Influence of ambient temperature and diurnal temperature range on incidence of cardiac arrhythmias

Ambient temperature anomalies induce electrocardiogram abnormalities: Findings from a nationwide longitudinal study

Electrocardiogram (ECG) outcomes serve as early manifestations of cardiovascular functional or structural changes. While temperature fluctuation has been demonstrated to be a risk factor for cardiovascular diseases, few epidemiological studies have reported its relationship with ECG outcomes. In this study, we employed temperature anomaly (TA) as an innovative indicator of temperature fluctuation to quantify its detrimental impacts on ECG outcomes. A longitudinal study design was conducted using the repeated ECG records of the China National Stroke Screening Survey from 2013 to 2019. Only individuals undergoing at least two ECG tests were included. The daily temperature was assimilated by combining three kinds of data: in situ observations, satellite remote sensing measurements and weather research forecast simulations. We used generalized estimating equations to control for autocorrelation among repeated records and to estimate the association between TA and the risk of ECG abnormalities. We found 6837 events of ECG abnormalities in 47,286 individuals with 102,030 visits. Each unit increment of TA increased the risk of ECG abnormalities [odds ratio (OR) = 1.009, 95% confidence interval (CI): 1.001-1.017] and the risk of myocardial ischemia (OR = 1.061, 95% CI: 1.012-1.111). Hierarchic analyses presented a similar association of TA with both ECG abnormalities (OR = 1.017, 95% CI: 1.008-1.026) and myocardial ischemia (OR = 1.061, 95%CI: 1.011-1.114) in Northern China, but not in Southern China. The exposure-response relationship was estimated as a U-shaped curve centered at the TA value of zero. Sudden warming tended to increase the risk of ECG abnormalities and myocardial ischemia, and sudden cooling tended to increase the risk of atrial fibrillation. All these detrimental effects of TA could be modified by specific individual characteristics. In summary, ambient temperature fluctuation increased the risk of ECG abnormalities. This result indicated that regular ECG tests could be an early-warning measure for monitoring the adverse health effects of temperature fluctuations.

Research on the cascading mechanism of "urban built environment-air pollution-respiratory diseases": a case of Wuhan city

Background

Most existing studies have only investigated the direct effects of the built environment on respiratory diseases. However, there is mounting evidence that the built environment of cities has an indirect influence on public health via influencing air pollution. Exploring the "urban built environment-air pollution-respiratory diseases" cascade mechanism is important for creating a healthy respiratory environment, which is the aim of this study.

Methods

The study gathered clinical data from 2015 to 2017 on patients with respiratory diseases from Tongji Hospital in Wuhan. Additionally, daily air pollution levels (sulfur dioxide (SO2), nitrogen dioxide (NO2), particulate matter (PM2.5, PM10), and ozone (O3)), meteorological data (average temperature and relative humidity), and data on urban built environment were gathered. We used Spearman correlation to investigate the connection between air pollution and meteorological variables; distributed lag non-linear model (DLNM) was used to investigate the short-term relationships between respiratory diseases, air pollutants, and meteorological factors; the impacts of spatial heterogeneity in the built environment on air pollution were examined using the multiscale geographically weighted regression model (MGWR).

Results

During the study period, the mean level of respiratory diseases (average age 54) was 15.97 persons per day, of which 9.519 for males (average age 57) and 6.451 for females (average age 48); the 24 h mean levels of PM10, PM2.5, NO2, SO2 and O3 were 78.056 μg/m3, 71.962 μg/m3, 54.468 μg/m3, 12.898 μg/m3, and 46.904 μg/m3, respectively; highest association was investigated between PM10 and SO2 (r = 0.762, p < 0.01), followed by NO2 and PM2.5 (r = 0.73, p < 0.01), and PM10 and PM2.5 (r = 0.704, p < 0.01). We observed a significant lag effect of NO2 on respiratory diseases, for lag 0 day and lag 1 day, a 10 μg/m3 increase in NO2 concentration corresponded to 1.009% (95% CI: 1.001, 1.017%) and 1.005% (95% CI: 1.001, 1.011%) increase of respiratory diseases. The spatial distribution of NO2 was significantly influenced by high-density urban development (population density, building density, number of shopping service facilities, and construction land, the bandwidth of these four factors are 43), while green space and parks can effectively reduce air pollution (R2 = 0.649).

