Air temperature-related human health outcomes: current impact and estimations of future risks in Central Italy

Spatiotemporal clusters of acute respiratory infections associated with socioeconomic, meteorological, and air pollution factors in South Punjab, Pakistan

BACKGROUND

In Pakistan, acute respiratory infections (ARI) continue to be a major public health problem. However, there is still a lack of scholarly work regarding different environmental and socioeconomic influencing factors and how they interact with respiratory infections. Furthermore, we do not know much about geographic variation in this context. Therefore, our study examines the ecological-level spatial and temporal patterns of acute respiratory infection incidence (ARI) and their geographic relationship with selected socio-economic, meteorological, and air pollution factors in Pakistan.

METHODS

We applied the spatiotemporal scan statistics to examine the purely temporal, spatial, and spatiotemporal clusters of ARI in South Punjab, Pakistan for five years (2016-2020). Generalized Linear Model (GLM) and geographically weighted regression (GWR) were also applied to model the linear and non-linear spatial relationships between selected variables and ARI.

RESULTS

Our results indicate that in the central and northern regions of Pakistan, two spatial clusters of ARI were present, accounting for 28.5% of the total cases. A spatiotemporal cluster with a relative risk of 1.57 was discovered in the northeastern area. The results obtained from the season-based GLM highlighted the significance of climatic factors (temperature, fog, dust storms) and air pollutants (NO2) in influencing ARI incidence, while socio-economic variables (rural population, literacy) had limited impact. In addition, GWR revealed that the relationships between predictors and ARI incidence varied across locations, emphasizing the importance of considering local settings. Season-based non-stationary GLM revealed a multifaceted interaction among socio-economic, meteorological, and air pollution factors.

CONCLUSIONS

Our study provides evidence about environmental and socio-economic factors significantly associated with ARI incidence. In addition, this study provides the first baseline of ARI cases in Pakistan to plan for intervention and adaptation strategies and may be replicated in other regions of comparable settings worldwide.

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

PURPOSE OF REVIEW

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

RECENT FINDINGS

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

Heat-health action planning in the WHO European Region: Status and policy implications

Adverse health effects from extreme heat remain a major risk, especially in a changing climate. Several European countries have implemented heat health action plans (HHAPs) to prevent ill health and excess mortality from heat. This paper assesses the state of implementation of HHAPs in the WHO European Region and discusses barriers and successes since the early 2000s. The results are based on a web-based survey among 53 member states on the current national and federal HHAPs in place. Guided by the eight core elements of HHAPs as outlined by the WHO Regional Office for Europe guidance from 2008, we analyzed which elements were fully or partially implemented and which areas of improvement countries identified. HHAP adaptations to account for COVID-19 were sought via literature search and expert consultations. 27 member states provided information, of which 17 countries reported having a HHAP. Five out of eight core elements, namely agreement on a lead body, accurate and timely alert systems, heat-related health information plans, strategies to reduce health exposure, and care for vulnerable groups, were at least partially implemented in all 17 plans. Alert systems were implemented most often at 94%. The least often implemented items were real-time surveillance, long-term urban planning, and preparedness of health and social systems. Five countries had published COVID-19 guidance online. Our findings suggest a progressive improvement in the development and rollout of HHAPs overall and awareness of vulnerable population groups in WHO/Europe, while integration of HHAPs into long-term climate change and health planning remains a challenge.

Economic burden of premature deaths attributable to non-optimum temperatures in Italy: A nationwide time-series analysis from 2015 to 2019

BACKGROUND

Human beings and society are experiencing substantial consequences caused by non-optimum temperatures. However, limited studies have assessed the economic burden of premature deaths attributable to non-optimum temperatures.

OBJECTIVES

To characterize the association between daily mean temperature and the economic burden of premature deaths.

METHODS

A total of 3 228 098 deaths were identified from a national mortality dataset in Italy during 2015 and 2019. We used the value of statistical life to quantify the economic losses of premature death. A two-stage time-series analysis was performed to evaluate the economic losses of premature deaths associated with non-optimum temperatures. Attributable burden for non-optimum temperatures compared with minimum risk temperature were estimated. Potential effect modifiers were further explored.

RESULTS

From 2015 to 2019, the economic loss of premature deaths due to non-optimum temperatures was $525.52 billion (95% CI: $461.84-$580.80 billion), with the attributable fraction of 5.74% (95% CI: 5.04%-6.34%). Attributable economic burden was largely due to moderate cold temperatures ($309.54 billion, 95% CI: $249.49-$357.34 billion). A higher economic burden was observed for people above the age of 65, accounting for 75.97% ($452.42, 95%CI: $406.97-$488.76 billion) of the total economic burden. In particular, higher fractions attributable to heat temperatures were observed for provinces with the lowest level of GDP per capita but the highest level of urbanization.

DISCUSSION

This study shows a considerable economic burden of premature deaths attributed to non-optimum temperatures. These figures can help inform tailored prevention to tackle the large economic burden imposed by non-optimum temperatures.

