Associations Between Extreme Temperatures and Cardiovascular Cause-Specific Mortality: Results From 27 Countries.

BACKGROUND Cardiovascular disease is the leading cause of death worldwide. Existing studies on the association between temperatures and cardiovascular deaths have been limited in geographic zones and have generally considered associations with total cardiovascular deaths rather than cause-specific cardiovascular deaths. METHODS We used unified data collection protocols within the Multi-Country Multi-City Collaborative Network to assemble a database of daily counts of specific cardiovascular causes of death from 567 cities in 27 countries across 5 continents in overlapping periods ranging from 1979 to 2019. City-specific daily ambient temperatures were obtained from weather stations and climate reanalysis models. To investigate cardiovascular mortality associations with extreme hot and cold temperatures, we fit case-crossover models in each city and then used a mixed-effects meta-analytic framework to pool individual city estimates. Extreme temperature percentiles were compared with the minimum mortality temperature in each location. Excess deaths were calculated for a range of extreme temperature days. RESULTS The analyses included deaths from any cardiovascular cause (32 154 935), ischemic heart disease (11 745 880), stroke (9 351 312), heart failure (3 673 723), and arrhythmia (670 859). At extreme temperature percentiles, heat (99th percentile) and cold (1st percentile) were associated with higher risk of dying from any cardiovascular cause, ischemic heart disease, stroke, and heart failure as compared to the minimum mortality temperature, which is the temperature associated with least mortality. Across a range of extreme temperatures, hot days (above 97.5th percentile) and cold days (below 2.5th percentile) accounted for 2.2 (95% empirical CI [eCI], 2.1-2.3) and 9.1 (95% eCI, 8.9-9.2) excess deaths for every 1000 cardiovascular deaths, respectively. Heart failure was associated with the highest excess deaths proportion from extreme hot and cold days with 2.6 (95% eCI, 2.4-2.8) and 12.8 (95% eCI, 12.2-13.1) for every 1000 heart failure deaths, respectively. CONCLUSIONS Across a large, multinational sample, exposure to extreme hot and cold temperatures was associated with a greater risk of mortality from multiple common cardiovascular conditions. The intersections between extreme temperatures and cardiovascular health need to be thoroughly characterized in the present day-and especially under a changing climate

Projections of Excess Mortality Related to Diurnal Temperature Range Under Climate Change Scenarios: a multi-country modelling study

Various retrospective studies have reported on the increase of mortality risk due to higher diurnal temperature range (DTR). This study projects the effect of DTR on future mortality across 445 communities in 20 countries and regions

Ambient Particulate Air Pollution and Daily Mortality in 652 Cities.

BACKGROUND: The systematic evaluation of the results of time-series studies of air pollution is challenged by differences in model specification and publication bias. METHODS: We evaluated the associations of inhalable particulate matter (PM) with an aerodynamic diameter of 10 μm or less (PM10) and fine PM with an aerodynamic diameter of 2.5 μm or less (PM2.5) with daily all-cause, cardiovascular, and respiratory mortality across multiple countries or regions. Daily data on mortality and air pollution were collected from 652 cities in 24 countries or regions. We used overdispersed generalized additive models with random-effects meta-analysis to investigate the associations. Two-pollutant models were fitted to test the robustness of the associations. Concentration-response curves from each city were pooled to allow global estimates to be derived. RESULTS: On average, an increase of 10 μg per cubic meter in the 2-day moving average of PM10 concentration, which represents the average over the current and previous day, was associated with increases of 0.44% (95% confidence interval [CI], 0.39 to 0.50) in daily all-cause mortality, 0.36% (95% CI, 0.30 to 0.43) in daily cardiovascular mortality, and 0.47% (95% CI, 0.35 to 0.58) in daily respiratory mortality. The corresponding increases in daily mortality for the same change in PM2.5 concentration were 0.68% (95% CI, 0.59 to 0.77), 0.55% (95% CI, 0.45 to 0.66), and 0.74% (95% CI, 0.53 to 0.95). These associations remained significant after adjustment for gaseous pollutants. Associations were stronger in locations with lower annual mean PM concentrations and higher annual mean temperatures. The pooled concentration-response curves showed a consistent increase in daily mortality with increasing PM concentration, with steeper slopes at lower PM concentrations. CONCLUSIONS: Our data show independent associations between short-term exposure to PM10 and PM2.5 and daily all-cause, cardiovascular, and respiratory mortality in more than 600 cities across the globe. These data reinforce the evidence of a link between mortality and PM concentration established in regional and local studies. (Funded by the National Natural Science Foundation of China and others.)

