Cold exposure and winter mortality from ischaemic heart disease, cerebrovascular disease, respiratory disease, and all causes in warm and cold regions of Europe. The Eurowinter Group

The associations between thermal variety and health: Implications for space heating energy use

Fossil fuels dominate domestic heating in temperate climates. In the EU, domestic space heating accounts for around 20% of final energy demand. Reducing domestic demand temperatures would reduce energy demand. However, cold exposure has been shown to be associated with adverse health conditions. Using an observational dataset of 77,762 UK Biobank participants, we examine the standard deviation of experienced temperature (named here thermal variety) measured by a wrist worn activity and temperature monitor. After controlling for covariates such as age, activity level and obesity, we show that thermal variety is 0.15°C 95% CI [0.07–0.23] higher for participants whose health satisfaction was ‘extremely happy’ compared to ‘extremely unhappy’. Higher thermal variety is also associated with a lower risk of having morbidities related to excess winter deaths. We argue that significant CO₂ savings would be made by increasing thermal variety and reducing domestic demand temperatures in the healthiest homes. However, great care is needed to avoid secondary health impacts due to mould and damp. Vulnerable households should receive increased attention.

Seasonal Variation of Home Blood Pressure and Its Association With Target Organ Damage: The J-HOP Study (Japan Morning Surge-Home Blood Pressure)

Background

Although seasonal variation of home blood pressure (BP) has been reported to be higher in winter, seasonal difference in home BP (HBP) and its association with target organ damage (TOD) remains unclear.

Methods

This is a cross-sectional study using the dataset from the Japan Morning Surge-Home Blood Pressure (J-HOP) study to assess seasonal differences in HBP, prevalence of masked hypertension, and association of HBP with TOD. The J-HOP study is a nationwide, multicenter prospective study whose participants with cardiovascular risks underwent morning and evening HBP measurements for a 14-day period in 71 institutions throughout Japan. Urine albumin–creatinine ratio (UACR) and serum-B-type natriuretic peptide (BNP) were obtained at enrollment.

Results

Among 4,267 participants (mean age, 64.9 ± 10.9 years; 46.9% male; 91.4% hypertensives), 1,060, 979, 1,224, and 1,004 participants were enrolled in spring, summer, autumn, and winter, respectively. Morning and evening home systolic/diastolic BP levels, and prevalence of masked hypertension (office BP <140/90 mm Hg and HBP ≥135/85 mm Hg) were significantly lower in summer than other seasons after adjustment for covariates. When we assessed the interaction between BP parameters and each season for an association with TOD, we found the association between morning home diastolic BP and each of UACR and BNP was stronger in winter than other seasons (both P for interaction <0.05).

Conclusions

In this study, we revealed that the prevalence of masked hypertension was higher in other seasons than in summer and found a notable association between morning home diastolic BP and TOD in winter.

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.

Gradual cold acclimation induces cardioprotection without affecting β-adrenergic receptor-mediated adenylyl cyclase signaling

Novel strategies are needed that can stimulate endogenous signaling pathways to protect the heart from myocardial infarction. The present study tested the hypothesis that appropriate regimen of cold acclimation (CA) may provide a promising approach for improving myocardial resistance to ischemia/reperfusion (I/R) injury without negative side effects. We evaluated myocardial I/R injury, mitochondrial swelling, and β-adrenergic receptor (β-AR)-adenylyl cyclase-mediated signaling. Male Wistar rats were exposed to CA (8°C, 8 h/day for a week, followed by 4 wk at 8°C for 24 h/day), while the recovery group (CAR) was kept at 24°C for an additional 2 wk. The myocardial infarction induced by coronary occlusion for 20 min followed by 3-h reperfusion was reduced from 56% in controls to 30% and 23% after CA and CAR, respectively. In line, the rate of mitochondrial swelling at 200 μM Ca2+ was decreased in both groups. Acute administration of metoprolol decreased infarction in control group and did not affect the CA-elicited cardiprotection. Accordingly, neither β1-AR-Gsα-adenylyl cyclase signaling, stimulated with specific ligands, nor p-PKA/PKA ratios were affected after CA or CAR. Importantly, Western blot and immunofluorescence analyses revealed β2- and β3-AR protein enrichment in membranes in both experimental groups. We conclude that gradual cold acclimation results in a persisting increase of myocardial resistance to I/R injury without hypertension and hypertrophy. The cardioprotective phenotype is associated with unaltered adenylyl cyclase signaling and increased mitochondrial resistance to Ca2+-overload. The potential role of upregulated β2/β3-AR pathways remains to be elucidated.

NEW & NOTEWORTHY We present a new model of mild gradual cold acclimation increasing tolerance to myocardial ischemia/reperfusion injury without hypertension and hypertrophy. Cardioprotective phenotype is accompanied by unaltered adenylyl cyclase signaling and increased mitochondrial resistance to Ca2+-overload. The potential role of upregulated β2/β3-adrenoreceptor activation is considered. These findings may stimulate the development of novel preventive and therapeutic strategies against myocardial ischemia/reperfusion injury.

Impacts of climate change on the public health of the Mediterranean Basin population - Current situation, projections, preparedness and adaptation

The Mediterranean Basin is undergoing a warming trend with longer and warmer summers, an increase in the frequency and the severity of heat waves, changes in precipitation patterns and a reduction in rainfall amounts. In this unique populated region, which is characterized by significant gaps in the socio-economic levels particularly between the North (Europe) and South (Africa), parallel with population growth and migration, increased water demand and forest fires risk - the vulnerability of the Mediterranean population to human health risks increases significantly. Indeed, climatic changes impact the health of the Mediterranean population directly through extreme heat, drought or storms, or indirectly by changes in water availability, food provision and quality, air pollution and other stressors. The main health effects are related to extreme weather events (including extreme temperatures and floods), changes in the distribution of climate-sensitive diseases and changes in environmental and social conditions. The poorer countries, particularly in North Africa and the Levant, are at highest risk. Climate change affects the vulnerable sectors of the region, including an increasingly older population, with a larger percentage of those with chronic diseases, as well as poor people, which are therefore more susceptible to the effects of extreme temperatures. For those populations, a better surveillance and control systems are especially needed. In view of the climatic projections and the vulnerability of Mediterranean countries, climate change mitigation and adaptation become ever more imperative. It is important that prevention Health Action Plans will be implemented, particularly in those countries that currently have no prevention plans. Most adaptation measures are "win-win situation" from a health perspective, including reducing air pollution or providing shading solutions. Additionally, Mediterranean countries need to enhance cross-border collaboration, as adaptation to many of the health risks requires collaboration across borders and also across the different parts of the basin.

Physical activity trails in an urban setting and cardiovascular disease morbidity and mortality in Winnipeg, Manitoba, Canada: a study protocol for a natural experiment

INTRODUCTION

Aspects of the built environment that support physical activity are associated with better population health outcomes. Few experimental data exist to support these observations. This protocol describes the study of the creation of urban trials on cardiovascular disease (CVD)-related morbidity and mortality in a large urban centre.

METHODS AND ANALYSIS

Between 2008 and 2010, the city of Winnipeg, Canada, built four, paved, multiuse (eg, cycling, walking and running), two-lane trails that are 5-8 km long and span ~60 neighbourhoods. Linking a population-based health data with census and environmental data, we will perform an interrupted time series analysis to assess the impact of this natural experiment on CVD-related morbidity and mortality among individuals 30-65 years of age residing within 400-1200 m of the trail. The primary outcome of interest is a composite measure of incident major adverse CVD events (ie, CVD-related mortality, ischaemic heart disease, stroke and congestive heart failure). The secondary outcome of interest is a composite measure of incident CVD-related risk factors (ie, diabetes, hypertension and dyslipidaemia). Outcomes will be assessed quarterly in the 10 years before the intervention and 5 years following the intervention, with a 4-year interruption. We will adjust analyses for differences in age, sex, ethnicity, immigration status, income, gentrification and other aspects of the built environment (ie, greenspace, fitness/recreation centres and walkability). We will also assess trail use and trail user profiles using field data collection methods.