The effect and prediction of diurnal temperature range in high altitude area on outpatient and emergency room admissions for cardiovascular diseases

PURPOSE

Diurnal temperature range (DTR) is a meteorological indicator closely associated with global climate change. Thus, we aim to explore the effects of DTR on the outpatient and emergency room (O&ER) admissions for cardiovascular diseases (CVDs), and related predictive research.

METHODS

The O&ER admissions data for CVDs from three general hospitals in Jinchang of Gansu Province were collected from 2013 to 2016. A generalized additive model (GAM) with Poisson regression was employed to analyze the effect of DTR on the O&ER admissions for all cardiovascular diseases, hypertension, ischemic heart disease (IHD) and stoke. GAM was also used to preform predictive research of the effect of DTR on the O&ER admissions for CVDs.

RESULTS

There were similar positive linear relationships between DTR and the O&ER visits with the four cardiovascular diseases. And the cumulative lag effects were higher than the single lag effects. A 1 °C increase in DTR corresponded to a 1.30% (0.99-1.62%) increase in O&ER admissions for all cardiovascular diseases. Males and elderly were more sensitivity to DTR. The estimates in non-heating season were higher than in heating season. The trial prediction accuracy rate of CVDs based on DTR was between 59.32 and 74.40%.

CONCLUSIONS

DTR has significantly positive association with O&ER admissions for CVDs, which can be used as a prediction index of the admissions of O&ER with CVDs.

Temperature-mortality relationship in North Carolina, USA: Regional and urban-rural differences

BACKGROUND

Health disparities exist between urban and rural populations, yet research on rural-urban disparities in temperature-mortality relationships is limited. As inequality in the United States increases, understanding urban-rural and regional differences in the temperature-mortality association is crucial.

OBJECTIVE

We examined regional and urban-rural differences of the temperature-mortality association in North Carolina (NC), USA, and investigated potential effect modifiers.

METHODS

We applied time-series models allowing nonlinear temperature-mortality associations for 17 years (2000-2016) to generate heat and cold county-specific estimates. We used second-stage analysis to quantify the overall effects. We also explored potential effect modifiers (e.g. social associations, greenness) using stratified analysis. The analysis considered relative effects (comparing risks at 99th to 90th temperature percentiles based on county-specific temperature distributions for heat, and 1st to 10th percentiles for cold) and absolute effects (comparing risks at specific temperatures).

RESULTS

We found null effects for heat-related mortality (relative effect: 1.001 (95% CI: 0.995-1.007)). Overall cold-mortality risk for relative effects was 1.019 (1.015-1.023). All three regions had statistically significant cold-related mortality risks for relative and absolute effects (relative effect: 1.019 (1.010-1.027) for Coastal Plains, 1.021 (1.015-1.027) for Piedmont, 1.014 (1.006-1.023) for Mountains). The heat mortality risk was not statistically significant, whereas the cold mortality risk was statistically significant, showing higher cold-mortality risks in urban areas than rural areas (relative effect for heat: 1.006 (0.997-1.016) for urban, 1.002 (0.988-1.017) for rural areas; relative effect for cold: 1.023 (1.017-1.030) for urban, 1.012 (1.001-1.023) for rural areas). Findings are suggestive of higher relative cold risks in counties with the less social association, higher population density, less green-space, higher PM_2.5, lower education level, higher residential segregation, higher income inequality, and higher income (e.g., Ratio of Relative Risks 1.72 (0.68, 4.35) comparing low to high education).

CONCLUSION

Results indicate cold-mortality risks in NC, with potential differences by regional, urban-rural areas, and community characteristics.

Effects of extreme temperature on respiratory diseases in Lanzhou, a temperate climate city of China

Under the global climate warming, extreme weather events occur more and more frequently. Epidemiological studies have proved that extreme temperature is strongly correlated with respiratory diseases. We evaluated extreme-temperature effect on respiratory emergency room (ER) visits for 5 years in Lanzhou, a northwest temperate climate city of China from January 1st, 2013, to August 31st, 2017. We built a distributed lag non-linear model (DLNM) to evaluate the lag effect up to 30 days. Results showed the relative risk (RR) of respiratory disease always reached the maximum at lag 0 day and decreased to 1.0 at lag 5 days. Extremely low temperature showed the lag effect of 22 days and the maximum RR was 1.415 (95% CI 1.295-1.546) at lag 0 day. Extremely high temperature showed the lag effect of 7 days and the maximum RR was 1.091 (95% CI 1.069-1.114) at lag 0 day. The elders (age > 65 years) were at the greatest risk to extreme temperatures and the response were very acute. Children (age ≤ 15 years) were at the lowest risk but the lag effect lasted the longest lag days than other subgroups. Males showed longer-term lag effect and higher RR than females. Our study indicated that the extremely low temperature has a significantly greater effect on respiratory diseases than extremely high temperature.

