Quantifying Excess Deaths Related to Heatwaves under Climate Change Scenarios: A multicountry time series modelling study

Background: Heatwaves are a critical public health problem. There will be an increase in the frequency and severity of heatwaves under changing climate. However, evidence about the impacts of climate change on heatwave-related mortality at a global scale is limited. Methods and findings: We collected historical daily time series of mean temperature and mortality for all causes or nonexternal causes, in periods ranging from January 1, 1984, to December 31, 2015, in 412 communities within 20 countries/regions. We estimated heatwave–mortality associations through a two-stage time series design. Current and future daily mean temperature series were projected under four scenarios of greenhouse gas emissions from 1971–2099, with five general circulation models. We projected excess mortality in relation to heatwaves in the future under each scenario of greenhouse gas emissions, with two assumptions for adaptation (no adaptation and hypothetical adaptation) and three scenarios of population change (high variant, median variant, and low variant). Results show that, if there is no adaptation, heatwave-related excess mortality is expected to increase the most in tropical and subtropical countries/regions (close to the equator), while European countries and the United States will have smaller percent increases in heatwave-related excess mortality. The higher the population variant and the greenhouse gas emissions, the higher the increase of heatwave-related excess mortality in the future. The changes in 2031–2080 compared with 1971–2020 range from approximately 2,000% in Colombia to 150% in Moldova under the highest emission scenario and high-variant population scenario, without any adaptation. If we considered hypothetical adaptation to future climate, under high-variant population scenario and all scenarios of greenhouse gas emissions, the heatwave-related excess mortality is expected to still increase across all the countries/regions except Moldova and Japan. However, the increase would be much smaller than the no adaptation scenario. The simple assumptions with respect to adaptation as follows: no adaptation and hypothetical adaptation results in some uncertainties of projections. Conclusions: This study provides a comprehensive characterisation of future heatwave-related excess mortality across various regions and under alternative scenarios of greenhouse gas emissions, different assumptions of adaptation, and different scenarios of population change. The projections can help decision makers in planning adaptation and mitigation strategies for climate change. © 2018 Guo et al. http://creativecommons.org/licenses/by/4.0/

Temperature-Related Mortality Impacts Under and Beyond Paris Agreement Climate Change Scenarios

The Paris Agreement binds all nations to undertake ambitious efforts to combat climate change, with the commitment to Bhold warming well below 2 °C in global mean temperature (GMT), relative to pre-industrial levels, and to pursue efforts to limit warming to 1.5 °C^. The 1.5 °C limit constitutes an ambitious goal for which greater evidence on its benefits for health would help guide policy and potentially increase the motivation for action. Here we contribute to this gap with an assessment on the potential health benefits, in terms of reductions in temperature-related mortality, derived from the compliance to the agreed temperature targets, compared to more extreme warming scenarios. We performed a multi-region analysis in 451 locations in 23 countries with different climate zones, and evaluated changes in heat and coldrelated mortality under scenarios consistent with the Paris Agreement targets (1.5 and 2 °C) and more extreme GMT increases (3 and 4 °C), and under the assumption of no changes in demographic distribution and vulnerability. Our results suggest that limiting warming below 2 °C could prevent large increases in temperature-related mortality in most regions worldwide. The comparison between 1.5 and 2 °C is more complex and characterized by higher uncertainty, with geographical differences that indicate potential benefits limited to areas located in warmer climates, where direct climate change impacts will be more discernible

Temperature-Related Mortality Impacts Under and Beyond Paris Agreement Climate Change Scenarios

The Paris Agreement binds all nations to undertake ambitious efforts to combat climate change, with the commitment to Bhold warming well below 2 °C in global mean temperature (GMT), relative to pre-industrial levels, and to pursue efforts to limit warming to 1.5 °C^. The 1.5 °C limit constitutes an ambitious goal for which greater evidence on its benefits for health would help guide policy and potentially increase the motivation for action. Here we contribute to this gap with an assessment on the potential health benefits, in terms of reductions in temperature-related mortality, derived from the compliance to the agreed temperature targets, compared to more extreme warming scenarios. We performed a multi-region analysis in 451 locations in 23 countries with different climate zones, and evaluated changes in heat and coldrelated mortality under scenarios consistent with the Paris Agreement targets (1.5 and 2 °C) and more extreme GMT increases (3 and 4 °C), and under the assumption of no changes in demographic distribution and vulnerability. Our results suggest that limiting warming below 2 °C could prevent large increases in temperature-related mortality in most regions worldwide. The comparison between 1.5 and 2 °C is more complex and characterized by higher uncertainty, with geographical differences that indicate potential benefits limited to areas located in warmer climates, where direct climate change impacts will be more discernible

