Changes in seasonal mortalities with improvement in home heating in England and Wales from 1964 to 1984

An Exploration of How Solar Radiation Affects the Seasonal Variation of Human Mortality Rates and the Seasonal Variation in Some Other Common Disorders

Many diseases have large seasonal variations in which winter overall mortality rates are about 25% higher than in summer in mid-latitude countries, with cardiovascular diseases and respiratory infections and conditions accounting for most of the variation. Cancers, by contrast, do not usually have pronounced seasonal variations in incidence or mortality rates. This narrative review examines the epidemiological evidence for seasonal variations in blood pressure, cardiovascular disease rates and respiratory viral infections in relation to atmospheric temperature and humidity, and solar UV exposure through vitamin D production and increased blood concentrations of nitric oxide. However, additional mechanisms most likely exist by which solar radiation reduces the risk of seasonally varying diseases. Some studies have been reported with respect to temperature without considering solar UV doses, although studies regarding solar UV doses, such as for respiratory infections, often consider whether temperature can affect the findings. More research is indicated to evaluate the relative effects of temperature and sun exposure on the seasonality of mortality rates for several diseases. Since solar ultraviolet-B (UVB) doses decrease to vanishingly small values at higher latitudes in winter, the use of safe UVB lamps for indoor use in winter may warrant consideration.

A large decrease in the magnitude of seasonal fluctuations in mortality among elderly explains part of the increase in longevity in Sweden during 20th century

BACKGROUND

Mortality rates are known to depend on the seasons and, in temperate climates, rates are highest during winter. The magnitude of these seasonal fluctuations in mortality has decreased substantially in many countries during the 20th century, but the extent to which this decrease has contributed to the concurrent increase in life expectancy is not known. Here, I describe how the seasonality of all-cause mortality among people ages 60 years or more has changed in Sweden between 1860 and 1995, and investigate how this change has contributed to the increase in life expectancy observed during the same time period.

METHODS

Yearly sex-specific birth cohorts consisting of all people born in Sweden between 1800 and 1901 who reached at least 59 years of age were obtained from a genealogical database. The mortality rates for each cohort were modeled by an exponential function of age modulated by a sinusoidal function of time of year. The potential impact of seasonal fluctuations on life expectancy was investigated by a novel decomposition of the total mortality rate into a seasonal part and a part independent of the seasons. Cohort life expectancy at age 60 was used to quantify changes in lifespan during the time period.

RESULTS

The magnitude of seasonal fluctuations in mortality rates decreased substantially between 1860 and 1995. For cohorts born in 1800, the risk of dying during the winter season was almost twice that of dying during summer. For cohorts born in 1900, the relative increase in winter mortality was 10%. Cohort life expectancy at age 60 increased by 4.3 years for men and 6.8 years for women, and the decrease in seasonal mortality fluctuations accounted for approximately 40% of this increase in average lifespan.

CONCLUSION

By following a large number of extinct cohorts, it was possible to show how the decrease in seasonal fluctuations in mortality has contributed to an increase in life expectancy. The decomposition of total mortality introduced here might be useful to better understand the processes and mechanisms underlying the marked improvements in life expectancy seen over the last 150 years.

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.

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

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

Effect of Socioeconomic Status and Underlying Disease on the Association between Ambient Temperature and Ischemic Stroke

PURPOSE

Inconsistent findings have been reported regarding the effect of ambient temperature on ischemic stroke. Furthermore, little is known about how underlying disease and low socioeconomic status influence the association. We, therefore, investigated the relationship between ambient temperature and emergency department (ED) visits for ischemic stroke, and aimed to identify susceptible populations.

MATERIALS AND METHODS

Using medical claims data, we identified ED visits for ischemic stroke during 2005-2009 in Seoul, Korea. We conducted piecewise linear regression analyses to find optimum ambient temperature thresholds in summer and winter, and estimated the relative risks (RR) and 95% confidence intervals (CI) per a 1°C increase in temperature above/below the thresholds, adjusting for relative humidity, holidays, day of the week, and air pollutant levels.

RESULTS

There were 63564 ED visits for ischemic stroke. In summer, the risk of ED visits for ischemic stroke was not significant, with the threshold at 26.8°C. However, the RRs were 1.055 (95% CI, 1.006-1.106) above 25.0°C in medical aid beneficiaries and 1.044 (1.007-1.082) above 25.8°C in patients with diabetes. In winter, the risk of ED visits for ischemic stroke significantly increased as the temperature decreased above the threshold at 7.2°C. This inverse association was significant also in patients with hypertension and diabetes mellitus above threshold temperatures.

CONCLUSION

Ambient temperature increases above a threshold were positively associated with ED visits for ischemic stroke in patients with diabetes and medical aid beneficiaries in summer. In winter, temperature, to a point, and ischemic stroke visits were inversely associated.

The Excess Winter Deaths Measure: Why Its Use Is Misleading for Public Health Understanding of Cold-related Health Impacts

Background:

Excess winter deaths, the ratio between average daily deaths in December–March versus other months, is a measure commonly used by public health practitioners and analysts to assess health burdens associated with wintertime weather. We seek to demonstrate that this measure is fundamentally biased and can lead to misleading conclusions about health impacts associated with current and future winter climate.

Methods:

Time series regression analysis of 779,372 deaths from natural causes in London over 15 years (1 August 1997–31 July 2012),collapsed by day of death and linked to daily temperature values. The outcome measures were the excess winter deaths index, and daily and annual deaths attributable specifically to cold.

Results:

Most of the excess winter deaths are driven by cold: The excess winter deaths index decreased from 1.19 to 1.07 after excluding deaths attributable to low temperatures. Over 40% of cold-attributable deaths occurred outside of the December–March period, leading to bias in the excess winter deaths measure. Although there was no relationship between winter severity and annual excess winter deaths, there was a clear correlation with annual cold-attributable deaths.