ETHICS AND DISSEMINATION

Ethical approvals for the study have been granted by the Health Research Ethics Board at the University of Manitoba and the Health Information Privacy Committee within the Winnipeg Regional Health Authority. We have adopted an integrated knowledge translation approach. Information will be disseminated with public and government partners.

TRIAL REGISTRATION NUMBER

NCT04057417.

Qualitative identification and characterisation of self-reported symptoms arising in humans during experimental exposure to cold air

Background: Exposure to cold air is associated with increased morbidity and mortality in the general population. It is difficult to study the effects of whole-body exposure to cold air under controlled conditions in real life. Objectives: The aim of this study was to (1) explore and describe the experience of symptoms in humans during experimental and controlled exposures to cold air, by using controlled environmental chamber exposures and qualitative methodology, and to (2) categorise the symptoms. Method: The study used a randomised, double blind design, in which 34 subjects undertook rest and moderate-intensity exercise in an environmental chamber set to two or three different temperatures (0, −10, and −17°C) on separate occasions. During the chamber exposures, subjects were interviewed. Qualitative content analysis was selected as the method of analysis. Findings: Subjects reported 50 distinct symptoms during the exposures. The symptoms were grouped into ten sub-categories and two major categories; airway versus whole-body symptoms. Conclusion: We have identified a broad range of symptoms in humans undertaking rest and moderate-intensity exercise at sub-zero temperatures. The symptoms and their categories may well be used to more extensively and quantitatively map cold-induced morbidity.

Exploring the Relationship between Green Space in a Neighbourhood and Cardiovascular Health in the Winter City of China: A Study Using a Health Survey for Harbin

A severely cold climate has a significant impact on cardiovascular health, involving temperature, air environment, exercise and diet. Existing studies have revealed that green space, as an important health resource, may play a positive role in promoting cardiovascular health through the air environment and exercise. Studies focusing on the correlation between green space and cardiovascular health are rarely carried out in winter cities. The purpose of this paper is to take a winter city in China as an empirical case to explore the correlation between green space in a neighbourhood and cardiovascular health in a representative sample at the neighbourhood level, combining the results with Urban Residential Area Planning and Design Standards (GB50180-2018) in China and the existing research. The results showed that green space characteristics of a neighbourhood were related to cardiovascular disease and some of its risk factors. In neighbourhoods with a Green Space Ratio lower than 28%, residents had a higher risk of physical inactivity, overweight or obesity, hypertension and stroke. In neighbourhoods with a Green View Index lower than 15%, residents had a higher risk of physical inactivity, overweight/obesity, hypertension, dyslipidemia and stroke. A correlation was found between evergreen tree configuration type and the prevalence of overweight/obesity and hypertension. No correlation was found between the type of sports field and cardiovascular disease and its risk factors, except for hypertension. Residents' cardiovascular health scores also showed significant differences among neighbourhoods with different green space characteristics. Intervention efforts may benefit from emphasising the importance of improving the Green Space Ratio and Green View Index effectively in a neighbourhood to reduce the risk of cardiovascular disease.

Weather patterns and all-cause mortality in England, UK

Cold- and heat-related mortality poses significant public health concerns worldwide. Although there are numerous studies dealing with the association between extreme ambient temperature and mortality, only a small number adopt a synoptic climatological approach in order to understand the nature of weather systems that precipitate increases in cold- or heat-related mortality. In this paper, the Lamb Weather Type synoptic classification is used to examine the relationship between daily mortality and weather patterns across nine regions of England. Analysis results revealed that the population in England is more susceptible to cold weather. Furthermore, it was found that the Easterly weather types are the most hazardous for public health all-year-long; however, during the cold period, the results are more evident and spatially homogenous. Nevertheless, it is noteworthy that the most dangerous weather conditions are not always associated with extreme (high or low) temperatures, a finding which points to the complexity of weather-related health effects and highlights the importance of a synoptic climatological approach in elucidating the relationship between temperature and mortality.

Temperature and Precipitation Associate With Ischemic Stroke Outcomes in the United States

Background

There is disagreement in the literature about the relationship between strokes and seasonal conditions. We sought to (1) describe seasonal patterns of stroke in the United States, and (2) determine the relationship between weather variables and stroke outcomes.

Methods and Results

We performed a cross‐sectional study using Get With The Guidelines‐Stroke data from 896 hospitals across the continental United States. We examined effects of season, climate region, and climate variables on stroke outcomes. We identified 457 638 patients admitted from 2011 to 2015 with ischemic stroke. There was a higher frequency of admissions in winter (116 862 in winter versus 113 689 in spring, 113 569 in summer, and 113 518 in fall; P<0.0001). Winter was associated with higher odds of in‐hospital mortality (odds ratio [OR] 1.08 relative to spring, confidence interval [CI] 1.04–1.13, P=0.0004) and lower odds of discharge home (OR 0.92, CI 0.91–0.94, P<0.0001) or independent ambulation at discharge (OR 0.96, CI 0.94–0.98, P=0.0006). These differences were attenuated after adjusting for climate region and case mix and became inconsistent after controlling for weather variables. Temperature and precipitation were independently associated with outcome after multivariable analysis, with increases in temperature and precipitation associated with lower odds of mortality (OR 0.95, CI 0.93–0.97, P<0.0001 and OR 0.95, CI 0.90–1.00, P=0.035, respectively).

Conclusions

Admissions for ischemic stroke were more frequent in the winter. Warmer and wetter weather conditions were independently associated with better outcomes. Further studies should aim to identify sensitive populations and inform public health measures aimed at resource allocation, readiness, and adaptive strategies.

Seasonality of deaths with respect to age and cause in Chitral District Pakistan

BACKGROUND

Seasonal variability in mortality has been studied in various regions globally. Proper evaluation of seasonally fluctuating mortality is important to establish effective public health measures. We investigated the overall, age-specific, and cause-specific seasonality of deaths in Chitral District in Pakistan.

METHOD

Data on 2577 deaths were provided by the Agha Khan Health Support Program. Seasonal mortality patterns concerning age and causes were examined using the X-12 ARIMA pseudo-additive decomposition method.

RESULTS

Of the total deceased, 59.6% were males. The proportion of deceased males was significantly higher than the female (40.4%, p< 0.001). The average age at death was 57.7 years (SD = 28.7). On average, approximately 43 deaths occurred each month. More than 10% of the deaths occurred in children less than 5-years-of-age. Among all the causes of death, the most frequent was cardiovascular disease (n = 666, 25.8%) followed by respiratory disease (n = 482, 18.7%). Significant seasonality in the overall deaths was evident, with a peak in winter. Deaths in people ≥ 55-years-of-age were significantly seasonal and peaked in winter. Deaths due to cardiovascular, respiratory, and kidney related diseases were also significantly seasonal with winter peaks. Further, deaths due to external causes were significantly seasonal with summer peak.

CONCLUSION

In the winter season, all-cause, except external, and age-specific mortality peaks in Chitral District, Pakistan. Deaths due to external causes and cardiovascular, respiratory, and kidney related diseases were significant seasonal effects.

Is There a Need to Integrate Human Thermal Models with Weather Forecasts to Predict Thermal Stress?