Impact of different heat wave definitions on daily mortality in Bandafassi, Senegal

Objective

The aim of this study is to find the most suitable heat wave definition among 15 different ones and to evaluate its impact on total, age-, and gender-specific mortality for Bandafassi, Senegal.

Methods

Daily weather station data were obtained from Kedougou situated at 17 km from Bandafassi from 1973 to 2012. Poisson generalized additive model (GAM) and distributed lag non-linear model (DLNM) are used to investigate the effect of heat wave on mortality and to evaluate the nonlinear association of heat wave definitions at different lag days, respectively.

Results

Heat wave definitions, based on three or more consecutive days with both daily minimum and maximum temperatures greater than the 90^th percentile, provided the best model fit. A statistically significant increase in the relative risk (RRs 1.4 (95% Confidence Interval (CI): 1.2–1.6), 1.7 (95% CI: 1.5–1.9), 1.21 (95% CI: 1.08–1.3), 1.2 (95% CI: 1.04–1.5), 1.5 (95% CI: 1.3–1.8), 1.4 (95% CI: 1.2–1.5), 1.5 (95% CI: 1.07–1.6), and 1.5 (95% CI: 1.3–1.8)) of total mortality was observed for eight definitions. By using the definition based on the 90^th percentile of minimum and maximum temperature with a 3-day duration, we also found that females and people aged ≥ 55 years old were at higher risks than males and other different age groups to heat wave related mortality.

Conclusion

The impact of heat waves was associated with total-, age-, gender-mortality. These results are expected to be useful for decision makers who conceive of public health policies in Senegal and elsewhere. Climate parameters, including temperatures and humidity, could be used to forecast heat wave risks as an early warning system in the area where we conduct this research. More broadly, our findings should be highly beneficial to climate services, researchers, clinicians, end-users and decision-makers.

The Association between Air Temperature and Mortality in Two Brazilian Health Regions

Air temperature, both cold and hot, has impacts on mortality and morbidities, which are exacerbated by poor health service and protection responses, particularly in under-developed countries. This study was designed to analyze the effects of air temperature on the risk of deaths for all and specific causes in two regions of Brazil (Florianopolis and Recife), between 2005 and 2014. The association between temperature and mortality was performed through the fitting of a quasi-Poisson non-linear lag distributed model. The association between air temperature and mortality was identified for both regions. The results showed that temperature exerted influence on both general mortality indicators and specific causes, with hot and cold temperatures bringing different impacts to the studied regions. Cerebrovascular and cardiovascular deaths were more sensitive to cold temperatures for Florianopolis and Recife, respectively. Based on the application of the very-well documented state-of-the-art methodology, it was possible to conclude that there was evidence that extreme air temperature influenced general and specific deaths. These results highlighted the importance of consolidating evidence and research in tropical countries such as Brazil as a way of understanding climate change and its impacts on health indicators.

Projections of Temperature-Attributable Deaths in Portuguese Metropolitan Areas: A Time-Series Modelling Approach

Climate change is now widely recognised as the greatest global threat over the coming decades. This study aimed to quantify and project the effects of climate change on future temperature-attributable mortality due to circulatory system diseases (CSD) in Lisbon metropolitan area (LMA) and in Porto metropolitan area (PMA). The future time slices of Representative Concentration Pathway (RCP 8.5), mid-term (2046–2065) and long-term (2080–2099) were compared with the reference period (1986–2005). There is a significant decreasing trend in proportion to the overall extreme cold temperature-attributable mortality due to CSD in the future periods (2045–2065 and 2081–2099) in LMA, −0.63% and −0.73%, respectively, and in PMA, −0.62% for 2045–2065 and −0.69% for 2081–2099, compared to the historical period. The fraction attributable to extreme hot temperature in the summer months increased by 0.08% and 0.23%, from 0.04% in the historical period to 0.11% during 2046–2065, and to 0.27% during 2081–2099 in LMA. While there were no noticeable changes due to extreme hot temperature during the summer in PMA, significant increases were observed with warmer winter temperatures: 1.27% and 2.80%. The projections of future temperature-attributable mortality may provide valuable information to support climate policy decision making and temperature-related risk management.

An Occupational Heat-Health Warning System for Europe: The HEAT-SHIELD Platform

Existing heat-health warning systems focus on warning vulnerable groups in order to reduce mortality. However, human health and performance are affected at much lower environmental heat strain levels than those directly associated with higher mortality. Moreover, workers are at elevated health risks when exposed to prolonged heat. This study describes the multilingual "HEAT-SHIELD occupational warning system" platform (https://heatshield.zonalab.it/) operating for Europe and developed within the framework of the HEAT-SHIELD project. This system is based on probabilistic medium-range forecasts calibrated on approximately 1800 meteorological stations in Europe and provides the ensemble forecast of the daily maximum heat stress. The platform provides a non-customized output represented by a map showing the weekly maximum probability of exceeding a specific heat stress condition, for each of the four upcoming weeks. Customized output allows the forecast of the personalized local heat-stress-risk based on workers' physical, clothing and behavioral characteristics and the work environment (outdoors in the sun or shade), also taking into account heat acclimatization. Personal daily heat stress risk levels and behavioral suggestions (hydration and work breaks recommended) to be taken into consideration in the short term (5 days) are provided together with long-term heat risk forecasts (up to 46 days), all which are useful for planning work activities. The HEAT-SHIELD platform provides adaptation strategies for "managing" the impact of global warming.

