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

Abstract

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.

Analysis of Heat Exposure During Pregnancy and Severe Maternal Morbidity

“…Our findings were supported by previously reported associations between heat exposure and cardiovascular-related outcomes with postulated mechanisms, such as leading to volume depletion and electrolyte imbalance, inducing inflammation and hypercoagulable states, and increasing heart rate and metabolic state. [22][23][24][53][54][55][56] We also looked at other prevalent SMM subconditions and observed significant associations for SMM sepsis . One possible explanation was that the hypovolemia resulting from heat exposure may promote localized infection to sepsis.…”

“…3,8,11,20,21 Existing literature has associated extreme heat exposure with adverse cardiovascular outcomes. 12, [22][23][24] Given the susceptibility of pregnant women, it would also be meaningful to investigate the underlying relationships between heat and maternal cardiovascular conditions with SMM, which may help to explain potential associations between heat and SMM and guide a more targeted intervention for minimizing heat-related SMM risks. In addition, since extreme heat may be increasingly associated with adverse maternal health outcomes in the changing climate, identifying effect modifiers such as maternal characteristics or other environmental factors (eg, residential green space) would provide important information for designing and implementing interventions for SMM.…”

Ambient Temperature and Myocardial Infarction

“… 2 A U-shaped association between ambient temperature and myocardial infarction has been found, which indicates that there is an increased risk of myocardial infarction in both the extremes of cold and warm temperatures. 3 , 4 , 5 This observation has been made globally, across different latitudes, meteorological conditions, and populations. Perhaps unsurprisingly given the heterogeneity in study design and study populations, the effect size is variable.…”

The Impact of Meteorological Parameters and Seasonal Changes on Reporting Patients with Selected Cardiovascular Diseases to Hospital Emergency Departments: A Pilot Study

“…The Polish population, compared to the European population (EU-28), is characterised by mortality that is almost 2 times higher for ischemic heart disease (Poland:131 deaths/100,000 inhabitants; and “EU-27”: 7 deaths/100,000 inhabitants) and 1.5 times higher for stroke (respectively, 53 deaths/100,000 compared to 38 deaths/100,000 inhabitants) [ 7 ]. The influence of seasonal changes, air temperature, or atmospheric pressure on the number of admissions of patients with symptoms of cardiovascular diseases to hospitals was the subject of many studies, which usually showed a relationship between the season and the days of the week, as well as air temperature and an increased incidence of cardiovascular diseases [ 8 , 9 , 10 , 11 ].…”