More and more people will experience thermal stress in the future as the global temperature is increasing at an alarming rate and the risk for extreme weather events is growing. The increased exposure to extreme weather events poses a challenge for societies around the world. This literature review investigates the feasibility of making advanced human thermal models in connection with meteorological data publicly available for more versatile practices and a wider population. By providing society and individuals with personalized heat and cold stress warnings, coping advice and educational purposes, the risks of thermal stress can effectively be reduced. One interesting approach is to use weather station data as input for the wet bulb globe temperature heat stress index, human heat balance models, and wind chill index to assess heat and cold stress. This review explores the advantages and challenges of this approach for the ongoing EU project ClimApp where more advanced models may provide society with warnings on an individual basis for different thermal environments such as tropical heat or polar cold. The biggest challenges identified are properly assessing mean radiant temperature, microclimate weather data availability, integration and continuity of different thermal models, and further model validation for vulnerable groups.

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.

Climate changes and ST-elevation myocardial infarction treated with primary percutaneous coronary angioplasty

BACKGROUND

The impact of seasonal changes on the incidence of acute myocardial infarction has been incompletely appraised, especially in the modern era of primary percutaneous coronary intervention (PPCI). We aimed to appraise the overall and season-specific impact of climate changes on the daily rate of PCCI.

METHODS

Details on PPCI and climate changes were retrospectively collected in three high-volume Italian institutions with different geographical features. The association between rate of PPCI and temperature, atmospheric pressure (ATM), humidity and rainfall was appraised with Poisson models, with overall analyses and according to season of the year.

RESULTS

Details on 6880 days with a total of 4132 PPCI were collected. Overall adjusted analysis showed that higher minimum atmospheric pressure 3 days before PPCI were associated with lower risk (regression coefficient = 0.999 [95% confidence interval 0.998-1.000], p = 0.030). Focusing on season, in Winter PPCI rates were increased by lower same day mean temperature (0.973 [0.956-0.990], p = 0.002) and lower rainfall (0.980 [0.960-1.000], p = 0.049). Conversely, in Spring greater changes in atmospheric pressure 3 days before PPCI were associated with increased risk (1.023 [1.002-1.045], p = 0.032), with similar effects in Summer for minimum temperature on the same day (1.022 [1.001-1.044], p = 0.040).

CONCLUSIONS

Climate has a significant impact on the risk of PPCI in the current era, with a complex interplay according to season. Higher risk risk is expected with lower minimum atmospheric pressure in the preceding days, lower rainfall in Winter, greater changes in atmospheric pressure in Spring, and higher temperatures in Summer. These findings have important implications for prevention strategies.

Association of Weather With Day-to-Day Incidence of Myocardial Infarction: A SWEDEHEART Nationwide Observational Study

Importance

Whether certain weather conditions modulate the onset of myocardial infarction (MI) is of great interest to clinicians because it could be used to prevent MIs as well as guide allocation of health care resources.

Objective

To determine if weather is associated with day-to-day incidence of MI.

Design, Setting, and Participants

In this prospective, population-based and nationwide setting, daily weather data from the Swedish Meteorological and Hydrological Institute were extracted for all MIs reported to the Swedish nationwide coronary care unit registry, Swedish Web-System for Enhancement and Development of Evidence-Based Care in Heart Disease Evaluated According to Recommended Therapies (SWEDEHEART), during 1998 to 2013 and then merged with each MI on date of symptom onset and coronary care unit. All patients admitted to any coronary care unit in Sweden owing to MI were included. A total of 280 873 patients were included, of whom 92 044 were diagnosed as having ST-elevation MI. Weather data were available for 274 029 patients (97.6%), which composed the final study population. Data were analyzed between February 2017 and April 2018.

Exposures

The nationwide daily mean air temperature, minimum air temperature, maximum air temperature, wind velocity, sunshine duration, atmospheric air pressure, air humidity, snow precipitation, rain precipitation, and change in air temperature.

Main Outcomes and Measures

The nationwide daily counts of MI as outcome.

Results

In 274 029 patients, mean (SD) age was 71.7 (12) years. Incidence of MI increased with lower air temperature, lower atmospheric air pressure, higher wind velocity, and shorter sunshine duration. The most pronounced association was observed for air temperature, where a 1-SD increase in air temperature (7.4°C) was associated with a 2.8% reduction in risk of MI (unadjusted incidence ratio, 0.972; 95% CI, 0.967-0.977; P <.001). Results were consistent for non-ST-elevation MI as well as ST-elevation MI and across a large range of subgroups and health care regions.

Conclusions and Relevance

In this large, nationwide study, low air temperature, low atmospheric air pressure, high wind velocity, and shorter sunshine duration were associated with risk of MI with the most evident association observed for air temperature.

Cross-Sectional Analysis of the Relationship Between Home Blood Pressure and Indoor Temperature in Winter

Mortality due to cardiovascular disease rises sharply in winter. Known as excess winter mortality, this phenomenon is partially explained by cold exposure-induced high blood pressure. Home blood pressure, especially in the morning, is closely associated with cardiovascular disease risk. We conducted the first large nationwide survey on home blood pressure and indoor temperature in 3775 participants (2095 households) who intended to conduct insulation retrofitting and were recruited by construction companies. Home blood pressure was measured twice in the morning and evening for 2 weeks. The relationship between home blood pressure and indoor temperature in winter was analyzed using a multilevel model with 3 levels: repeatedly measured day-level variables (eg, indoor ambient temperature and quality of sleep), nested within individual-level (eg, age and sex), and nested within household level. Cross-sectional analyses involving about 2900 participants (1840 households) showed that systolic blood pressure in the morning had significantly higher sensitivity to changes in indoor temperature (8.2 mm Hg increase/10°C decrease) than that in the evening (6.5 mm Hg increase/10°C decrease) in participants aged 57 years (mean age in this survey). We also found a nonlinear relationship between morning systolic blood pressure and indoor temperature, suggesting that the effect of indoor temperature on blood pressure varied depending on room temperature range. Interaction terms between age/women and indoor temperature were significant, indicating that systolic blood pressure in older residents and women was vulnerable to indoor temperature change. We expect that these results will be useful in determining optimum home temperature recommendations for men and women of each age group.

Clinical Trial Registration—

URL: http://www.umin.ac.jp/ctr/index.htm . Unique identifier: UMIN000030601.

Atmospheric fronts as minor cardiovascular risk factors, a new approach to preventive cardiology

BACKGROUND

Cardiovascular diseases are the number one cause of death globally and represent 31% of all global deaths. The aim of our study was to determine the influence of front effects on acute cardiovascular diseases (ACVDs).

METHODS

We obtained all ACVD admissions in a Central-European region, Hungary, Budapest. A time-series analysis was applied to 6499 morbidity cases during a five-year period (2009-2013). Poisson-regression model was used and adjusted for air temperature, pressure, humidity, wind velocity, their interactions and seasonality to assess the association of fronts and ACVDs.

RESULTS

There is a positive significant association between ACVDs and a cold front effect lagged by one day (p=0.018) with a relative risk (RR) of 1.095 [95% CI (1.021,1.181)]. Our findings show that among patient subgroups with major cardiovascular risk factors (hypertension, diabetes, hyperlipidemia, history of CVDs) the patterns are similar, but occluded fronts also have a significant effect.

CONCLUSION

Atmospheric fronts could play an important role in the pathogenesis of ACVDs. Our findings might help to provide a better understanding about fronts as minor cardiovascular risk factors and to organize medical prevention more effectively. Our research project may become a basis of a new field of preventive cardiovascular medicine in the future.