Conclusions:

Excess winter deaths is not an appropriate indicator of cold-related health impacts, and its use should be discontinued. We advocate alternative measures. The findings we present bring into doubt previous claims that cold-related deaths in the UK will not reduce in future as a result of climate change.

Health effects of milder winters: a review of evidence from the United Kingdom

Cold-related mortality and morbidity remains an important public health problem in the UK and elsewhere. Health burdens have often reported to be higher in the UK compared to other countries with colder climates, however such assessments are usually based on comparison of excess winter mortality indices, which are subject to biases. Daily time-series regression or case-crossover studies provide the best evidence of the acute effects of cold exposure. Such studies report a 6% increase in all-cause deaths in England & Wales for every 1 °C fall in daily mean temperature within the top 5% of the coldest days. In major Scottish cities, a 1 °C reduction in mean temperature below 11 °C was associated with an increase in mortality of 2.9%, 3.4%, 4.8% and 1.7% from all-causes, cardiovascular, respiratory, and non-cardio-respiratory causes respectively. In Northern Ireland, a 1 °C fall during winter months led to increases of 4.5%, 3.9% and 11.2% for all-cause, cardiovascular and respiratory deaths respectively among adults. Raised risks are also observed with morbidity outcomes. Hip fractures among the elderly are only weakly associated with snow and ice conditions in the UK, with the majority of cases occurring indoors. A person's susceptibility to cold weather is affected by both individual- and contextual-level risk factors. Variations in the distributions of health, demographic, socio-economic and built-environment characteristics are likely to explain most differences in cold risk observed between UK regions. Although cold-related health impacts reduced throughout much of the previous century in UK populations, there is little evidence on the contribution that milder winters due to climate change may have made to reductions in more recent decades. Intervention measures designed to minimise cold exposure and reduce fuel poverty will likely play a key role in determining current and future health burdens associated with cold weather.

A heat and moisture mask attenuates cardiovascular stress during cold air exposure

Background:

Exposure to cold has been shown to cause cardiovascular stress and increased morbidity and mortality. Inhalation of cold, dry air can increase blood pressure and induce myocardial ischemia, particularly in people with preexisting hypertensive cardiovascular disease. Face masks that can warm and humidify inhaled cold air may reduce these cold air pressor effects.

Method:

We compared blood pressure measurements using a heat and moisture exchange mask (HME), a placebo mask (PL), and no mask (NM) in 53 patients with hypertension exposed to a cold chamber environment at −5°C for 1 h. Blood pressure and heart rate were recorded at baseline, and at 15 min intervals from 0 to 60 min of chamber exposure. All patients were taking antihypertensive medications with drug and dosage determined by their own physicians. Data were analyzed by a one-way analysis of variance test with repeated measures, and significant interactions were analyzed by Fisher’s least significant differences tests. A post hoc subgroup analysis for the effect of age was performed using Wilcoxon matched-pair rank tests.

Results:

Wearing the HME resulted in significantly lower systolic and mean arterial blood pressures than the PL and NM conditions. Diastolic blood pressures were significantly lower for the HME than the NM, but not the PL condition.

Conclusion:

Subgroup analyses suggested that the effect of the HME in mitigating systolic blood pressure increase from inhalation of cold air was significantly greater for patients aged 60 years or over than for those under 60 years.

Housing improvements for health and associated socio-economic outcomes

BACKGROUND

The well established links between poor housing and poor health indicate that housing improvement may be an important mechanism through which public investment can lead to health improvement. Intervention studies which have assessed the health impacts of housing improvements are an important data resource to test assumptions about the potential for health improvement. Evaluations may not detect long term health impacts due to limited follow-up periods. Impacts on socio-economic determinants of health may be a valuable proxy indication of the potential for longer term health impacts.

OBJECTIVES

To assess the health and social impacts on residents following improvements to the physical fabric of housing.

SEARCH METHODS

Twenty seven academic and grey literature bibliographic databases were searched for housing intervention studies from 1887 to July 2012 (ASSIA; Avery Index; CAB Abstracts; The Campbell Library; CINAHL; The Cochrane Library; COPAC; DH-DATA: Health Admin; EMBASE; Geobase; Global Health; IBSS; ICONDA; MEDLINE; MEDLINE In-Process & Other Non-Indexed Citations; NTIS; PAIS; PLANEX; PsycINFO; RIBA; SCIE; Sociological Abstracts; Social Science Citations Index; Science Citations Index expanded; SIGLE; SPECTR). Twelve Scandinavian grey literature and policy databases (Libris; SveMed+; Libris uppsök; DIVA; Artikelsök; NORART; DEFF; AKF; DSI; SBI; Statens Institut for Folkesundhed; Social.dk) and 23 relevant websites were searched. In addition, a request to topic experts was issued for details of relevant studies. Searches were not restricted by language or publication status.

SELECTION CRITERIA

Studies which assessed change in any health outcome following housing improvement were included. This included experimental studies and uncontrolled studies. Cross-sectional studies were excluded as correlations are not able to shed light on changes in outcomes. Studies reporting only socio-economic outcomes or indirect measures of health, such as health service use, were excluded. All housing improvements which involved a physical improvement to the fabric of the house were included. Excluded interventions were improvements to mobile homes; modifications for mobility or medical reasons; air quality; lead removal; radon exposure reduction; allergen reduction or removal; and furniture or equipment. Where an improvement included one of these in addition to an included intervention the study was included in the review. Studies were not excluded on the basis of date, location, or language.

DATA COLLECTION AND ANALYSIS

Studies were independently screened and critically appraised by two review authors. Study quality was assessed using the risk of bias tool and the Hamilton tool to accommodate non-experimental and uncontrolled studies. Health and socio-economic impact data were extracted by one review author and checked by a second review author. Studies were grouped according to broad intervention categories, date, and context before synthesis. Where possible, standardized effect estimates were calculated and statistically pooled. Where meta-analysis was not appropriate the data were tabulated and synthesized narratively following a cross-study examination of reported impacts and study characteristics. Qualitative data were summarized using a logic model to map reported impacts and links to health impacts; quantitative data were incorporated into the model.