Projection of temperature-related mortality due to cardiovascular disease in beijing under different climate change, population, and adaptation scenarios

Human health faces unprecedented challenges caused by climate change. Thus, studies of the effect of temperature change on total mortality have been conducted in numerous countries. However, few of those studies focused on temperature-related mortality due to cardiovascular disease (CVD) or considered future population changes and adaptation to climate change. We present herein a projection of temperature-related mortality due to CVD under different climate change, population, and adaptation scenarios in Beijing, a megacity in China. To this end, 19 global circulation models (GCMs), 3 representative concentration pathways (RCPs), 3 socioeconomic pathways, together with generalized linear models and distributed lag non-linear models, were used to project future temperature-related CVD mortality during periods centered around the years 2050 and 2070. The number of temperature-related CVD deaths in Beijing is projected to increase by 3.5-10.2% under different RCP scenarios compared with that during the baseline period. Using the same GCM, the future daily maximum temperatures projected using the RCP2.6, RCP4.5, and RCP8.5 scenarios showed a gradually increasing trend. When population change is considered, the annual rate of increase in temperature-related CVD deaths was up to fivefold greater than that under no-population-change scenarios. The decrease in the number of cold-related deaths did not compensate for the increase in that of heat-related deaths, leading to a general increase in the number of temperature-related deaths due to CVD in Beijing. In addition, adaptation to climate change may enhance rather than ameliorate the effect of climate change, as the increase in cold-related CVD mortality greater than the decrease in heat-related CVD mortality in the adaptation scenarios will result in an increase in the total number of temperature-related CVD mortalities.

Mortality risks during extreme temperature events (ETEs) using a distributed lag non-linear model

This study investigates the relationship between all-cause mortality and extreme temperature events (ETEs) from 1975 to 2004. For 50 U.S. locations, these heat and cold events were defined based on location-specific thresholds of daily mean apparent temperature. Heat days were defined by a 3-day mean apparent temperature greater than the 95th percentile while extreme heat days were greater than the 97.5th percentile. Similarly, calculations for cold and extreme cold days relied upon the 5th and 2.5th percentiles. A distributed lag non-linear model assessed the relationship between mortality and ETEs for a cumulative 14-day period following exposure. Subsets for season and duration effect denote the differences between early- and late-season as well as short and long ETEs. While longer-lasting heat days resulted in elevated mortality, early season events also impacted mortality outcomes. Over the course of the summer season, heat-related risk decreased, though prolonged heat days still had a greater influence on mortality. Unlike heat, cold-related risk was greatest in more southerly locations. Risk was highest for early season cold events and decreased over the course of the winter season. Statistically, short episodes of cold showed the highest relative risk, suggesting unsettled weather conditions may have some relationship to cold-related mortality. For both heat and cold, results indicate higher risk to the more extreme thresholds. Risk values provide further insight into the role of adaptation, geographical variability, and acclimatization with respect to ETEs.

Understanding heat patterns produced by vehicular flows in urban areas

Vehicular traffic has strong implication in the severity and degree of Urban Heat Island (UHI) effect in a city. It is crucial to map and monitor the spatio-temporal heat patterns from vehicular traffic in a city. Data observed from traffic counting stations are readily available for mapping the traffic-related heat across the stations. However, macroscopic models utilizing traffic counting data to estimate dynamic directional vehicular flows are rarely established. Our work proposes a simple and robust cell-transmission-model to simulate all the possible cell-based origin-destination trajectories of vehicular flows over time, based on the traffic counting stations. Result shows that the heat patterns have notable daily and weekly periodical circulation/pattern, and volumes of heat vary significantly in different grid cells. The findings suggest that vehicular flows in some places are the dominating influential factor that make the UHI phenomenon more remarkable.

Analysis of the synoptic winter mortality climatology in five regions of England: Searching for evidence of weather signals

Although heat-related mortality has received considerable research attention, the impact of cold weather on public health is less well-developed, probably due to the fact that physiological responses to cold weather can vary substantially among individuals, age groups, diseases etc., depending on a number of behavioral and physiological factors. In the current work we use the classification techniques provided by the COST-733 software to link synoptic circulation patterns with excess cold-related mortality in 5 regions of England. We conclude that, regardless of the classification scheme used, the most hazardous conditions for public health in England are associated with the prevalence of the Easterly type of weather, favoring advection of cold air from continental Europe. It is noteworthy that there has been observed little-to-no regional variation with regards to the classification results among the 5 regions, suggestive of a spatially homogenous response of mortality to the atmospheric patterns identified. In general, the 10 different groupings of days used reveal that excess winter mortality is linked with the lowest daily minimum/maximum temperatures in the area. However it is not uncommon to observe high mortality rates during days with higher, in relative terms, temperatures, when rapidly changing weather results in an increase of mortality. Such a finding confirms the complexity of cold-related mortality and highlights the importance of synoptic climatology in understanding of the phenomenon.