Excess winter mortality and morbidity before, during, and after the Great Recession: the Portuguese case

Although winter mortality and morbidity are phenomena common to most European countries, their magnitude varies significantly from country to country. The geographical disparities among regions with similar climates are the result of several social, economic, demographic, and biological conditions that influence an individual's vulnerability to winter conditions. The impact of poor socioeconomic conditions may be of such magnitude that an economic recession may aggravate the seasonal mortality pattern. This paper aims to measure the seasonal winter mortality, morbidity, and their related costs during the Great Recession (2009-2012) in mainland Portugal and its Regional Health Administrations (RHAs) and to compare it with the periods preceding and following it. Monthly mortality and morbidity data were collected and clustered into three periods: Great Recession (2009-2012), Pre-Recession (2005-2008), and Post-Recession (2013-2016). The impact of seasonal winter mortality and morbidity during the Great Recession in Portugal and its Regional Health Administrations was measured through the assessment of age-standardized excess winter (EW) death and hospital admissions rate and index, expected life expectancy gains without EW deaths, EW rate of potential years of life lost, and EW rate of emergency hospital admission costs. Important increases of winter deaths and hospital admissions were identified, resulting in an important number of potential years of life lost (87 years of life lost per 100,000 inhabitants in 2009-2012), life expectancy loss (1 year in 2009-2012), and National Health Service costs with explicit temporal and spatial variations. These human and economic costs have decreased consistently during the analyzed periods, while no significant increase was found during the Great Recession. Despite its reduction, the winter excess morbidity and mortality highlight that Portugal still faces substantial challenges related to a highly vulnerable population, calling for investments in better social and health protection.

Winter Peaks in Heart Failure: An Inevitable or Preventable Consequence of Seasonal Vulnerability?

Climate change is a major contributor to annual winter peaks in cardiovascular events across the globe. However, given the paradoxical observation that cardiovascular seasonality is observed in relatively mild as well as cold climates, global warming may not be as positive for the syndrome of heart failure (HF) as some predict. In this article, we present our Model of Seasonal Flexibility to explain the spectrum of individual responses to climatic conditions. We have identified distinctive phenotypes of resilience and vulnerability to explain why winter peaks in HF occur. Moreover, we identify how better identification of climatic vulnerability and the use of multifaceted interventions focusing on modifiable bio-behavioural factors may improve HF outcomes.

Association between Weather Types based on the Spatial Synoptic Classification and All-Cause Mortality in Sweden, 1991⁻2014

Much is known about the adverse health impact of high and low temperatures. The Spatial Synoptic Classification is a useful tool for assessing weather effects on health because it considers the combined effect of meteorological factors rather than temperature only. The aim of this study was to assess the association between oppressive weather types and daily total mortality in Sweden. Time-series Poisson regression with distributed lags was used to assess the relationship between oppressive weather (Dry Polar, Dry Tropical, Moist Polar, and Moist Tropical) and daily deaths over 14 days in the extended summer (May to September), and 28 days during the extended winter (November to March), from 1991 to 2014. Days not classified as oppressive weather served as the reference category. We computed relative risks with 95% confidence intervals, adjusting for trends and seasonality. Results of the southern (Skåne and Stockholm) and northern (Jämtland and Västerbotten) locations were pooled using meta-analysis for regional-level estimates. Analyses were performed using the dlnm and mvmeta packages in R. During summer, in the South, the Moist Tropical and Dry Tropical weather types increased the mortality at lag 0 through lag 3 and lag 6, respectively. Moist Polar weather was associated with mortality at longer lags. In the North, Dry Tropical weather increased the mortality at shorter lags. During winter, in the South, Dry Polar and Moist Polar weather increased mortality from lag 6 to lag 10 and from lag 19 to lag 26, respectively. No effect of oppressive weather was found in the North. The effect of oppressive weather types in Sweden varies across seasons and regions. In the North, a small study sample reduces precision of estimates, while in the South, the effect of oppressive weather types is more evident in both seasons.

Frailty, inequality and resilience

Frailty is a common condition in later life in which minor stressors may result in major changes in health. While the biological mechanisms of frailty are increasingly understood, relationships with the wider determinants of health, health inequalities and the concept of resilience are less well-established and the role of the clinician in their modification is less well understood.The wider determinants are the modifiable conditions in which people are born, grow, work and live, and the wider set of systems shaping the conditions of daily life. They interact across the life course, driving a well-recognised social gradient in health. The wider determinants are closely linked to the concept of resilience, which is the process of effectively negotiating, adapting to or managing significant sources of stress or trauma. Better recognition of the relationship between frailty, the wider determinants, inequalities and resilience can enable a framework around which policy responses may be developed to build resilience in people living with frailty at an individual and community level as well as enabling clinicians to better identify how they may support their patients.

Early-life exposure to weather shocks and child height: Evidence from industrializing Japan

In this study, we estimate the long-run effects of early-life exposure to weather shocks on the height of primary school children. To estimate the global impacts on almost the entire child population in an industrializing country, we utilize both a unique nationwide multi-dimensional longitudinal dataset of Japanese children aged 6-11 and official monthly statistics on meteorological conditions in the 1920s. We observe that the exposure to cold waves in early-life exerted stunting effects on both the boys and girls. In the coldest regions in the northeastern area of Japan, the stunting effects of cold weather shocks on the boys and girls are estimated to be approximately 0.8 and 0.6 cm, respectively. Our observation indicates that prenatal (postnatal) exposure is important for the boys (girls). Our results suggest that the marginal effects of cold waves are stronger in the warmer regions than in the colder regions.

The effects of temperature on short-term mortality risk in Kuwait: A time-series analysis

BACKGROUND

In light of climate change, health risks are expected to be exacerbated by extreme temperatures. Many studies showed that high and low ambient temperatures are associated with increased short-term mortality risk, but little is known about these risks in Kuwait and the Gulf Region.

OBJECTIVE

To examine the dose-response relationship between 24-h average ambient temperatures and daily mortality risk in Kuwait.

METHODS

We gathered mortality and meteorological data from 2010 to 2016 in Kuwait. We did a time-series analysis using a negative binomial distribution, and studied the lag effects of temperature with distributed lag non-linear models.

RESULTS

A total of 33,574 all-cause non-accidental deaths were analyzed. The relationship was shown to be non-linear. Overall relative risks of death comparing the 1st percentile (10.9 °C) and the 99th percentile (42.7 °C) to the optimum temperature were 1.67 (1.02-2.73), and 1.65 (1.09-2.48), respectively. Cold effects persisted for 9 days, while the effects of hot temperatures were the highest at lag 0 and only persisted for a week. Adjusting for PM₁₀ and ozone did not change the temperature-mortality estimates.

CONCLUSION

Our findings show evidence that there is a statistically significant positive association between temperature extremes and mortality in Kuwait. The evidence has significant implications in assessing climate vulnerability and provides insight into environmental challenges in an inherently hot and arid region.

Effects of extreme temperatures on cerebrovascular mortality in Lisbon: a distributed lag non-linear model

Cerebrovascular diseases are the leading cause of mortality in Portugal, especially when related with extreme temperatures. This study highlights the impacts of the exposure-response relationship or lagged effect of low and high temperatures on cerebrovascular mortality, which can be important to reduce the health burden from cerebrovascular diseases. The purpose of this study was to assess the effects of weather on cerebrovascular mortality, measured by ambient temperature in the District of Lisbon, Portugal. A quasi-Poisson generalized additive model combined with a distributed lag non-linear model was applied to estimate the delayed effects of temperature on cerebrovascular mortality up to 30 days. With reference to minimum mortality temperature threshold of 22 °C, there was a severe risk (RR = 2.09, 95% CI 1.74, 2.51) of mortality for a 30-day-cumulative exposure to extreme cold temperatures of 7.3 °C (1st percentile). Similarly, the cumulative effect of a 30-day exposure to an extreme hot temperature of 30 °C (99th percentile) was 52% (RR = 1.65, 95% CI 1.37, 1.98) higher than same-day exposure. Over the 13 years of study, non-linear effects of temperature on mortality were identified, and the probability of dying from cerebrovascular disease in Lisbon was 7% higher in the winter than in the summer. The findings of this study provide a baseline for future public health prevention programs on weather-related mortality.