MAIN RESULTS

Thirty-nine studies which reported quantitative or qualitative data, or both, were included in the review. Thirty-three quantitative studies were identified. This included five randomised controlled trials (RCTs) and 10 non-experimental studies of warmth improvements, 12 non-experimental studies of rehousing or retrofitting, three non-experimental studies of provision of basic improvements in low or mIddle Income countries (LMIC), and three non-experimental historical studies of rehousing from slums. Fourteen quantitative studies (42.4%) were assessed to be poor quality and were not included in the synthesis. Twelve studies reporting qualitative data were identified. These were studies of warmth improvements (n = 7) and rehousing (n = 5). Three qualitative studies were excluded from the synthesis due to lack of clarity of methods. Six of the included qualitative studies also reported quantitative data which was included in the review.Very little quantitative synthesis was possible as the data were not amenable to meta-analysis. This was largely due to extreme heterogeneity both methodologically as well as because of variations in the intervention, samples, context, and outcome; these variations remained even following grouping of interventions and outcomes. In addition, few studies reported data that were amenable to calculation of standardized effect sizes. The data were synthesised narratively.Data from studies of warmth and energy efficiency interventions suggested that improvements in general health, respiratory health, and mental health are possible. Studies which targeted those with inadequate warmth and existing chronic respiratory disease were most likely to report health improvement. Impacts following housing-led neighbourhood renewal were less clear; these interventions targeted areas rather than individual households in most need. Two poorer quality LMIC studies reported unclear or small health improvements. One better quality study of rehousing from slums (pre-1960) reported some improvement in mental health. There were few reports of adverse health impacts following housing improvement. A small number of studies gathered data on social and socio-economic impacts associated with housing improvement. Warmth improvements were associated with increased usable space, increased privacy, and improved social relationships; absences from work or school due to illness were also reduced.Very few studies reported differential impacts relevant to equity issues, and what data were reported were not amenable to synthesis.

AUTHORS' CONCLUSIONS

Housing investment which improves thermal comfort in the home can lead to health improvements, especially where the improvements are targeted at those with inadequate warmth and those with chronic respiratory disease. The health impacts of programmes which deliver improvements across areas and do not target according to levels of individual need were less clear, but reported impacts at an area level may conceal health improvements for those with the greatest potential to benefit. Best available evidence indicates that housing which is an appropriate size for the householders and is affordable to heat is linked to improved health and may promote improved social relationships within and beyond the household. In addition, there is some suggestion that provision of adequate, affordable warmth may reduce absences from school or work.While many of the interventions were targeted at low income groups, a near absence of reporting differential impacts prevented analysis of the potential for housing improvement to impact on social and economic inequalities.

Association of monthly frequencies of diverse diseases in the calls to the public emergency service of the city of Buenos Aires during 1999-2004 with meteorological variables and seasons

This work aims to study associations between monthly averages of meteorological variables and monthly frequencies of diverse diseases in the calls to the public ambulance emergency service of the city of Buenos Aires during the years 1999-2004. Throughout this time period no changes were made in the classification codes of the illnesses. Heart disease, arrhythmia, heart failure, cardiopulmonary arrest, angina pectoris, psychiatric diseases, stroke, transient ischemic attack, syncope and the total number of calls were analyzed against 11 weather variables and the four seasons. All illnesses exhibited some seasonal behavior, except cardiorespiratory arrest and angina pectoris. The largest frequencies of illnesses that exhibited some association with the meteorological variables used to occur in winter, except the psychiatric cases. Heart failure, stroke, psychiatric diseases and the total number of calls showed significant correlations with the 11 meteorological variables considered, and the largest indices (absolute values above 0.6) were found for the former two pathologies. On the other side, cardiorespiratory arrest and angina pectoris revealed no significant correlations and nearly null indices. Variables associated with temperature were the meteorological proxies with the largest correlations against diseases. Pressure and humidity mostly exhibited positive correlations, which is the opposite of variables related to temperature. Contrary to all other diseases, psychiatric pathologies showed a clear predominance of positive correlations. Finally, the association degree of the medical dataset with recurrent patterns was further evaluated through Fourier analysis, to assess the presence of statistically significant behavior. In the Northern Hemisphere high morbidity and mortality rates in December are usually assigned to diverse factors in relation to the holidays, but such an effect is not observed in the present analysis. There seems to be no clearly preferred meteorological proxy among the different types of temperatures used. It is shown that the amount of occurrences depends mainly on season rather on its strength quantified by temperature.

Seasonal variations of all-cause and cause-specific mortality by age, gender, and socioeconomic condition in urban and rural areas of Bangladesh

BACKGROUND

Mortality exhibits seasonal variations, which to a certain extent can be considered as mid-to long-term influences of meteorological conditions. In addition to atmospheric effects, the seasonal pattern of mortality is shaped by non-atmospheric determinants such as environmental conditions or socioeconomic status. Understanding the influence of season and other factors is essential when seeking to implement effective public health measures. The pressures of climate change make an understanding of the interdependencies between season, climate and health especially important.

METHODS

This study investigated daily death counts collected within the Sample Vital Registration System (VSRS) established by the Bangladesh Bureau of Statistics (BBS). The sample was stratified by location (urban vs. rural), gender and socioeconomic status. Furthermore, seasonality was analyzed for all-cause mortality, and several cause-specific mortalities. Daily deviation from average mortality was calculated and seasonal fluctuations were elaborated using non parametric spline smoothing. A seasonality index for each year of life was calculated in order to assess the age-dependency of seasonal effects.

RESULTS

We found distinctive seasonal variations of mortality with generally higher levels during the cold season. To some extent, a rudimentary secondary summer maximum could be observed. The degree and shape of seasonality changed with the cause of death as well as with location, gender, and SES and was strongly age-dependent. Urban areas were seen to be facing an increased summer mortality peak, particularly in terms of cardiovascular mortality. Generally, children and the elderly faced stronger seasonal effects than youths and young adults.