Geographical Variations of the Minimum Mortality Temperature at a Global Scale

Background: Minimum mortality temperature (MMT) is an important indicator to assess the temperature-mortality association, indicating long-term adaptation to local climate. Limited evidence about the geographical variability of the MMT is available at a global scale.Methods: We collected data from 658 communities in 43 countries under different climates. We estimated temperature-mortality associations to derive the MMT for each community using Poisson regression with distributed lag nonlinear models. We investigated the variation in MMT by climatic zone using a mixed-effects meta-analysis and explored the association with climatic and socioeconomic indicators.Results: The geographical distribution of MMTs varied considerably by country between 14.2 and 31.1 °C decreasing by latitude. For climatic zones, the MMTs increased from alpine (13.0 °C) to continental (19.3 °C), temperate (21.7 °C), arid (24.5 °C), and tropical (26.5 °C). The MMT percentiles (MMTPs) corresponding to the MMTs decreased from temperate (79.5th) to continental (75.4th), arid (68.0th), tropical (58.5th), and alpine (41.4th). The MMTs indreased by 0.8 °C for a 1 °C rise in a community’s annual mean temperature, and by 1 °C for a 1 °C rise in its SD. While the MMTP decreased by 0.3 centile points for a 1 °C rise in a community’s annual mean temperature and by 1.3 for a 1 °C rise in its SD.Conclusions: The geographical distribution of the MMTs and MMTPs is driven mainly by the mean annual temperature, which seems to be a valuable indicator of overall adaptation across populations. Our results suggest that populations have adapted to the average temperature, although there is still more room for adaptation

Mortality risk attributable to wildfire-related PM2·5 pollution : a global time series study in 749 locations

BACKGROUND : Many regions of the world are now facing more frequent and unprecedentedly large wildfires. However, the association between wildfire-related PM2·5 and mortality has not been well characterised. We aimed to comprehensively assess the association between short-term exposure to wildfire-related PM2·5 and mortality across various regions of the world. METHODS : For this time series study, data on daily counts of deaths for all causes, cardiovascular causes, and respiratory causes were collected from 749 cities in 43 countries and regions during 2000–16. Daily concentrations of wildfire-related PM2·5 were estimated using the three-dimensional chemical transport model GEOS-Chem at a 0·25° × 0·25° resolution. The association between wildfire-related PM2·5 exposure and mortality was examined using a quasi-Poisson time series model in each city considering both the current-day and lag effects, and the effect estimates were then pooled using a random-effects meta-analysis. Based on these pooled effect estimates, the population attributable fraction and relative risk (RR) of annual mortality due to acute wildfire-related PM2·5 exposure was calculated. FINDINGS : 65·6 million all-cause deaths, 15·1 million cardiovascular deaths, and 6·8 million respiratory deaths were included in our analyses. The pooled RRs of mortality associated with each 10 μg/m³ increase in the 3-day moving average (lag 0–2 days) of wildfire-related PM2·5 exposure were 1·019 (95% CI 1·016–1·022) for all-cause mortality, 1·017 (1·012–1·021) for cardiovascular mortality, and 1·019 (1·013–1·025) for respiratory mortality. Overall, 0·62% (95% CI 0·48–0·75) of all-cause deaths, 0·55% (0·43–0·67) of cardiovascular deaths, and 0·64% (0·50–0·78) of respiratory deaths were annually attributable to the acute impacts of wildfire-related PM2·5 exposure during the study period. INTERPRETATION : Short-term exposure to wildfire-related PM2·5 was associated with increased risk of mortality. Urgent action is needed to reduce health risks from the increasing wildfires.The Australian Research Council, the Australian National Health and Medical Research Council, a Career Development Fellowship of the Australian National Health and Medical Research Council, an Early Career Fellowship of the Australian National Health and Medical Research Council, the National Natural Science Foundation of China, the Czech Science Foundation, the Spanish Ministry of Economy, Industry and Competitiveness, the National Key Research and Development Program of China, EU’s Horizon 2020 Project Exhaustion, the Ministry of Science and Technology of Taiwan, the Medical Research Council UK, the Natural Environment Research Council UK, a fellowship of the Fundação para a Ciência e a Tecnologia, the Science and Technology Commission of Shanghai Municipality and the National Institute of Environmental Health Sciences-funded HERCULES Center.http://www.thelancet.com/planetary-healtham2022Geography, Geoinformatics and Meteorolog