Bootstrap approach to validate the performance of models for predicting mortality risk temperature in Portuguese Metropolitan Areas

BACKGROUND

There has been increasing interest in assessing the impacts of extreme temperatures on mortality due to diseases of the circulatory system. This is further relevant for future climate scenarios where marked changes in climate are expected. This paper presents a solid method do identify the relationship between extreme temperatures and mortality risk by using as predictors simulated temperature data for cold and hot conditions in two urban areas in Portugal.

METHODS

Based on the mortality and meteorological data from Porto Metropolitan Area (PMA) and Lisbon Metropolitan Area (LMA), a distributed lag nonlinear model (DLNM) was implemented to estimate the temperature effects on mortality due to diseases of the circulatory system. The performance of the models was validated via bootstrapping approaching by creating resamples with replacement from the validating data. Bootstrapping was also used to identify the best candidate model and to evaluate the sensitivity of the spline functions to the exposure-lag-response relationship.

RESULTS

It is found that the model is able to reproduce the temperature-related mortality risk for two metropolitan areas. Temperature previously simulated by climate models is useful and even better than observed temperature. Although, the biases in predictions in both metropolitan areas are low, mortality risk predictions in PMA are more accurate than in LMA. Using parametric bootstrapping, we found that the overall cumulative association estimated under different bi-dimensional exposure-lag-response relationship are relatively stable, especially for the model selected by Quasi-Akaike Information Criteria (QAIC). Exposure to summer temperature conditions is best related to mortality risk. The association between winter temperature and mortality risk is somewhat less strong.

CONCLUSIONS

The use of QAIC to choose from several candidate models provides valid predictions and reduced the uncertainty in the estimated relative risk for circulatory disease mortality. Our findings can be applied to better understand the characteristics and facilitate the prevention of circulatory disease mortality in Porto and Lisbon Metropolitan Areas, namely if we consider the actual context of climate change.

Prevalence and profile of "seasonal frequent flyers" with chronic heart disease: Analysis of 1598 patients and 4588 patient-years follow-up

BACKGROUND

Peaks and troughs in cardiovascular events correlated with seasonal change is well established from an epidemiological perspective but not a clinical one.

METHODS

Retrospective analysis of the recruitment, baseline characteristics and outcomes during minimum 12-month exposure to all four seasons in 1598 disease-management trial patients hospitalised with chronic heart disease. Seasonality was prospectively defined as ≥4 hospitalisations (all-cause) AND >45% of related bed-days occurring in any one season during median 988 (IQR 653, 1394) days follow-up.

RESULTS

Patients (39% female) were aged 70 ± 12 years and had a combination of coronary artery disease (58%), heart failure (54%), atrial fibrillation (50%) and multimorbidity. Overall, 29.9% of patients displayed a pattern of seasonality. Independent correlates of seasonality were female gender (adjusted OR 1.27, 95% CI 1.01-1.61; p = 0.042), mild cognitive impairment (adjusted OR 1.51, 95% CI 1.16-1.97; p = 0.002), greater multimorbidity (OR 1.20, 95% CI 1.15-1.26 per Charlson Comorbidity Index Score; p < 0.001), higher systolic (OR 1.01, 95%CI 1.00-1.01 per 1 mmHg; p = 0.002) and lower diastolic (OR 0.99, 95% CI 0.98-1.00 per 1 mmHg; p = 0.002) blood pressure. These patients were more than two-fold more likely to die (adjusted HR 2.16, 95% CI 1.60-2.90; p < 0.001) with the highest and lowest number of deaths occurring during spring (31.7%) and summer (19.9%), respectively.

CONCLUSIONS

Despite high quality care and regardless of their diagnosis, we identified a significant proportion of "seasonal frequent flyers" with concurrent poor survival in this real-world cohort of patients with chronic heart disease.

Assessment of the Relationship Between Ambient Temperature and Home Blood Pressure in Patients From a Web-Based Synchronous Telehealth Care Program: Retrospective Study

BACKGROUND

Decreased ambient temperature significantly increases office blood pressure, but few studies have evaluated the effect of ambient temperature on home blood pressure.

OBJECTIVE

We aimed to investigate the relationship between short-term ambient temperature exposure and home blood pressure.

METHODS

We recruited patients with chronic cardiovascular diseases from a telehealth care program at a university-affiliated hospital. Blood pressure was measured at home by patients or their caregivers. We obtained hourly meteorological data for Taipei (temperature, relative humidity, and wind speed) for the same time period from the Central Weather Bureau, Taiwan.

RESULTS

From 2009 to 2013, we enrolled a total of 253 patients. Mean patient age was 70.28 (SD 13.79) years, and 66.0% (167/253) of patients were male. We collected a total of 110,715 home blood pressure measurements. Ambient temperature had a negative linear effect on all 3 home blood pressure parameters after adjusting for demographic and clinical factors and antihypertensive agents. A 1°C decrease was associated with a 0.5492-mm Hg increase in mean blood pressure, a 0.6841-mm Hg increase in systolic blood pressure, and a 0.2709-mm Hg increase in diastolic blood pressure. This temperature effect on home blood pressure was less prominent in patients with diabetes or hypertension. Antihypertensive agents modified this negative effect of temperature on home blood pressure to some extent, and angiotensin receptor blockers had the most favorable results.

CONCLUSIONS

Short-term exposure to low ambient temperature significantly increased home blood pressure in patients with chronic cardiovascular diseases. Antihypertensive agents may modify this effect.

Cardiovascular effects and risks of recreational alpine skiing in the elderly

OBJECTIVES

Alpine skiing is one of the most popular recreational winter sports and attracts millions of tourists every year alone in the Alpine region. Several studies highlight the positive effects of alpine skiing as aerobic physical training and isometric muscle activity that is able to increase exercise capacity and reduce cardiovascular risk factors. However, a certain cardiovascular risk mainly related to an abrupt increase of myocardial oxygen consumption during skiing especially in otherwise sedentary subjects and effects of hypoxia in untrained patients have to be acknowledged.

DESIGN

In this article, we provide an up-to-date evaluation of risks and benefits of alpine skiing in relation of cardiovascular disease and elderly persons.

METHODS

Narrative Review.

RESULTS

In the first section, the current recommendations of physical activity and effects of alpine skiing - with particular attention to the elderly population - are described. In the second section, the present knowledge regarding cardiovascular risk and alpine skiing is summarized and possible pathophysiological mechanisms are highlighted. Finally, a summary regarding actual clinical recommendations is provided.

CONCLUSIONS

Alpine skiing may safely be recommended also to the elderly if certain precautions are applied, as the benefits outbalance the potential risks in most subjects.

Changes in cold-related mortalities between 1995 and 2016 in South East England

Objective

The aim of the study was to examine trends in cold-related mortalities between 1995 and 2016.

Study design

This is a longitudinal mortality study.

Methods

For men and women aged 65–74 years or those older than 85 years in South East England, the relationship between daily mortality (deaths per million population) and outdoor temperatures below 18 °C, with allowance for influenza epidemics, was assessed by linear regression on an annual basis. The regression coefficients were expressed as a percentage of the mortality at 18 °C to adjust for changes in mortality through health care. Trends in ‘specific’ cold-related mortalities were then examined over two periods, 1977–1994 and 1995–2016.

Results

In contrast to the early period, annual trends in cold-related specific mortalities showed no decline between 1995 and 2016. ‘Specific’ cold-related mortality of women, but not men, in the age group older than 85 years showed a significant increase over the 1995–2016 period, which was different from the trend over the earlier period (P < 0.01).

Conclusion

Despite state-funded benefits to help alleviate fuel poverty and public health advice, very elderly women appear to be at increasing risk of cold-related mortality—greater help may be necessary.

•

In contrast to 1977-94, a reduction of excess winter mortality from all causes did not take place between 1995 and 2016.

•

Similar trends are seen in mortality from ischaemic heart, cerebrovascular and respiratory diseases.