CONCLUSION

This study clearly demonstrated the complex and dynamic nature of seasonal impacts on mortality. The modifying effect of spatial and population characteristics were highlighted. While tropical regions have been, and still are, associated with a marked excess of mortality in summer, only a weakly pronounced secondary summer peak could be observed for Bangladesh, possibly due to the reduced incidence of diarrhoea-related fatalities. These findings suggest that Bangladesh is undergoing an epidemiological transition from summer to winter excess mortality, as a consequence of changes in socioeconomic conditions and health care provision.

Are fuel poverty reduction schemes associated with decreased excess winter mortality in elders? A case study from London, U.K

The London Borough of Newham, London piloted the Warm Zone, a government-led fuel poverty reduction scheme. Fuel poverty is often cited as a factor in excess winter mortality (EWM) in the U.K. This study reported in this paper assessed whether EWM decreased for people aged > or =65 years in Newham as compared to all London, employing data from before and throughout the duration of the Warm Zone project. The paper also discusses the difficulties surrounding the measurement and interpretation of health impact relating to fuel poverty. We calculated and compared the yearly EWM indices for people aged > or =65 years for all of London, and for Newham over 12 years (1993-2005). The yearly EWM ratio for Newham in relation to all London was then calculated and compared. No definitive evidence to support the effect of the War Zone on EMW were noted. Relationships between EWM and fewer poverty reduction schemes are difficult to interpret, as many factors are entangled. These include cold strain and biological, genetic, gender, physiological, thermoregulation, environmental, meteorological, socio-economic, healthcare provision/expenditure, lifestyle and co-morbidity aspects, besides the challenges of sample sizes and whether other fuel poverty reduction schemes were simultaneously in operation. Those in privately owned housing might be ;masked' (underestimated) in their vulnerability to fuel poverty. Redefining the specific criteria for eligibility for fuel poverty grants and tackling heat inefficiency in privately owned homes not eligible for home heating improvement despite fulfilling other criteria for vulnerability requires attention. The implications are discussed.

Excess winter morbidity and mortality: do housing and socio-economic status have an effect?

OBJECTIVE

To review the published research evidence on the links between excess winter mortality (EWM) or excess winter hospitalization (EWH) and housing quality or socioeconomic status (SES).

DESIGN

Systematic review.

CRITERIA

Linked data on EWM or EWH and potential associations with housing quality or SES.

RESULTS

No consistent relations between SES and EWM or EWH. The results for housing quality are also inconsistent, with some studies showing a weak protective effect of home heating.

CONCLUSION

Studies to date do not provide good evidence that housing quality or SES factors affect EWM and EWH. More research is needed, particularly studies using individual level housing and SES data. Controlled trials of interventions would be desirable.

Energy, energy efficiency, and the built environment

Since the last decades of the 19th century, technological advances have brought substantial improvements in the efficiency with which energy can be exploited to service human needs. That trend has been accompanied by an equally notable increase in energy consumption, which strongly correlates with socioeconomic development. Nonetheless, feasible gains in the efficiency and technology of energy use in towns and cities and in homes have the potential to contribute to the mitigation of greenhouse-gas emissions, and to improve health, for example, through protection against temperature-related morbidity and mortality, and the alleviation of fuel poverty. A shift towards renewable energy production would also put increasing focus on cleaner energy carriers, especially electricity, but possibly also hydrogen, which would have benefits to urban air quality. In low-income countries, a vital priority remains the dissemination of affordable technology to alleviate the burdens of indoor air pollution and other health effects in individuals obliged to rely on biomass fuels for cooking and heating, as well as the improvement in access to electricity, which would have many benefits to health and wellbeing.

A deadly harvest: the effects of cold on older people in the UK

Excess winter mortality of some thousands of deaths of older people has occurred in the UK for the past 150 years and shows only moderate abatement. Government policies in both health and social care have had little apparent effect, other than a slow decline in seasonality due largely to secular trends. There are a number of apparent misconceptions, commonly held in the public mind and subsumed in public policy, which need to be corrected in order to reduce the toll of winter cold on older people. The evidence shows that winter deaths are to a large extent avoidable. They are not due to hypothermia as is widely believed, may not be necessarily reduced by climate change in the foreseeable future and may only be partially reduced by improving indoor warmth alone. The key is an integrated policy which reduces all risks equally. Community nursing is well placed to play a pivotal role in such policies.

Heat-related and cold-related deaths in England and Wales: who is at risk?

BACKGROUND

Despite the high burden from exposure to both hot and cold weather each year in England and Wales, there has been relatively little investigation on who is most at risk, resulting in uncertainties in informing government interventions.

OBJECTIVE

To determine the subgroups of the population that are most vulnerable to heat-related and cold-related mortality.

METHODS

Ecological time-series study of daily mortality in all regions of England and Wales between 1993 and 2003, with postcode linkage of individual deaths to a UK database of all care and nursing homes, and 2001 UK census small-area indicators.

RESULTS

A risk of mortality was observed for both heat and cold exposure in all regions, with the strongest heat effects in London and strongest cold effects in the Eastern region. For all regions, a mean relative risk of 1.03 (95% confidence interval (CI) 1.02 to 1.03) was estimated per degree increase above the heat threshold, defined as the 95th centile of the temperature distribution in each region, and 1.06 (95% CI 1.05 to 1.06) per degree decrease below the cold threshold (set at the 5th centile). Elderly people, particularly those in nursing and care homes, were most vulnerable. The greatest risk of heat mortality was observed for respiratory and external causes, and in women, which remained after control for age. Vulnerability to either heat or cold was not modified by deprivation, except in rural populations where cold effects were slightly stronger in more deprived areas.

CONCLUSIONS

Interventions to reduce vulnerability to both hot and cold weather should target all elderly people. Specific interventions should also be developed for people in nursing and care homes as heat illness is easily preventable.

