Effects of extreme temperatures on years of life lost for cardiovascular deaths: a time series study in Brisbane, Australia

Stroke risk associated with cold spells occurring during the warm season

BACKGROUND

Recent climate changes have resulted in a rising frequency of extreme cold events that take place during the warm season. Few studies have investigated the impact of these warm-season cold spells on cardiovascular health. Here, we aimed to investigate the potential relationship between exposure to relatively low temperature exposure during the warm season and stroke risk.

METHODS

We conducted a time-stratified case-crossover study using a validated, complete, and detailed registration of all stroke cases in the city of Augsburg, Germany, from 2006 to 2020 to assess the association between the occurrence of stroke and exposure to cold spell events during the warm season (May-October). Six cold spell definitions were created using different relative temperature thresholds (1st, 2.5th, and 5th percentiles) and durations (more than 1-2 consecutive days). Conditional logistic regression with distributed lag models was then applied to assess the accumulated effects of these warm-season cold spells on stroke risk over a lag period of 0-6 days, with adjustments for daily mean temperature.

RESULTS

Results confirmed that warm-season cold spells were significantly linked to an elevated risk of stroke with effects that could persist three days after exposure. The cumulative odds ratio (OR) estimates for the cold spells using the 2.5th percentile as air temperature threshold reached 1.29 (95% confidence interval (CI): 1.09-1.53) and 1.23 (95%CI: 1.05-1.44) for durations more than one and two days, respectively. Warm-season cold spells also had significant associations with both transient ischemic attacks and ischemic strokes. The stratified analysis showed that the elderly population (aged ≥ 65 years), females, and stroke cases characterized by minor symptoms demonstrated a significantly increased stroke risk of the effects of warm season cold spells.

CONCLUSIONS

This study presents strong evidence for an overlooked association between warm-season cold spells and an increased risk of stroke occurrence. These findings further highlight the multifaceted ways in which climate change can affect human health.

Effect of PM2.5 and its constituents on hospital admissions for cardiometabolic multimorbidity in Urumqi, China

Cardiometabolic multimorbidity (CMM) is caused by two or more of the diseases ischemic heart disease (CVD), type 2 diabetes mellitus (T2DM), and stroke, and therefore requires more hospitalization and healthcare costs. However, few studies have investigated fine particulate matter (PM2.5) and its constituents and the risk of hospital admissions for CMM. We aimed to study these associations in Urumqi, a representative area in northwest China. The effect of PM2.5 and its constituents on the hospital admissions for CMM was determined using the quantile-based g-computation (QBGC) and bayesian kernel machine regression (BKMR) method, in which the constituents with the greatest effect on the hospital admissions for CMM were ranked as NO3- > SO42- > NH4+ > BC > OM. Among all constituents, NO3- presented the highest risk, with the largest effect observed at lag 21-day at the maximum concentration (RR = 2.079, 95% CI: 1.396-3.097). Per IQR increase in NO3- had the significantly effect on hospital admissions for IHD (RR = 1.079, 95% CI: 1.028-1.132) and on hospital admissions for CMM (RR = 1.094, 95% CI: 1.039-1.152). Female patients hospitalized for CMM indicated heightened sensitivity to elevated NO3- levels (RR = 1.170, 95% CI: 1.077-1.271). The interaction between the high concentrations of PM2.5 and its constituents with low temperature, high relative humidity (RH), and low sunshine duration (SSD) significantly affected hospital admissions for CMM. Additionally, cold waves, defined as the minimum temperature of below P2.5 and sustained for 5 days (CW5), intensified the interaction with PM2.5 and its constituents.

Effect of various temperature indicators on patients' hospitalization with cardiovascular diseases in Zhangye city, China

This study assessed the impact of various temperature indices, including mean temperature (MT), diurnal temperature range (DTR), and temperature changes between neighboring days (TCN) on hospitalization rates for cardiovascular system diseases among residents of Zhangye City, a typical western city in China. The Quasi-Poisson generalized additive regression model (GAM) in conjunction with a distributed lag nonlinear model (DLNM) was applied to estimate the association of temperature indices with CVD hospitalization rates in Zhangye City during the periods of 2015-2021. The exposure-response relationship and relative risk were discussed and stratified analyses by age and gender were conducted. We found that the hospitalization rates of cardiovascular disease (CVD) patients in Zhangye City was significantly related to different temperature indicators (MT, DTR, TCN). Both low and high MT, DTR, and TCN increased the risk of cardiovascular disease (CVD) among residents. Besides, different demographic populations exhibited distinct sensitivities to temperature conditions. Relevant authorities should devise corresponding preventive and control measures to protect vulnerable populations.

Global, regional, and national burden of childhood cardiovascular disease: trends from 1990 to 2021

Background

Childhood cardiovascular disease (CVD) is an emerging public health concern, with rising incidence linked to obesity and diabetes. Despite advancements in care, significant disparities persist across regions and socioeconomic groups. This study analyzed the global, regional, and national burden of childhood CVD from 1990 to 2021.

Methods

A cross-sectional study utilizing data from the Global Burden of Disease (GBD) 2021 was conducted. We analyzed children aged 0-14 years, categorizing them into age groups and assessing trends in incidence, mortality, and disability-adjusted life years (DALYs) across 204 countries. Statistical analyses included linear regression to calculate estimated annual percentage changes and assess temporal trends.

Results

The study revealed a 25% global increase in childhood CVD incidence over three decades, with significant disparities observed across different socioeconomic regions. Mortality and DALYs associated with CVD had decreased globally by 59% and 55% respectively, reflecting advances in medical technology and healthcare access. However, these improvements were not uniformly distributed, with low socio-demographic index regions exhibiting both the highest incidences and slowest declines in CVD-related health burdens. Environmental risks, such as extreme temperatures, also contributed to CVD mortality.

Conclusions

While mortality and DALYs due to childhood CVD have declined globally, rising incidence and persistent disparities highlight the need for targeted interventions. Addressing socio-economic factors and enhancing access to quality care are crucial for reducing the global burden of childhood CVD.

The effect of foot immersion and neck cooling on cardiac autonomic function in older adults exposed to indoor overheating: a randomized crossover trial

Foot immersion and neck cooling are recommended cooling strategies for protecting heat-vulnerable persons during heat waves. While we recently showed that these strategies do not limit core temperature increases in older adults during prolonged heat exposure, we did observe small reductions in heart rate. Expanding on these findings, we examined the effects of foot immersion with and without neck cooling on cardiac autonomic function. Seventeen adults (9 females; 65-81 years) underwent 3 randomized, 6 h exposures to 38 °C and 35% relative humidity with: no cooling (control), foot immersion (20 °C water), or foot immersion with a wet towel (20 °C) around the neck. Cardiac autonomic responses were measured at baseline and end-exposure. These included heart rate variability, cardiac and systolic blood pressure responses to standing, indexed via the 30:15 ratio and supine-to-standing systolic pressure change, respectively, and baroreflex sensitivity during repeated sit-to-stand maneuvers. The 30:15 ratio was 0.04 [95% CI: 0.01, 0.07] greater with foot immersion and neck cooling (1.08 (SD: 0.04)) relative to control (1.04 (0.06); P = 0.018). Similarly, standing systolic blood pressure was elevated 9 [0, 17] mmHg with foot immersion and neck cooling (P = 0.043). That said, neither difference remained statistically significant after adjusting for multiplicity (Padjusted ≥ 0.054). No differences in 30:15 ratio or standing systolic blood pressure were observed with foot immersion alone, while heart rate variability and baroreflex sensitivity were unaffected by either cooling intervention. While foot immersion with neck cooling potentially improved cardiac autonomic responses in older adults exposed to simulated indoor overheating, these effects were small and of questionable clinical importance.

Potential mechanisms of ischemic stroke induced by heat exposure

Recent decades of epidemiological and clinical research have suggested that heat exposure could be a potential risk factor for ischemic stroke. Despite climate factors having a minor impact on individuals compared with established risk factors such as smoking, their widespread and persistent effects significantly affect public health. The mechanisms by which heat exposure triggers ischemic stroke are currently unclear. However, several potential mechanisms, such as the impact of temperature variability on stroke risk factors, inflammation, oxidative stress, and coagulation system changes, have been proposed. This article details the potential mechanisms by which heat exposure may induce ischemic stroke, aiming to guide the prevention and treatment of high-risk groups in hot climates and support public health policy development.