•

Excess winter mortality from all causes rose over this period in women older than 85 years.

The effect characteristics of temperature on stroke mortality in Inner Mongolia and globally

The current study investigated the correlation between stroke mortality and temperature. Monthly and seasonal variations in stroke mortality were plotted and daily stroke-related deaths were calculated. The lag times were calculated using the time series analysis. The correlation between stroke incidence and the diurnal temperature range (DTR) was analyzed using case-crossover analysis. Global stroke mortality was described in five latitudes. In the eastern region of Inner Mongolia, the stroke mortality was 174.18/105, about twice of that of the midwestern regions (87.07/105), and temperature was negatively correlated with stroke mortality. Mortality peaked in the winter and troughed in the summer (χ² = 13.634, P < 0.001). The days in which stroke-related deaths were greater than ten occurred between late October and early April. The effect of temperature on stroke incidence occurred during a lag time of 1 (P = 0.024) or 2 months (P = 0.039). A DTR over 13 °C was positively correlated (r = 0.95, P = 0.004) with stroke with a lag time of 1 day. The effect of temperature on stroke was shown to be the same for various populations. As the latitude increases, stroke mortality also increases with latitudes > 40°; the highest mortality was 188.05/105 at the highest latitude. Only in relatively cold regions as the temperature decreases does stroke mortality increase for various populations. Differences in the time lag as well as in the DTR lag and DTR critical point vary for both the temperature and region.

Impacts of cold weather on emergency hospital admission in Texas, 2004-2013

Cold weather has been identified as a major cause of weather-related deaths in the U.S. Although the effects of cold weather on mortality has been investigated extensively, studies on how cold weather affects hospital admissions are limited particularly in the Southern United States. This study aimed to examine impacts of cold weather on emergency hospital admissions (EHA) in 12 major Texas metropolitan statistical areas (MSAs) for the 10-year period, 2004-2013. A two-stage approach was employed to examine the associations between cold weather and EHA. First, the cold effects on each MSA were estimated using distributed lag non-linear models (DLNM). Then a random effects meta-analysis was applied to estimate pooled effects across all 12 MSAs. Percent increase in risk and corresponding 95% confidence intervals (CIs) were estimated as with a 1 °C (°C) decrease in temperature below a MSA-specific threshold for cold effects. Age-stratified and cause-specific EHA were modeled separately. The majority of the 12 Texas MSAs were associated with an increased risk in EHA ranging from 0.1% to 3.8% with a 1 ⁰C decrease below cold thresholds. The pooled effect estimate was 1.6% (95% CI: 0.9%, 2.2%) increase in all-cause EHA risk with 1 ⁰C decrease in temperature. Cold wave effects were also observed in most eastern and southern Texas MSAs. Effects of cold on all-cause EHA were highest in the very elderly (2.4%, 95% CI: 1.2%, 3.6%). Pooled estimates for cause-specific EHA association were strongest in pneumonia (3.3%, 95% CI: 2.8%, 3.9%), followed by chronic obstructive pulmonary disease (3.3%, 95% CI: 2.1%, 4.5%) and respiratory diseases (2.8%, 95% CI: 1.9%, 3.7%). Cold weather generally increases EHA risk significantly in Texas, especially in respiratory diseases, and cold effects estimates increased by elderly population (aged over 75 years). Our findings provide insight into better intervention strategy to reduce adverse health effects of cold weather among targeted vulnerable populations.

Sociodemographic, climatic variability and lower respiratory tract infections: a systematic literature review

Pneumonia is the leading cause of mortality and morbidity in developing countries, particularly for children and elderly. The main objective of this review paper is to review the epidemiological evidence about the effects of sociodemographic and climatic variability on pneumonia and other lower respiratory tract infections. A detailed literature search was conducted in PubMed and Scopus following PRISMA guidelines. The articles, which considered the effect of only climatic or both climatic and sociodemographic factors on pneumonia and other lower respiratory tract infections, included in this review. A total thirty-four relevant articles were reviewed. Of 34 studies, only 14 articles (41%) examined the joint effects of sociodemographic and climate factors on pneumonia and other lower respiratory infections while most of them (59%) assessed climate factors separately. Among these fourteen, only three articles (8.8%) considered detailed sociodemographic factors. All of the reviewed articles suggested different degrees of positive or negative relationship of temperature with pneumonia or other lower respiratory tract infections. Fifteen (44%) articles suggested an association with relative humidity and 13 (38%) with rainfall. Only 3 articles (8.8%) found a relationship with wind speed. Three articles (8.8%) considered other risk factors such as particulate matter 2.5 (PM_2.5) and particulate matter 10 (PM₁₀). One study among the reviewed articles used spatial analysis methods but this study did not examine the joint effects. Among the reviewed articles, 18 (53%) articles used different time series models, one article (3%) used spatiotemporal time series model, 8 (23%) studies used other models and rest 7 (21%) studies used simple descriptive analysis. A total of 18 studies (53%) were conducted in Asia, most of them in China. There were 6 studies (17%) in Europe and 8 studies (23%) in America (South, North and Central). In Africa and Oceania, only one study was found for each region. The joint effect of climate and sociodemographic factors on pneumonia and other lower respiratory tract infections remain to be determined and further research is highly recommended for future prevention of this important and common disease.

The effect of the Winter Fuel Payment on household temperature and health: a regression discontinuity design study

Background

The Winter Fuel Payment (WFP) is a non-NHS population-level policy intervention that aims to reduce cold exposure and enhance the health and well-being of older adults. Labelling this cash transfer as ‘winter fuel’ has been shown to lead to increased household energy expenditure, but it is not known if this expenditure produces warmer homes or health benefits.

Objectives

First, the association between indoor temperature and health was established to identify the outcome measures most likely to be affected by the WFP. Then, whether or not receiving the WFP is associated with raised household temperature levels and/or improved health was assessed.

Design

Random and fixed effects regression models were used to estimate the link between ambient indoor temperature and health. A regression discontinuity (RD) design analysis exploiting the sharp eligibility criteria for the WFP was employed to estimate the potential impact of the payment.

Setting

The sample was drawn from the English Longitudinal Study of Ageing (ELSA), an observational study of community-dwelling individuals aged ≥ 50 years in England.

Participants

Analyses examining the association between household temperature and health had a maximum sample of 12,210 adults aged 50–90 years. The RD analyses drew on a maximum of 5902 observations.

Intervention

The WFP provides households with a member who is aged > 60 years (up to 2010, from which point the minimum age increased) in the qualifying week with a lump sum annual payment, typically in November or December.

Main outcome measures

Differences in indoor temperature were examined, and, following an extensive literature review of relevant participant-reported health indicators and objectively recorded biomarkers likely to be affected by indoor temperature, a series of key measures were selected: blood pressure, inflammation, lung function, the presence of chest infections, subjective health and depressive symptom ratings.

Data sources

The first six waves of the ELSA were drawn from, accessible through the UK Data Service (SN:5050 English Longitudinal Study of Ageing: Waves 0–7, 1998–2015).

Results

Results from both random and fixed-effects multilevel regression models showed that low levels of indoor temperature were associated with raised systolic and diastolic blood pressure levels and raised fibrinogen levels. However, across the RD models, no evidence was found that the WFP was consistently associated with differences in either household temperature or the health of qualifying (vs. non-qualifying) households.

Limitations

The presence of small effects cannot be ruled out, not detectable because of the sample size in the current study.

Conclusions

This study capitalised on the sharp assignment rules regarding WFP eligibility to estimate the potential effect of the WFP on household temperature and health in a national sample of English adults. The RD design employed did not identify evidence linking the WFP to warmer homes or potential health and well-being effects.