The use of climate information to estimate future mortality from high ambient temperature: A systematic literature review

BACKGROUND AND OBJECTIVES

Heat related mortality is of great concern for public health, and estimates of future mortality under a warming climate are important for planning of resources and possible adaptation measures. Papers providing projections of future heat-related mortality were critically reviewed with a focus on the use of climate model data. Some best practice guidelines are proposed for future research.

METHODS

The electronic databases Web of Science and PubMed/Medline were searched for papers containing a quantitative estimate of future heat-related mortality. The search was limited to papers published in English in peer-reviewed journals up to the end of March 2017. Reference lists of relevant papers and the citing literature were also examined. The wide range of locations studied and climate data used prevented a meta-analysis.

RESULTS

A total of 608 articles were identified after removal of duplicate entries, of which 63 were found to contain a quantitative estimate of future mortality from hot days or heat waves. A wide range of mortality models and climate model data have been used to estimate future mortality. Temperatures in the climate simulations used in these studies were projected to increase. Consequently, all the papers indicated that mortality from high temperatures would increase under a warming climate. The spread in projections of future climate by models adds substantial uncertainty to estimates of future heat-related mortality. However, many studies either did not consider this source of uncertainty, or only used results from a small number of climate models. Other studies showed that uncertainty from changes in populations and demographics, and the methods for adaptation to warmer temperatures were at least as important as climate model uncertainty. Some inconsistencies in the use of climate data (for example, using global mean temperature changes instead of changes for specific locations) and interpretation of the effects on mortality were apparent. Some factors which have not been considered when estimating future mortality are summarised.

CONCLUSIONS

Most studies have used climate data generated using scenarios with medium and high emissions of greenhouse gases. More estimates of future mortality using climate information from the mitigation scenario RCP2.6 are needed, as this scenario is the only one under which the Paris Agreement to limit global warming to 2°C or less could be realised. Many of the methods used to combine modelled data with local climate observations are simplistic. Quantile-based methods might offer an improved approach, especially for temperatures at the ends of the distributions. The modelling of adaptation to warmer temperatures in mortality models is generally arbitrary and simplistic, and more research is needed to better quantify adaptation. Only a small number of studies included possible changes in population and demographics in their estimates of future mortality, meaning many estimates of mortality could be biased low. Uncertainty originating from establishing a mortality baseline, climate projections, adaptation and population changes is important and should be considered when estimating future mortality.

Temporal Changes in Mortality Related to Extreme Temperatures for 15 Cities in Northeast Asia: Adaptation to Heat and Maladaptation to Cold

Understanding how the temperature-mortality association worldwide changes over time is crucial to addressing questions of human adaptation under climate change. Previous studies investigated the temporal changes in the association over a few discrete time frames or assumed a linear change. Also, most studies focused on attenuation of heat-related mortality and studied the United States or Europe. This research examined continuous temporal changes (potentially nonlinear) in mortality related to extreme temperature (both heat and cold) for 15 cities in Northeast Asia (1972-2009). We used a generalized linear model with splines to simultaneously capture 2 types of nonlinearity: nonlinear association between temperature and mortality and nonlinear change over time in the association. We combined city-specific results to generate country-specific results using Bayesian hierarchical modeling. Cold-related mortality remained roughly constant over decades and slightly increased in the late 2000s, with a larger increase for cardiorespiratory deaths than for deaths from other causes. Heat-related mortality rates have decreased continuously over time, with more substantial decrease in earlier decades, for older populations and for cardiorespiratory deaths. Our findings suggest that future assessment of health effects of climate change should account for the continuous changes in temperature-related health risk and variations by factors such as age, cause of death, and location.

Global climate change: impact of heat waves under different definitions on daily mortality in Wuhan, China

Background

There was no consistent definition for heat wave worldwide, while a limited number of studies have compared the mortality effect of heat wave as defined differently. This paper aimed to provide epidemiological evidence for policy makers to determine the most appropriate definition for local heat wave warning systems.

Methods

We developed 45 heat wave definitions (HWs) combining temperature indicators and temperature thresholds with durations. We then assessed the impact of heat waves under various definitions on non-accidental mortality in hot season (May–September) in Wuhan, China during 2003–2010.