The effect of temperature on infectious diarrhea disease: A systematic review

This study aimed to ascertain the delayed effects of various exposure temperatures on infectious diarrhea. We performed a Bayesian random-effects network meta-analysis to calculate relative risks (RR) with 95 % confidence intervals (95 % CI). The heterogeneity was analyzed by subgroup analysis. There were 25 cross-sectional studies totaling 6858735 patients included in this analysis, with 12 articles each investigating the effects of both hyperthermia and hypothermia. Results revealed that both high temperature (RRsingle = 1.22, 95%CI:1.04-1.44, RRcum = 2.96, 95%CI:1.60-5.48, P < 0.05) and low temperature (RRsingle = 1.17, 95%CI:1.02-1.37, RRcum = 2.19, 95%CI:1.33-3.64, P < 0.05) significantly increased the risk of infectious diarrhea, while high temperature caused greater. As-sociations with strengthening in bacillary dysentery were found for high temperatures (RRcum = 2.03, 95%CI:1.41-3.01, P < 0.05; RRsingle = 1.17, 95%CI:0.90-1.62, P > 0.05), while the statistical significance of low temperatures in lowering bacterial dysentery had vanished. This investigation examined that high temperature and low temperature were the conditions that posed the greatest risk for infectious diarrhea. This research offers fresh perspectives on preventing infectious diarrhea and will hopefully enlighten future studies on the impact of temperature management on infectious diarrhea.

Intensification of compound temperature extremes by rapid urbanization under static and dynamic Urban-rural division: A comparative case study in Hunan Province, Central-South China

Climate extremes, notably compound extremes, pose significant risks to human society and environmental systems. These extremes, heightened by urbanization-a hallmark of modern socioeconomic progression-inflict persistent, intense thermal conditions. The comprehension of urbanization's impact on compound temperature extremes, particularly in Central-South China, a region with rapid urbanization and a subtropical climate, remains limited. In addition, most existing studies relied on static urban-rural division, and few used dynamic division, with no research yet juxtaposing findings from both methods. Against this backdrop, this study provided an unprecedented assessment of urbanization's impact on both individual and compound temperature extremes in Central South China, focusing on Hunan Province during long-time period of 1960-2022 under both static and dynamic urban-rural divisions. In both urban and rural stations, a pronounced warming trend was evident across individual and compound temperature extremes. Besides, a tendency of independent day/night extremes shifting towards extremes spanning both was observed. Notably, the escalation of heat compound extreme temperature indices (ETIs) outpaces that of cold ones, with a larger urban-rural discrepancy under dynamic classifications. Urbanization intensifies temperature extremes, particularly affecting the reduction of independent cold days (30.97 %-33.94 %) and the increase in compound hot events (23.91 %-24.87 %). Interestingly, urbanization's impact is more substantial on independent daytime extremes than on independent nighttime ones. Urbanization's influence on ETIs was consistently observed under both static and dynamic classifications, with the latter revealing a more pronounced contribution (1 %-3 %), and the contribution to compound ETIs is 6 %-8 % higher than to individual ETIs. These findings emphasize the importance of considering urbanization's multifaceted impacts on climate strategies and underscore the need for adaptive infrastructure and sustainable practices to mitigate escalating climate risks.

Unraveling the link: exploring the effects of environmental change on the cardiovascular system

Climate change has a particularly detrimental effect on the cardiovascular system, which is highly vulnerable to harmful impacts. The accumulation of particulate matter (PM) and greenhouse gasses in the environment negatively impacts the cardiovascular system through several mechanisms. The burden of climate change-related diseases falls disproportionately on vulnerable populations, including the elderly, the poor, and those with pre-existing health conditions. A key component of addressing the complex interplay between climate change and cardiovascular diseases is acknowledging health disparities among vulnerable populations resulting from climate change, familiarizing themselves with strategies for adapting to changing conditions, educating patients about climate-related cardiovascular risks, and advocating for policies that promote cleaner environments and sustainable practices.

The Impacts of Heat Waves on Hospital Admissions and Mortality in the Fethiye Province of Turkey

tHeat waves (HWs) are one of the most important atmospheric events that negatively affect human health. In this study, HWs which occurred between May 1 and September 30, 2019 in Fethiye Province (SW Turkey) were investigated for their effects on human health. For this purpose, as a first step, percentile-based threshold criteria and at least three consecutive days' methodology were applied to the daily maximum temperatures to identify HWs. Using these criteria, a total of 3 HWs (HW 1, HW 2, and HW 3) with lengths of 6, 7, and 5 days, respectively, were found in 2019. In statistical analyses, hospital data recorded on HW days (including the 3 lag days) on reference days were compared using the logarithmic Z test method. Hospital data between May 1 and September 30 in the 5 years between 2014 and 2018 were used as reference data. As a result, in the 3 HWs that occurred in 2019, the risk ratios (RRs) and their confidence intervals in HW 1, HW 2, and HW 3 at hospital admissions were 1.09 (95% CI: 1.06-1.12), 1.11 (95% CI: 1.08-1.14), and 1.13 (95% CI: 1.09-1.16), (p < 0.05), respectively. When the effect of HW on death was examined, the RR values and confidence intervals in HW 1, HW 2, and HW 3 were 1.90 (95% CI: 1.04-3.46), 1.96 (95% CI: 1.03-3.75), and 2.18 (95% CI: 1.13-4.20), (p < 0.005), respectively. As a result, it was found that a total of 22 extra deaths occurred when three HWs were recorded in 2019. When the deaths were analysed by age, it was seen that the most affected group was the elderly (≥65 years), accounting for 82% of deaths. It was determined that 64% of the deaths were male, and 36% were female. These results show that HWs in Fethiye are an important natural disaster that negatively affects human health.

Cold Spells and the Onset of Acute Myocardial Infarction: A Nationwide Case-Crossover Study in 323 Chinese Cities

BACKGROUND

Few studies have explored the relationships between cold spells and acute myocardial infarction (AMI) using the information of symptom onset.

OBJECTIVES

We assessed the impact of cold spells on AMI onset and the potential effect modifiers.

METHODS

We conducted a time-stratified case-crossover study among 456,051 eligible patients with AMI from 2,054 hospitals in 323 Chinese cities between January 2015 and June 2021 during cold seasons (November to March). Nine definitions of cold spells were used by combining three relative temperature thresholds (i.e., lower than the 7.5th, 5th, and 2.5th percentiles) and three durations of at least 2-4 consecutive d. Conditional logistic regressions with distributed lag models were applied to evaluate the cumulated effects of cold spells on AMI onset over lags 0-6 d, after adjusting for daily mean temperature.

RESULTS

The associations generally appeared on lag 1 d, peaked on lag 3 d, and became nonsignificant approximately on lag 5 d. Cold spells defined by more stringent thresholds of temperature were associated with higher risks of AMI onset. For cold spell days defined by a daily mean temperature of ≤ 7.5 th percentile and durations of ≥ 2 d , ≥ 3 d , and ≥ 4 d , the percentage changes in AMI risk were 4.24% [95% confidence interval (CI): 2.31%, 6.20%], 3.48% (95% CI: 1.62%, 5.38%), and 2.82% (95% CI: 0.98%, 4.70%), respectively. Significant AMI risks associated with cold spells were observed among cases from regions without centralized heating, whereas null or much weaker risks were found among those from regions with centralized heating. Patients ≥ 65 years of age were more susceptible to cold spells.

DISCUSSION

This national case-crossover study presents compelling evidence that cold spells could significantly increase the risk of AMI onset. https://doi.org/10.1289/EHP11841.

The effects of heatwaves on hospital admissions in the Edirne province of Turkey: A cohort study

Studies show that heat waves (HWs) are among the most important atmospheric phenomena that negatively affect human health. This study aims to determine the effects of HWs on hospital admissions (HA) in the Edirne province of Turkey. Polyclinic admission and atmospheric data, including daily maximum temperatures, were used. HW is defined as temperature at the % 90 threshold of daily maximum temperatures that persists for at least 3 consecutive days or more. With this definition, a 6-day HW was detected, and a lag of 3 days was added to this HW. Logarithmic Z test was used for the analysis. As a result of the study, The Risk Ratio (RR) showing the relationship between 9-day HW and HAs was calculated as 1.19 (95% confident interval [CI]: 1.17-1.21, P < .05), and it was determined that there were 2557 extra HAs in total. When HAs were analyzed according to sex, it was observed that female admissions were higher than male admissions. To analyze admissions by age, the data were divided into 3 groups: children (<15 years), adult (15-64 years), and elderly (≥65 years). As a result of the analysis, the highest increase was observed in patients < 15 years of age, and the RR was 1.33 (95% CI: 1.24-1.42 P < .05). When the patient density in polyclinics was analyzed, the Cardiology polyclinic had the highest number of patient admissions with an RR, 1.36 (95% CI: 1.30-1.43 P < .05). The results of this study will guide measures to be taken against HWs.