Declining vulnerability to temperature-related mortality in London over the 20th century

The degree to which population vulnerability to outdoor temperature is reduced by improvements in infrastructure, technology, and general health has an important bearing on what realistically can be expected with future changes in climate. Using autoregressive Poisson models with adjustment for season, the authors analyzed weekly mortality in London, United Kingdom, during four periods (1900-1910, 1927-1937, 1954-1964, and 1986-1996) to quantify changing vulnerability to seasonal and temperature-related mortality throughout the 20th century. Mortality patterns showed an epidemiologic transition over the century from high childhood mortality to low childhood mortality and towards a predominance of chronic disease mortality in later periods. The ratio of winter deaths to nonwinter deaths was 1.24 (95% confidence interval (CI): 1.16, 1.34) in 1900-1910, 1.54 (95% CI: 1.42, 1.68) in 1927-1937, 1.48 (95% CI: 1.35, 1.64) in 1954-1964, and 1.22 (95% CI: 1.13, 1.31) in 1986-1996. The temperature-mortality gradient for cold deaths diminished progressively: The increase in mortality per 1 degree C drop below 15 degrees C was 2.52% (95% CI: 2.00, 3.03), 2.34% (95% CI: 1.72, 2.96), 1.64% (1.10, 2.19), and 1.17% (95% CI: 0.88, 1.45), respectively, in the four periods. Corresponding population attributable fractions were 12.5%, 11.2%, 8.7%, and 5.4%. Heat deaths also diminished over the century. There was a progressive reduction in temperature-related deaths over the 20th century, despite an aging population. This trend is likely to reflect improvements in social, environmental, behavioral, and health-care factors and has implications for the assessment of future burdens of heat and cold mortality.

Impact of extreme temperatures on daily mortality in Madrid (Spain) among the 45-64 age-group

This paper analyses the relationship between extreme temperatures and mortality among persons aged 45-64 years. Daily mortality in Madrid was analysed by sex and cause, from January 1986 to December 1997. Quantitative analyses were performed using generalised additive models, with other covariables, such as influenza, air pollution and seasonality, included as controls. Our results showed that impact on mortality was limited for temperatures ranging from the 5th to the 95th percentiles, and increased sharply thereafter. During the summer period, the effect of heat was detected solely among males in the target age group, with an attributable risk (AR) of 13.3% for circulatory causes. Similarly, NO(2) concentrations registered the main statistically significant associations in females, with an AR of 15% when circulatory causes were considered. During winter, the impact of cold was exclusively observed among females having an AR of 7.7%. The magnitude of the AR indicates that the impact of extreme temperature is by no means negligible.

The impact of ambient temperature on mortality among the urban population in Skopje, Macedonia during the period 1996-2000

Background

This study assesses the relationship between daily numbers of deaths and variations in ambient temperature within the city of Skopje, R. Macedonia.

Methods

The daily number of deaths from all causes, during the period 1996–2000, as well as those deaths from cardiovascular diseases, occurring within the city of Skopje were related to the average daily temperature on the same day using Multiple Regression statistical analyses. Temperature was measured within the regression model as two complementary variables: 'Warm' and 'Cold'. Excess winter mortality was calculated as winter deaths (deaths occurring in December to March) minus the average of non-winter deaths (April to July of the current year and August to November of the previous year).

Results

In this study the average daily total of deaths was 7% and 13% greater in the cold when compared to the whole period and warm period respectively. The same relationship was noticed for deaths caused by cardiovascular diseases. The Regression Beta Coefficient (b = -0.19) for the total mortality as a function of the temperature in Skopje during the period 1996–2000 was statistically significant with negative connotation as was the circulatory mortality due to average temperature (statistically significant regression Beta coefficient (b = -0.24)). A measure of this increase is provided, on an annual basis, in the form of the excess winter mortality figure.

Conclusion

Mortality with in the city of Skopje displayed a marked seasonality, with peaks in the winter and relative troughs in the summer.

Secular trends and seasonality in first-time hospitalization for acute myocardial infarction--a Danish population-based study

BACKGROUND

The incidence of acute myocardial infarction has declined in several Western countries during the last decades. The incidence and mortality of acute myocardial infarction follow a seasonal pattern. We examined if changes in the incidence of acute myocardial infarction were associated with any changes in seasonality.

METHODS

The study was based on 17,989 patients hospitalized with first-time acute myocardial infarction identified in the Hospital Discharge Registry of the County of North Jutland, Denmark, from 1 January 1983 to 31 December 1999. The seasonality of acute myocardial infarction was estimated using a Poisson regression model.

RESULTS

The incidence rate decreased by 3.2% (95% confidence interval: 2.7-3.3%) annually. Hospitalizations followed different seasonal patterns depending on age, but not on gender. In the <59-year-old group, the seasonal pattern was dominated by a broad spring peak (April/May) and a minor autumn peak. With increasing age, the spring peak decreased while the autumn peak increased and moved towards December. A seasonal pattern dominated by one peak (December) and one trough (August) was found in the > or =80-year-old category. The shape and extent of these seasonal patterns remained stable throughout the study period despite the decline in hospitalizations for acute myocardial infarction.

CONCLUSION

Hospitalizations for first-time acute myocardial infarction decreased from 1983 to 1999, but the seasonal pattern remained stable over time.

The Impact of Global Warming on Health and Mortality

Initial concern about the possible effects of global warming on infections has declined with the realization that the spread of tropical diseases is likely to be limited and controllable. However, the direct effects of heat already cause substantial numbers of deaths among vulnerable people in the summer. Action to prevent these deaths from rising is the most obvious medical challenge presented by a global rise in temperature. Strategies to prevent such deaths are in place to some extent, and they differ between the United States and Europe. Air conditioning has reduced them in the United States, and older technologies such as fans, shade, and buildings designed to keep cool on hot days have generally done so in Europe. Since the energy requirements of air conditioning accelerate global warming, a combination of the older methods, backed up by use of air conditioning when necessary, can provide the ideal solution. Despite the availability of these technologies, occasional record high temperatures still cause sharp rises in heat-related deaths as the climate warms. The most important single piece of advice at the time a heat wave strikes is that people having dangerous heat stress need immediate cooling, eg, by a cool bath. Such action at home can be more effective than transporting the patient to hospital. Meanwhile, it must not be forgotten that cold weather in winter causes-many more deaths than heat in summer, even in most subtropical regions, and measures to control cold-related deaths need to continue.