Results

Heat waves defined by HW14 (daily mean temperature ≥ 99.0th percentile and duration ≥ 3 days) had the best predictive ability in assessing the mortality effects of heat wave with the relative risk of 1.63 (95% CI: 1.43, 1.89) for total mortality. The group-specific mortality risk using official heat wave definition of Chinese Meteorological Administration was much smaller than that using HW14. We also found that women, and the elderly (age ≥ 65) were more susceptible to heat wave effects which were stronger and longer lasting.

Conclusion

These findings suggest that region specific heat wave definitions are crucial and necessary for developing efficient local heat warning systems and for providing evidence for policy makers to protect the vulnerable population.

Electronic supplementary material

The online version of this article (doi:10.1186/s41256-017-0030-2) contains supplementary material, which is available to authorized users.

Heat or Cold: Which One Exerts Greater Deleterious Effects on Health in a Basin Climate City? Impact of Ambient Temperature on Mortality in Chengdu, China

Background: Although studies from many countries have estimated the impact of ambient temperature on mortality, few have compared the relative impacts of heat and cold on health, especially in basin climate cities. We aimed to quantify the impact of ambient temperature on mortality, and to compare the contributions of heat and cold in a large basin climate city, i.e., Chengdu (Sichuan Province, China); Methods: We estimated the temperature-mortality association with a distributed lag non-linear model (DLNM) with a maximum lag-time of 21 days while controlling for long time trends and day of week. We calculated the mortality risk attributable to heat and cold, which were defined as temperatures above and below an "optimum temperature" that corresponded to the point of minimum mortality. In addition, we explored effects of individual characteristics; Results: The analysis provides estimates of the overall mortality burden attributable to temperature, and then computes the components attributable to heat and cold. Overall, the total fraction of deaths caused by both heat and cold was 10.93% (95%CI: 7.99%-13.65%). Taken separately, cold was responsible for most of the burden (estimate 9.96%, 95%CI: 6.90%-12.81%), while the fraction attributable to heat was relatively small (estimate 0.97%, 95%CI: 0.46%-2.35%). The attributable risk (AR) of respiratory diseases was higher (19.69%, 95%CI: 14.45%-24.24%) than that of cardiovascular diseases (11.40%, 95%CI: 6.29%-16.01%); Conclusions: In Chengdu, temperature was responsible for a substantial fraction of deaths, with cold responsible for a higher proportion of deaths than heat. Respiratory diseases exert a larger effect on death than other diseases especially on cold days. There is potential to reduce respiratory-associated mortality especially among the aged population in basin climate cities when the temperature deviates beneath the optimum. The result may help to comprehensively assess the impact of ambient temperature in basin cities, and further facilitate an appropriate estimate of the health consequences of various climate-change scenarios.

Long-term changes in the heat-mortality relationship according to heterogeneous regional climate: a time-series study in South Korea

OBJECTIVES

Several studies identified a heterogeneous impact of heat on mortality in hot and cool regions during a fixed period, whereas less evidence is available for changes in risk over time due to climate change in these regions. We compared changes in risk during periods without (1996-2000) and with (2008-2012) heatwave warning forecasts in regions of South Korea with different climates.

METHODS

Study areas were categorised into 3 clusters based on the spatial clustering of cooling degree days in the period 1993-2012: hottest cluster (cluster H), moderate cluster (cluster M) and cool cluster (cluster C). The risk was estimated according to increases in the daily all-cause, cardiovascular and respiratory mortality per 1°C change in daily temperature above the threshold, using a generalised additive model.

RESULTS

The risk of all types of mortality increased in cluster H in 2008-2012, compared with 1996-2000, whereas the risks in all-combined regions and cooler clusters decreased. Temporal increases in mortality risk were larger for some vulnerable subgroups, including younger adults (<75 years), those with a lower education and blue-collar workers, in cluster H as well as all-combined regions. Different patterns of risk change among clusters might be attributable to large increases in heatwave frequency or duration during study periods and the degree of urbanisation in cluster H.

CONCLUSIONS

People living in hotter regions or with a lower socioeconomic status are at higher risk following an increasing trend of heat-related mortality risks. Continuous efforts are needed to understand factors which affect changes in heat-related mortality risks.

Mortality during a Large-Scale Heat Wave by Place, Demographic Group, Internal and External Causes of Death, and Building Climate Zone

Mortality increases during periods of elevated heat. Identification of vulnerable subgroups by demographics, causes of death, and geographic regions, including deaths occurring at home, is needed to inform public health prevention efforts. We calculated mortality relative risks (RRs) and excess deaths associated with a large-scale California heat wave in 2006, comparing deaths during the heat wave with reference days. For total (all-place) and at-home mortality, we examined risks by demographic factors, internal and external causes of death, and building climate zones. During the heat wave, 582 excess deaths occurred, a 5% increase over expected (RR = 1.05, 95% confidence interval (CI) 1.03-1.08). Sixty-six percent of excess deaths were at home (RR = 1.12, CI 1.07-1.16). Total mortality risk was higher among those aged 35-44 years than ≥ 65, and among Hispanics than whites. Deaths from external causes increased more sharply (RR = 1.18, CI 1.10-1.27) than from internal causes (RR = 1.04, CI 1.02-1.07). Geographically, risk varied by building climate zone; the highest risks of at-home death occurred in the northernmost coastal zone (RR = 1.58, CI 1.01-2.48) and the southernmost zone of California's Central Valley (RR = 1.43, CI 1.21-1.68). Heat wave mortality risk varied across subpopulations, and some patterns of vulnerability differed from those previously identified. Public health efforts should also address at-home mortality, non-elderly adults, external causes, and at-risk geographic regions.