Extreme temperatures and circulatory mortality in a temperate continental monsoon climate city in Northeast China

Epidemiological studies have proven that extreme temperatures have a significant threat to public health. This study aimed to investigate the association between extreme temperatures and circulatory mortality from January 1, 2014, to December 31, 2016, in Harbin, a city with a cold climate in Northeast China. We set a maximum lag of 27 days to evaluate the hysteresis effects of different temperatures on circulatory mortality using a distributed lag nonlinear model (DLNM). Results indicated that daily mean temperature and circulatory mortality presented approximately an L-shaped, and the cumulative relative risks (RRs) decreased continuously as the temperature increased in both low and high temperatures. Extremely low temperature showed a hysteresis and durability on circulatory mortality, with the largest RR of 1.023 (95%CI: 1.001-1.046) at lag 26, and RR of the cumulative cold effect of 0-27 days was 1.302 (95%CI: 1.160-1.462). The effect of extremely high temperatures presented more acute and intense, with the largest RR of 1.033 (95%CI: 1.004-1.063) at lag 0. RR of the cumulative hot effect of 0-3 days was 1.056 (1.008-1.106). In addition, females were more susceptible to extremely low temperatures, while males were more vulnerable to extremely high temperatures. This study demonstrated that extremely low temperatures have a stronger effect on circulatory mortality than extremely high temperatures in Harbin.

Mortality burden attributable to temperature variability in China

BACKGROUND

Several studies have investigated the associations between temperature variability (TV) and death counts. However, evidence of TV-attributable years of life lost (YLL) is scarce.

OBJECTIVES

To investigate the associations between TV and YLL rates (/100,000 population), and quantify average life loss per death (LLD) caused by TV in China.

METHODS

We calculated daily YLL rates (/100,000 population) of non-accidental causes and cardiorespiratory diseases by using death data from 364 counties of China during 2006-2017, and collected meteorological data during the same period. A distributed lag non-linear model (DLNM) and multivariate meta-analysis were used to estimate the effects of TV at national or regional levels. Then, we calculated the LLD to quantify the mortality burden of TV.

RESULTS

U-shaped curves were observed in the associations of YLL rates with TV in China. The minimum YLL TV (MYTV) was 2.5 °C nationwide. An average of 0.89 LLD was attributable to TV in total, most of which was from high TV (0.86, 95% CI: 0.56, 1.16). However, TV caused more LLD in the young (<65 years old) (1.87, 95% CI: 1.03, 2.71) than 65-74 years old (0.85, 95% CI: 0.40-1.31) and ≥75 years old (0.40, 95% CI: 0.21-0.59), cerebrovascular disease (0.74, 95% CI: 0.36, 1.11) than respiratory disease (0.54, 95% CI: 0.21, 0.87), South (1.23, 95% CI: 0.77, 1.68) than North (0.41, 95% CI: -0.7, 1.52) and Central China (0.40, 95% CI: -0.02, 0.81). TV-attributed LLD was modified by annual mean temperature, annual mean relative humidity, altitude, latitude, longitude, and education attainment.

SIGNIFICANCE

Our findings indicate that high and low TVs are both associated with increases in premature death, however the majority of LLD was attributable to high TV. TV-related LLD was modified by county level characteristics. TV should be considered in planning adaptation to climate change or variability.

IMPACT

(1) We estimated the associations of TV with YLL rates, and quantified the life loss per death (LLD) caused by TV. (2) An average of 0.89 years of LLD were attributable to TV, most of which were from high TVs. (3) TV caused more LLD in the young, cerebrovascular disease, and southern China. (4) The mortality burdens were modified by county level characteristics.

Associations of climate variability driven by El Niño-southern oscillation with excess mortality and related medical costs in Chinese elderly

Climate variability driven by El Niño-Southern Oscillation (ENSO) is a significant public health concern in parallel with global population aging; however, its role in healthy aging is less studied. We examined the longitudinal impacts of ENSO exposure on excess mortality and related medical costs in the elderly from 23 provinces of China. A total of 27,533 non-accidental all-cause deaths were recorded in 30,763 participants during 1998-2018. We found that both low and high levels of ENSO metrics over lags of 0-12 months were associated with increased mortality risks. Specifically, comparing the 10th percentile (-1.8) and 90th percentile (2.0) multivariate El Niño index (MEI) levels to the reference level with the minimum effect of MEI exposure, the risk of mortality was 1.87 (95 % confidence interval [CI], 1.75, 2.00) and 4.89 (95 % CI, 4.36, 5.49), respectively. ENSO exposure was also positively related to medical costs. Further, the associations were stronger among drinkers, lower-income participants, and those with higher blood pressure and heart rate measured at the most recent follow-ups. Our results suggested that ENSO exposure was capable of heightening mortality risks and medical burden among older elderly adults, highlighting that climate variability driven by ENSO could be a crucial determinant of healthy aging.

Climate change and cardiovascular disease: implications for global health

Climate change is the greatest existential challenge to planetary and human health and is dictated by a shift in the Earth's weather and air conditions owing to anthropogenic activity. Climate change has resulted not only in extreme temperatures, but also in an increase in the frequency of droughts, wildfires, dust storms, coastal flooding, storm surges and hurricanes, as well as multiple compound and cascading events. The interactions between climate change and health outcomes are diverse and complex and include several exposure pathways that might promote the development of non-communicable diseases such as cardiovascular disease. A collaborative approach is needed to solve this climate crisis, whereby medical professionals, scientific researchers, public health officials and policymakers should work together to mitigate and limit the consequences of global warming. In this Review, we aim to provide an overview of the consequences of climate change on cardiovascular health, which result from direct exposure pathways, such as shifts in ambient temperature, air pollution, forest fires, desert (dust and sand) storms and extreme weather events. We also describe the populations that are most susceptible to the health effects caused by climate change and propose potential mitigation strategies, with an emphasis on collaboration at the scientific, governmental and policy levels.

Effect of ambient temperature and other environmental factors on stroke emergency department visits in Beijing: A distributed lag non-linear model

Background

Most studies have focused on the relationship between ambient temperature and stroke mortality, but studies on the relationship between ambient temperature and stroke occurrence are still limited and inconsistent.

Objective

This study aimed to analyze the effect of ambient temperature and other environmental factors on emergency stroke visits in Beijing.

Methods

Our study utilized stroke visit data from the Beijing Red Cross Emergency Medical Center during 2017-2018, and applied a generalized additive model (GAM) as well as a distributed lag non-linear model (DLNM), respectively, regarding the direct, lagged, and cumulative effects of ambient temperature alone and with correction for other environmental factors on stroke occurrence.

Results

With a total of 26,984 emergency stroke patients in 2017-2018, both cold and hot effects were observed and weakened after correction for other environmental factors. Compared to the reference temperature, in the multi-factor model, extreme cold (-10°C) reached a maximum relative risk (RR) of 1.20 [95% Confidence Interval (CI): 1.09, 1.32] at lag 14 days, and extreme hot (30°C) had a maximum RR of 1.07 (95% CI: 1.04, 1.11) at lag 6 days. The cumulative effect of extreme cold reached a maximum of 2.02 (95% CI: 1.11, 3.67) at lag 0-14 days, whereas the cumulative effect of extreme hot temperature is greatest at lag 0-10 days, but no statistically significant effect was found. In addition, ischemic stroke patients, the elderly, and males were more susceptible to the effects of cold temperature.

Conclusions

There is a non-linear relationship between ambient temperature and stroke occurrence, with cold temperature having a greater and longer-lasting impact than hot temperature.

Effects of daily mean temperature and other meteorological variables on bacillary dysentery in Beijing-Tianjin-Hebei region, China

Background

Although previous studies have shown that meteorological factors such as temperature are related to the incidence of bacillary dysentery (BD), researches about the non-linear and interaction effect among meteorological variables remain limited. The objective of this study was to analyze the effects of temperature and other meteorological variables on BD in Beijing-Tianjin-Hebei region, which is a high-risk area for BD distribution.

Methods

Our study was based on the daily-scale data of BD cases and meteorological variables from 2014 to 2019, using generalized additive model (GAM) to explore the relationship between meteorological variables and BD cases and distributed lag non-linear model (DLNM) to analyze the lag and cumulative effects. The interaction effects and stratified analysis were developed by the GAM.