Vulnerability to winter mortality in elderly people in Britain: population based study

OBJECTIVE

To examine the determinants of vulnerability to winter mortality in elderly British people.

DESIGN

Population based cohort study (119,389 person years of follow up).

SETTING

106 general practices from the Medical Research Council trial of assessment and management of older people in Britain.

PARTICIPANTS

People aged > or = 75 years.

MAIN OUTCOME MEASURES

Mortality (10,123 deaths) determined by follow up through the Office for National Statistics.

RESULTS

Month to month variation accounted for 17% of annual all cause mortality, but only 7.8% after adjustment for temperature. The overall winter:non-winter rate ratio was 1.31 (95% confidence interval 1.26 to 1.36). There was little evidence that this ratio varied by geographical region, age, or any of the personal, socioeconomic, or clinical factors examined, with two exceptions: after adjustment for all major covariates the winter:non-winter ratio in women compared with men was 1.11 (1.00 to 1.23), and those with a self reported history of respiratory illness had a winter:non-winter ratio of 1.20 (1.08 to 1.34) times that of people without a history of respiratory illness. There was no evidence that socioeconomic deprivation or self reported financial worries were predictive of winter death.

CONCLUSION

Except for female sex and pre-existing respiratory illness, there was little evidence for vulnerability to winter death associated with factors thought to lead to vulnerability. The lack of socioeconomic gradient suggests that policies aimed at relief of fuel poverty may need to be supplemented by additional measures to tackle the burden of excess winter deaths in elderly people.

Housing standards: a glossary of housing and health

This glossary has been designed to provide definitions that take account of different disciplinary and policy traditions and to consider the aspects of housing that provide scope for possible concerted research and action.

Socio-economic deprivation and excess winter mortality and emergency hospital admissions in the South Yorkshire Coalfields Health Action Zone, UK

The aims of this study were to describe the pattern of excess winter mortality and emergency hospital admissions in the South Yorkshire Coalfields Health Action Zone, and to examine the relationship between excess winter mortality and emergency hospital admissions and socio-economic deprivation at the enumeration district level. We analysed monthly deaths from 1981 to 1999 and monthly emergency hospital admissions from 1990 to 1999 for cardiovascular disease, respiratory disease and all other causes of death for people aged 45 years and above. We used the enumeration district level Townsend socio-economic deprivation score to categorize enumeration districts by quintile. Excess winter mortality ratios (observed/expected) for females and males, respectively, were 1.70 and 1.58 for respiratory disease, 1.25 and 1.20 for cardiovascular disease, and 1.09 and 1.07 for all other causes of death. The excess winter hospital admission ratio for respiratory disease was 1.80 for females and 1.58 for males. No excess was evident for the other two groups of conditions. We found no significant increase in excess winter mortality ratios with increasing socio-economic deprivation. There was also no significant increase in the excess winter respiratory admission ratio with increasing deprivation. With regard to age, we found P<0.0001 and for all other diseases P>0.001 and also in the excess winter hospital admission ratio for respiratory disease P<0.0001 With regard to sex, the excess ratios were lower in men than in women for both respiratory mortality P<0.05 and respiratory hospital admissions P<0.0001 We also observed that excess winter mortality ratios decreased significantly over the 18-year period for cardiovascular disease P<0.05 and for all other diseases P<0.05. Our results suggest that measures to reduce excess winter mortality should be implemented on a population-wide basis and not limited to socio-economically deprived areas. There may also be a case for tailoring interventions to specifically meet the needs of older people.

Temperature, housing, deprivation and their relationship to excess winter mortality in Great Britain, 1986-1996

OBJECTIVES

To examine the associations between temperature, housing, deprivation and excess winter mortality using census variables as proxies for housing conditions.

DESIGN

Small area ecological study at electoral ward level. Setting Great Britain between 1986 and 1996.

PARTICIPANTS

Men and women aged 65 and over.

MAIN OUTCOME MEASURES

Deaths from all causes (International Classification of Diseases, Ninth Revision [ICD-9] codes 0-999), coronary heart disease (ICD-9 410-414), stroke (ICD-9 430-438) and respiratory diseases (ICD-9 460-519). Odds of death occurring in winter period of the four months December to March compared to the rest of the year.

RESULTS

During the study period (excluding the influenza epidemic year of 1989/90), a total of 1,682,687 deaths occurred in winter and 2,825,223 deaths occurred during the rest of the year among people aged > or =65 (around 30,000 excess winter deaths per year). A trend of higher excess winter mortality with age was apparent across all disease categories (P < 0.01). There was a significant association between winter mortality and temperature with a 1.5% higher odds of dying in winter for every 1 degrees C reduction in 24-h mean winter temperature. The amount of rain, wind and hours of sunshine were inversely associated with excess winter mortality. Selected housing variables derived from the English House Condition Survey showed little agreement with census-derived variables at electoral ward level. For all-cause mortality there was little association between deprivation and excess winter mortality, although lack of central heating was associated with a higher risk of dying in winter (odds ratio [OR] = 1.016, 95% CI : 1.009-1.022).

CONCLUSIONS

Excess winter mortality continues to be an important public health problem in Great Britain. There was a strong inverse association with temperature. Lack of central heating was associated with higher excess winter mortality. Further work is needed to disentangle the complex relationships between different indicators of housing quality and other measures of socioeconomic deprivation and their relationship to the high number of excess winter deaths in Great Britain.

