Cold periods and coronary events: an analysis of populations worldwide

Associations of heat with diseases and specific symptoms in Flanders, Belgium: An 8-year retrospective study of general practitioner registration data

INTRODUCTION

Global temperature rise has become a major health concern. Most previous studies on the impact of heat on morbidity have used hospital data.

OBJECTIVE

This study aimed to quantify the association between ambient temperature and a variety of potentially heat-related medical conditions and symptoms using general practitioner (GP) data, in Flanders, Belgium.

METHODS

We used eight years (2012-2019) of aggregated data of daily GP visits during the Belgian summer period (May-September). A distributed lag nonlinear model (DLNM) with time-stratified conditional quasi-Poisson regression was used to account for the non-linear and delayed effect of temperature indicators (minimum, mean and maximum). We controlled for potential confounders such as particulate matter, humidity, and ozone.

RESULTS

The overall (lag0-14) association between heat and most of the outcomes was J-shaped, with an increased risk of disease observed at higher temperatures. The associations were more pronounced using the minimum temperatures indicator. Comparing the 99th (20 °C) to the minimum morbidity temperature (MMT) of the minimum temperature distribution during summer, the relative risk (RR) was significantly higher for heat-related general symptoms (RR = 1.30 [95 % CI: 1.07, 1.57]), otitis externa (RR = 4.87 [95 % CI:2.98, 7.98]), general heart problems (RR = 2.43 [95 % CI: 1.33, 4.42]), venous problems (RR = 2.48 [95 % CI:1.55, 3.96]), respiratory complaints (RR = 1.97 [95 % CI: 1.25, 3.09]), skin problems (RR = 3.26 [95 % CI: 2.51, 4.25]), and urinary infections (RR = 1.37 [95 % CI: 1.11, 1.69]). However, we did not find evidence for heat-related increases in gastrointestinal problems, cerebrovascular events, cardiovascular events, arrhythmia, mental health problems, upper respiratory problems and lower respiratory problems. An increased risk of allergy was observed when the minimum temperature reached 17.8 °C (RR = 1.50 [95 % CI: 1.23, 1.83]). Acute effects of heat were observed (largest effects at the first few lags).

SUMMARY

Our findings indicated that the occurrence of certain symptoms and illnesses during summer season is associated to high temperature or environmental exposures that are augmented by elevated temperatures. Overall, unlike hospitalization data, GP visits data provide broader population coverage, revealing a more accurate representation of heat-health association.

Prediction of emergency department presentations for acute coronary syndrome using a machine learning approach

The relationship between weather and acute coronary syndrome (ACS) incidence has been the subject of considerable research, with varying conclusions. Harnessing machine learning techniques, our study explores the relationship between meteorological factors and ACS presentations in the emergency department (ED), offering insights into seasonal variations and inter-day fluctuations to optimize patient care and resource allocation. A retrospective cohort analysis was conducted, encompassing ACS presentations to Dutch EDs from 2010 to 2017. Temporal patterns were analyzed using heat-maps and time series plots. Multivariable linear regression (MLR) and Random Forest (RF) regression models were employed to forecast daily ACS presentations with prediction horizons of one, three, seven, and thirty days. Model performance was assessed using the coefficient of determination (R²), Mean Absolute Error (MAE), and Mean Absolute Percentage Error (MAPE). The study included 214,953 ACS presentations, predominantly unstable angina (UA) (94,272; 44%), non-ST-elevated myocardial infarction (NSTEMI) (78,963; 37%), and ST-elevated myocardial infarction (STEMI) (41,718; 19%). A decline in daily ACS admissions over time was observed, with notable inter-day (estimated median difference: 41 (95%CI = 37-43, p = < 0.001) and seasonal variations (estimated median difference: 9 (95%CI 6-12, p = < 0.001). Both MLR and RF models demonstrated similar predictive capabilities, with MLR slightly outperforming RF. The models showed moderate explanatory power for ACS incidence (adjusted R² = 0.66; MAE (MAPE): 7.8 (11%)), with varying performance across subdiagnoses. Prediction of UA incidence resulted in the best-explained variability (adjusted R² = 0.80; MAE (MAPE): 5.3 (19.1%)), followed by NSTEMI and STEMI diagnoses. All models maintained consistent performance over extended prediction horizons. Our findings indicate that ACS presentation exhibits distinctive seasonal changes and inter-day differences, with marked reductions in incidence during the summer months and a distinct peak prevalence on Mondays. The predictive performance of our model was moderate. Nonetheless, we obtained good explanatory power for UA presentations. Our model emerges as a potentially valuable supplementary tool to enhance ED resource allocation or future predictive models predicting ACS incidence in the ED.

Modification of the association between cold spells and cardiovascular disease by changes in natural gas prices: A nationwide time-series study

BACKGROUND

Although the association between low ambient temperature and cardiovascular disease (CVD) is well-established, the effect of winter energy prices on this association remains unknown.

AIM

This ecological study aimed to investigate whether changes in natural gas prices (NGP), which account for a significant portion of winter energy prices in Korea, affect the association of cold spells with hospital admissions and mortality due to CVD.

METHODS

Data from the National Health Insurance Service and Statistics Korea were used to determine the daily number of hospital admissions and mortality rates associated with CVD. From January 2012 to February 2017, the NGP continually increased by 24.1%. From January 2012 to December 2014 the NGP continually decreased by 32.6% owing to the Korea Gas Corporation's management decisions, independent of external socioeconomic factors. We investigated the differences in the associations between cold spells and CVD-related outcomes in price-increasing and price-decreasing periods using a Poisson regression with a distributed lag nonlinear model. Cold spells were assessed on two consecutive days at the 5th percentile of the temperature for each region.

RESULTS

The meteorological factors and air pollution levels were similar between the two periods. The association between cold spells and hospital admissions due to CVD was stronger during the price-increasing period than during the price-decreasing period [ratio of cumulative relative risk (RRR) = 1.71, 95% confidence interval (CI): 1.31-2.22]. The difference in the association with mortality due to CVD between the two periods was not significant, although the point estimate remained >1 (RRR = 1.11, 95% CI: 0.90-1.38).

CONCLUSIONS

Changes in energy prices may modify the cold spell-related CVD risk, possibly by inducing behavioral changes to manage energy expenditure. Policymakers should take into account the potential public health implications of changes in energy prices, alongside their economic effects.

Relationship between temperature and acute myocardial infarction: a time series study in Xuzhou, China, from 2018 to 2020

BACKGROUND

It is widely known that the incidence rate and short-term mortality of acute myocardial infarctions (AMIs) are generally higher during the winter months. The goal of this study was to determine how the temperature of the environment influences fatal acute myocardial infarctions in Xuzhou.

METHODS

This observational study used the daily meteorological data and the data on the cause of death from acute myocardial infarction in Xuzhou from January 1, 2018, to December 31, 2020. After controlling meteorological variables and pollutants, the distributed nonlinear lag model (DLNM) was used to estimate the correlation between temperature and lethal AMI.

RESULTS

A total of 27,712 patients with fatal AMI were enrolled. 82.4% were over the age of 65, and 50.9% were men. Relative to the reference temperature (15 ℃), the 30-day cumulative RRs of the extremely cold temperature (- 2 ℃) for the general population, women, and people aged 65 years and above were 4.66 (95% CI: 1.76, 12.30), 15.29 (95% CI: 3.94, 59.36), and 7.13 (95% CI: 2.50, 20.35), respectively. The 30-day cumulative RRs of the cold temperature (2 ℃) for the general population, women, and people aged 65 years and above were 2.55 (1.37, 4.75), 12.78 (2.24, 5.36), and 3.15 (1.61, 6.16), respectively. No statistically significant association was observed between high temperatures and the risk of fatal AMI. The influence of the cold effect (1st and 10th) was at its peak on that day, and the entire cold effect persisted for 30 days. Temperature extremes had an effect on the lag patterns of distinct age and gender stratifications.

CONCLUSION

According to this study, the risk of fatal AMI increases significantly in cold weather but not in hot weather. Women above the age of 65 are particularly sensitive to severe weather events. The influence of frigid weather on public health should also be considered.

Seasonal variations in admissions for atrial fibrillation or atrial flutter in the Northeast and the Midwest regions of the United States

Background

Previous studies conflict on whether seasonal variability exists in atrial fibrillation (AF) admissions, and contemporary studies are lacking.

Methods

We identified admissions for AF or atrial flutter in the Midwest and Northeast regions of the US from the National Inpatient Database for 2016 to 2020, grouped them into the four seasons (spring, summer, fall, winter), and compared the number of admissions. Subgroup analyses were performed stratified to sex, age, race, AF alone, and geographical regions.

Results

A total of 955,320 admissions for AF or atrial flutter occurred. The number of admissions was highest during winter (243,990, 25.5% of the total), followed by fall (239,250, 25.0% of the total), summer (236,910, 24.8% of the total), and spring (235,170, 24.6% of the total). The differences were statistically significant (P < 0.001). An increasing trend in the number of admissions was observed from March to February of the next year (P trend <0.001). Admissions were most common in the winter and least common in the spring in subgroups of both sexes, age ≥65 years, Whites, non-Whites, AF alone, Northeast region, and Midwest region.

Conclusion

Contemporary analysis of a national database demonstrates seasonal variability in the number of admissions for AF, with a slight increase observed during the winter.