Results

A total of 147,001 cases were reported from 2014 to 2019. The relationship between temperature and BD was approximately liner above 0 °C, but the turning point of total temperature effect was 10 °C. Results of DLNM indicated that the effect of high temperature was significant on lag 5d and lag 6d, and the lag effect showed that each 5 °C rise caused a 3% [Relative risk (RR) = 1.03, 95% Confidence interval (CI): 1.02–1.05] increase in BD cases. The cumulative BD cases delayed by 7 days increased by 31% for each 5 °C rise in temperature above 10 °C (RR = 1.31, 95% CI: 1.30–1.33). The interaction effects and stratified analysis manifested that the incidence of BD was highest in hot and humid climates.

Conclusions

This study suggests that temperature can significantly affect the incidence of BD, and its effect can be enhanced by humidity and precipitation, which means that the hot and humid environment positively increases the incidence of BD.

Supplementary information

The online version contains supplementary material available at https://doi.org/10.1265/ehpm.21-00005.

The effects of extreme temperatures on emergency room visits-a population-based analysis by age, sex, and comorbidity

This study evaluated the effect of extreme temperatures on events requiring emergency room visits (ERVs) for hypertensive disease, ischemic heart disease (IHD), cerebrovascular disease, and chronic kidney disease (CKD) for population stratified by sex and age living in Taiwan's metropolitan city from 2000 to 2014. The distributed lag non-linear model was adopted to examine the association between ambient temperature and area-age-sex-disease-specific ERVs for a population aged 40 years and above. The reference temperature was defined by a percentile value to describe the temperature in each city. Area-age-sex-disease-specific relative risk (RR) and 95% confidence intervals (CI) were estimated in association with extreme high (99th percentile) and low (5th percentile) temperatures. Temperature-related ERV risks varied by area, age, sex, and disease. Patients with CKD tend to have comorbidities with hypertensive disease. All study populations with hypertensive disease have significant risk associations with extreme low temperatures with the highest RR of 2.64 (95% CI: 2.08, 3.36) appearing in New Taipei City. The risk of IHD was significantly associated with extreme high temperature for male subpopulation aged 40-64 years. A less significant association was observed between the risks of cerebrovascular disease with extreme temperature. The risk of CKD was most significantly associated with extreme high temperature especially for a subpopulation aged 40-64 years. All study subpopulations with hypertensive disease have significant risk associations with extreme low temperature. Male subpopulations were more vulnerable to extreme temperatures, especially for those aged 40-64 years.

Temperature-sensitive morbidity indicator: consequence from the increased ambulance dispatches associated with heat and cold exposure

Current development of temperature-related health early warning systems mainly arises from knowledge of temperature-related mortality or hospital-based morbidity. However, due to the delay in data reporting and limits in hospital capacity, these indicators cannot be used in health risk assessments timely. In this study, we examine temperature impacts on emergency ambulance and discuss the benefits of using this near real-time indicator for risk assessment and early warning. We collected ambulance dispatch data recording individual characteristics and preliminary diagnoses between 2015 and 2016 in Shenzhen, China. Distributed lag nonlinear model was used to examine the effects of high and low temperatures on ambulance dispatches during warm and cold seasons. Lag effects were also assessed to evaluate the sensitivity of ambulance dispatches in reflecting immediate health reactions. Stratified analyses by gender, age, and a wide range of diagnoses were performed to identify vulnerable subgroups. Disease-specific numbers of ambulance dispatches attributable to non-optimal temperature were calculated to determine the related medical burdens. Effects of temperature on ambulance dispatches appeared to be acute on the current day. Males, people aged 18-44 years, were more susceptible to non-optimal temperatures. Highest RR during heat exposure by far was for urinary disease, alcohol intoxication, and traumatic injury, while alcohol intoxication and cardiovascular disease were especially sensitive to cold exposure, causing the main part of health burden. The development of local health surveillance systems by utilizing ambulance dispatch data are important for temperature impact assessments and medical resource reallocation.

Revised road traffic safety law and years of life lost due to traffic deaths in China, 2002-2019

Legal intervention is a powerful tool to reduce road traffic injuries (RTIs). China amended the Road Traffic Safety Law in 2011, but the impact of amended law on traffic crash deaths is still unknown. In this study, we conducted an interrupted time series analysis and examined years of life lost (YLLs) per 100,000 population as the assessment indicator to evaluate the association of road traffic safety law and traffic crash mortality. Annual YLLs data due to traffic deaths from 2002 to 2019 in China were obtained from the Global Burden of Disease (GBD) 2019. After implementation of the revised law, the average level of total YLLs per 100,000 population due to traffic deaths decreased from 1133.14 to 848.87, and the slope of annual YLLs per 100,000 population decreased by 30.11 (95% CI: 22.46, 37.75), indicating a steeper downward trend. The revised traffic law was associated with YLLs reduction due to traffic deaths for males, females, all age groups, pedestrians, motor vehicle users, and other road users, as well as traffic deaths attributed to alcohol use and tobacco use. These findings suggested that the revised Road Traffic Safety Law improved road safety by decreasing YLLs due to traffic deaths in China. However, the burden of RTIs is still heavy and efforts to further improve traffic laws and the adoption of other interventions are urgently needed.

Low ambient temperature shortened life expectancy in Hong Kong: A time-series analysis of 1.4 million years of life lost from cardiorespiratory diseases

Ambient temperature is an important contributor to mortality burden worldwide, most of which is from cold exposure. However, little is known about the cold impact on life expectancy loss. This paper aimed to estimate cold-related life expectancy loss from cause-, age-, and gender-specific cardiovascular and respiratory diseases. Daily deaths from cardiovascular and respiratory diseases and weather records were acquired for Hong Kong, China during 2000-2016. Years of life lost (YLL) that considers life expectancy at the time of death was calculated by matching each death by age and sex to annual life tables. Using a generalized additive model that fits temperature-YLL association, we estimated loss of years in life expectancy from cold. Cold was estimated to cause life expectancy loss of 0.9 years in total cardiovascular disease, with more years of loss in males than in females and in people aged 65 years and older than in people aged up to 64 years. Cold-related life expectancy loss in total respiratory diseases was 1.2 years, with more years of loss in females than in males and comparable years of loss in people aged up to 64 years and in people aged 65 years and older. Among cause-specific diseases, we observed the greatest life expectancy loss in pneumonia (1.5 years), followed by ischaemic heart disease (1.2 years), COPD (1.1 years), and stroke (0.3 years). Between two periods of 2000-2007 and 2008-2016, cold-related life expectancy loss due to cardiovascular disease did not decrease and cold-related life expectancy loss due to respiratory disease even increased by five times. Our findings suggest an urgent need to develop prevention measures against adverse cold effects on cardiorespiratory disease in Hong Kong.

Mortality and morbidity of asthma and chronic obstructive pulmonary disease associated with ambient environment in metropolitans in Taiwan

Background

This study investigated risks of mortality from and morbidity (emergency room visits (ERVs) and outpatient visits) of asthma and chronic obstructive pulmonary disease (COPD) associated with extreme temperatures, fine particulate matter (PM_2.5), and ozone (O₃) by sex, and age, from 2005 to 2016 in 6 metropolitan cities in Taiwan.

Methods

The distributed lag non-linear model was employed to assess age (0–18, 19–39, 40–64, and 65 years and above), sex-cause-specific deaths, ERVs, and outpatient visits associated with extreme high (99^th percentile) and low (5^th percentile) temperatures and PM_2.5 and O₃ concentrations at 90^th percentile. Random-effects meta-analysis was adopted to investigate cause-specific pooled relative risk (RR) and 95% confidence intervals (CI) for the whole studied areas.

Results

Only the mortality risk of COPD in the elderly men was significantly associated with the extreme low temperatures. Exposure to the 90^th percentile PM_2.5 was associated with outpatient visits for asthma in 0–18 years old boys [RR = 1.15 (95% CI: 1.09–1.22)]. Meanwhile, significant elevation of ERVs of asthma for females aged 40–64 years was associated with exposure to ozone, with the highest RR of 1.21 (95% CI: 1.05–1.39).

Conclusions

This study identified vulnerable subpopulations who were at risk to extreme events associated with ambient environments deserving further evaluation for adaptation.

The Mortality Effect of Apparent Temperature: A Multi-City Study in Asia

(1) Background: The health effect of temperature has become a rising public health topic. The objective of this study is to assess the association between apparent temperature and non-accidental deaths, and the mortality burden attributed to cold and heat temperature; (2) Methods: The daily data on temperature and deaths were collected from 10 cities in Thailand, Korea and China. We fitted a time-series regression with a distributed lag nonlinear model (DLNM) to derive the health risk of temperature for each city and then pooled them to get the overall cumulative risk by multivariate meta-analysis. Additionally, we calculated the attributable fraction of deaths for heat and cold, which was defined as temperatures above and below minimum-mortality temperature (MMT); (3) Results: There are regional heterogeneities in the minimum mortality percentiles (MMP) and attributable fractions for different countries. The MMP varied from about the 5-10th percentile in Thailand to 63-93rd percentile in China and Korea. The attributable fractions of the total deaths due to short-term exposure to temperature in Asia is 7.62%, of which the cold effect (6.44%) is much higher than the heat effect (1.18%); (4) Conclusions: Our study suggested that apparent temperature was associated with an increase in non-accidental mortality. Most of the temperature-related mortality burden was attributable to cold, except for Thailand.