Climate change, thermal stress and mortality changes

One of the potential effects of an anthropogenically induced climate change is a change in mortality related to thermal stress. In this paper, existing literature on the relationship between average temperatures and mortality is evaluated. By means of a simple meta-analysis an aggregated effect of a change in temperature on mortality is estimated for total, cardiovascular and respiratory mortality. These effect estimates are combined with projections of changes in baseline climate conditions of 20 cities, according to climate change scenarios of three General Circulation Models (GCMs). The results indicate that for most of the cities included, global climate change is likely to lead to a reduction in mortality rates due to decreasing winter mortality. This effect is most pronounced for cardiovascular mortality in elderly people in cities which experience temperate or cold climates at present. The sensitivity of the results to physiological and socio-economical adaptation is examined. However, more research is necessary to extend this work by inclusion of data from a wider range of populations.

Early increases in ischaemic heart disease mortality dissociated from and later changes associated with respiratory mortality after cold weather in south east England

STUDY OBJECTIVE

To identify the time courses and magnitude of ischaemic heart (IHD), respiratory (RES), and all cause mortality associated with common 20-30 day patterns of cold weather in order to assess links between cold exposure and mortality.

DESIGN

Daily temperatures and daily mortality on successive days before and after a reference day were regressed on the temperature of the reference day using high pass filtered data in which changes with a cycle length < 80 days were unaffected (< 2%), but slower cyclical changes and trends were partly or completely suppressed. This provided the short term patterns of both temperature and mortality associated with a one day displacement of temperature. The results were compared with simple regressions of unfiltered mortality on temperature at successive delays.

STUDY POPULATION AND SETTING

Population of south east England, including London, over 50 years of age from 1976-92.

MAIN RESULTS

Colder than average days in the linear range 15 to 0 degrees C were associated with a "run up" of cold weather for 10-15 days beforehand and a "run down" for 10-15 days afterwards. The increases in deaths were maximal at 3 days after the peak in cold for IHD, at 12 days for RES, and at 3 days for all cause mortality. The increase lasted approximately 40 days after the peak in cold. RES deaths were significantly delayed compared with IHD deaths. Excess deaths per million associated with these short term temperature displacements were 7.3 for IHD, 5.8 for RES, and 24.7 for all cause, per one day fall of 1 degree C. These were greater by 52% for IHD, 17% for RES, and 37% for all cause mortality than the overall increases in daily mortality per degree C fall, at optimal delays, indicated by regressions using unfiltered data. Similar analyses of data at 0 to -6.7 degrees C showed an immediate rise in IHD mortality after cold, followed by a fall in both IHD and RES mortality rates which peaked 17 and 20 days respectively after a peak in cold.

CONCLUSION

Twenty to 30 day patterns of cold weather below 15 degrees C were followed:(1) rapidly by IHD deaths, consistent with known thrombogenic and reflex consequences of personal cold exposure; and (2) by delayed increases in RES and associated IHD deaths in the range 0 to 15 degrees C, which were reversed for a few degrees below 0 degree C, and were probably multifactorial in cause. These patterns provide evidence that personal exposure to cold has a large role in the excess mortality of winter.

An evaluation of climate/mortality relationships in large U.S. cities and the possible impacts of a climate change

A new air mass-based synoptic procedure is used to evaluate climate/mortality relationships as they presently exist and to estimate how a predicted global warming might alter these values. Forty-four large U.S. cities with metropolitan areas exceeding 1 million in population are analyzed. Sharp increases in mortality are noted in summer for most cities in the East and Midwest when two particular air masses are present. A very warm air mass of maritime origin is most important in the eastern United States, which when present can increase daily mortality by as many as 30 deaths in large cities. A hot, dry air mass is important in many cities, and, although rare in the East, can increase daily mortality by up to 50 deaths. Cities in the South and Southwest show lesser weather/mortality relationships in summer. During winter, air mass-induced increases in mortality are considerably less than in summer. Although daily winter mortality is usually higher than summer, the causes of death that are responsible for most winter mortality do not vary much with temperature. Using models that estimate climate change for the years 2020 and 2050, it is estimated that summer mortality will increase dramatically and winter mortality will decrease slightly, even if people acclimatize to the increased warmth. Thus, a sizable net increase in weather-related mortality is estimated if the climate warms as the models predict.

The potential effects of climate change on winter mortality in England and Wales

In Britain death rates from several important causes, particularly circulatory and respiratory diseases, rise markedly during the colder winter months. This close association between temperature and mortality suggests that climate change as a result of global warming may lead to a future reduction in excess winter deaths. This paper gives a brief introductory review of the literature on the links between cold conditions and health, and statistical models are subsequently developed of the associations between temperature and monthly mortality rates for the years 1968 to 1988 for England and Wales. Other factors, particularly the occurrence of influenza epidemics, are also taken into account. Highly significant negative associations were found between temperature and death rates from all causes and from chronic bronchitis, pneumonia, ischaemic heart disease and cerebrovascular disease. The statistical models developed from this analysis were used to compare death rates for current conditions with those that might be expected to occur in a future warmer climate. The results indicate that the higher temperatures predicted for 2050 might result in nearly 9000 fewer winter deaths each year with the largest contribution being from mortality from ischaemic heart disease. However, these preliminary estimates might change when further research is able to make into account a number of additional factors affecting the relationship between mortality and climate.