On health effects of cold spells with a special reference to sudden cardiac death

Abstract There is substantial evidence on the associations between cold ambient temperature and adverse health effects. Less is known about the role of prolonged episodes of cold weather denoted as cold spells. This study assessed relations between cold spells and adverse health effects globally, and quantified and elaborated the associations between cold spells and sudden cardiac death (SCD) in northern Finland. Based on random-effects models in the meta-analyses of evidence from 9 studies around the world, cold spells were associated with increased mortality rates from all or all non-accidental causes (RR 1.10; 95% CI: 1.04–1.17), cardiovascular diseases (RR 1.11; 95% CI: 1.03–1.19), and respiratory diseases (RR 1.21; 95% CI: 0.97–1.51). Suggestive evidence of other health effects was identified. Investigating 51-years of coordinate-specific weather data at the home coordinates of autopsy-verified cases of SCD, conditional logistic regression in a case-crossover setting produced an estimate for the association between cold spells and the risk of SCD (OR 1.33; 95% CI: 1.00–1.78). A greater number of cold days preceding death increased the risk of SCD approximately 19% per day (OR 1.19; 95% CI: 1.07–1.32). The association between season-specific cold spells and SCD was strongest during autumn and winter, and lowest during spring and summer. The association was stronger for ischemic (OR 1.55; 95% CI: 1.12–2.13) than for non-ischemic SCD (OR 0.68; 95% CI: 0.32–1.45) (Q-statistic 3.85, p 0.05), confirmed by the autopsy finding. Among cases suffering ischemic SCD, the association seemed stronger in those without a prior diagnosis of ischemic heart disease than in those diagnosed during lifetime. The association seemed stronger with severe coronary stenosis (OR 1.60; 95% CI: 1.11–2.30), and weaker with moderate stenosis (OR 0.97; 95% CI: 0.37–2.55). The use of aspirin, β-blockers, and nitrates seemed to decrease the risk of ischemic SCD during cold spells. In conclusion, cold spells increased the risk of ischemic SCD, and patients without appropriate diagnosis and medications for ischemic heart disease seemed most susceptible. The results indicate that coronary stenosis plays a central role in the cold-related pathogenesis of SCD. Timely diagnosis and treatment of ischemic heart disease might reduce weather-related SCDs in a community.Tiivistelmä Kylmän lämpötilan ja terveyshaittojen välisistä yhteyksistä on vahva tutkimusnäyttö. Vähemmän tiedetään pitkittyneiden kylmäjaksojen ja terveyshaittojen välisistä yhteyksistä. Tutkimuksessa arvioitiin kylmäjaksojen ja terveyshaittojen välisiä yhteyksiä globaalisti, ja määritettiin kylmäjaksojen ja sydänperäisen äkkikuoleman (SÄK) välisiä yhteyksiä Pohjois-Suomessa. Yhdeksän eri puolella maailmaa toteutetun tutkimuksen tulosten meta-analyysissa satunnaisvaikutusten malli osoitti yhteyden kylmäjaksojen ja kaikkien tai luonnollisien syiden (RR 1.10; 95% CI: 1.04–1.17), sydän- ja verisuonisairauksien (RR 1.11; 95% CI: 1.03–1.19), ja hengityselimistön sairauksien (RR 1.21; 95% CI: 0.97–1.51) kuolleisuuden välillä. Viitteellistä näyttöä havaittiin muista terveyshaitoista. Tutkittaessa 51-vuoden koordinaattikohtaista säätä case-crossover-asetelmassa oikeuslääketieteellisesti vahvistettujen SÄK-tapausten kotiosoitteissa, ehdollisen logistisen regression mukaan SÄK:n riski oli yhteydessä kuolemaa edeltävään kylmäjaksoon (OR 1.33; 95% CI: 1.00–1.78). Lisääntyvä kylmien päivien lukumäärä ennen kuolemaa lisäsi riskiä keskimäärin 19% päivää kohden (OR 1.19; 95% CI: 1.07–1.32). Yhteys kausikohtaisten kylmäjaksojen ja SÄK:n välillä oli vahvin syksyllä ja talvella, ja heikoin keväällä ja kesällä. Yhteys oli vahvempi kylmäjaksojen ja iskeemisen SÄK:n (OR 1.55; 95% CI: 1.12–2.13) kuin kylmäjaksojen ja ei-iskeemisen SÄK:n (OR 0.68; 95% CI: 0.32–1.45) välillä (Q-statistic 3.85, p 0.05). Iskeemisen SÄK:n kokeneilla yhteys vaikutti vahvemmalta tapauksilla joilla ei ollut aiempaa iskeemisen sydänsairauden diagnoosia, kuin tapauksilla jotka oli diagnosoitu elinaikana. Yhteys vaikutti vahvemmalta vaikea-asteisesta sepelvaltimostenoosia sairastavilla (OR 1.60; 95% CI: 1.11–2.30), kuin lievempi-asteisessa stenoosissa (OR 0.97; 95% CI: 0.37–2.55). Aspiriini, β-salpaajat, ja nitraatit vaikuttivat vähentävän iskeemisen SÄK:n riskiä kylmäjakson aikana. Yhteenvetona, kylmäjaksot lisäsivät iskeemisen SÄK:n riskiä, ja potilaat vailla iskeemisen sydänsairauden diagnoosia ja lääkityksiä vaikuttivat olevan alttiimpia kylmäjaksojen haittavaikutuksille. Tulokset viittaavat sepelvaltimostenoosin keskeiseen rooliin kylmään liittyvän SÄK:n patogeneesissä. Varhainen iskeemisen sydänsairauden diagnoosi ja siihen liittyvä sydäntä suojaava lääkitys voisivat vähentää säähän liittyviä SÄK:a