A systematic review and meta-analysis of the association between daily mean temperature and mortality in China

Abstract Purpose: We summarized the evidence on the effects of heat and cold exposures on mortality in China. We included studies published on this topic in both Chinese and English, thereby filling a gap in knowledge using data from a country that consists of one-fifth of the world’s population. Methods: We conducted a systematic search of peer-reviewed studies on the association between daily mean temperature and mortality published from 2001 up to July 2018. We searched one Chinese database (China National Knowledge infrastructure, http://www.cnki.net) and three English databases (PubMed, Scopus, Web of Science). We converted the effect estimates of heat/cold to rate ratios (RRs) associated with 1° increase/decrease beyond the heat/cold reference temperatures. For studies that provided lag-specific estimates, we used both the maximum and minimum of RR estimates. We calculated summary effect estimates for all-cause and cause-specific mortalities, as well as RRs stratified by sex, age, and socioeconomic status. We also investigated patterns of heat and cold adaptation at different latitudes, and at different reference temperatures. Results: In total, 45 articles were included in this systematic review. For every 1° temperature increase/decrease beyond reference points, the rate of non-accidental mortality increased by 2% (RR, 1.02; 95% confidence interval (95% CI [1.01–1.02]) for heat and 4% (RR, 1.04; 95% CI [1.03–1.04]) for cold, respectively; the rate of cardiovascular mortality increased 3% (RR, 1.03; 95% CI [1.03–1.04]) for heat and 6% (RR, 1.06; 95% CI [1.04–1.07]) for cold; the rate of respiratory mortality increased 2% (RR, 1.02; 95% CI [1.01–1.03]) for heat and 2% (RR, 1.02; 95% CI [1.00–1.04]) for cold; the rate of cerebrovascular mortality increased 2% (RR, 1.02; 95% CI [1.02–1.03]) for heat and 3% (RR, 1.03; 95% CI [1.02–1.04]) for cold. We identified a variation in optimal temperature range related to latitude of the residential area, and differences in people’s capability to adapt to heat versus cold. Conclusion: We found consistent evidence of the association between temperature and mortality, as well as evidence of patterns in human adaptation, and we discussed the implications of our findings

Dental caries is associated with lower respiratory tract infections:a population-based cohort study

Abstract Introduction: Dental caries and respiratory tract infections are among the most common infectious diseases worldwide and they both are appearing in the respiratory system. However, their relations are still unclear. This study investigated the association of dental caries on the risk of lower respiratory tract infections (LRTI) in young adulthood. Methods: The study population consisted of 1,592 Finnish young adults participating in the 20-year follow-up of The Espoo Cohort Study. The information on the occurrence of LRTIs (pneumonia or acute bronchitis) during the preceding 12 months was based on the follow-up questionnaire and the National Hospital Discharge Register. Lifelong caries on permanent teeth was defined as a self-reported number of filled teeth (FT). The risk ratios (RR) of LRTIs with 95% confidence intervals (CI) were estimated using Poisson regression models. Results: High FT number was associated with an increased occurrence of LRTIs with an adjusted RR of 1.24 per interquartile range (IQR) of FT (95% CI 1.06–1.44). The risk of LRTIs increased according to the increasing number of FTs, being highest among those subjects with 10 or more filled teeth (adjusted RR 2.30; 1.27–4.17). Family’s socioeconomic status or smoking did not modify the effect. Conclusions: Our results suggest that dental caries increases the risk of LRTIs. We did not find any significant effect modification by shared determinants of caries and LRTIs. However, it is possible, that common risk factors might explain at least partly the observed relation between FT and LRTIs or that the causality is bidirectional

Cold weather-related cardiorespiratory symptoms predict higher morbidity and mortality