Respiratory illness and mortality in England and Wales. A study of the relationships between weekly data for the incidence of respiratory disease presenting to general practitioners, and registered deaths

The possible relationship between the incidence of respiratory diseases as reported to general practitioners and numbers of registered deaths in England and Wales has been examined. Morbidity data from sentinel practices for the period 1986-1990 (population covered increased from 220,000 to 470,000) were used to calculate weekly rates of aggregated respiratory disease for persons of all ages and for elderly persons (aged 65 years and over). The elderly respiratory disease rates and numbers of deaths were aggregated into 4-week periods; secular and seasonal trends were removed from each series and the two sets of residuals were examined graphically and cross correlation coefficients calculated. There was a very strong positive association between the respiratory disease rate and number of deaths in the same 4-week period and there was also a significant but less pronounced association between respiratory disease in one 4-week period and deaths in the next. After prior separation of weeks according to temperature into four bands, weekly rates for respiratory disease were also strongly associated with the number of weekly deaths for each temperature band. The synchronisation of peaks and troughs in the two series throughout the year supports the hypothesis that a cause and effect relationship exists between respiratory disease in the elderly and number of deaths. Other climatic and meteorological variables besides temperature may play a part in determining the spread of a respiratory disease. There is a for further research to identify the micro-organisms responsible for acute respiratory infections in the elderly.

Meteorotropy and medical-meteorological forecasts

The meteorotropic reaction of the human organism is a function of different factors, such as the type and intensity of the effects of the physical environment as well as individual conditions like adaptive capacity and state of health. Many medical-meteorological studies show causal correlations between conditions in the lower atmosphere and reactions of the human organism, but also combined or synergistic effects of different weather situations, which can only be proved stochastically. These effects are described and the methodology of the investigations, as well as the results, critically discussed. Furthermore, application of the results in the areas of medical-meteorological consultation, with the goal of improving living conditions, is considered.

Relationship between changes in serum thyrotropin and total and lipoprotein cholesterol with prolonged Antarctic residence

Antarctic residence (AR) is associated with a 50% increase in the thyrotropin (TSH) response to TSH-releasing hormone (TRH) and an expanded triiodothyronine (T3) distribution volume and extravascular hormone pool, collectively called the polar T3 syndrome. To investigate the possible biologic significance of this syndrome, we studied the relationship between nonstimulated TSH and serum lipid profiles in nine subjects, once while in California and monthly during 9 months of AR. We measured serum levels of TSH, total thyroxine (TT4), free T4 (FT4), total T3 (TT3), free T3 (FT3), thyroid-binding globulin (TBG), total cholesterol (T-CHOL), high-density lipoprotein cholesterol (HDL-C), triglyceride (TG), dietary cholesterol (D-CHOL), dietary fat (D-FAT), and dietary kilocalories at each month. The paired mean monthly change from baseline was used to determine significance. The group's mean levels of TSH (approximately 30%), TBG (approximately 16%), T-CHOL (approximately 4%), HDL-C (approximately 10%), and D-CHOL (approximately 19%) increased with AR (P < .05). Small but significant decreases (P < .05) were observed in the mean changes of TT4 (approximately 8%), FT4 (approximately 6%), and TT3 (approximately 6%). FT3, D-FAT, dietary kilocalories, body weight, TG, and the calculated low-density lipoprotein (LDL-C) were unchanged with AR. A significant rate of change (P < .05) during AR was also calculated from the slope of a fitted logarithmic function for TSH (0.96 +/- 0.31 mU.L-1 x mo-1), TBG (61.19 +/- 12.29 nmol.L-1 x mo-1), TT3 (0.09 +/- 0.04 nmol.L-1 x mo-1), TT4/TBG (-0.06 +/- 0.01/mo), TT3/TBG (-8.49 +/- 1.98 x 10(-4)/mo), and TG (-0.33 +/- 0.15 mmol.L-1 x mo-1).(ABSTRACT TRUNCATED AT 250 WORDS)

Seasonal variations in the onset of retinal vein occlusion

Seasonal variation in the development of retinal vein occlusion in 1003 consecutive patients with various types of retinal vein occlusion was studied prospectively from 1973 to 1990. No seasonal variation in the onset of any type or combination of types of retinal vein occlusion was found. This refutes previous reports of such seasonal variation, which were based on small retrospective series.

Seasonal variations in fibrinogen concentrations among elderly people

Mortality and morbidity in elderly people are higher in winter than in summer months, with seasonal variations in rates of both fatal and non-fatal myocardial infarction and stroke. To identify factors that might contribute to the excess winter frequency of cardiovascular disease in the elderly, we studied 100 subjects aged 75 and over who lived in either their own homes or in sheltered or residential accommodation. Each person was visited each month for one year, body and environmental temperatures were noted, and cardiovascular risk factors were measured. 32 subjects withdrew from the study. Significant seasonal effects were found for fibrinogen, plasma viscosity, and HDL cholesterol (p less than 0.003, Bonferroni adjustment). Plasma fibrinogen concentrations showed the greatest seasonal change and were 23% higher in the coldest six months compared with summer months. Fibrinogen was significantly (p less than 0.05) and negatively related to core body temperature and all measures of environmental temperature. Those living in institutions had greater changes in plasma fibrinogen than those living in the community. The seasonal variation in plasma fibrinogen concentration is large enough to increase the risk of both myocardial infarction and stroke in winter.

Factors associated with hypothermia in patients admitted to a group of inner city hospitals

In a case-control study of factors contributing to hypothermia all fourteen patients (mean age 80 years) admitted to hospital with hypothermia after being found ill indoors also had some other serious illness. They were more likely than control patients to have been alone when taken ill (93 vs 39% of controls), to live alone (86 vs 43%), and to have been found on the floor (79 vs 14%). They were less likely to have been wearing more than indoor clothing (0 vs 50%), or to have had heating on when found (50 vs 89%), but 93% of patients in both groups had heating available. Healthy young adult volunteers who lay immobile on the ground in air at 5 degrees C lightly clothed cooled progressively by 0.57 degrees C (SD 0.32) (rectal T degrees) in 90 min despite doubling of metabolic rate. With better insulation in bed, core temperature stabilised within 90 min, and when they were in an armchair it fell slowly, with no increase in metabolic rate in either case. The findings suggest that hypothermia indoors resulted largely from collapse due to illness when the patient was alone lightly clothed and not in bed. Eight hypothermic patients found outside (in December and January) were younger (mean age 60 years) than the fourteen found indoors; six of these were chronic alcoholics or acutely intoxicated, and six lacked, or had wandered from, a fixed home.