Conclusion

Previous studies have focused on the effects of air pollution on respiratory diseases and the effects of built environment on air pollution, while this study combines these three aspects and explores the relationship between them. Furthermore, the theory of the "built environment-air pollution-respiratory diseases" cascading mechanism is practically investigated and broken down into specific experimental steps, which has not been found in previous studies. Additionally, we observed a lag effect of NO2 on respiratory diseases and spatial heterogeneity of built environment in the distribution of NO2.

The Impact of Climate Change and Extreme Weather Conditions on Cardiovascular Health and Acute Cardiovascular Diseases

Climate change is widely recognized as one of the most significant challenges facing our planet and human civilization. Human activities such as the burning of fossil fuels, deforestation, and industrial processes release greenhouse gases into the atmosphere, leading to a warming of the Earth's climate. The relationship between climate change and cardiovascular (CV) health, mediated by air pollution and increased ambient temperatures, is complex and very heterogeneous. The main mechanisms underlying the pathogenesis of CV disease at extreme temperatures involve several regulatory pathways, including temperature-sympathetic reactivity, the cold-activated renin-angiotensin system, dehydration, extreme temperature-induced electrolyte imbalances, and heat stroke-induced systemic inflammatory responses. The interplay of these mechanisms may vary based on individual factors, environmental conditions, and an overall health background. The net outcome is a significant increase in CV mortality and a higher incidence of hypertension, type II diabetes mellitus, acute myocardial infarction (AMI), heart failure, and cardiac arrhythmias. Patients with pre-existing CV disorders may be more vulnerable to the effects of global warming and extreme temperatures. There is an urgent need for a comprehensive intervention that spans from the individual level to a systemic or global approach to effectively address this existential problem. Future programs aimed at reducing CV and environmental burdens should require cross-disciplinary collaboration involving physicians, researchers, public health workers, political scientists, legislators, and national leaders to mitigate the effects of climate change.

Large sex differences in vulnerability to circulatory-system disease under current and future climate in Bucharest and its rural surroundings

Circulatory-system diseases (CSDs) are responsible for 50-60% of all deaths in Romania. Due to its continental climate, with cold winters and very warm summers, there is a strong temperature dependence of the CSD mortality. Additionally, within its capital Bucharest, the urban heat island (UHI) is expected to enhance (reduce) heat (cold)-related mortality. Using distributed lag non-linear models, we establish the relation between temperature and CSD mortality in Bucharest and its surroundings. A striking finding is the strong temperature-related response to high urban temperatures of women in comparison with men from the total CSDs mortality. In the present climate, estimates of the CSDs attributable fraction (AF) of mortality at high temperatures is about 66% higher in Bucharest than in its rural surroundings for men, while it is about 100% times higher for women. Additionally, the AF in urban areas is also significantly higher for elderly people, and for those with hypertensive and cerebrovascular diseases than in the rural surroundings. On the other hand, in rural areas, men but especially women are currently more vulnerable with respect to low temperatures than in the urban environment. In order to project future thermal-related mortality, we have used five bias-corrected climate projections from regional circulation models under two climate-change scenarios, RCP4.5 and RCP8.5. Analysis of the temperature-mortality associations for future climate reveals the strongest signal under the scenario RCP8.5 for women, elderly people as well as for groups with hypertensive and cerebrovascular diseases. The net AF increase is much larger in urban agglomeration for women (8.2 times higher than in rural surroundings) and elderly people (8.5 times higher than in rural surroundings). However, our estimates of thermal attributable mortality are most likely underestimated due to the poor representation of UHI and future demography.