Metabolic consequences of obesity and type 2 diabetes: Balancing genes and environment for personalized care

The prevalence of type 2 diabetes and obesity has risen dramatically for decades and is expected to rise further, secondary to the growing aging, sedentary population. The strain on global health care is projected to be colossal. This review explores the latest work and emerging ideas related to genetic and environmental factors influencing metabolism. Translational research and clinical applications, including the impact of the COVID-19 pandemic, are highlighted. Looking forward, strategies to personalize all aspects of prevention, management and care are necessary to improve health outcomes and reduce the impact of these metabolic diseases.

Ambient Temperature and Years of Life Lost: A National Study in China

Although numerous studies have investigated premature deaths attributable to temperature, effects of temperature on years of life lost (YLL) remain unclear. We estimated the relationship between temperatures and YLL, and quantified the YLL per death caused by temperature in China. We collected daily meteorological and mortality data, and calculated the daily YLL values for 364 locations (2013–2017 in Yunnan, Guangdong, Hunan, Zhejiang, and Jilin provinces, and 2006–2011 in other locations) in China. A time-series design with a distributed lag nonlinear model was first employed to estimate the location-specific associations between temperature and YLL rates (YLL/100,000 population), and a multivariate meta-analysis model was used to pool location-specific associations. Then, YLL per death caused by temperatures was calculated. The temperature and YLL rates consistently showed U-shaped associations. A mean of 1.02 (95% confidence interval: 0.67, 1.37) YLL per death was attributable to temperature. Cold temperature caused 0.98 YLL per death with most from moderate cold (0.84). The mean YLL per death was higher in those with cardiovascular diseases (1.14), males (1.15), younger age categories (1.31 in people aged 65–74 years), and in central China (1.34) than in those with respiratory diseases (0.47), females (0.87), older people (0.85 in people ≥75 years old), and northern China (0.64) or southern China (1.19). The mortality burden was modified by annual temperature and temperature variability, relative humidity, latitude, longitude, altitude, education attainment, and central heating use. Temperatures caused substantial YLL per death in China, which was modified by demographic and regional characteristics.

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Years of life lost (YLL) is used to estimate the effects of temperature

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Both low and high temperatures can increase the YLLs

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Average 1.02 YLL per death is attributed to temperature exposure

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Temperature causes larger YLLs per death in males, younger people, and central China

Associations of extreme temperatures with hospitalizations and post-discharge deaths for stroke: What is the role of pre-existing hyperlipidemia?

BACKGROUND

Existing evidence has suggested that heat exposure was associated with increase of low-density lipoprotein (LDL) and decrease of high-density lipoprotein (HDL). This study aimed to assess the effects of extreme temperatures (i.e., heat and cold) on hospitalizations and post-discharge deaths for stroke amongst individuals with and without pre-existing hyperlipidemia, and examine whether individual- and community-level characteristics modified the temperature-stroke relationship.

METHODS

People who were hospitalized for stroke from 1^st January 2005 to 31^st December 2013 in Brisbane, Australia, and died from stroke within two months after discharge were included in this cohort study. The effects of extreme temperatures on hospitalizations and post-discharge deaths for stroke in patients with and without pre-existing hyperlipidemia were quantified using a time-stratified case-crossover design with conditional logistic regression. Suburb-level temperature data were used to minimize exposure measurement bias. Relative humidity, NO₂ and PM₁₀ were adjusted as potential confounders in the regression. Subgroup analyses were conducted to examine if age, sex, and suburb-level greenspace (measured as normalized difference vegetation index (NDVI)) and socioeconomic status (measured as Socio-Economic Indexes for Areas (SEIFA)) modified the temperature-stroke relationship in the hyperlipidemia group and the non-hyperlipidemia group.

RESULTS

There were 11,469 hospitalizations for stroke during the study period, and 2270 (19.79%) of them died within two months after discharge. Significant effect of heat on hospitalizations for stroke was observed only in individuals with pre-existing hyperlipidemia (odds ratio (OR): 1.85; 95% confidence interval (CI): 1.07-3.19), and significant effect of cold on hospitalizations was found in individuals without pre-existing hyperlipidemia (OR: 1.60; 95% CI: 1.03-2.47). Males appeared to be more vulnerable to the effects of heat and cold on hospitalizations for stroke than females. People living in suburbs with low-level greenspace (OR: 4.23; 95% CI: 1.08-16.61) were more vulnerable to heat effect on stroke hospitalizations than those living in suburbs with high-level greenspace (OR: 1.41; 95% CI: 0.32-6.16). People living in suburbs with the lowest socioeconomic advantage level or the lowest economic resources level were most vulnerable the effects of heat and cold on hospitalizations for stroke. No significant effect of heat or cold on post-discharge deaths from stroke was observed.

CONCLUSIONS

This study provides suggestive evidence that heat adaptation strategies aiming to reduce stroke attacks may need to target those individuals with pre-existing hyperlipidemia.

Ambient temperatures, heatwaves and out-of-hospital cardiac arrest in Brisbane, Australia

BACKGROUND

The health impacts of temperatures are gaining attention in Australia and worldwide. While a number of studies have investigated the association of temperatures with the risk of cardiovascular diseases, few examined out-of-hospital cardiac arrest (OHCA) and none have done so in Australia. This study examined the exposure-response relationship between temperatures, including heatwaves and OHCA in Brisbane, Australia.

METHODS

A quasi-Poisson regression model coupled with a distributed lag non-linear model was employed, using OHCA and meteorological data between 1 January 2007 and 31 December 2019. Reference temperature was chosen to be the temperature of minimum risk (21.4°C). Heatwaves were defined as daily average temperatures at or above a heat threshold (90th, 95th, 98th, 99th percentile of the yearly temperature distribution) for at least two consecutive days.

RESULTS

The effect of any temperature above the reference temperature was not statistically significant; whereas low temperatures (below reference temperature) increased OHCA risk. The effect of low temperatures was delayed for 1 day, sustained up to 3 days, peaking at 2 days following exposures. Heatwaves significantly increased OHCA risk across the operational definitions. When a threshold of 95th percentile of yearly temperature distribution was used to define heatwaves, OHCA risk increased 1.25 (95% CI 1.04 to 1.50) times. When the heat threshold for defining heatwaves increased to 99th percentile, the relative risk increased to 1.48 (1.11 to 1.96).

CONCLUSIONS

Low temperatures and defined heatwaves increase OHCA risk. The findings of this study have important public health implications for mitigating strategies aimed at minimising temperature-related OHCA.

Physiological factors characterizing heat-vulnerable older adults: A narrative review

More frequent and intense periods of extreme heat (heatwaves) represent the most direct challenge to human health posed by climate change. Older adults are particularly vulnerable, especially those with common age-associated chronic health conditions (e.g., cardiovascular disease, hypertension, obesity, type 2 diabetes, chronic kidney disease). In parallel, the global population is aging and age-associated disease rates are on the rise. Impairments in the physiological responses tasked with maintaining homeostasis during heat exposure have long been thought to contribute to increased risk of health disorders in older adults during heatwaves. As such, a comprehensive overview of the provisional links between age-related physiological dysfunction and elevated risk of heat-related injury in older adults would be of great value to healthcare officials and policy makers concerned with protecting heat-vulnerable sectors of the population from the adverse health impacts of heatwaves. In this narrative review, we therefore summarize our current understanding of the physiological mechanisms by which aging impairs the regulation of body temperature, hemodynamic stability and hydration status. We then examine how these impairments may contribute to acute pathophysiological events common during heatwaves (e.g., heatstroke, major adverse cardiovascular events, acute kidney injury) and discuss how age-associated chronic health conditions may exacerbate those impairments. Finally, we briefly consider the importance of physiological research in the development of climate-health programs aimed at protecting heat-vulnerable individuals.