Risk of ischemic and hemorrhagic stroke in relation to cold spells in four seasons

Background: Cold winter weather increases the risk of stroke, but the evidence is scarce on whether the risk increases during season-specific cold weather in the other seasons. The objective of our study was to test the hypothesis of an association between personal cold spells and different types of stroke in the season-specific context, and to formally assess effect modification by age and sex. Methods: We conducted a case-crossover study of all 5396 confirmed 25–64 years old cases with stroke in the city of Kaunas, Lithuania, 2000–2015. We assigned to each case a one-week hazard period and 15 reference periods of the same calendar days of other study years. A personal cold day was defined for each case with a mean temperature below the fifth percentile of the frequency distribution of daily mean temperatures of the hazard and reference periods. Conditional logistic regression was applied to estimate odds ratios (OR) and 95% confidence intervals (95% CI) representing associations between time- and place-specific cold weather and stroke. Results: There were positive associations between cold weather and stroke in Kaunas, with each additional cold day during the week before the stroke increases the risk by 3% (OR 1.03; 95% CI 1.00–1.07). The association was present for ischemic stroke (OR 1.05; 95% CI 1.01–1.09) but not hemorrhagic stroke (OR 0.98; 95% CI 0.91–1.06). In the summer, the risk of stroke increased by 8% (OR 1.08; 95% CI 1.00–1.16) per each additional cold day during the hazard period. Age and sex did not modify the effect. Conclusions: Our findings show that personal cold spells increase the risk of stroke, and this pertains to ischemic stroke specifically. Most importantly, cold weather in the summer season may be a previously unrecognized determinant of stroke.Peer reviewe