Effect of Temperature Variation on the Incidence of Acute Myocardial Infarction

BACKGROUND

Harsh temperature exposure has been associated with a high risk of cardiovascular events. We sought to investigate the influence of temperature change on long-term incidence of acute myocardial infarction (AMI) in Korean patients.

METHODS

From the National Health Insurance Service (NHIS) customized health information database (from 2005 to 2014), data from a total of 192,567 AMI patients was assessed according to the International Classification of Disease 10th edition code and matched with temperature reports obtained from the Korea Meteorological Administration database. We analyzed data for a 10-year period on a monthly and seasonal basis.

RESULTS

The incidence rate per 100,000 year of AMI exhibited a downward trend from 69.1 to 56.1 over the period 2005 to 2014 (P < 0.005), and the seasonal AMI incidence rate per 100,000 year was highest in spring (63.1), and winter (61.3) followed by autumn (59.5) and summer (57.1). On a monthly basis, the AMI incidence rate per 100,000 year was highest during March (64.4) and December (63.9). The highest incidence of AMI occurred during temperature differences of 8-10° in each season. Moreover, AMI incidence tended to increase as the mean temperature decreased (r = -0.233, P = 0.001), and when the mean daily temperature difference increased (r = 0.353, P < 0.001).

CONCLUSION

The AMI incidence rate per 100,000 year has a decreasing trend over the 10-year period, derived from the Korean NHIS database. Modest daily temperature differences (8-10°) and the spring season are related to higher AMI incidence, indicating that daily temperature variation is more important than the mean daily temperature.

Effect of Cold Adaptation on the State of Cardiovascular System and Cardiac Tolerance to Ischemia/Reperfusion Injury

Despite the unconditional success achieved in the treatment and prevention of AMI over the past 40 years, mortality in this disease remains high. Hence, it is necessary to develop novel drugs with mechanism of action different from those currently used in clinical practices. Studying the molecular mechanisms involved in the cardioprotective effect of adapting to cold could contribute to the development of drugs that increase cardiac tolerance to the impact of ischemia/reperfusion. An analysis of the published data shows that the long-term human stay in the Far North contributes to the occurrence of cardiovascular diseases. At the same time, chronic and continuous exposure to cold increases tolerance of the rat heart to ischemia/ reperfusion. It has been demonstrated that the cardioprotective effect of cold adaptation depends on the activation of ROS production, stimulation of the β2-adrenergic receptor and protein kinase C, MPT pore closing, and KATP channel.

Excess winter mortality in Finland, 1971-2019: a register-based study on long-term trends and effect modification by sociodemographic characteristics and pre-existing health conditions

OBJECTIVES

Excess winter mortality is a well-established phenomenon across the developed world. However, whether individual-level factors increase vulnerability to the effects of winter remains inadequately examined. Our aim was to assess long-term trends in excess winter mortality in Finland and estimate the modifying effect of sociodemographic and health characteristics on the risk of winter death.

DESIGN

Nationwide register study.

SETTING

Finland.

PARTICIPANTS

Population aged 60 years and over, resident in Finland, 1971-2019.

OUTCOME MEASURES

Age-adjusted winter and non-winter death rates, and winter-to-non-winter rate ratios and relative risks (multiplicative interaction effects between winter and modifying characteristics).

RESULTS

We found a decreasing trend in the relative winter excess mortality over five decades and a drop in the series around 2000. During 2000-2019, winter mortality rates for men and women were 11% and 14% higher than expected based on non-winter rates. The relative risk of winter death increased with age but did not vary by income. Compared with those living with at least one other person, individuals in institutions had a higher relative risk (1.07, 95% CI 1.05 to 1.08). Most pre-existing health conditions did not predict winter death, but persons with dementia emerged at greater relative risk (1.06, 95% CI 1.04 to 1.07).

CONCLUSIONS

Although winter mortality seems to affect frail people more strongly-those of advanced age, living in institutions and with dementia-there is an increased risk even beyond the more vulnerable groups. Protection of high-risk groups should be complemented with population-level preventive measures.

Heavy Metal Scavenger Metallothionein Rescues Against Cold Stress-Evoked Myocardial Contractile Anomalies Through Regulation of Mitophagy

Cold stress prompts an increased prevalence of cardiovascular morbidity yet the underneath machinery remains unclear. Oxidative stress and autophagy appear to contribute to cold stress-induced cardiac anomalies. Our present study evaluated the effect of heavy metal antioxidant metallothionein on cold stress (4 °C)-induced in cardiac remodeling and contractile anomalies and cell signaling involved including regulation of autophagy and mitophagy. Cold stress (3 weeks) prompted interstitial fibrosis, mitochondrial damage (mitochondrial membrane potential and TEM ultrastructure), oxidative stress (glutathione, reactive oxygen species and superoxide), lipid peroxidation, protein injury, elevated left ventricular (LV) end systolic and diastolic diameters, decreased fractional shortening, ejection fraction, Langendorff heart function, cardiomyocyte shortening, maximal velocities of shortening/relengthening, and electrically stimulated intracellular Ca2+ rise along with elongated relaxation duration and intracellular Ca2+ clearance, the responses of which were overtly attenuated or mitigated by metallothionein. Levels of apoptosis, cell death (Bax and loss of Bcl2, IL-18), and autophagy (LC3BII-to-LC3BI ratio, Atg7 and Beclin-1) were overtly upregulated with comparable p62 under cold stress. Cold stress also evoked elevated mitophagy (decreased TOM20, increased Parkin and FUNDC1 with unaltered BNIP3). Cold stress overtly dampened phosphorylation of autophagy/mitophagy inhibitory molecules Akt and mTOR, stimulated and suppressed phosphorylation of ULK1 and eNOS, respectively, in the absence of altered pan protein levels. Cold stress-evoked responses in cell death, autophagy, mitophagy and their regulatory domains were overtly attenuated or ablated by metallothionein. Suppression of autophagy and mitophagy with 3-methyladenine, bafilomycin A1, cyclosporine A, and liensinine rescued hypothermia-instigated cardiomyocyte LC3B puncta formation and mechanical anomalies. Our findings support a protective nature for metallothionein in deep hypothermia-evoked cardiac abnormalities associated with regulation of autophagy and mitophagy.

Impact of Temperature and Atmospheric Pressure on Hospitalizations of Patients Presenting With Acute Coronary Syndrome

AIM

 This study aims to investigate the impact of temperature and atmospheric pressure on hospitalizations of patients with acute coronary syndrome (ACS).

MATERIALS AND METHODS

This is a retrospective, observational, analytical study conducted in a single center, University Hospital Center "Mother Teresa," Tirana, Albania, in the period January-December 2018. This study included 1,165 patients with ACS, who performed urgent coronary angiography, from January 2018 to December 2018. Patients were diagnosed with ACS based on clinical and examination findings. The data were collected retrospectively using patient files. Baseline demographic, clinical, and procedural characteristics were collected. Data on atmospheric parameters, measured at the weather monitoring station, were obtained from the National Meteorological Service database. Measurements from the meteorological service provided values ​​for each parameter: average daily temperature and atmospheric pressure in each country district. Atmospheric data measurements were taken for the day under review. The number of inhabitants for the respective districts is taken from the National Institute of Statistics (INSTAT).

RESULTS

The study involved 1,165 patients, with a mean age of 63.1 years, ranging from 27 years to 89 years old. The majority of patients (78.6%) were male, while 21.4% were female. A statistically significant relationship was observed between seasonal changes in temperature and atmospheric pressure concerning the number of cases with ACS; the autumn season prevails with 27.9% of the total cases, followed by the spring season with 25.6%, the summer season with 24.2%, and winter season with 22.3% (p = 0.04). Additionally, significant changes in the average monthly values ​​of temperature and atmospheric pressure were accompanied by a statistically significant increase in the number of cases as occurred in March-April and October-November (p ≤ 0.05). Most cases in the cold period (November-March) occurred on days with a change in temperature or atmospheric pressure with a statistically significant value of p < 0.05.

CONCLUSION

 An important relationship between seasonal, monthly, and daily changes in temperature and atmospheric pressure concerning the frequency of cases with ACS was observed.

Temperature fluctuation and acute myocardial infarction in Beijing: an extended analysis of temperature ranges and differences

Purpose

Few studies examined the relationship between temperature fluctuation metrics and acute myocardial infarction (AMI) hospitalizations within a single cohort. We aimed to expand knowledge on two basic measures: temperature range and difference.

Methods

We conducted a time-series analysis on the correlations between temperature range (TR), daily mean temperature differences (DTDmean), and daily mean-maximum/minimum temperature differences (TDmax/min) and AMI hospitalizations, using data between 2013 and 2016 in Beijing, China. The effects of TRn and DTDmeann over n-day intervals were compared, respectively. Subgroup analysis by age and sex was performed.

Results

A total of 81,029 AMI hospitalizations were included. TR1, TDmax, and TDmin were associated with AMI in J-shaped patterns. DTDmean1 was related to AMI in a U-shaped pattern. These correlations weakened for TR and DTDmean with longer exposure intervals. Extremely low (1st percentile) and high (5°C) DTDmean1 generated cumulative relative risk (CRR) of 2.73 (95% CI: 1.56-4.79) and 2.15 (95% CI: 1.54-3.01). Extremely high TR1, TDmax, and TDmin (99th percentile) correlated with CRR of 2.00 (95% CI: 1.73-2.85), 1.71 (95% CI: 1.40-2.09), and 2.73 (95% CI: 2.04-3.66), respectively. Those aged 20-64 had higher risks with large TR1, TDmax, and TDmin, while older individuals were more affected by negative DTDmean1. DTDmean1 was associated with a higher AMI risk in females.