The association between air pollution and the daily hospital visits for atrial fibrillation recorded by ECG: a cross-sectional study

BACKGROUND

The relationship between air pollution and atrial fibrillation (AF) recorded by electrocardiograph (ECG) has not yet been illustrated which worsens AF precaution and treatment. This research evaluated the association between air pollution and daily hospital visits for AF with ECG records.

METHODS

The study enrolled 4933 male and 5392 female patients whose ECG reports indicated AF from 2015 to 2018 in our hospital. Such data were then matched with meteorological data, including air pollutant concentrations, collected by local weather stations. A case-crossover study was performed to assess the relationship between air pollutants and daily hospital visits for AF recorded by ECG and to investigate its lag effect.

RESULTS

Our analysis revealed statistically significant associations between AF occurrence and demographic data, including age and gender. This effect was stronger in female (k = 0.02635, p < 0.01) and in patients over 65 y (k = 0.04732, p < 0.01). We also observed a hysteretic effect that when exposed to higher nitrogen dioxide(NO2), counting AF cases recorded by ECG may elevate at lag 0 with a maximum odds ratio(OR) of 1.038 (95% CI 1.014-1.063), on the contrary, O3 reduced the risk of daily visits for AF and its maximum OR was at lag 2, and the OR value was 0.9869 (95% CI 0.9791-0.9948). Other air pollutants such as PM2.5, PM10, and SO2 showed no clear relationship with the recorded AF.

CONCLUSION

The associations between air pollution and AF recorded with ECG were preliminarily discovered. Short-term exposure to NO2 was significantly associated with daily hospital visits for AF management.

Augmented temperature fluctuation aggravates muscular atrophy through the gut microbiota

Large temperature difference is reported to be a risk factor for human health. However, little evidence has reported the effects of temperature fluctuation on sarcopenia, a senile disease characterized by loss of muscle mass and function. Here, we demonstrate that higher diurnal temperature range in humans has a positive correlation with the prevalence of sarcopenia. Fluctuated temperature exposure (10-25 °C) accelerates muscle atrophy and dampens exercise performance in mid-aged male mice. Interestingly, fluctuated temperature alters the microbiota composition with increased levels of Parabacteroides_distasonis, Duncaniella_dubosii and decreased levels of Candidatus_Amulumruptor, Roseburia, Eubacterium. Transplantation of fluctuated temperature-shaped microbiota replays the adverse effects on muscle function. Mechanically, we find that altered microbiota increases circulating aminoadipic acid, a lysine degradation product. Aminoadipic acid damages mitochondrial function through inhibiting mitophagy in vitro. And Eubacterium supplementation alleviates muscle atrophy and dysfunction induced by fluctuated temperature. Our results uncover the detrimental impact of fluctuated temperature on muscle function and provide a new clue for gut-muscle axis.

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.

Seasonal variation in association between temperature change and emergency department visits: A multi-site study in China

BACKGROUND

There is limited evidence of effects and seasonal variation of temperature change on emergency department visits (EDVs).

OBJECTIVE

To investigate the association between diurnal temperature range (DTR), temperature change between neighboring days (TCN) and a comprehensive collection of cause-specific EDVs in China.

METHODS

We collected EDVs, weather, and air pollution data in 20 sites in China from 2014 to 2018. We applied a quasi-Poisson regression with distributed lag nonlinear model to evaluate DTR- and TCN-EDVs association. We used meta-analysis to pool site-specific estimates. We also conducted seasonal analysis and assess effects of modifiers.

RESULTS

A 1 °C increase of DTR and TCN was associated with 0.29% [95% confidence interval (CI): 0.07%, 0.51%)] and 1.44% (95% CI: 0.93%, 1.96%) increase of total EDVs, respectively. People aged 18-44 were sensitive to DTR and TCN, while the elderly population was sensitive to TCN only in spring and autumn. In seasonal analysis, effects of temperature change on total EDVs were lower in summer. TCN increased risks of genitourinary diseases in summer, respiratory diseases in winter, injury in autumn, and mental diseases in spring. DTR increased the risk of respiratory diseases in autumn.

CONCLUSION

Exposure to DTR and TCN was associated with elevated risk of EDVs but with great seasonal variations. Our results provided potential time and target populations for adaptive strategies and preventive measures.