Years of life lost and mortality due to heat and cold in the three largest English cities

There is a well-established relationship between temperature and mortality, with older individuals being most at risk in high-income settings. This raises the question of the degree to which lives are being shortened by exposure to heat or cold. Years of life lost (YLL) take into account population life expectancy and age at which mortality occurs. However, YLL are rarely used as an outcome-metric in studies of temperature-related mortality. This represents an important gap in knowledge; to better comprehend potential impacts of temperature in the context of climate change and an ageing population, it is important to understand the relationship between temperature and YLL, and also whether the risks of temperature related mortality and YLL have changed over recent years. Gridded temperature data derived from observations, and mortality data were provided by the UK Met Office and the Office for National Statistics (ONS), respectively. We derived YLL for each death using sex-specific yearly life expectancy from ONS English-national lifetables. We undertook an ecological time-series regression analysis, using a distributed-lag double-threshold model, to estimate the relationship between daily mean temperature and daily YLL and mortality between 1996 and 2013 in Greater London, the West Midlands including Birmingham, and Greater Manchester. Temperature-thresholds, as determined by model best fit, were set at the 91st (for heat-effects) and 35th (for cold-effects) percentiles of the mean temperature distribution. Secondly, we analysed whether there had been any changes in heat and cold related risk of YLL and mortality over time. Heat-effects (lag 0-2 days) were greatest in London, where for each 1 °C above the heat-threshold the risk of mortality increased by 3.9% (CI 3.5%, 4.3%) and YLL increased by 3.0% (2.5%, 3.5%). Between 1996 and 2013, the proportion of total deaths and YLL attributable to heat in London were 0.50% and 0.40% respectively. Cold-effects (lag 0-27 days) were greatest in the West Midlands, where for each 1 °C below the cold-threshold, risk of mortality increased by 3.1% (2.4%, 3.7%) and YLL also increased by 3.1% (2.2%, 3.9%). The proportion of deaths and YLL attributable to cold in the West Midlands were 3.3% and 3.2% respectively. We found no evidence of decreasing susceptibility to heat and cold over time. The addition of life expectancy information into calculations of temperature-related risk and mortality burdens for English cities is novel. We demonstrate that although older individuals are at greatest risk of temperature-related mortality, heat and cold still make a significant contribution to the YLL due to premature death.

Years of life lost with premature death due to ambient temperatures in a southwest plateau region of China: a cause-specific and individual characteristics stratified mortality study

We aimed to explore whether there were cold and heat temperature adverse effects on years of life lost (YLL) for non-accidental mortality in Yuxi, a southwest plateau region of China. From data for 89,467 non-accidental deaths over an 8-year study period, we used a general linear regression model combined with a distributed lag non-linear model to assess the burden of disease non-accidental mortality due to ambient temperature with the YLL indicator. We estimated the mean YLL change per 1 °C decrease from the 25th to 1st percentile mean temperature as the cold effect and per 1 °C increase from the 75th to 99th percentile as the heat effect. The 95% empirical confidence intervals (eCIs) were calculated by using a bootstrap simulation method. The exposure-response curve between average temperature and YLL was U-shaped. The cold effect peaked at the first day after exposure and disappeared at 2 weeks, and the heat effect only lasted for the first 3 days. A per 1 °C decrease from the 25th to 1st mean temperature percentile was associated with an increase of 15.6 (95% eCI: 2.4, 22.9) in YLL for non-accidental diseases, and the cumulative effects due to cold were stronger in contrast to that attributed by heat. Cold temperature had a significant impact on YLL among the subgroups, with higher YLL in cardiovascular disease, stroke, males, Han nationality, married, and those engaged in agriculture than their corresponding categories. An increasing death burden of non-accidental in Yuxi of China due to cold temperature was demonstrated, and the association was also modified by specific disease causes and individual features.

Association between moderately cold temperature and mortality in China

Ambient air temperature is a key factor affecting human health. Adverse effects of extreme weather on mortality have been well explored and expounded in numerous epidemiological studies. The relationship between moderate temperature and mortality is, however, underexplored. This study quantitatively investigated the temperature-dependent mortality burden in China. Data on daily average temperature and mortality in 15 Chinese cities during 2010-2016 were collected for this study. The association between temperature and city-specific mortality was investigated with a quasi-Poisson regression combined with a distributed lag nonlinear model across lag 0-21 days. The results were then included in a multivariate meta-analysis to derive the pooled estimates of the effect of temperature on mortality at the multi-city level. Mortality fractions attributable to cold and heat (i.e., at temperatures below and above the minimum mortality temperature (MMT)) were calculated. Additionally, temperature ranges were further divided into 1 °C intervals of ambient temperature, and the attributable fractions were calculated for each range. The MMT varied from the 71th to 93th percentiles of temperature in the 15 Chinese cities, centering at the 78th percentile at the multi-city level. In total, 12.65% of non-accidental mortality was attributable to non-optimum temperature, of which cold and hot temperatures corresponded to attributable fractions of 11.38% and 1.27%, respectively. The results of temperature stratifications suggested that moderately cold temperatures provided the highest contribution to mortality caused by temperature. Specifically, the highest attributable fractions were at 7 °C, 7 °C, 8 °C, 8 °C, 4 °C, 4 °C, 5 °C, 7 °C, 7 °C, 4 °C, 5 °C, 5 °C, 6 °C, 11 °C, and 12 °C, for Harbin, Changchun, Shenyang, Urumqi, Beijing, Tianjin, Shijiazhuang, Xining, Lanzhou, Nanjing, Shanghai, Hefei, Chengdu, Kunming, and Guangzhou, respectively. Cold temperature was responsible for a higher proportion of deaths than heat. Moderate cold temperature contributed to most of the total health burden. Finally, the cumulative total counts of deaths caused by moderate cold were the largest. Although moderate cold conferred a slightly lower relative risk than extreme cold, it was more common than extreme cold. Taken together, our results show that the effects of moderate cold temperature on health should receive more attention. Furthermore, our findings could help improve the prediction of climate change effects on human health and support the development of response strategies for the changing climate.

Winter temperature and myocardial infarction in Brisbane, Australia: Spatial and temporal analyses

Myocardial infarction (MI) incidence often peaks in winter, but it remains unclear how winter temperature affects MI temporally and spatially. We examined the short-term effects of winter temperature on the risk of MI and explored spatial associations of winter MI hospitalizations with temperature and socioeconomic status (area-based index) in Brisbane, Australia. We used a distributed lag non-linear model to fit the association at the city level between population-weighted daily mean temperature and daily MI hospitalizations during 11 winters of 2005-2015. For each winter, a Bayesian spatial conditional autoregressive model was fitted to examine the associations at postal code level of MI hospitalisations with temperature and socioeconomic status measured as the Index of Relative Socio-Economic Advantage and Disadvantage (IRSAD). Area-specific winter temperature was categorised into three levels: cold (<25th percentile of average winter temperature across postal areas), mild (25th-75th percentile) and warm (>75th percentile). This study included 4978 MI hospitalizations. At the city level, each 1 °C drop in temperature below a threshold of 15.6 °C was associated with a relative risk (RR) of 1.016 (95% confidence interval (CI): 1.008-1.024) for MI hospitalizations on the same day. Low temperature had a much delayed and transient effect on women but an immediate and longer-lasting effect on men. Winter MI incidence rate varied spatially in Brisbane, with a higher incidence rate in warmer areas (RR for mild areas: 1.214, 95%CI: 1.116-1.320; RR for warm areas: 1.251, 95%CI: 1.127-1.389; cold areas as the reference) and in areas with lower socioeconomic levels (RR: 0.900, 95%CI: 0.886-0.914 for each decile increase in IRSAD). This study provides compelling evidence that short-term winter temperature drops were associated with an elevated risk of MI in the subtropical region with a mild winter. Particular attention also needs to be paid to people living in relatively warm and socioeconomically disadvantaged communities in winter.

Regional Temperature-Sensitive Diseases and Attributable Fractions in China

Few studies have been carried out to systematically screen regional temperature-sensitive diseases. This study was aimed at systematically and comprehensively screening both high- and low-temperature-sensitive diseases by using mortality data from 17 study sites in China located in temperate and subtropical climate zones. The distributed lag nonlinear model (DLNM) was applied to quantify the association between extreme temperature and mortality to screen temperature-sensitive diseases from 18 kinds of diseases of eight disease systems. The attributable fractions (AFs) of sensitive diseases were calculated to assess the mortality burden attributable to high and low temperatures. A total of 1,380,713 records of all-cause deaths were involved. The results indicate that injuries, nervous, circulatory and respiratory diseases are sensitive to heat, with the attributable fraction accounting for 6.5%, 4.2%, 3.9% and 1.85%, respectively. Respiratory and circulatory diseases are sensitive to cold temperature, with the attributable fraction accounting for 13.3% and 11.8%, respectively. Most of the high- and low-temperature-sensitive diseases seem to have higher relative risk in study sites located in subtropical zones than in temperate zones. However, the attributable fractions for mortality of heat-related injuries were higher in temperate zones. The results of this research provide epidemiological evidence of the relative burden of mortality across two climate zones in China.