Conclusion

Temperature fluctuations were linked to increased AMI hospitalizations, with low-temperature extremes having a more pronounced effect. Females and the older adult were more susceptible to daily mean temperature variations, while younger individuals were more affected by larger temperature ranges.

Nonoptimum Temperatures Are More Closely Associated With Fatal Myocardial Infarction Than With Nonfatal Events

BACKGROUND

Ambient temperatures trigger hospitalisation, mortality, and emergency department visits for myocardial infarction (MI). However, nonoptimum temperature-related risks of fatal and nonfatal MI have not yet been compared.

METHODS

From 2007 to 2019, 416,894 MI events (233,071 fatal and 183,823 nonfatal) were identified in Beijing, China. A time-series analysis with a distributed-lag nonlinear model was used to compare the relative and population-attributable risks of fatal and nonfatal MI associated with nonoptimum temperatures.

RESULTS

The reference was the optimum temperature of 24.3°C. For single-lag effects, cold (-5.2°C) and heat (29.6°C) effects had associations that persisted for more days for fatal MI than for nonfatal MI. For cumulative-lag effects over 0 to 21 days, cold effects were higher for fatal MI (relative risk [RR] 1.99, 95% confidence interval [CI] 1.68-2.35) than for nonfatal MI (RR 1.60, 95% CI 1.32-1.94) with a P value for difference in effect sizes of 0.048. In addition, heat effects were higher for fatal MI (RR 1.33, 95% CI 1.24-1.44) than for nonfatal MI (RR 0.99, 95% CI 0.91-1.08) with a P value for difference in effect sizes of 0.002. The attributable fraction of nonoptimum temperatures was higher for fatal MI (25.6%, 95% CI 19.7%-30.6%) than for nonfatal MI (19.1%, 95% CI 12.1%-25.0%).

CONCLUSIONS

Fatal MI was more closely associated with nonoptimum temperatures than nonfatal MI, as evidenced by single-lag effects that have associations which persisted for more days, higher cumulative-lag effects, and higher attributable risks for fatal MI. Strategies are needed to mitigate the adverse effects of nonoptimum temperatures.

Study on the relationship among typhoon, climate change, and acute Stanford type A aortic dissection in southern of Zhejiang in China

BACKGROUND

The aim of this study was to investigate the relationship between typhoon, climate change, and acute Stanford type A aortic dissection (TAAD) in southern of Zhejiang Province in China.

METHOD

371 patients with TAAD were admitted to three hospitals (the aortic dissection center) in southern of Zhejiang Province, China from January 2015 to December 2020, and data were retrospectively collected, the data included (1) the number of patients admitted in different months and seasons, (2) daily meteorological data in southern of Zhejiang Province, and (3) typhoon information were retrospectively analyzed.

RESULTS

The number of TAAD occurred in winter was the highest and in summer was the lowest. The incidence of TAAD was correlated with minimum temperature, maximum wind speed, mean wind speed, and water vapor pressure (P < 0.05). Maximum wind speed (RR 0.37; 95% CI 0.17 to 0.80, P = 0.01) and water vapor pressure (RR 0.96; 95% CI 0.92 to 1, P = 0.03) were the protective factor. The occurrence incidence of TAAD under the influence of typhoon climate was less than that during the period not affected by typhoon (P < 0.05).

CONCLUSION

There was a correlation between typhoon, climate change, and the occurrence of TAAD in southern Zhejiang Province. Wind speed, vapor pressure, and typhoon may be protective factors.

Evaluation of the Effects of Thermal Comfort Conditions on Cardiovascular Diseases in Amasya City, Turkey

Aim

Studies fall short when it comes to determining the relationship between thermal comfort and cardiovascular diseases. Studies examining the relationship between thermal comfort conditions and human health in Turkey, located in the transition zone of air masses at mid-latitudes, are quite limited. This is the first study conducted in Turkey that deals with thermal comfort conditions and CVDs, which is the leading cause of death. This study aimed to examine the relationship between thermal comfort conditions and CVDs of Amasya, a medium-sized exemplary Turkish city.

Subject and methods

To determine the thermal comfort conditions in the study area between 2014-2019, the physiologically equivalent temperature (PET) index obtained from the Rayman model, which uses hourly air temperature (ºC), relative humidity (%), wind speed (m/s), and cloud cover (octa) data, was used. The relationship between PET values and CVDs was determined by Pearson correlation analysis and linear regression analysis.

Results

The study indicated a negative, high, and moderate correlation between PET values and cardiovascular diseases (p < 0.001). The results show that when PET values increase by 1 ºC, patient admissions will decrease by about 104 to 108 patients (-104.737 to -108.619 units.).

Conclusion

These results can be informative and guiding for both the protection of public health and studies on climate change and human health.

The Impact of Winter Months on Venous Thromboembolism (VTE) Patients: A Retrospective Analysis of Hospital Outcomes in the United States

Objective: We aimed to analyze the Health Care Utilization Project’s (HCUP) Nationwide Inpatient Sample (NIS) and compare mortality rates in hospitals by month to determine if there is seasonal variability in outcomes associated with venous thromboembolism (VTE).

Methods: The Nationwide Inpatient Sample database was queried from 1998 to 2011. Inclusion criteria were a diagnosis of deep vein thrombosis (DVT) (ICD-9 {International Classification of Diseases, Ninth Revision, Clinical Modification} 453.4, 453.8) and/or VTE (ICD-9 415.1) in patients aged 18 years or more. Admission data was then analyzed to compare mortality rates in teaching and non-teaching hospitals over that time and by month. Demographics, Charlson Comorbidity Index, length of stay (LOS), hospital region, and admission types (emergent/urgent versus elective admissions) were assessed. Linear and logistic models were generated for complex survey design to analyze predictors of mortality and LOS.

Results: A total of 1,449,113 DVT/VTE cases were identified in the Nationwide Inpatient Sample (weighted n= 7,150,613), 54.7% female, 56.38% white, 49% in teaching hospitals. Higher mortality was found in the months of November 6.52%, December 6.9%, January 6.94%, and February 6.93% versus overall mortality of 6.4% over 12 months. Higher mortality was noted in these winter months in all regions, along with a significantly increased LOS. Mortality in the total cohort was found to be higher in January, with odds ratio (OR) 1.11 (1.08-1.15), p<0.0001; February, OR 1.11 (1.07-1.15), p<0.0001; and December, OR 1.10 (1.06-1.14), p<0.0001 compared to June. Mortality was significantly lower in the Midwest or North Central regions (OR 0.78 {0.72-0.83}, p<0.0001) and West (OR 0.80 {0.73-0.87}, p<0.0001) compared to the Northeast. Mortality was also significantly higher in teaching hospitals than in non-teaching hospitals (OR 1.16 {1.10-1.22}, p<0.0001), with mortality trending higher in teaching hospitals each month. Emergent/urgent admission, larger hospital size, female sex, age, and urban location were also significantly associated with increased mortality.

Conclusions: This national study identified an increased risk of mortality associated with hospitalizations for DVT/VTE in the winter months, independent of hospital teaching status or region.

Clustering of Environmental Parameters and the Risk of Acute Myocardial Infarction

The association between days with similar environmental parameters and cardiovascular events is unknown. We investigate the association between clusters of environmental parameters and acute myocardial infarction (AMI) risk in Singapore. Using k-means clustering and conditional Poisson models, we grouped calendar days from 2010 to 2015 based on rainfall, temperature, wind speed and the Pollutant Standards Index (PSI) and compared the incidence rate ratios (IRR) of AMI across the clusters using a time-stratified case-crossover design. Three distinct clusters were formed with Cluster 1 having high wind speed, Cluster 2 high rainfall, and Cluster 3 high temperature and PSI. Compared to Cluster 1, Cluster 3 had a higher AMI incidence with IRR 1.04 (95% confidence interval 1.01–1.07), but no significant difference was found between Cluster 1 and Cluster 2. Subgroup analyses showed that increased AMI incidence was significant only among those with age ≥65, male, non-smokers, non-ST elevation AMI (NSTEMI), history of hyperlipidemia and no history of ischemic heart disease, diabetes or hypertension. In conclusion, we found that AMI incidence, especially NSTEMI, is likely to be higher on days with high temperature and PSI. These findings have public health implications for AMI prevention and emergency health services delivery during the seasonal Southeast Asian transboundary haze.

Machine Learning Analyzed Weather Conditions as an Effective Means in the Predicting of Acute Coronary Syndrome Prevalence

Background

The prediction of the number of acute coronary syndromes (ACSs) based on the weather conditions in the individual climate zones is not effective. We sought to investigate whether an artificial intelligence system might be useful in this prediction.

Methods

Between 2008 and 2018, a total of 105,934 patients with ACS were hospitalized in Lesser Poland Province, one covered by two meteorological stations. The predicted daily number of ACS has been estimated with the Random Forest machine learning system based on air temperature (°C), air pressure (hPa), dew point temperature (Td) (°C), relative humidity (RH) (%), wind speed (m/s), and precipitation (mm) and their daily extremes and ranges derived from the day of ACS and from 6 days before ACS.