Extreme diurnal temperature range and cardiovascular emergency hospitalisations in a Mediterranean region

OBJECTIVES

The impact of extreme diurnal temperature range (DTR) on cardiovascular morbidity in Mediterranean regions remains uncertain. We aimed to analyse the impact of extreme low DTR (stable temperature) or high DTR (changeable temperature) on cardiovascular hospitalisations in Catalonia (Southern Europe).

METHODS

We conducted a self-controlled case series study using whole-year data from the System for the Development of Research in Primary Care database and 153 weather stations from the Catalan Meteorological Service. The outcome was first emergency hospitalisation. Monthly DTR percentiles were used to define extreme DTR as low (DTR <the 5th percentile) and high (DTR>95th percentile). We assessed two effects: same-day (1-day exposure, coinciding with the extreme DTR episode) and cumulative (3-day exposure, adding two subsequent days). Incidence rate ratios (IRR) were calculated adjusted by age, season and air pollution. Stratified analyses by gender, age or cardiovascular type and regions are provided.

RESULTS

We computed 121 206 cardiovascular hospitalisations from 2006 to 2013. The IRR was 1.032 (95% CI 1.005 to 1.061) for same day and 1.024 (95% CI 1.006 to 1.042) for cumulative effects of extreme high DTR. The impact was significant for stroke and heart failure, but not for coronary heart disease. Conversely, extreme low DTR did not increase cardiovascular hospitalisations.

CONCLUSIONS

Extreme high DTR increased the incidence of cardiovascular hospitalisations, but not extreme low DTR. Same-day effects of extreme high DTR were stronger than cumulative effects. These findings contribute to better understand the impact of outdoor temperature on health, and to help defining public health strategies to mitigate such impact.

Temperature variability and hospitalization for cardiac arrhythmia in Brazil: A nationwide case-crossover study during 2000-2015

BACKGROUND

There is growing recognition of a potential role for environmental and climatic factors in influencing cardiovascular risk. It has been speculated that temperature variability (TV) is a risk factor for cardiac arrhythmia but evidence is limited.

OBJECTIVE

To quantify the geographic and demographic variations in the association between TV and hospitalization for cardiac arrhythmia in Brazil during 2000-2015.

METHODS

Data on hospitalization for arrhythmia and weather conditions were collected from 1,814 cities. TV was calculated as the standard deviation of daily maximum and minimum temperatures during exposure days. A time-stratified case-crossover approach was applied to examine the city-specific association between TV and hospitalization for arrhythmia. City-specific estimates were pooled at the national and regional levels using a random-effect meta-analysis. Stratified analyses were conducted by sex, three age-groups (0-64, 65-74 and ≥75 years), and three arrhythmia subtypes (paroxysmal tachycardia, atrial fibrillation and flutter, and other arrhythmias).

RESULTS

There were 447,667 arrhythmia-related hospitalizations during 2000-2015. The odds ratio of hospitalization per 1 °C increase in TV peaked on 0-1 days' exposure [1.012 (95% confidence interval: 1.010-1.015)]. There were no substantial differences in effect estimates of TV_0-1 by region, age or sex, except for the non-significant association observed in the north. However, women were more affected by prolonged TV exposure than men. For the three arrhythmias subtypes, only paroxysmal tachycardia and other arrhythmias were sensitive to TV. Assuming a causal relationship, 35,813 (95%CI: 18,302-51,665) cases were attributable to TV_0-1 in Brazil during 2000-2015, accounting for 8.0% (95%CI: 4.1-11.5%) of hospitalizations for cardiac arrhythmia.

CONCLUSIONS

At a population-level exposure to TV was associated with increased risk of arrhythmia-related hospitalization in Brazil, with the relationship equally distributed across most residents but varied by arrhythmia subtypes. Our findings add to the accumulating evidence-base that climatic factors can influence cardiovascular outcomes in populations.