Abstract Symptoms perceived in cold weather reflect physiological responses to body cooling and may worsen the course of a pre-existing disease or precipitate disease events in ostensibly healthy individuals. However, the associations between cold-related symptoms and their health effects have remained unknown. We examined whether cold-related cardiac and respiratory symptoms perceived in cold weather predict future morbidity and mortality. Methods: Cold-related symptoms were inquired in four national FINRISK surveys conducted in 1997, 2002, 2007, 2012 in Finland including altogether 17 040 respondents. A record linkage was made to national hospital discharge and cause-of-death registers. The participants were followed up until the first hospital admission due to a cardiovascular or respiratory disease or death, or until the end of 2015. The individual follow-up times ranged from 0 to 18 years (mean 11 years). The association of cold-related symptoms with morbidity and mortality was examined by Kaplan-Meyer and Cox-regression analyses. Results: Cold-related cardiac [hazard ratio (HR), 1.76 and its 95% confidence interval (95% CI), 1.44–2.15] and combined cardiac and respiratory symptoms [1.50 (1.29–1.73)] were associated with hospitalization due to cardiovascular causes. The respective HRs for admissions due to respiratory causes were elevated for cold-related respiratory [1.22 (1.07–1.40)], cardiac [1.24 (0.88–1.75)] and cardiorespiratory [1.82 (1.50–2.22)] symptoms. Cold-related cardiorespiratory symptoms were associated with deaths from all natural [1.38 (1.11–1.72)], cardiovascular [1.77 (1.28–2.44)] and respiratory [2.19 (0.95–5.06)] causes. Interpretation: Cold weather-related symptoms predict a higher occurrence of hospital admissions and mortality. The information may prove useful in planning measures to reduce cold-related adverse health effects

Mediating role of oxidative/nitrosative stress biomarkers in the associations between phthalate exposure and thyroid function in Taiwanese adults

Abstract Phthalate exposure was shown to alter thyroid function, however it is unclear, whether oxidative and nitrosative stress explains the intermediate biological mechanism. This study aimed to investigate the associations between phthalate exposure, oxidative/nitrosative stress, and thyroid function in adults, and to examine the mediating role of oxidative/nitrosative stress in the associations between phthalate exposure and thyroid function. Levels of eleven urinary phthalate metabolites, three urinary biomarkers of oxidative/nitrosative stress (malondialdehyde [MDA], 8-OHdG, and 8-NO₂Gua) and five serum thyroid hormones (thyroxine [T₄], free T₄, triiodothyronine, thyroid-stimulating hormone, and thyroxine-binding globulin) were measured in 266 Taiwanese adults. Cross-sectional associations between phthalate metabolites, biomarkers of oxidative/ nitrosative stress and thyroid hormones were analyzed using multivariate regression models. Mediation analysis was conducted to assess the role of oxidative/nitrosative stress in the associations between phthalate metabolites and thyroid hormone levels. Sum of di-(2-ethylhexyl) phthalate (DEHP) metabolites was positively associated with MDA (βT1−T2 = 0.253, 95%CI [0.060, 0.447]; β ≧T2 = 0.317, 95% CI [0.098, 0.536]; Ptrend = 0.005) and 8-NO₂Gua (βT1−T2 = −0.010, 95%CI [−0.138, 0.118]; β ≧T2 = 0.144, 95% CI [−0.001, 0.289]; Ptrend = 0.045). Mono-n-butyl phthalate (MnBP) was positively associated with 8-NO₂Gua (βT1−T2 = 0.201, 95% CI [0.078, −0.324]; β ≧T2 = 0.161, 95% CI [0.031, −0.292]; Ptrend = 0.018). T4 was negatively associated with MDA (βT1−T2 = −0.027, 95% CI [−0.088, 0.0034]; β≧T2 = −0.094, 95% CI [−0.161, −0.028]; Ptrend = 0.005) and 8-NO₂Gua (βT1−T2 = −0.068, 95% CI [−0.127, −0.010]; β≧T2 = −0.125, 95% CI [−0.184, −0.066]; Ptrend < 0.001). Free T₄ was positively associated with MDA (Ptrend = 0.047) and with 8-NO₂Gua (Ptrend < 0.001). 8-NO₂Gua mediated 11% of the association between the sum of DEHP metabolites and T₄, and 17% of the association between MnBP and free T₄. These results suggest that phthalate exposure may influence thyroid hormone levels through induced oxidative/nitrosative stress