Results

Of 840 pairwise comparisons between individual weather parameters and the number of ACS, 128 (15.2%) were significant but weak with the correlation coefficients ranged from −0.16 to 0.16. None of weather parameters correlated with the number of ACS in all the seasons and stations. The number of ACS was higher in warm front days vs. days without any front [40 (29–50) vs. 38 (27–48), respectively, P &lt; 0.05]. The correlation between the predicted and observed daily number of ACS derived from machine learning was 0.82 with 95% CI of 0.80–0.84 (P &lt; 0.001). The greatest importance for machine learning (range 0–1.0) among the parameters reached Td daily range with 1.00, pressure daily range with 0.875, pressure maximum daily range with 0.864, and RH maximum daily range with 0.853, whereas among the clinical parameters reached hypertension daily range with 1.00 and diabetes mellitus daily range with 0.28. For individual seasons and meteorological stations, the correlations between the predicted and observed number of ACS have ranged for spring from 0.73 to 0.77 (95% CI 0.68–0.82), for summer from 0.72 to 0.76 (95% CI 0.66–0.81), for autumn from 0.72 to 0.83 (95% CI 0.67–0.87), and for winter from 0.76 to 0.79 (95% CI 0.71–0.83) (P &lt; 0.001 for each).

Conclusion

The weather parameters have proven useful in predicting the prevalence of ACS in a temperate climate zone for all the seasons, if analyzed with an artificial intelligence system. Simultaneously, the analysis of individual weather parameters or frontal scenarios has provided only weak univariate relationships. These findings will require validation in other climatic zones.

Ambient temperature and infarct size, microvascular obstruction, left ventricular function and clinical outcomes after ST-segment elevation myocardial infarction

OBJECTIVES

Incidence and prognosis of ST-segment elevation myocardial infarction (STEMI) vary according to ambient temperature and season. We sought to assess whether season and temperature on the day of STEMI are associated with infarct size, microvascular obstruction (MVO), left ventricular ejection fraction (LVEF) and clinical outcomes after primary percutaneous coronary intervention (PCI).

METHODS

Individual patient data from 1598 patients undergoing primary PCI in six randomized clinical trials were pooled. Infarct size was evaluated by cardiac magnetic resonance within 30 days in all trials. Patients were categorized either by whether they presented on a day of temperature extremes (minimum temperature <0 °C or maximum temperature >25 °C) or according to season.

RESULTS

A total of 558/1598 (34.9%) patients presented with STEMI on a day of temperature extremes, and 395 (24.7%), 374 (23.4%), 481 (30.1%) and 348 (21.8%) presented in the spring, summer, fall and winter. After multivariable adjustment, temperature extremes were independently associated with larger infarct size (adjusted difference 2.8%; 95% CI, 1.3-4.3; P < 0.001) and smaller LVEF (adjusted difference -2.3%; 95% CI, -3.5 to -1.1; P = 0.0002) but not with MVO (adjusted P = 0.12). In contrast, infarct size, MVO and LVEF were unrelated to season (adjusted P = 0.67; P = 0.36 and P = 0.95, respectively). Neither temperature extremes nor season were independently associated with 1-year risk of death or heart failure hospitalization (adjusted P = 0.79 and P = 0.90, respectively).

CONCLUSION

STEMI presentation during temperature extremes was independently associated with larger infarct size and lower LVEF but not with MVO after primary PCI, whereas season was unrelated to infarct severity.

Seasonal variation in mortality and the role of temperature: a multi-country multi-city study

BACKGROUND

Although seasonal variations in mortality have been recognized for millennia, the role of temperature remains unclear. We aimed to assess seasonal variation in mortality and to examine the contribution of temperature.

METHODS

We compiled daily data on all-cause, cardiovascular and respiratory mortality, temperature and indicators on location-specific characteristics from 719 locations in tropical, dry, temperate and continental climate zones. We fitted time-series regression models to estimate the amplitude of seasonal variation in mortality on a daily basis, defined as the peak-to-trough ratio (PTR) of maximum mortality estimates to minimum mortality estimates at day of year. Meta-analysis was used to summarize location-specific estimates for each climate zone. We estimated the PTR with and without temperature adjustment, with the differences representing the seasonal effect attributable to temperature. We also evaluated the effect of location-specific characteristics on the PTR across locations by using meta-regression models.

RESULTS

Seasonality estimates and responses to temperature adjustment varied across locations. The unadjusted PTR for all-cause mortality was 1.05 [95% confidence interval (CI): 1.00-1.11] in the tropical zone and 1.23 (95% CI: 1.20-1.25) in the temperate zone; adjusting for temperature reduced the estimates to 1.02 (95% CI: 0.95-1.09) and 1.10 (95% CI: 1.07-1.12), respectively. Furthermore, the unadjusted PTR was positively associated with average mean temperature.

CONCLUSIONS

This study suggests that seasonality of mortality is importantly driven by temperature, most evidently in temperate/continental climate zones, and that warmer locations show stronger seasonal variations in mortality, which is related to a stronger effect of temperature.

Energy Poverty and Depression in Rural China: Evidence from the Quantile Regression Approach

Despite the growing awareness and interest in the impact of energy poverty on depression, studies in developing economies are relative limited, and there is a gap of knowledge of such impact among rural individuals in China. In this study, we investigate the impact of energy poverty on depression among rural Chinese individuals aged 16 and above, and our sample includes 13,784 individuals from 6103 households. With data from the 2018 China Family Panel Studies, we apply the instrumental variable (IV) quantile regression approach to address the potential endogeneity of energy poverty and allow for heterogeneous effects of energy poverty on depression across individuals with different levels of depression. Our estimates from the IV quantile regression suggest a strong positive impact of energy poverty on depression at the upper quantile of depression scores, but no impact at the middle and lower quantiles. The primary results are robust and consistent with alternative energy poverty measures, and we find that energy poverty does not affect depression of low-risk individuals (with low depression scores), but it does affect that of high-risk individuals. We also find individual socio-demographic factors of age, gender, household size, religious belief, education, marriage and employment status play roles in affecting depression. The findings of this study generate policy implications for energy poverty alleviation and mental health promotion.

The Thermal Environment of Housing and Its Implications for the Health of Older People in South Australia: A Mixed-Methods Study

Older people are often over-represented in morbidity and mortality statistics associated with hot and cold weather, despite remaining mostly indoors. The study “Improving thermal environment of housing for older Australians” focused on assessing the relationships between the indoor environment, building characteristics, thermal comfort and perceived health/wellbeing of older South Australians over a study period that included the warmest summer on record. Our findings showed that indoor temperatures in some of the houses reached above 35 °C. With concerns about energy costs, occupants often use adaptive behaviours to achieve thermal comfort instead of using cooling (or heating), although feeling less satisfied with the thermal environment and perceiving health/wellbeing to worsen at above 28 °C (and below 15 °C). Symptoms experienced during hot weather included tiredness, shortness of breath, sleeplessness and dizziness, with coughs and colds, painful joints, shortness of breath and influenza experienced during cold weather. To express the influence of temperature and humidity on perceived health/wellbeing, a Temperature Humidity Health Index (THHI) was developed for this cohort. A health/wellbeing perception of “very good” is achieved between an 18.4 °C and 24.3 °C indoor operative temperature and a 55% relative humidity. The evidence from this research is used to inform guidelines about maintaining home environments to be conducive to the health/wellbeing of older people.

Weather Impact on Acute Myocardial Infarction Hospital Admissions With a New Model for Prediction: A Nationwide Study

Introduction: Cardiovascular disease is one of the leading causes of mortality worldwide. Acute myocardial infarction (AMI) is associated with weather change. The study aimed to investigate if weather change was among the risk factors of coronary artery disease to influence AMI occurrence in Taiwan and to generate a model to predict the probabilities of AMI in specific weather and clinical conditions.

Method: This observational study utilized the National Health Insurance Research Database and daily weather reports from Taiwan Central Weather Bureau to evaluate the discharge records of patients diagnosed with AMI from various hospitals in Taiwan between January 1, 2008 and December 31, 2011. Generalized additive models (GAMs) were used to estimate the effective parameters on the trend of the AMI incidence rate with respect to the weather and health factors in the time-series data and to build a model for predicting AMI probabilities.

Results: A total of 40,328 discharges were listed. The minimum temperature, maximum wind speed, and antiplatelet therapy were negatively related to the daily AMI incidence; however, a drop of 1° when the air temperature was below 15°C was associated with an increase of 1.6% of AMI incidence. By using the meaningful parameters including medical and weather factors, an estimated GAM was built. The model showed an adequate correlation in both internal and external validation.

Conclusion: An increase in AMI occurrence in colder weather has been evidenced in the study, but the influence of wind speed remains uncertain. Our analysis demonstrated that the novel GAM model can predict daily onset rates of AMI in specific weather conditions.

The impact of extreme temperatures on human mortality in the most populated cities of Romania

The impact of extreme weather conditions on humans is one of the most important topics in biometeorology studies. The main objective of this study is to analyze the relationship between temperature-related weather conditions and natural mortality in the five most populated cities of Romania, namely, Bucharest, Cluj-Napoca, Constanța, Iași, and Timișoara. The results of this study aim to bridge a gap in national research. In the present paper, we used daily natural mortality data and daily minimum and maximum air temperatures. The distributed lag nonlinear model (DLNM) allowed us to identify weather conditions associated with natural mortality. The most important results are as follows: (i) a higher daily mortality is related to a high frequency of heat stress conditions; (ii) a higher maximum temperature increases the relative risk (RR) of natural mortality; (iii) the maximum number of fatalities is recorded on the first day of high-temperature events; and (iv) individuals much more easily adapt to cold stress conditions. The main conclusion in this study is that the inhabitants of the most populated cities in Romania are more sensitive to high-temperature stress than to low-temperature stress.