Excess Mortality in Istanbul during Extreme Heat Waves between 2013 and 2017

Heat waves are one of the most common direct impacts of anthropogenic climate change and excess mortality their most apparent impact. While Turkey has experienced an increase in heat wave episodes between 1971 and 2016, no epidemiological studies have examined their potential impacts on public health so far. In this study excess mortality in Istanbul attributable to extreme heat wave episodes between 2013 and 2017 is presented. Total excess deaths were calculated using mortality rates across different categories, including age, sex, and cause of death. The analysis shows that three extreme heat waves in the summer months of 2015, 2016, and 2017, which covered 14 days in total, significantly increased the mortality rate and caused 419 excess deaths in 23 days of exposure. As climate simulations show that Turkey is one of the most vulnerable countries in the Europe region to the increased intensity of heat waves until the end of the 21st century, further studies about increased mortality and morbidity risks due to heat waves in Istanbul and other cities, as well as intervention studies, are necessary.

The effects of temperature on human mortality in a Chinese city: burden of disease calculation, attributable risk exploration, and vulnerability identification

Few studies have examined the attributable fraction (AF) of temperature to mortality and Years of Life Lost (YLL), especially in developing countries. This study aims to explore the short-term effect of the cold and hot temperatures on the cause-specific YLL and mortality, discover the attributable contributions from the temperature variations, and identify the vulnerable populations in Weifang, China. Daily registered death information and meteorological data over the period 2010-2016 were obtained in Weifang, a northern Chinese city. Generalized additive Poisson and Gaussian regression models were used to assess the impacts of temperatures on both mortality and YLL, explore the AF of the temperature variations on mortality, after adjusting for other covariates. Both hot and cold temperatures have had significant negative impacts on cause-specific mortality counts and YLL, with heat presented an acute and short effect and the cold temperatures had delayed effects and lasted for several days. In terms of the attributable fraction calculations, the contributions from cold effects was higher than that of hot effects on non-accidental, cardiovascular, and respiratory deaths (YLL 10.88 vs. 1.23%, 19.58 vs. 1.71%, and 14.47 vs. 3.05%; mortality 13.97 vs. 1.65%, 19.20 vs. 1.59%, and 14.89 vs. 3.09%), respectively. The elderly and women and people with low education level were the most vulnerable. The findings will provide important scientific evidences and policy implications for developing adaptation strategies to reduce the adverse effect of cold and hot exposure in Weifang, in terms of resource allocation, healthcare workforce capacity building, and community health education, especially for the vulnerable groups.

The impact of heat waves on mortality and years of life lost in a dry region of Iran (Kerman) during 2005-2017

The present study was conducted to compare the impact of heat waves on mortality and years of life lost (YLL) in Kerman, Iran during the years 2005-2017. Daily mean temperature in a combination of intensity and duration were used in order to define heat waves (90, 95, and 98th percentile and ≥ 2, 3, and 4 consecutive days). YLL was calculated according to Iran's life table and by considering the discount rate. In order to investigate the impact of heat waves in different lags and its cumulative effect on mortality and YLL, Poisson and linear models within distributed lag nonlinear models were used respectively. A maximum lag of 14 days was considered. The best model was selected based on AIC (Akaike Information Criteria). The model was adjusted for air pollutants, public holidays, days of the week, and humidity. The average daily mortality and YLL were 10.54 ± 4.31 deaths and 175.58 ± 91.39 years respectively. They were higher in men and in heat waves matching a definition of above the 98th temperature percentile and ≥ 3 days, than others. Except heat waves defined as the 98th percentile and ≥ 4 days, the impact of heat waves on mortality and YLL were the highest at lag 0. The cumulative relative risk of total mortality was significantly higher in heat waves above the 95 and 98th percentiles. The cumulative effect of heat waves on total YLL was significantly higher only above the 98th percentile. Men over 65 years old were the most vulnerable and had the highest mortality and YLL. Heat waves with temperatures above the 98th percentile that lasted at least 2 or 3 consecutive days had a significant effect in increasing both total YLL and mortality in Kerman, Iran.

Impacts of exposure to ambient temperature on burden of disease: a systematic review of epidemiological evidence

Ambient temperature is an important determinant of mortality and morbidity, making it necessary to assess temperature-related burden of disease (BD) for the planning of public health policies and adaptive responses. To systematically review existing epidemiological evidence on temperature-related BD, we searched three databases (PubMed, Web of Science, and Scopus) on 1 September 2018. We identified 97 studies from 56 counties for this review, of which 75 reported the fraction or number of health outcomes (include deaths and diseases) attributable to temperature, and 22 reported disability-adjusted life years (include years of life lost and years lost due to disability) related to temperature. Non-optimum temperatures (i.e., heat and cold) were responsible for > 2.5% of mortality in all included high-income countries/regions, and > 3.0% of mortality in all included middle-income countries. Cold was mostly reported to be the primary source of mortality burden from non-optimum temperatures, but the relative role of three different temperature exposures (i.e., heat, cold, and temperature variability) in affecting morbidity and mortality remains unclear so far. Under the warming climate scenario, almost all projections assuming no population adaptation suggested future increase in heat-related but decrease in cold-related BD. However, some studies emphasized the great uncertainty in future pattern of temperature-related BD, largely depending on the scenarios of climate, population adaptation, and demography. We also identified important discrepancies and limitations in current research methodologies employed to measure temperature exposures and model temperature-health relationship, and calculate the past and project future temperature-related BD. Overall, exposure to non-optimum ambient temperatures has become and will continue to be a considerable contributor to the global and national BD, but future research is still needed to develop a stronger methodological framework for assessing and comparing temperature-related BD across different settings.

Impact of summer heat on mortality and years of life lost: Application of a novel indicator of daily excess hourly heat

BACKGROUND

Previous studies have widely assessed heat-mortality relationships across global regions, while the epidemiological evidence regarding the heat effect on years of life lost (YLL) is relatively sparse. Current investigations using daily mean data cannot take hourly temperature variation into consideration and may underestimate heat effects. We developed a novel indicator, daily excess hourly heat (DEHH), to precisely evaluate the potential heat effects on mortality and YLL.

METHODS

Hourly data on temperature and daily information, including concentrations of air pollutants, relative humidity, and records of all registered deaths were obtained in Wuhan, China during the warm seasons (May-September) of 2009-2012. DEHH, developed in this study, is defined as daily total hourly temperatures that exceed a specific heat threshold. By performing time series regression analyses, we assessed the changes in daily mortality and YLL per interquartile range (IQR) increase in DEHH across different lag days.

RESULTS

The heat threshold evaluated by the Akaike Information Criterion for DEHH calculation is 30 °C (92th percentile of whole-year mean temperature distribution). Daily average DEHH was 13.9 °C, with an IQR of 19.9 °C. Linear exposure-response curves were found between DEHH and two health outcomes. Generally, heat effects lasted for 2-3 days and DEHH at lag 0-1 was most strongly associated with increased mortality and YLL. The effects were especially remarkable for stroke and ischemic heart disease mortality. Most intense effect on YLL was found in non-accidental deaths (20.11, 95% confidence interval: 8.90-31.33) at lag 0-1. More DEHH-related mortality and YLL from cardiovascular deaths were observed among males. People aged 0-74 years and males suffered more from YLL burden due to high temperatures.

CONCLUSIONS

Our study demonstrated that DEHH may be an alternative indicator to precisely measure heat effects on daily mortality and YLL. Further DEHH-based evidence from large scale investigations is needed so as to better understand heat-associated health burden and improve public response to extremely high temperatures.

The impact of extreme heat events on hospital admissions to the Royal Hobart Hospital

Background

Extreme heat (EH) events are increasing in frequency and duration and cause more deaths in Australia than any other extreme weather event. Consequently, EH events lead to an increase in the number of patient presentations to hospitals.

Methods

Climatic observations for Hobart’s region and Royal Hobart Hospital (RHH) emergency department admissions data were collected retrospectively for the study period of 2003–2010. A distributed lag non-linear model (DLNM) was fitted using a generalized linear model with quasi-Poisson family to obtain adjusted estimates for the relationship between temperature and the relative risk of being admitted to the RHH.

Results

The model demonstrated that relative to the annual mean temperature of 14°C, the relative risk of being admitted to the RHH for the years 2003–2010 was significantly higher for all temperatures above 27°C (P &lt; 0.05 in all cases). The peak effect upon admission was noted on the same day as the EH event, however, the model suggests that a lag effect exists, increasing the likelihood of admission to the RHH for a further 14 days.