Cold Weather and Cardiac Arrest in 4 Seasons: Helsinki, Finland, 1997‒2018

Objectives. To test the a priori hypothesis that out-of-hospital cardiac arrest (OHCA) is associated with cold weather during all seasons, not only during the winter. Methods. We applied a case–crossover design to all cases of nontraumatic OHCA in Helsinki, Finland, over 22 years: 1997 to 2018. We statistically defined cold weather for each case and season, and applied conditional logistic regression with 2 complementary models a priori according to the season of death. Results. There was an association between cold weather and OHCA during all seasons, not only during the winter. Each additional cold day increased the odds of OHCA by 7% (95% confidence interval [CI] 5 4%, 10%), with similar strength of association during the autumn (6%; 95% CI 5 0%, 12%), winter (6%; 95% CI 5 1%, 12%), spring (8%; 95% CI 5 2%, 14%), and summer (7%; 95% CI 5 0%, 15%). Conclusions. Cold weather, defined according to season, increased the odds of OHCA during all seasons in similar quantity. Public Health Implications. Early warning systems and cold weather plans focus implicitly on the winter season. This may lead to incomplete measures in reducing excess mortality related to cold weather

Risk of ischemic and hemorrhagic stroke in relation to cold spells in four seasons

Abstract Background: Cold winter weather increases the risk of stroke, but the evidence is scarce on whether the risk increases during season-specific cold weather in the other seasons. The objective of our study was to test the hypothesis of an association between personal cold spells and different types of stroke in the season-specific context, and to formally assess effect modification by age and sex. Methods: We conducted a case-crossover study of all 5396 confirmed 25–64 years old cases with stroke in the city of Kaunas, Lithuania, 2000–2015. We assigned to each case a one-week hazard period and 15 reference periods of the same calendar days of other study years. A personal cold day was defined for each case with a mean temperature below the fifth percentile of the frequency distribution of daily mean temperatures of the hazard and reference periods. Conditional logistic regression was applied to estimate odds ratios (OR) and 95% confidence intervals (95% CI) representing associations between time- and place-specific cold weather and stroke. Results: There were positive associations between cold weather and stroke in Kaunas, with each additional cold day during the week before the stroke increases the risk by 3% (OR 1.03; 95% CI 1.00–1.07). The association was present for ischemic stroke (OR 1.05; 95% CI 1.01–1.09) but not hemorrhagic stroke (OR 0.98; 95% CI 0.91–1.06). In the summer, the risk of stroke increased by 8% (OR 1.08; 95% CI 1.00–1.16) per each additional cold day during the hazard period. Age and sex did not modify the effect. Conclusions: Our findings show that personal cold spells increase the risk of stroke, and this pertains to ischemic stroke specifically. Most importantly, cold weather in the summer season may be a previously unrecognized determinant of stroke

Association between winter cold spells and acute myocardial infarction in Lithuania 2000–2015

Abstract Acute myocardial infarction (AMI) is a major public health problem. Cold winter weather increases the risk of AMI, but factors influencing susceptibility are poorly known. We conducted an individual-level case-crossover study of the associations between winter cold spells and the risk of AMI, with special focus on survival at 28 days and effect modification by age and sex. All 16,071 adult cases of AMI among the residents of the city of Kaunas in Lithuania in 2000–2015 were included in the study. Cold weather was statistically defined using the 5th percentile of frequency distribution of daily mean temperatures over the winter months. According to conditional logistic regression controlling for time-varying and time-invariant confounders, each additional cold spell day during the week preceding AMI increased the risk of AMI by 5% (95% CI 1–9%). For nonfatal and fatal cases, the risk increase per each additional cold spell day was 5% (95% CI 1–9%) and 6% (95% CI − 2–13%), respectively. The effect estimate was greater for men (OR 1.07, 95% CI 1.02–1.12) than for women (OR 1.02, 95% CI 0.97–1.08), but there was no evidence of effect modification by age. Evidence on factors increasing susceptibility is critical for targeted cold weather planning