Heat and cold-related morbidity risk in north-east of Iran: a time-stratified case crossover design

This study aimed to estimate morbidity risk/number attributed to air extreme temperatures using time-stratified case crossover study and distributed lag non-linear model in a region of Iran during 2015-2019. A time-stratified case crossover design based on aggregated exposure data was used in this study. In order to have no overlap bias in the estimations, a fixed and disjointed window by using 1-month strata was used in the design. A conditional Poisson regression model allowing for over dispersion (Quasi-Poisson) was applied into Distributed Lag Non-linear Model (DLNM). Different approaches were applied to estimate Optimum Temperature (OT). In the model, the interaction effect between temperature and humidity was assessed to see if the impact of heat or cold on Hospital Admissions (HAs) are different between different levels of humidity. The cumulative effect of heat during 21 days was not significant and it was the cold that had significant cumulative adverse effect on all groups. While the number of HAs attributed to any ranges of heat, including medium, high, extreme, and even all values were negligible, but a large number was attributable to cold values; about 10000 HAs were attributable to all values of cold temperature, of which about 9000 were attributed to medium range and about 1000 and less than 500 were attributed to high and extreme values of cold, respectively. This study highlights the need for interventions in cold seasons by policymakers. The results inform researchers as well as policy makers to address both men and women and elderly when any plan or preventive program is developed in the area under study.

Effects of temperature and humidity on acute myocardial infarction hospitalization in a super-aging society

Weather conditions affect the incidence of acute myocardial infarction (AMI). However, little is known on the association of weather temperature and humidity with AMI hospitalizations in a super-aging society. This study sought to examine this association. We included 87,911 consecutive patients with AMI admitted to Japanese acute-care hospitals between April 1, 2012 and March 31, 2015. The primary outcome was the number of AMI hospitalizations per day. Multilevel mixed-effects linear regression models were used to estimate the association of the average temperature and humidity, 1 day before hospital admission, with AMI hospitalizations, after adjusting for weather, hospital, and patient demographics.Lower temperature and humidity were associated with an increased number of AMI hospitalizations (coefficient − 0.500 [− 0.524 to − 0.474] per °C change, p < 0.001 and coefficient − 0.012 [− 0.023 to − 0.001] per % change, p = 0.039, respectively). The effects of temperature and humidity on AMI hospitalization did not differ by age and sex (all interaction p > 0.05), but differed by season. However, higher temperatures in spring (coefficient 0.089 [0.025 to 0.152] per °C change, p = 0.010) and higher humidity in autumn (coefficient 0.144 [0.121 to 0.166] per % change, p < 0.001) were risk factors for AMI hospitalization. Increased average temperatures and humidity, 1 day before hospitalization, are associated with a decreased number of AMI hospitalizations.

Extreme Weather Conditions and Cardiovascular Hospitalizations in Southern Brazil

This research concerns the identification of a pattern between the occurrence of extreme weather conditions, such as cold waves and heat waves, and hospitalization for cardiovascular diseases (CVDs), in the University Hospital of Santa Maria (HUSM) in southern Brazil between 2012 and 2017. The research employed the field experiment method to measure the biometeorological parameters associated with hospital admissions in different seasons, such as during extreme weather conditions such as a cold wave (CW) or a heat wave (HW), using five thermal comfort indices: physiologically equivalent temperature (PET), new standard effective temperature (SET), predicted mean vote (PMV), effective temperatures (ET), and effective temperature with wind (ETW). The hospitalizations were recorded as 0.775 and 0.726 admissions per day for the winter and entire study periods, respectively. The records for extreme events showed higher admission rates than those on average days. The results also suggest that emergency hospitalizations for heart diseases during extreme weather events occurred predominantly on days with thermal discomfort. Furthermore, there was a particularly high risk of hospitalization for up to seven days after the end of the CW. Further analyses showed that cardiovascular hospitalizations were higher in winter than in summer, suggesting that CWs are more life threatening in wintertime.

Weather Trumps Festivity? More Cardiovascular Disease Events Occur in Winter than in December Holidays in Queensland, Australia

Objective: Cardiovascular disease (CVD) is the leading cause of hospitalisations and deaths in Australia. This study estimates the excess CVD hospitalisations and deaths across seasons and during the December holidays in Queensland, Australia. Methods: The study uses retrospective, longitudinal, population-based cohort data from Queensland, Australia from January 2010 to December 2015. The outcomes were hospitalisations and deaths categorised as CVD-related. CVD events were grouped according to when they occurred in the calendar year. Excess hospitalisations and deaths were estimated using the multivariate ordinary least squares method after adjusting for confounding effects. Results: More CVD hospitalisations and deaths occurred in winter than in summer, with 7811 (CI: 1353, 14,270; p < 0.01) excess hospitalisations and 774 (CI: 35, 1513; p < 0.01) deaths compared to summer. During the coldest month (July), there was an excess of 42 hospitalisations and 7 deaths per 1000 patients. Fewer CVD hospitalisations (-20 (CI: -29, -9; p < 0.01)) occurred during the December holidays than any other period during the calendar year. Non-CVD events were mostly not statistically significant different between periods. Conclusion: Most CVD events in Queensland occurred in winter rather than during the December holidays. Potentially cost-effective initiatives should be explored such as encouraging patients with CVD conditions to wear warmer clothes during cold temperatures and/or insulating the homes of CVD patients who cannot otherwise afford to.

Mortality due to circulatory causes in hot and cold environments in Greece

Ambient temperature can affect the survival rate of humans. Studies have shown a relationship between ambient temperature and mortality rate in hot and cold environments. This effect of ambient temperature on mortality seems to be more pronounced in older people. The aim of this study is to examine the effects of thermal stress on cardiovascular mortality and the associated relative risk per degree Celsius in Greek individuals ≥70 years old. Mortality data 1999-2012 were matched with the midday temperature. The present study found a higher circulatory mortality when ambient temperature is below or above the temperature range 6 to 39 °C.

Importance of applying Mixed Generalized Additive Model (MGAM) as a method for assessing the environmental health impacts: Ambient temperature and Acute Myocardial Infarction (AMI), among elderly in Shanghai, China

Association between acute myocardial infarction (AMI) morbidity and ambient temperature has been examined with generalized linear model (GLM) or generalized additive model (GAM). However, the effect size by these two methods might be biased due to the autocorrelation of time series data and arbitrary selection of degree of freedom of natural cubic splines. The present study analyzed how the climatic factors affected AMI morbidity for older adults in Shanghai with Mixed generalized additive model (MGAM) that addressed these shortcomings mentioned. Autoregressive random effect was used to model the relationship between AMI and temperature, PM10, week days and time. The degree of freedom of time was chosen based on the seasonal pattern of temperature. The performance of MGAM was compared with GAM on autocorrelation function (ACF), partial autocorrelation function (PACF) and goodness of fit. One-year predictions of AMI counts in 2011 were conducted using MGAM with the moving average. Between 2007 and 2011, MGAM adjusted the autocorrelation of AMI time series and captured the seasonal pattern after choosing the degree of freedom of time at 5. Using MGAM, results were well fitted with data in terms of both internal (R2 = 0.86) and external validity (correlation coefficient = 0.85). The risk of AMI was relatively high in low temperature (Risk ratio = 0.988 (95% CI 0.984, 0.993) for under 12°C) and decreased as temperature increased and speeded up within the temperature zone from 12°C to 26°C (Risk ratio = 0.975 (95% CI 0.971, 0.979), but it become increasing again when it is 26°C although not significantly (Risk ratio = 0.999 (95% CI 0.986, 1.012). MGAM is more appropriate than GAM in the scenario of response variable with autocorrelation and predictors with seasonal variation. The risk of AMI was comparatively higher when temperature was lower than 12°C in Shanghai as a typical representative location of subtropical climate.

Effect of diurnal temperature change on cardiovascular risks differed under opposite temperature trends

Temperature change between neighboring days (TCN) is an important trigger for cardiovascular diseases, but the modulated effects by seasonal temperature trends have been barely taken into account. A quantified comparison between impacts of positive TCNs (temperature rise) and negative situations (temperature drop) is also needed. We evaluated the associations of TCNs with emergency room (ER) visits for coronary heart disease (CHD) and cerebral infarction (CI) in Beijing, China, from 2008 to 2012. A year was divided into two segments dominated by opposite temperature trends, quasi-Poisson regression with distributed lag nonlinear models estimating TCN-morbidity relations were employed, separately for each period. High morbidities of CHD and CI both occurred in transitional seasons accompanied by large TCNs. Under warming backgrounds, positive TCNs increased CHD risk in patients younger than 65 years, and old people showed limited sensitivity. In the cooling periods, negative TCNs induced CHD risk in females and the elderly; the highest RR showed on lag 6 d. In particular, a same diurnal temperature decrease (e.g., - 2°C) induced greater RR (RR = 1.113, 95% CIs: 1.033-1.198) on old people during warming periods than cooling counterparts (RR = 1.055, 95% CIs: 1.011-1.100). Moreover, positive TCNs elevated CI risk regardless of background temperatures, and males were particularly vulnerable. Seasonal temperature trends modify TCN-cardiovascular morbidity associations significantly, which may provide new insights into the health impact of unstable weathers.

Impact of diurnal temperature range on cardiovascular disease hospital admissions among Chinese farmers in Dingxi (the Northwest China)

Background

Diurnal temperature range (DTR) has been widely applied in exploring its effect on cardiovascular disease (CVD). However, few studies have investigated the correlations between DTR and CVD in poor rural areas in China. This study aimed to examine the association between DTR and CVD in rural China.