Distinct atmospheric patterns and associations with acute heat-induced mortality in five regions of England

The main objective of this paper was to identify possible acute heat-induced summer mortality in five regions of England namely the Yorkshire and the Humber, West Midlands, North East, North West and South East regions and reveal associations with specific air flows. For this purpose, backward air mass trajectories corresponding to daily episodes of increased temperatures were produced and divided to clusters, in order to define atmospheric pathways associated with warm air mass intrusions. A statistically significant at 95 % confidence interval increase in daily total mortality (DTMORT) was observed during the selected episodes at all five regions and thus, heat-induced mortality was indicated. The calculated raise was more intense in the West Midlands, North West and South East regions, whereas the results in the North East and Yorkshire and the Humber regions were less evident. Large fractions of thermal episodes, elevated average temperature values and higher average DTMORT levels were primarily associated with the short-medium range South West (SW) and/or East-South East (E-SE) trajectory clusters, suggesting relations among heat-induced mortality and specific atmospheric circulations. Short-medium length of SW and E-SE airflows, calculated by an application of Haversine formula along the centroid trajectory of each cluster, implies the arrival of slow moving air masses. Atmospheric stagnation could enhance human thermal stress due to low wind speed.

Urban-hazard risk analysis: mapping of heat-related risks in the elderly in major Italian cities

BACKGROUND

Short-term impacts of high temperatures on the elderly are well known. Even though Italy has the highest proportion of elderly citizens in Europe, there is a lack of information on spatial heat-related elderly risks.

OBJECTIVES

Development of high-resolution, heat-related urban risk maps regarding the elderly population (≥ 65).

METHODS

A long time-series (2001-2013) of remote sensing MODIS data, averaged over the summer period for eleven major Italian cities, were downscaled to obtain high spatial resolution (100 m) daytime and night-time land surface temperatures (LST). LST was estimated pixel-wise by applying two statistical model approaches: 1) the Linear Regression Model (LRM); 2) the Generalized Additive Model (GAM). Total and elderly population density data were extracted from the Joint Research Centre population grid (100 m) from the 2001 census (Eurostat source), and processed together using "Crichton's Risk Triangle" hazard-risk methodology for obtaining a Heat-related Elderly Risk Index (HERI).

RESULTS

The GAM procedure allowed for improved daytime and night-time LST estimations compared to the LRM approach. High-resolution maps of daytime and night-time HERI levels were developed for inland and coastal cities. Urban areas with the hazardous HERI level (very high risk) were not necessarily characterized by the highest temperatures. The hazardous HERI level was generally localized to encompass the city-centre in inland cities and the inner area in coastal cities. The two most dangerous HERI levels were greater in the coastal rather than inland cities.

CONCLUSIONS

This study shows the great potential of combining geospatial technologies and spatial demographic characteristics within a simple and flexible framework in order to provide high-resolution urban mapping of daytime and night-time HERI. In this way, potential areas for intervention are immediately identified with up-to-street level details. This information could support public health operators and facilitate coordination for heat-related emergencies.

Metrics for biogeophysical climate forcings from land use and land cover changes and their inclusion in life cycle assessment: a critical review

The regulation by vegetation of heat, momentum, and moisture exchanges between the land surface and the atmosphere is a major component in Earth's climate system. By altering surface biogeophysics, anthropogenic land use activities often perturb these exchanges and thereby directly affect climate. Although long recognized scientifically as being important, biogeophysical climate forcings from land use and land cover changes (LULCC) are rarely included in life cycle assessment (LCA). Here, I review climate metrics for characterizing biogeophysical climate forcings from LULCC, focusing mostly on those that do not require coupled land-atmosphere climate models to compute. I discuss their merits, highlight their pros and cons in terms of their compatibility with the LCA framework, outline near-term practical guidelines and solutions for their integration, and point to areas of longer term research needs in both the climate science and LCA research communities.