Conclusions

To relieve the added burden on emergency departments during these events, adaptation strategies adopted by public health organizations could include preventative health initiatives.

Effects of Extreme Temperatures on Mortality and Hospitalization in Ho Chi Minh City, Vietnam

There is a lack of research focusing on the association of temperature with mortality and hospitalization in developing countries with tropical climates and a low capacity to cope with the influences of extreme weather events. This study aimed to examine and compare the effect of temperature, including heat waves, on mortality and hospitalization in the most populous city of Vietnam. We used quasi-Poisson time series regression coupled with the distributed lag non-linear model (DLNM) to examine the overall pattern and compare the temperature-health outcome relationship. The main and added effects of heat waves were evaluated. The main effect of heat waves significantly increased the risk of all cause-specific mortality. Significant main effects of heat waves on hospitalization were observed only for elderly people and people with respiratory diseases (elderly, relative risk (RR) = 1.28, 95% confidence interval (CI) = 1.14–3.45; respiratory diseases, RR = 1.3, 95% CI = 1.19–1.42). The RRs of the main effect were substantially higher than those of the added effect in mortality; the same was applicable for hospitalizations of people with respiratory diseases and elderly people. The findings of this study have important implications for public health adaptation and prevention program implementation in the protection of residents from the adverse health effects of temperature.

Effects of extreme temperatures on hospital emergency room visits for respiratory diseases in Beijing, China

Extreme temperature is closely associated with human health, but limited evidence is available for the effects of extreme temperatures on respiratory diseases in China. The goal of this study is to evaluate the effects of extreme temperatures on hospital emergency room (ER) visits for respiratory diseases in Beijing, China. We used a distributed lag non-linear model (DLNM) coupled with a generalized additive model (GAM) to estimate the association between extreme temperatures and hospital ER visits for different age and gender subgroups in Beijing from 2009 to 2012. The results showed that the exposure-response curve between temperature and hospital ER visits was almost W-shaped, with increasing relative risks (RRs) at extremely low temperature. In the whole year period, strong acute hot effects were observed, especially for the elders (age > 65 years). The highest RR associated with the extremely high temperature was 1.36 (95% CI, 0.96-1.92) at lag 0-27. The longer-lasting cold effects were found the strongest at lag 0-27 for children (age ≤ 15 years) and the relative risk was 1.96 (95% CI, 1.70-2.26). We also found that females were more susceptible to extreme temperatures than males.

What “new” factors should be considered when assessing cardiovascular risk?

One of the causes of high mortality from cardiovascular diseases is the lack of effective measures for the primary and secondary prevention of cardiovascular complications (CCO), due to the difficulty of timely identification risk factors (RF) and individuals with a high individual risk of CCO. This is especially true for patients from low/mean risk. This group is heterogeneous. Often, clinical manifestations of atherosclerosis occur for the first time without “classical” RF. Possible factors that increase the risk of developing cardiovascular diseases and CCO, are: heart rate, increased formation of advanced glycation endproducts, disorders of bone mineral metabolism, thyroid function, low adherence to therapy, psychosocial factors and climatic features. This review is devoted to the analysis of the evidence base of the influence of these “new” CCO RF and the individual patient prognosis.

Future temperature-related years of life lost projections for cardiovascular disease in Tianjin, China

It is widely accepted that temperatures is associated with cardiovascular mortality, however, few studies have explored the effects of temperature on years of life lost (YLL) from cardiovascular mortality in China under future global warming scenarios. Therefore, there is an urgent need to obtain projections of YLL from cardiovascular diseases. Here we applied nineteen global-scale climate models (GCMs) and three Representative Concentration Pathway emission scenarios (RCPs) in the 2050s and 2070s for temperature-related YLL projection in Tianjin, China. We found the relationships between daily maximum temperatures with YLL from cardiovascular mortality were basically U-shaped. We observed increasing net annual YLL across a range of multiple models under different climate scenarios, suggesting that increasing heat-related YLL from cardiovascular mortality could offset decreasing cold-related YLL from cardiovascular mortality. The largest temperature-related YLL from cardiovascular mortality were observed under the RCP8.5 scenario and increased more rapidly in the 2070s versus the 2050s. Monthly analyses of percent changes in YLL from cardiovascular mortality showed that the largest percent increases occurred from May to September. If warm adaptation occurs, only the adverse effects under RCP2.6 could be fully offset in both 2050 and 2070. Our exploration provided further evidence for the potential health impacts of global warming and highlighted that government should develop environmental policies for future health risks.

Effects of diurnal temperature range on mortality in Hefei city, China

Although several studies indicated an association between diurnal temperature range (DTR) and mortality, the results about modifiers are inconsistent, and few studies were conducted in developing inland country. This study aims to evaluate the effects of DTR on cause-specific mortality and whether season, gender, or age might modify any association in Hefei city, China, during 2007-2016. Quasi-Poisson generalized linear regression models combined with a distributed lag non-linear model (DLNM) were applied to evaluate the relationships between DTR and non-accidental, cardiovascular, and respiratory mortality. We observed a J-shaped relationship between DTR and cause-specific mortality. With a DTR of 8.3 °C as the reference, the cumulative effects of extremely high DTR were significantly higher for all types of mortality than effects of lower or moderate DTR in full year. When stratified by season, extremely high DTR in spring had a greater impact on all cause-specific mortality than other three seasons. Male and the elderly (≥ 65 years) were consistently more susceptible to extremely high DTR effect than female and the youth (< 65 years) for non-accidental and cardiovascular mortality. To the contrary, female and the youth were more susceptible to extremely high DTR effect than male and the elderly for respiratory morality. The study suggests that extremely high DTR is a potential trigger for non-accidental mortality in Hefei city, China. Our findings also highlight the importance of protecting susceptible groups from extremely high DTR especially in the spring.

The burden of ambient temperature on years of life lost: A multi-community analysis in Hubei, China

BACKGROUND

Compared with death rates, years of life lost (YLL) has been widely used as a more informative indicator to quantify the burden of premature death. In the context of global climate change, existing evidence linking ambient temperatures and YLL was very scarce across the globe.

METHODS

Daily mortality and meteorological data during 2009-2012 were obtained from 12 communities across Hubei Province in central China. A two-stage approach was used for statistical analysis. At the first stage, a generalized linear regression combined with distributed lag non-linear model was applied to estimate community-specific temperature-YLL associations. A second-stage multivariable meta-analysis was then conducted to pool the community-specific estimates of temperature-related effects on YLL.

RESULTS

A pooled J- or U-shaped association was observed between ambient temperature and YLL due to different mortality categories. Heat effects occurred immediately and only persisted for several days, whereas cold effects were delayed and much longer-lasting. At the provincial level, heat effect (per 1°C increase from 75th to 99th percentile of temperature) at lag 0-2days and cold effect (per 1°C decrease from 25th to 1st percentile of temperature) at lag 0-21days was associated with an increase of 1.91% (95% CI: 0.83, 3.00) and 5.09% (2.79, 7.40) in YLL due to non-accidental deaths, respectively. Much greater effect estimates of cold than heat were also observed for other mortality-specific YLLs (except for respiratory mortality). Heat effects on YLL were higher for males and the youth, while cold effects were greater for females and the elderly. Additionally, relatively stronger associations between heat, cold and YLL were consistently observed in low-educated persons.

CONCLUSIONS

This multi-community study strengthened the evidence that both cold and hot temperatures were associated with increased years of life lost. Our findings may have important implications for better understanding the burden of premature death related to temperature extremes.

Risks, Health Consequences, and Response Challenges for Small-Island-Based Populations: Observations From the 2017 Atlantic Hurricane Season

ABSTRACTThe intensely active 2017 Atlantic basin hurricane season provided an opportunity to examine how climate drivers, including warming oceans and rising seas, exacerbated tropical cyclone hazards. The season also highlighted the unique vulnerabilities of populations residing on Small Island Developing States (SIDS) to the catastrophic potential of these storms. During 2017, 22 of the 29 Caribbean SIDS were affected by at least one named storm, and multiple SIDS experienced extreme damage. This paper aims to review the multiplicity of storm impacts on Caribbean SIDS throughout the 2017 season, to explicate the influences of climate drivers on storm formation and intensity, to explore the propensity of SIDS to sustain severe damage and prolonged disruption of essential services, to document the spectrum of public health consequences, and to delineate the daunting hurdles that challenged emergency response and recovery operations for island-based, disaster-affected populations. (Disaster Med Public Health Preparedness. 2019;13:5-17).