Methods

A distributed lag nonlinear model was used to evaluate the relationship between DTR and CVD risk among farmers living in the city of Dingxi (Northwest China) in the period from January 1, 2016 to December 31, 2019.

Results

We observed nonlinear M-patterns between the relative risk (RR) of DTR (reference: median DTR, 12 °C) and CVD hospitalizations in all subgroups. The peak RR of CVD was noticed at DTR of 6 °C (total: 1.418; men: 1.546; women: 1.403; young: 1.778; old: 2.549) and 17 °C (total: 1.781; men: 1.937; women: 1.712; young: 2.233; old: 1.798). The adverse effect of DTR on CVD risk was more pronounced in females (RR 1.438) and elderly (RR 2.034) than males (RR 1.141) and younger adults (RR 1.852) at the extremely low (5th, 4 °C) DTR. The reverse was observed at the extremely high DTR (95th, 19 °C) (male: 1.267; females: 0.993; young: 1.586; old: 1.212).

Conclusions

DTR is associated with CVD morbidity. This association was more pronounced in women and elderly, but men and younger peoples at extremely high DTR (19 °C). Future measures should take DTR into account to prevent CVD among susceptible populations.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12872-021-02065-8.

Extreme weather conditions as a gender-specific risk factor for acute myocardial infarction

BACKGROUND

Acute coronary syndrome is a disease with high prevalence and high mortality. Exposure to heat or cold increases the risks of myocardial infarction significantly. Gender-specific effects of this have not yet been examined. Our goal was to determine whether extreme weather conditions, which become more and more frequent, are gender-specific risk factors for myocardial infarction, in order to help provide faster diagnosis and revascularization therapy for patients.

METHODS

We analysed the incidence of ST-elevation myocardial infarction (STEMI) in a large urban area over a 65-months period in a cohort study. A day was the unit of analysis. Incidence rate ratios (IRR) with Poisson regression models were calculated. All patients with STEMI on Saturdays and Sundays were included. Gender, high or low perceived temperatures (PT), a function of temperature, wind speed and humidity, and meteorological cold and heat warnings by the Austrian Central Institute for Meteorology and Geodynamics (ZAMG) were considered as risk factors.

RESULTS

During the 562 days of the study period, a total of 1109 patients with STEMI (803; 72% men, mean age 61;14 years) were included. The gender difference between men and women was much more pronounced on cold (0 °C) days (85% of patients male; 1.8 per day) than on hot (20 °C) days (71% male; 1.4 per day) or days without extreme temperatures (72% male; 1.4 per day). We found significant interaction between gender and cold days (IRR of the interaction term 2.3 (95% CI 1.2-4.6), p = 0.02). No gender-specific effect was observed on warm days (IRR for interaction 0.9 (95% CI 0.6-1.3), p = 0.3).

CONCLUSION

Low perceived temperature pronouncedly increases the already elevated risk for STEMI in males. Whether this effect is based on gender alone, or on one of the cardiovascular risk factors which are more common in men, is up to further study.

Excess mortality at Christmas due to cardiovascular disease in the HUNT study prospective population-based cohort in Norway

Background

Although it is known that winter inclusive of the Christmas holiday period is associated with an increased risk of dying compared to other times of the year, very few studies have specifically examined this phenomenon within a population cohort subject to baseline profiling and prospective follow-up. In such a cohort, we sought to determine the specific characteristics of mortality occuring during the Christmas holidays.

Methods

Baseline profiling and outcome data were derived from a prospective population-based cohort with longitudinal follow-up in Central Norway - the Trøndelag Health (HUNT) Study. From 1984 to 1986, 88% of the target population comprising 39,273 men and 40,353 women aged 48 ± 18 and 50 ± 18 years, respectively, were profiled. We examined the long-term pattern of mortality to determine the number of excess (all-cause and cause-specific) deaths that occurred during winter overall and, more specifically, the Christmas holidays.

Results

During 33.5 (IQR 17.1–34.4) years follow-up, 19,879 (50.7%) men and 19,316 (49.3%) women died at age-adjusted rate of 5.3 and 4.6 deaths per 1000/annum, respectively. Overall, 1540 (95% CI 43–45 deaths/season) more all-cause deaths occurred in winter (December to February) versus summer (June to August), with 735 (95% CI 20–22 deaths per season) of these cardiovascular-related. December 25th–27th was the deadliest 3-day period of the year; being associated with 138 (95% CI 96–147) and 102 (95% CI 72–132) excess all-cause and cardiovascular-related deaths, respectively. Accordingly, compared to 1st–21st December (equivalent winter conditions), the incidence rate ratio of all-cause mortality increased to 1.22 (95% CI 1.16–1.27) and 1.17 (95% 1.11–1.22) in men and women, respectively, during the next 21 days (Christmas/New Year holidays). All observed differences were highly significant (P < 0.001). A less pronounced pattern of mortality due to respiratory illnesses (but not cancer) was also observed.

Conclusion

Beyond a broader pattern of seasonally-linked mortality characterised by excess winter deaths, the deadliest time of year in Central Norway coincides with the Christmas holidays. During this time, the pattern and frequency of cardiovascular-related mortality changes markedly; contrasting with a more stable pattern of cancer-related mortality. Pending confirmation in other populations and climates, further research to determine if these excess deaths are preventable is warranted.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-021-10503-7.

A comparison of the effect of weather and climate on emergency department visitation in Roanoke and Charlottesville, Virginia

Compared with mortality, the impact of weather and climate on human morbidity is less well understood, especially in the cold season. We examined the relationships between weather and emergency department (ED) visitation at hospitals in Roanoke and Charlottesville, Virginia, two locations with similar climates and population demographic profiles. Using patient-level data obtained from electronic medical records, each patient who visited the ED was linked to that day's weather from one of 8 weather stations in the region based on each patient's ZIP code of residence. The resulting 2010-2017 daily ED visit time series were examined using a distributed lag non-linear model to account for the concurrent and lagged effects of weather. Total ED visits were modeled separately for each location along with subsets based on gender, race, and age. The relationship between the relative risk of ED visitation and temperature or apparent temperature over lags of one week was positive and approximately linear at both locations. The relative risk increased about 5% on warm, humid days in both cities (lag 0 or lag 1). Cold conditions had a protective effect, with up to a 15% decline on cold days, but ED visits increased by 4% from 2 to 5 days after the cold event. The effect of thermal extremes tended to be larger for non-whites and the elderly, and there was some evidence of a greater lagged response for non-whites in Roanoke. Females in Roanoke were more impacted by winter cold conditions than males, who were more likely to show a lagged response at high temperatures. In Charlottesville, males sought ED attention at lower temperatures than did females. The similarities in the ED response patterns between these two hospitals suggest that certain aspects of the response may be generalizable to other locations that have similar climates and demographic profiles.

Investigating Mitonuclear Genetic Interactions Through Machine Learning: A Case Study on Cold Adaptation Genes in Human Populations From Different European Climate Regions

Cold climates represent one of the major environmental challenges that anatomically modern humans faced during their dispersal out of Africa. The related adaptive traits have been achieved by modulation of thermogenesis and thermoregulation processes where nuclear (nuc) and mitochondrial (mt) genes play a major role. In human populations, mitonuclear genetic interactions are the result of both the peculiar genetic history of each human group and the different environments they have long occupied. This study aims to investigate mitonuclear genetic interactions by considering all the mitochondrial genes and 28 nuclear genes involved in brown adipose tissue metabolism, which have been previously hypothesized to be crucial for cold adaptation. For this purpose, we focused on three human populations (i.e., Finnish, British, and Central Italian people) of European ancestry from different biogeographical and climatic areas, and we used a machine learning approach to identify relevant nucDNA–mtDNA interactions that characterized each population. The obtained results are twofold: (i) at the methodological level, we demonstrated that a machine learning approach is able to detect patterns of genetic structure among human groups from different latitudes both at single genes and by considering combinations of mtDNA and nucDNA loci; (ii) at the biological level, the analysis identified population-specific nuclear genes and variants that likely play a relevant biological role in association with a mitochondrial gene (such as the “obesity gene” FTO in Finnish people). Further studies are needed to fully elucidate the evolutionary dynamics (e.g., migration, admixture, and/or local adaptation) that shaped these nucDNA–mtDNA interactions and their functional role.

Energy poverty, its intensity and health in vulnerable populations in a Southern European city

OBJECTIVE

To describe and compare the health status between vulnerable population participating in a program to tackle energy poverty (Energía, la justa) and the non-energy poor Barcelona (Spain) population and to analyse among participants the effect of energy poverty intensity on health.

METHOD

Cross-sectional study based on data from program participants obtained before the intervention. Participants (1799 women and 671 men) were compared to non-energy poor population of Barcelona (1393 women and 1215 men) sampled from the Barcelona Public Health Survey (2016). Standardized prevalence and prevalence ratios of self-perceived poor health, asthma, chronic bronchitis, and depression and/or anxiety were estimated, and among participants the association between health status and energy poverty intensity was estimated with multivariate models.

RESULTS

The probability of poor self-perceived physical and mental health ranged from 2.2 to 5.3 times greater in the program participants than non-energy poor Barcelona population. Among program participants, those most affected were found to be the most likely to report poor health outcomes, regardless of other sociodemographic factors.

