green spaces: a systematic review of heat-related morbidity and mortality.

OBJECTIVES: The objective of this review was to scrutinise the impact of urban green spaces on heat-related morbidity and mortality. DESIGN: This systematic review was meticulously carried out following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines DATA SOURCES: A comprehensive search was conducted across PubMed, Scopus and Google Scholar including studies from January 2000 to December 2022. ELIGIBILITY CRITERIA: Studies that examined the influence of urban green spaces on heat-related morbidity and mortality, including randomised controlled trials, observational and modelling studies, were included. DATA EXTRACTION AND SYNTHESIS: A total of 3301 publications were initially identified, out of which 12 studies met the inclusion criteria and were selected for analysis. The selected studies were predominantly from high-income and upper-middle-income nations (95%). RESULTS: The research points towards a pattern where regions abundant in green spaces report lower rates of heat-related morbidity and mortality in contrast to those with sparse greenery. Additionally, urban vegetation appears to exert a positive influence on mental health and well-being, potentially aiding in offsetting the adverse health repercussions of high temperatures. CONCLUSION: Urban green spaces play a vital role in mitigating heat-related health risks, offering a potential strategy for urban planning to address climate change and enhance public health. Additional research is required to thoroughly comprehend the magnitude of urban greenery's impact on heat-related morbidity and mortality, as well as its interplay with other variables, including air pollution, socioeconomic status, among others.

Unbiased temperature-related mortality estimates using weekly and monthly health data: a new method for environmental epidemiology and climate impact studies.

BACKGROUND: Exposure to environmental factors has a high burden on human health, with millions of premature annual deaths associated with the short-term health effects of ambient temperatures and air pollution. However, direct estimations of exposure-related mortality from real data are still not available in most parts of the world, especially in low-resource settings, due to the unavailability of daily health records to calibrate epidemiological models. METHODS: In this study, we have filled the crucial gap in available direct estimations by developing a method to make valid inference for the relationship between exposure and response data that uses only exposure and temporally aggregated response data. We provided the mathematical derivation of the method, and compared the results by using simulations applied to daily temperature and daily, weekly, and monthly mortality data. The method was then applied to the newly created database of the EARLY-ADAPT project. FINDINGS: The daily and weekly models produced similar and unbiased estimates of the temperature-related relative risks and attributable mortality, with only slightly more imprecision in the weekly model. Even the estimates of the monthly model were unbiased when using enough data, although at the expense of a substantial increase in variability. The real data analysis showed that the similarity between the regional values of two aggregation models increased with the number of years and regions of the dataset, and decreased with the difference in their degree of temporal aggregation. INTERPRETATION: Our method opens the door to conducting epidemiological studies in low-resource settings, where access to daily health data is not possible. Moreover, it allows accurate estimation of the short-term health effects of environmental exposures in near-real time, when daily health data are still not available, such as in the estimation of the mortality burden of recent record-breaking heat episodes. Overall, our method represents an important new approach to how the public health community can use data to create new evidence for research, translation and policy making. FUNDING: European Research Council (ERC).

Risk and attributable fraction estimation for the impact of exposure to compound drought and hot events on daily stroke admissions.

BACKGROUND: The projection indicates that compound drought and hot events (CDHEs) will intensify, posing risks to cardiovascular health by potentially increasing stroke incidents. However, epidemiological evidence on this topic remains scarce. This study investigates the association between exposure to CDHEs and the risk of daily stroke admissions, specifically examining the effects on various stroke categories such as Subarachnoid Hemorrhage (SAH), Intracerebral Hemorrhage (ICH), Ischemic Stroke (IS), Transient Ischemic Attack (TIA), and other types of stroke. METHODS: Data on daily stroke admissions from 2010 to 2015 were obtained from the Urban Employee Basic Medical Insurance (UEBMI) and Urban Resident Basic Medical Insurance (URBMI) claims databases in Guangzhou, China. Hot events were identified as days when the daily mean temperature exceeded the 75th percentile during the warm season (May to October) over the study period. The Standardized Precipitation Evapotranspiration Index (SPEI) was utilized to identify drought conditions, with thresholds set at -1 and -1.5 for low-severity and high-severity drought events, respectively. Through a generalized additive model (GAM), we analyzed the cumulative effects of CDHE exposure on daily stroke admissions and calculated the Attributable Fraction (AF) related to CDHEs. RESULTS: The analysis included 179,963 stroke admission records. We observed a significant increase in stroke admission risks due to exposure to hot events coupled with high-severity drought conditions (RR = 1.18, 95%CI: 1.01-1.38), with IS being the most affected category (RR = 1.20, 95%CI: 1.03-1.40). The AF of total stroke admission attributed to hot events in conjunction with high-severity drought conditions was 24.40% (95%CI: 1.86%-50.20%). CONCLUSION: The combination of hot events with high-severity drought conditions is likely linked to an increased risk of stroke and IS admissions, which providing new insights into the impact of temperature and climate-related hazards on cardiovascular health.