Association between Weather-Related Factors and Cardiac Arrest of Presumed Cardiac Etiology: A Prospective Observational Study Based on Out-of-Hospital Care Data

OBJECTIVE

The objective of this study was to determine the association between weather-related factors and out-of-hospital cardiac arrest (OHCA) of presumed cardiac etiology.

METHODS

This was a prospective observational study performed in a prehospital setting. Data from the Emergency Medical Service in Hamburg (Germany) and data from the local weather station were evaluated over a 5-year period. Weather data (temperature, humidity, air pressure, wind speed) were obtained every minute and matched with the associated rescue mission data. Lowess-Regression analysis was performed to assess the relationship between the above-mentioned weather-related factors and OHCA of presumed cardiac etiology. Additionally, varying measuring-ranges were defined for each weather-related factor in order to compare them with each other with regard to the probability of occurrence of OHCA.

RESULTS

During the observation period 1,558 OHCA with presumed cardiac etiology were registered (age: 67 ± 19 yrs; 62% male; hospital admission: 37%; survival to hospital discharge: 6.7%). Compared to moderate temperatures (5 - 25°C), probability of OHCA-occurrence increased significantly at temperatures above 25°C (p = 0.028) and below 5°C p = 0.011). Regarding air humidity, probability of OHCA-occurrence increased below a threshold-value of 75% compared to values above this cut-off (p = 0.006). Decreased probability was seen at moderate atmospheric pressure (1000 hPa - 1020 hPa), whereas increased probability was seen above 1020 hPa (p = 0.023) and below 1000 hPa (p = 0.035). Probability of OHCA-occurrence increased continuously with increasing wind speed (p < 0.001).

CONCLUSIONS

There are associations between several weather-related factors such as temperature, humidity, air pressure, and wind speed, and occurrence of OHCA of presumed cardiac etiology. Particularly dangerous seem to be cold weather, dry air and strong wind.

The association of ambient temperature with incidence of cardiac arrhythmias in a short timescale

The body response time and an association between the exposure to outdoor temperature and cardiac arrhythmia were not fully understood. Hence, we further investigated the association between ambient temperature and the exacerbations of arrhythmia symptoms on a short timescale using the emergency department (ED) visit data. We used a total of 17,088 arrhythmia-related ED visits in Seoul, from 2008 to 2011 and fitted the model adjusting for other meteorological variables and air pollutants under the case-crossover analysis with the same year-month time stratification. The association was presented as an odds ratio (OR) with a 95% confidence interval (CI) by a 5 °C decrease in the ambient temperature. The delay time (h) between exposure and the onset of arrhythmia exacerbation was considered with time blocks for every 3 h as 1-3 h, up to 118-120 h; and daily lags (1 day), from 25-48 h to 97-120 h, as a multi-time average of exposures. The overall association was increased at lag 4-6 h and the increased association was statistically significant at lag 40-42 h (OR 1.027, 95% CI 1.003-1.051) and the adverse association continued at 97-120 h (OR 1.053, 95% CI 1.027-1.080). However, the delay of several days between ambient temperature and body response should be further investigated considering the modification according to varied demographic characteristics or different environmental circumstances.

The association of air temperature with cardiac arrhythmias

The body response to meteorological influences may activate pathophysiological mechanisms facilitating the occurrence of cardiac arrhythmias in susceptible patients. Putative underlying mechanisms include changes in systemic vascular resistance and blood pressure, as well as a network of proinflammatory and procoagulant processes. Such a chain reaction probably occurs within the time window of several hours, so use of daily average values of meteorological elements do not seem appropriate for investigation in this area. In addition, overall synoptic situation, and season-specific combinations of meteorological elements and air pollutant levels probably cause the overall effect rather than a single atmospheric element. Particularly strong interrelations have been described among wind speed, air pressure and temperature, relative air humidity, and suspended particulate matter. This may be the main reason why studies examining the association between temperature and ventricular arrhythmias have found linear positive, negative, J-shaped or no association. Further understanding of the pathophysiological adaptation to atmospheric environment may help in providing recommendations for protective measures during "bad" weather conditions in patients with cardiac arrhythmias.