CONCLUSIONS

The prevalence of poor physical and mental health was considerably higher among women and men participating in the programme compared to the non-energy poor population and was even worse among those who were more severely affected. Public policies that tackle energy poverty and its consequences are urgently needed in Spain.

General and specified vulnerability to extreme temperatures among older adults

Extreme temperatures pose significant risks to human health and well-being. Older adults are particularly at risk and their susceptibility is a function of vulnerability to general daily life circumstances and to specified events or threats. For the first time, this paper develops a combined general and specified approach to understand the determinants of vulnerability. The findings show that most participants exhibit high levels of heat-related vulnerability, followed by cold-related vulnerability and lastly, general vulnerability. General vulnerability was shown to be primarily shaped by financial, physical and social assets. Whilst, specified vulnerability was found to be mainly shaped by human, physical and placed based assets. Such findings present opportunities to focus on the types of assets that contribute to reducing vulnerability. These findings also suggest that the role assets play in shaping vulnerability must be attended to if we are to fully understand and effectively implement strategies to reduce vulnerability.

Temporal trends of the association between ambient temperature and hospitalisations for cardiovascular diseases in Queensland, Australia from 1995 to 2016: A time-stratified case-crossover study

BACKGROUND

In the context of global warming, studies have turned to assess the temporal trend of the association between temperature and health outcomes, which can be used to reflect whether human beings have adapted to the local temperature. However, most studies have only focused on hot temperature and mortality. We aim to investigate the temporal variations in the association between ambient temperature and hospitalisations for cardiovascular diseases in Queensland, Australia from 1995 to 2016.

METHODS AND FINDINGS

We obtained data on 1,855,717 cardiovascular hospitalisations (mean age: 65.9 years, 42.7% female) from all 443 postal areas in Queensland, Australia between January 1, 1995 and December 31, 2016. Grid-level meteorological data were downloaded from scientific information for landowners. We used a time-stratified case-crossover design fitted with a conditional quasi-Poisson regression model and time-varying distributed lag nonlinear model (DLNM) to evaluate the association between temperature and cardiovascular hospitalisations and the temporal trends of the associations. Stratified analyses were performed in different age, sex, and climate zones. In all groups, relative risks (RRs) of cardiovascular hospitalisations associated with high temperatures (heat effects) increased, but cold effects showed a decreasing trend from 1995 to 2016. The increasing magnitude of heat effects was larger (p = 0.002) in men than in women and larger (p < 0.001) in people aged ≤69 years than in those aged ≥70 years. There was no apparent difference amongst different climate zones. The study was limited by the switch from ICD-9 to ICD-10 coding systems, by being unable to separate first-time hospitalisation from repeated hospitalisations, and possibly by confounding by air pollution or by influenza infections.

CONCLUSION

The impacts of cold temperatures on cardiovascular hospitalisations have decreased, but the impacts of high temperatures have increased in Queensland, Australia. The findings highlight that Queensland people have adapted to the impacts of cold temperatures, but not high temperatures. The burden of cardiovascular hospitalisations due to high temperatures is likely to increase in the context of global warming.

Association of uncoupling protein (Ucp) gene polymorphisms with cardiometabolic diseases

The hereditary aspect of obesity is a major focus of modern medical genetics. The genetic background is known to determine a higher-than-average prevalence of obesity in certain regions, like Oceania. There is evidence that dysfunction of brown adipose tissue (BAT) may be a risk factor for obesity and type 2 diabetes (T2D). A significant number of studies in the field focus on the UCP family. The Ucp genes code for electron transport carriers. UCP1 (thermogenin) is the most abundant protein of the UCP superfamily and is expressed in BAT, contributing to its capability of generating heat. Single nucleotide polymorphisms (SNPs) of Ucp1-Ucp3 were recently associated with risk of cardiometabolic diseases. This review covers the main Ucp SNPs A-3826G, A-1766G, A-112C, Met229Leu, Ala64Thr (Ucp1), Ala55Val, G-866A (Ucp2), and C-55 T (Ucp3), which may be associated with the development of obesity, disturbance in lipid metabolism, T2D, and cardiovascular diseases.

Effect modification of the short-term effects of air pollution on morbidity by season: A systematic review and meta-analysis

Studies of the health effects of air pollution have traditionally controlled for ambient temperature as a confounder, and vice versa. However, season might be an important factor contributing to adverse health effects of air pollution. Given the current inconsistencies in results of previous studies on the effect modification of air pollution on morbidity by season, a systematic review and meta-analysis was conducted to synthesize the current evidence on effects of season on air pollution and morbidity. The electronic databases including PubMed, Web of Science, Embase, CNKI, and Wanfang were used to identify papers published up to the 30st of November in 2019. We identified 4284 articles, after screening, eighty papers met the inclusion criteria. Significant effect modification of CO, O₃, SO₂ and NO₂ on morbidity by season was observed, with corresponding ratio of relative risk of 1.0009 (95% CI: 1.0001-1.0018), 1.0080 (95% CI: 1.0021-1.0138), 0.9828 (95% CI: 0.9697-0.9962) and 0.9896 (95% CI: 0.9824-0.9968), respectively. Season significantly modified the effect of CO on pneumonia, the effect of SO₂ on cardiovascular disease, the effect of PM₁₀ on stroke, and the effect of O₃ on stroke, asthma and pneumonia. The effect modifications of air pollution by season were similar among males and females, while the effect estimates seem to be higher among children under 18 years old and the elderly aged 75 or over. Further research is needed to better understand the mechanisms underlying the seasonal variance of the effect of air pollutants on morbidity.

Quality Improvement in the Emergency Department: A Project to Reduce Door-to-Electrocardiography Times for Patients Presenting With Chest Pain

INTRODUCTION

The American Heart Association/American College of Cardiology guidelines recommend obtaining electrocardiography for patients who present to the emergency department with chest pain in less than 10 minutes of arrival. Reducing door-to-electrocardiography time is an important step in adhering to the recommended door-to-balloon times (≤ 90 minutes) for patients who present with ST-segment elevation myocardial infarction.

METHODS

Based on lean sigma principles, a protocol was implemented in an adult emergency department that included deferring nurse triage for patients with complaints of chest pain, chest tightness, and chest pressure and providing them with a red heart symbol as an indicator for clinical technicians to prioritize their electrocardiography order. Pre- and postintervention data were collected over a 12-month period.

RESULTS

Before the intervention, the mean door-to-electrocardiography time was 17 minutes for patients with chest pain (n = 893). After the intervention, the mean door-to-electrocardiography time for patients with chest pain significantly decreased to 7 minutes (n = 1,057) (t = 10.47, P ≤ 0.001). Initially, the percentage of compliance with door-to-electrocardiography standard of 10 minutes was 31% and improved to 83% after implementation of the new protocol.

DISCUSSION

Implementation of the optimized door-to-electrocardiography protocol decreased the time for obtaining diagnostics and improved compliance with the American Heart Association/American College of Cardiology guidelines, potentially decreasing door-to-balloon times for patients who presented with ST-segment elevation myocardial infarction.

Winter temperature and myocardial infarction in Brisbane, Australia: Spatial and temporal analyses

Myocardial infarction (MI) incidence often peaks in winter, but it remains unclear how winter temperature affects MI temporally and spatially. We examined the short-term effects of winter temperature on the risk of MI and explored spatial associations of winter MI hospitalizations with temperature and socioeconomic status (area-based index) in Brisbane, Australia. We used a distributed lag non-linear model to fit the association at the city level between population-weighted daily mean temperature and daily MI hospitalizations during 11 winters of 2005-2015. For each winter, a Bayesian spatial conditional autoregressive model was fitted to examine the associations at postal code level of MI hospitalisations with temperature and socioeconomic status measured as the Index of Relative Socio-Economic Advantage and Disadvantage (IRSAD). Area-specific winter temperature was categorised into three levels: cold (<25th percentile of average winter temperature across postal areas), mild (25th-75th percentile) and warm (>75th percentile). This study included 4978 MI hospitalizations. At the city level, each 1 °C drop in temperature below a threshold of 15.6 °C was associated with a relative risk (RR) of 1.016 (95% confidence interval (CI): 1.008-1.024) for MI hospitalizations on the same day. Low temperature had a much delayed and transient effect on women but an immediate and longer-lasting effect on men. Winter MI incidence rate varied spatially in Brisbane, with a higher incidence rate in warmer areas (RR for mild areas: 1.214, 95%CI: 1.116-1.320; RR for warm areas: 1.251, 95%CI: 1.127-1.389; cold areas as the reference) and in areas with lower socioeconomic levels (RR: 0.900, 95%CI: 0.886-0.914 for each decile increase in IRSAD). This study provides compelling evidence that short-term winter temperature drops were associated with an elevated risk of MI in the subtropical region with a mild winter. Particular attention also needs to be paid to people living in relatively warm and socioeconomically disadvantaged communities in winter.

Association Between Air Temperature and the Incidence of Acute Coronary Heart Disease in Northeast China

Aim

The aim of this study was to examine the association between air temperature and incidence of acute coronary heart disease in Northeast China.

Methods

We obtained coronary heart disease (CHD) daily hospitalization data from January 2017 to June 2019, and collected meteorological data including average daily air temperature, air pressure, relative humidity, wind velocity, sunshine duration and water vapor pressure, for the same period. Totally, This study included data from 6775 patients with CHD.

Results

After adjusting for confounding factors, low air temperature was inversely associated with CHD. Additionally, in the warm season (April–September), the number of daily hospital admissions for CHD was higher (≥24.2°C) if the average daily air temperature was low (≤15.4°C).