Links between thermoregulation and aging in endotherms and ectotherms

While the link between thermoregulation and aging is generally accepted, much further research, reflection, and debate is required to elucidate the physiological and molecular pathways that generate the observed thermal-induced changes in lifespan. Our aim in this review is to present, discuss, and scrutinize the thermoregulatory mechanisms that are implicated in the aging process in endotherms and ectotherms. Our analysis demonstrates that low body temperature benefits lifespan in both endothermic and ectothermic organisms. Research in endotherms has delved deeper into the physiological and molecular mechanisms linking body temperature and longevity. While research in ectotherms has been steadily increasing during the past decades, further mechanistic work is required in order to fully elucidate the underlying phenomena. What is abundantly clear is that both endotherms and ectotherms have a specific temperature zone at which they function optimally. This zone is defended through both physiological and behavioral means and plays a major role on organismal senescence. That low body temperature may be beneficial for lifespan is contrary to conventional medical theory where reduced body temperature is usually considered as a sign of underlying pathology. Regardless, this phenomenon has been targeted by scientists with the expectation that advancements may compress morbidity, as well as lower disease and mortality risk. The available evidence suggests that lowered body temperature may prolong life span, yet finding the key to temperature regulation remains the problem. While we are still far from a complete understanding of the mechanisms linking body temperature and longevity, we are getting closer.

Influence of daily individual meteorological parameters on the incidence of acute coronary syndrome

BACKGROUND

A nationwide study was conducted to explore the short term association between daily individual meteorological parameters and the incidence of acute coronary syndrome (ACS) treated with coronary emergency catheter interventions in the Republic of Slovenia, a south-central European country.

METHOD

We linked meteorological data with daily ACS incidence for the entire population of Slovenia, for the population over 65 years of age and for the population under 65 years of age. Data were collected daily for a period of 4 years from 1 January 2008 to 31 December 2011. In line with existing studies, we used a main effect generalized linear model with a log-link-function and a Poisson distribution of ACS.

RESULTS AND CONCLUSIONS

Three of the studied meteorological factors (daily average temperature, atmospheric pressure and relative humidity) all have relevant and significant influences on ACS incidences for the entire population. However, the ACS incidence for the population over 65 is only affected by daily average temperature, while the ACS incidence for the population under 65 is affected by daily average pressure and humidity. In terms of ambient temperature, the overall findings of our study are in line with the findings of the majority of contemporary European studies, which also note a negative correlation. The results regarding atmospheric pressure and humidity are less in line, due to considerable variations in results. Additionally, the number of available European studies on atmospheric pressure and humidity is relatively low. The fourth studied variable-season-does not influence ACS incidence in a statistically significant way.

Is planned adaptation to heat reducing heat-related mortality and illness? A systematic review

BACKGROUND

Extreme heat is an important public health risk. Climate change will likely increase the temperatures humans are exposed to through exacerbated heat wave intensity and frequency, possibly increasing health risks from heat. To prevent adverse effects on human health, heat prevention plans and climate change adaptation strategies are being implemented. But are these measures effectively reducing heat-related mortality and morbidity? This study assesses the evidence base in 2014.

METHODS

We conducted a systematic review of peer-reviewed published literature. We applied a combined search strategy of automated search and journal content search using the electronic databases PubMed, Web of Knowledge, Biological Abstracts, CAB Abstracts and ProQuest Dissertation & Theses A&I. Quality appraisal was conducted using CASP checklists, and we identified recurrent themes in studies with content analysis methodology. We conducted sub-group analyses for two types of studies: survey and interview research on behavioral change and perception, and observational studies with regression.

RESULTS

30 articles were included in the review. The majority of studies (n = 17) assessed mortality or morbidity reductions with regression analysis. Overall, the assessments report a reduction of adverse effects during extreme heat in places where preventive measures have been implemented. Population perception and behavior change were assessed in five studies, none of which had carried out a pre-test. Two themes emerged from the review: methodological challenges are a major hindrance to rigorous evaluation, and what counts as proof of an effective reduction in adverse health outcomes is disputed.

CONCLUSIONS

Attributing health outcomes to heat adaptation remains a challenge. Recent study designs are less rigorous due to difficulties assigning the counterfactual. While sensitivity to heat is decreasing, the examined studies provide inconclusive evidence on individual planned adaptation measures.

Environmental temperature and thermal indices: what is the most effective predictor of heat-related mortality in different geographical contexts?

The aim of this study is to identify the most effective thermal predictor of heat-related very-elderly mortality in two cities located in different geographical contexts of central Italy. We tested the hypothesis that use of the state-of-the-art rational thermal indices, the Universal Thermal Climate Index (UTCI), might provide an improvement in predicting heat-related mortality with respect to other predictors. Data regarding very elderly people (≥75 years) who died in inland and coastal cities from 2006 to 2008 (May–October) and meteorological and air pollution were obtained from the regional mortality and environmental archives. Rational (UTCI) and direct thermal indices represented by a set of bivariate/multivariate apparent temperature indices were assessed. Correlation analyses and generalized additive models were applied. The Akaike weights were used for the best model selection. Direct multivariate indices showed the highest correlations with UTCI and were also selected as the best thermal predictors of heat-related mortality for both inland and coastal cities. Conversely, the UTCI was never identified as the best thermal predictor. The use of direct multivariate indices, which also account for the extra effect of wind speed and/or solar radiation, revealed the best fitting with all-cause, very-elderly mortality attributable to heat stress.