Future work

Further research should utilise larger samples of participants close to the WFP eligibility cut-off point examined during particularly cold weather in order to identify whether or not the WFP is linked to health benefits not detected in the current study, which may have implications for population health and the evaluation of the effectiveness of the WFP.

Funding

The National Institute for Health Research Public Health Research programme.

Associations between Ambient Temperature and Acute Myocardial Infarction

Background

The associations between incidence of acute myocardial infarction (AMI) and the ambient temperature were mixed in prior studies.

Methods

Data of 2033 consecutive admissions of AMI in a central tertiary hospital in North China from 1st Jan 2003 to 31st Dec 2011 were collected. The weather data in this period were from the local meteorological department. Based on the ambient temperature information, we defined several ambient temperature indices, including daily average temperature, extremely low temperature, and daily temperature range, then characterized the independent associations between them and the incidence of AMI.

Results

The daily average temperature one day before was independently associated with AMI incidence rate: a rise of 5°C of the daily average temperature led to a 5% decrease in AMI admissions. Daily average temperature and temperature range two days before were independently associated with AMI incidence rate: a rise of 5°C of the daily average temperature led to a fall of 6% in AMI admissions, and a rise of 2°C of the daily temperature range led to a rise of 4% in AMI admission.

Conclusion

Low ambient temperature has substantial association with AMI, and can play an important role in warning and forecasting the incidence.

Annual and seasonal trends in mortality rates from cardiovascular diseases in Hungary between 1984 and 2013

OBJECTIVES

The aim of this study was to investigate annual and seasonal trends in mortality rates from cardiovascular diseases in Hungary between 1984 and 2013.

METHODS

Annual and monthly mortality and population data were obtained from the Hungarian Central Statistical Office. The annual mortality data by gender and age were available for the following disease classifications of the circulatory system: all cardiovascular diseases, all diseases of the heart, hypertension, coronary heart disease, and cerebrovascular diseases. Six age groups were defined for both sexes. Negative binomial regression was carried out to analyse annual trends in age-standardized mortality rates. The Walter-Elwood method was used to identify seasonal variation using monthly numbers of deaths.

RESULTS

Significant decreases in annual mortality rates for all cardiovascular diseases were found, but not for hypertension. Age-standardized death rates were higher for men for all causes, except for hypertension. The greatest sex difference in the average risk of death was observed in the middle-aged groups. The greatest percentage decrease in death rates during the study period was seen for both sexes in the under 35 age group. The lowest percentage change was observed among people aged over 75. Significant seasonality was found in monthly death rates from all causes, with a peak in February.

CONCLUSIONS

In spite of a decreasing trend in the annual mortality rates for cardiovascular diseases, the Hungarian mortality rate is still high. Moreover, this study demonstrated a significant winter peak in mortality from cardiovascular diseases over a thirty-year period.

What is cold-related mortality? A multi-disciplinary perspective to inform climate change impact assessments

BACKGROUND

There is a growing discussion regarding the mortality burdens of hot and cold weather and how the balance between these may alter as a result of climate change. Net effects of climate change are often presented, and in some settings these may suggest that reductions in cold-related mortality will outweigh increases in heat-related mortality. However, key to these discussions is that the magnitude of temperature-related mortality is wholly sensitive to the placement of the temperature threshold above or below which effects are modelled. For cold exposure especially, where threshold effects are often ill-defined, choices in threshold placement have varied widely between published studies, even within the same location. Despite this, there is little discussion around appropriate threshold selection and whether reported associations reflect true causal relationships - i.e. whether all deaths occurring below a given temperature threshold can be regarded as cold-related and are therefore likely to decrease as climate warms.

OBJECTIVES

Our objectives are to initiate a discussion around the importance of threshold placement and examine evidence for causality across the full range of temperatures used to quantify cold-related mortality. We examine whether understanding causal mechanisms can inform threshold selection, the interpretation of current and future cold-related health burdens and their use in policy formation.

METHODS

Using Greater London data as an example, we first illustrate the sensitivity of cold related mortality to threshold selection. Using the Bradford Hill criteria as a framework, we then integrate knowledge and evidence from multiple disciplines and areas- including animal and human physiology, epidemiology, biomarker studies and population level studies. This allows for discussion of several possible direct and indirect causal mechanisms operating across the range of 'cold' temperatures and lag periods used in health impact studies, and whether this in turn can inform appropriate threshold placement.

RESULTS

Evidence from a range of disciplines appears to support a causal relationship for cold across a range of temperatures and lag periods, although there is more consistent evidence for a causal effect at more extreme temperatures. It is plausible that 'direct' mechanisms for cold mortality are likely to occur at lower temperatures and 'indirect' mechanisms (e.g. via increased spread of infection) may occur at milder temperatures.

CONCLUSIONS

Separating the effects of 'extreme' and 'moderate' cold (e.g. temperatures between approximately 8-9 °C and 18 °C in the UK) could help the interpretation of studies quoting attributable mortality burdens. However there remains the general dilemma of whether it is better to use a lower cold threshold below which we are more certain of a causal relationship, but at the risk of under-estimating deaths attributable to cold.

The impact of home energy efficiency interventions and winter fuel payments on winter- and cold-related mortality and morbidity in England: a natural equipment mixed-methods study

Background

England, and the UK more generally, has a large burden of winter- and cold-related mortality/morbidity in comparison with nearby countries in continental Europe. Improving the energy efficiency of the housing stock may help to reduce this, as well as being important for climate change and energy security objectives.

Objectives

To evaluate the impact of home energy efficiency (HEE) interventions on winter- and cold-related mortality/morbidity, including assessing the impact of winter fuel payments (WFPs) and fuel costs.

Design

A mixed-methods study – an epidemiological time-series analysis, an analysis of data on HEE interventions, the development and application of modelling methods including a multicriteria decision analysis and an in-depth interview study of householders.

Setting

England, UK.

Participants

The population of England. In-depth interviews were conducted with 12 households (2–4 participants each) and 41 individuals in three geographical regions.

Interventions

HEE interventions.

Main outcome measures

Mortality, morbidity and intervention-related changes to the home indoor environment.

Data sources

The Homes Energy Efficiency Database, mortality and hospital admissions data and weather (temperature) data.

Results

There has been a progressive decline in cold-related deaths since the mid-1970s. Since the introduction of WFPs, the gradient of association between winter cold and mortality [2.00%, 95% confidence interval (CI) 1.74% to 2.28%] per degree Celsius fall in temperature is somewhat weaker (i.e. that the population is less vulnerable to cold) than in earlier years (2.37%, 95% CI 0.22% to 2.53%). There is also evidence that years with above-average fuel costs were associated with higher vulnerability to outdoor cold. HEE measures installed in England in 2002–10 have had a relatively modest impact in improving the indoor environment. The gains in winter temperatures (around +0.09 °C on a day with maximum outdoor temperature of 5 °C) are associated with an estimated annual reduction of ≈280 cold-related deaths in England (an eventual maximum annual impact of 4000 life-years gained), but these impacts may be appreciably smaller than those of changes in indoor air quality. Modelling studies indicate the potential importance of the medium- and longer-term impacts that HEE measures have on health, which are not observable in short-term studies. They also suggest that HEE improvements of similar annualised cost to current WFPs would achieve greater improvements in health while reducing (rather than increasing) carbon dioxide emissions. In-depth interviews suggest four distinct householder framings of HEE measures (as home improvement, home maintenance, subsidised public goods and contributions to sustainability), which do not dovetail with current ‘consumerist’ national policy and may have implications for the uptake of HEE measures.

Limitations

The quantification of intervention impacts in this national study is reliant on various indirect/model-based assessments.

Conclusions

Larger-scale changes are required to the housing stock in England if the full potential benefits for improving health and for reaching increasingly important climate change mitigation targets are to be realised.

Future work

Studies based on data linkage at individual dwelling level to examine health impacts. There is a need for empirical assessment of HEE interventions on indoor air quality.