Conclusion

Low air temperature might be a risk factor for CHD among the elderly, especially in the warm season.

Analysis of weather exposure 7 days before occurrence of ST-segment elevation myocardial infarction

BACKGROUND

Several studies have highlighted the relationship between weather patterns and the occurrence of ST-elevation myocardial infarction (STEMI).

AIM

To evaluate the statistical association between the occurrence of STEMI and meteorological variables over the preceding 7 days.

METHODS

This was a retrospective study, using prespecified data from the ORBI (Breton Regional Observatory on Myocardial Infarction) registry, which includes all consecutive patients hospitalized for STEMI in the geographical area of Brest, France. Over a 7-year period, we compared the number of STEMIs per week with the mean values of meteorological variables over the preceding 7 days.

RESULTS

Overall, 7517 patients with STEMI were recorded in the ORBI registry between January 2009 and January 2016. After exclusion of patients not living in the geographical area of interest, 742 patients were included. The weekly incidence of STEMI ranged from 0 to 7 (median 2, interquartile range 1-3). In the univariate analysis, air temperature (odds ratio [OR] 1.05, 95% confidence interval [CI] 1.005-1.01 per 1°C decrease; P=0.03) and atmospheric pressure (OR 1.03, 95% CI 1.01-1.06 per 1 hPa increase; P=0.008) were associated with the weekly incidence of STEMI. In the multivariable analysis, air temperature (OR 1.06, 95% CI 1.01-1.10 per 1°C decrease; P=0.01), atmospheric pressure (OR 1.05, 95% CI 1.02-1.08 per 1 hPa increase; P<0.001) and duration of humidity>80% (OR 1.09, 95% CI 1.02-1.15 per 1hour increase; P=0.007) in the previous 7 days were associated with the occurrence of STEMI.

CONCLUSIONS

In this specific geographical area, occurrence of STEMI was statistically associated with a decrease in air temperature, an increase in atmospheric pressure and an increase in humidity over the preceding 7-day period.

Household energy efficiency and health: Area-level analysis of hospital admissions in England

INTRODUCTION

Fuel poverty affects up to 35% of European homes, which represents a significant burden on society and healthcare systems. Draught proofing homes to prevent heat loss, improved glazing, insulation and heating (energy efficiency measures) can make more homes more affordable to heat. This has prompted significant investment in energy efficiency upgrades for around 40% of UK households to reduce the impact of fuel poverty. Despite some inconsistent evidence, household energy efficiency interventions can improve cardiovascular and respiratory health outcomes. However, the health benefits of these interventions have not been fully explored; this is the focus of this study.

METHODS

In this cross sectional ecological study, we conducted two sets of analyses at different spatial resolution to explore population data on housing energy efficiency measures and hospital admissions at the area-level (counts grouped over a 3-year period). Housing data were obtained from three data sets covering housing across England (Household Energy Efficiency Database), Energy Performance Certificate (EPC) and, in the South West of England, the Devon Home Analytics Portal. These databases provided data aggregated to Lower Area Super Output Area and postcode level (Home Analytics Portal only). These datasets provided measures of both state (e.g. EPC ratings) and intervention (e.g. number of boiler replacements), aggregated spatially and temporally to enable cross-sectional analyses with health outcome data. Hospital admissions for adult (over 18 years) asthma, chronic obstructive pulmonary disease (COPD) and cardiovascular disease (CVD) were obtained from the Hospital Episode Statistics database for the national (1st April 2011 to 31st March 2014) and Devon, South West of England (1st April 2014 to 31st March 2017) analyses. Descriptive statistics and regression models were used to describe the associations between small area household energy efficiency measures and hospital admissions. Three main analyses were undertaken to investigate the relationships between; 1) household energy efficiency improvements (i.e. improved glazing, insulation and boiler upgrades); 2) higher levels of energy efficiency ratings (measured by Energy Performance Certificate ratings); 3) energy efficiency improvements and ratings (i.e. physical improvements and rating assessed by the Standard Assessment Procedure) and hospital admissions.

RESULTS

In the national analyses, household energy performance certificate ratings ranged from 37 to 83 (mean 61.98; Standard Deviation 5.24). There were a total of 312,837 emergency admissions for asthma, 587,770 for COPD and 839,416 for CVD. While analyses for individual energy efficiency metrics (i.e. boiler upgrades, draught proofing, glazing, loft and wall insulation) were mixed; a unit increase in mean energy performance rating was associated with increases of around 0.5% in asthma and CVD admissions, and 1% higher COPD admission rates. Admission rates were also influenced by the type of dwelling, tenure status (e.g. home owner versus renting), living in a rural area, and minimum winter temperature.

DISCUSSION

Despite a range of limitations and some mixed and contrasting findings across the national and local analyses, there was some evidence that areas with more energy efficiency improvements resulted in higher admission rates for respiratory and cardiovascular diseases. This builds on existing evidence highlighting the complex relationships between health and housing. While energy efficiency measures can improve health outcomes (especially when targeting those with chronic respiratory illness), reduced household ventilation rates can impact indoor air quality for example and increase the risk of diseases such as asthma. Alternatively, these findings could be due to the ecological study design, reverse causality, or the non-detection of more vulnerable subpopulations, as well as the targeting of areas with poor housing stock, low income households, and the lack of "whole house approaches" when retrofitting the existing housing stock.

CONCLUSION

To be sustainable, household energy efficiency policies and resulting interventions must account for whole house approaches (i.e. consideration of the whole house and occupant lifestyles). These must consider more alternative 'greener' and more sustainable measures, which are capable of accounting for variable lifestyles, as well as the need for adequate heating and ventilation. Larger natural experiments and more complex modelling are needed to further investigate the impact of ongoing dramatic changes in the housing stock and health.

STUDY IMPLICATIONS

This study supports the need for more holistic approaches to delivering healthier indoor environments, which must consider a dynamic and complex system with multiple interactions between a range of interrelated factors. These need to consider the drivers and pressures (e.g. quality of the built environment and resident behaviours) resulting in environmental exposures and adverse health outcomes.

Do hospital admission rates increase in colder winters? A decadal analysis from an eastern county in England

Background

The aim of the study was to measure the effect of colder winters compared to warmer winters on hospital admission rates in Suffolk County.

Methods

The setting of this study was Suffolk County in eastern England. The period of the study was financial years 2003/04-2012/13. The study was an analytic ecological study. Analysis involved calculation of rate ratios of hospital admission rates in colder winters compared to warmer winters, in all persons and the elderly.

Results

The main finding of the study was that all rate ratios for hospital admission rates in colder winters compared to warmer winters were significantly raised with effects of 2-5%. Rate ratios for all admissions in persons of all ages and persons aged 65 years and over were, respectively, 1.02 (99% confidence interval (CI): 1.01, 1.03; P < 0.001) and 1.02 (99% CI: 1.01, 1.04; P < 0.001). Rate ratios for emergency admissions in persons of all ages and persons aged 65 years and over were, respectively, 1.05 (99% CI: 1.03, 1.06; P < 0.001) and 1.04 (99% CI: 1.01, 1.06; P < 0.001).

Conclusion

In Suffolk County, hospital admission rates are significantly raised in colder winters compared to warmer winters. This evidence may be useful in planning hospital services.

Effects of pollution, low temperature and influenza syndrome on the excess mortality risk in winter 2016-2017

BACKGROUND

In the winter of 2016-2017, the number of deaths recorded in the north-west Europe was significantly higher than that in previous years. This spike in mortality was attributed principally to an influenza epidemic, but the contribution of air pollution and cold temperature has not been investigated. Information on the combined effect of low temperatures, influenza epidemic, and air pollution on mortality is inadequate. The objective of this study was to estimate the excess mortality in the winter of 2016-2017 in the metropolitan area of Milan, and to evaluate the independent short-term effect of 3 risk factors: low temperatures, the influenza epidemic, and air pollution.

METHODS

We used a case-crossover, time-stratified study design. Mortality data were collected on all people aged > 65 years who died of natural causes, due to respiratory diseases or cardiovascular diseases, between December 1, 2016 and February 15, 2017. Environmental data were extracted from the Regional Environmental Protection Agency. The National Surveillance Network provided data on influenza epidemic.

RESULTS

Among the 7590 natural deaths in people aged > 65 years, 965 (13%) were caused by respiratory conditions, and 2688 (35%) were caused by cardiovascular conditions. There were statistically significant associations between the minimum recorded temperature and deaths due to natural causes (OR = 0.966, 95% CI: 0.944-0.989), and cardiovascular conditions (OR = 0.961, 95% CI: 0.925-0.999). There were also statistically significant association between the influenza epidemic and deaths due to natural causes (OR = 1.198, 95% CI: 1.156-1.241), cardiovascular conditions (OR = 1.153, 95% CI: 1.088-1.223), and respiratory conditions (OR = 1.303, 95% CI: 1.166-1.456). High levels of PM10 (60 and 70 μg/m3) were associated with a statistically significant increase in natural and cause-specific mortality. There were statistically significant interactions between PM10 and influenza for cardiovascular-related mortality, and between influenza and temperature for deaths due to natural causes.

CONCLUSIONS

Excess of mortality in Milan during winter 2016-2017 was associated with influenza epidemic and concomitant environmental exposures, specifically, the combined effect of air pollution and low temperatures. Policies mitigating the effects of environmental risk factors should be implemented to prevent future excess mortality.