Funding

This project was funded by the National Institute for Health Research (NIHR) Public Health Research programme and will be published in full in Public Health Research; Vol. 6, No. 11. See the NIHR Journals Library website for further project information.

Meteorological Factors and Air Pollutants Contributing to Seasonal Variation of Acute Exacerbation of Atrial Fibrillation: A Population-Based Study

OBJECTIVE

We investigated seasonal variation of acute exacerbation of atrial fibrillation (AAF) and contributing environmental factors.

METHODS

AAF events, meteorological elements, and air pollutants in Seoul between 2013 and 2015 were obtained from the nationwide database. AAF was defined if a patient visited the emergency room due to any AF-relevant symptoms or signs.

RESULTS

AAF occurred less frequently in summer than in other seasons (6.71 vs 7.25 events/d, P = 0.005). AAF tended to decrease with an increase of air temperature (r = -0.058). Among air pollutants, NO2 was significantly lower in summer and positively correlated with AAF after adjusting for other variables (β = 3.197).

CONCLUSIONS

The rate of AAF events was the lowest in summer; air temperature and NO2 were contributing factors. The weather and environmental conditions should be considered as risk factors of AAF.

Daylight saving time, circadian rhythms, and cardiovascular health

Very recently, the European Parliament, called to decide on possible abolition of the Daylight Saving Time (DST), approved a resolution calling the scientific community to conduct a more in-depth evaluation. The question is based on disruption of body's circadian rhythms. We review here the relationship between DST and cardiovascular health. The available evidence suggests the existence of an association between DST and a modest increase of occurrence of acute myocardial infarction, especially in the first week after the spring shift. Possible mechanisms include sleep deprivation, circadian misalignment and environmental conditions. The role of gender and individual preference in circadian rhythms (chronotype) will need further assessment.

Seasonal variation in mortality secondary to acute myocardial infarction in England and Wales: a secondary data analysis

BACKGROUND

Acute myocardial infarction (AMI) is a leading cause of death globally. Increase in AMI mortality during winter has also been identified in existing literature. This has been associated with low outdoor and indoor temperatures and increasing age. The relationship between AMI and other factors such as gender and socioeconomic factors varies from study to study. Influenza epidemics have also been identified as a contributory factor.

OBJECTIVE

This paper aims to illustrate the seasonal trend in mortality due to AMI in England and Wales with emphasis on excess winter mortality (EWM).

METHODS

Monthly mortality rates per 10 000 population were calculated from data provided by the UK Office for National Statistics (ONS) for 1997-2005. To quantify the seasonal variation in winter, the EWM estimates (EWM, EWM ratio, Excess Winter Mortality Index) for each year were calculated. Negative binomial regression model was used to estimate the relationship between increasing age and EWM.

RESULTS

The decline in mortality rate for AMI was 6.8% yearly between August 1997 and July 2005. Significant trend for reduction in AMI-associated mortality was observed over the period (p<0.001). This decline was not seen with EWM (p<0.001). 17% excess deaths were observed during winter. This amounted to about 20 000 deaths over the 8-year period. Increasing winter mortality was seen with increasing age for AMI.

CONCLUSION

EWM secondary to AMI does occur in England and Wales. Excess winter deaths due to AMI have remained high despite decline in overall mortality. More research is needed to identify the relationship of sex, temperature, acclimatisation, vitamin D and excess winter deaths due to AMI.

Incidence and mortality of myocardial infarction among Catalonian older adults with and without underlying risk conditions: The CAPAMIS study

BACKGROUND

Population-based data about the epidemiology of acute myocardial infarction is limited. This study investigated incidence and mortality of acute myocardial infarction in older adults with specific underlying chronic conditions and evaluated the influence of these conditions in developing acute myocardial infarction.

DESIGN AND METHODS

This was a population-based cohort study involving 27,204 individuals ≥ 60 years of age in Tarragona (Catalonia, Spain). Data on all cases of hospitalised acute myocardial infarction were collected from 1 December 2008-30 November 2011. Incidence rates and 30-day mortality were estimated according to age, sex, chronic illnesses and underlying conditions. Multivariable Cox regression analysis was used to calculate hazard ratios and to estimate the association between baseline conditions and risk of developing acute myocardial infarction.

RESULTS

The incidence of acute myocardial infarction was 475 per 100,000 person-years. Maximum rates appeared among individuals with history of coronary artery disease (2839 per 100,000), chronic severe nephropathy (1407 per 100,000), atrial fibrillation (1226 per 100,000), chronic heart disease (1149 per 100,000), history of stroke (1147 per 100,000) and diabetes mellitus (914 per 100,000). Thirty-day mortality was 15.3% overall, reaching 31.6% among patients over 80 years. In the multivariable analysis, history of coronary artery disease, age > 70 years, sex male, chronic heart disease, history of stroke, atrial fibrillation, diabetes mellitus and hypertension emerged as significantly associated with an increased risk of acute myocardial infarction.

CONCLUSIONS

The incidence and mortality of acute myocardial infarction remain considerable in our setting. Considering classical major risk factors, diabetes mellitus and hypertension were the underlying conditions most strongly associated with an increased risk in our study population.

Climate Change Impacts on Disaster and Emergency Medicine Focusing on Mitigation Disruptive Effects: an International Perspective

In recent decades, climate change has been responsible for an increase in the average temperature of the troposphere and of the oceans, with consequences on the frequency and intensity of many extreme weather phenomena. Climate change’s effects on natural disasters can be expected to induce a rise in humanitarian crises. In addition, it will surely impact the population’s long-term general health, especially among the most fragile. There are foreseeable health risks that both ambulatory care organizations and hospitals will face as global temperatures rise. These risks include the geographic redistribution of infectious (particularly zoonotic) diseases, an increase in cardiac and respiratory illnesses, as well as a host of other health hazards. Some of these risks have been detailed for most developed countries as well as for some developing countries. Using these existing risk assessments as a template, organizational innovations as well as implementation strategies should be proposed to mitigate the disruptive effects of these health risks on emergency departments and by extension, reduce the negative impact of climate change on the populations they serve.

Seasonal variation in the risk of ischemic stroke in patients with atrial fibrillation: A nationwide cohort study

BACKGROUND

Several cardiovascular diseases exhibit seasonal variations, but data about cold temperature and risk of ischemic stroke in patients with atrial fibrillation (AF) are limited.

OBJECTIVE

The purpose of this study was to investigate the risk of ischemic stroke in different seasons, testing the hypothesis that the cold weather season would increase the risk of stroke in AF.

METHODS

This study used the National Health Insurance Research Database in Taiwan. From 2000 to 2012, a total of 289,559 AF patients were enrolled, and 34,991 experienced ischemic stroke after mean follow-up of 3 years. The relationship between risk of ischemic stroke and temperatures was analyzed.

RESULTS

The highest incidence of ischemic stroke was observed in winter, which was the coldest season, with an incidence rate of 0.33 per 100 person-months. Compared with the summer period, the risk of ischemic stroke increased by 10% in spring (incidence rate ratio [IRR] 1.10; 95% confidence interval [CI] 1.07-1.13) and by 19% in winter (IRR 1.19; 95% CI 1.15-1.22) but did not differ significantly between summer and autumn (IRR 1.00; 95% CI 0.97-1.03). Compared with the days with an average temperature of 30°C, the risk of ischemic stroke for days with an average temperature <20°C significantly increased. Lower 7-, 10-, or 14-day average temperatures were significantly associated with an increased risk of ischemic stroke in the case-crossover analysis.

CONCLUSION

In this nationwide study, a seasonal variation of incidence of ischemic stroke in AF patients was observed, with an increased risk of stroke on days with an average temperature <20°C. AF-related stroke may be influenced by environmental interactions.