Mortality related to cold and air pollution in London after allowance for effects of associated weather patterns.

We looked for atypical weather patterns that could confound, and explain large inconsistencies in, conventional estimates of mortality due to SO(2), CO, and smoke. Using Greater London data for 1976-1995 in the linear temperature/mortality range 0-15 degrees C we determined weather patterns associated with pollutants (all deseasonalized) by single regressions of daily temperature, wind, rain, humidity, and sunshine at successive days advance and delay. Polluted days were colder (P<0.01 for SO(2), CO, and smoke) and less windy and rainy than usual, and this cold weather was more prolonged than usual with 50% maximum temperature depression 5.9 days (95% interval 4.0-7.7) before high SO(2), compared to 2.0 (1.6-2.3) days before average cold days. We also used multiple regression of mortality at 50+ years of age on all these weather factors and pollutants at 0-, 1-, 2- to 4-, 5- to 13-, and 14- to 24-day delays to allow for the atypical weather patterns. This showed cold weather associated with 2.77 excess deaths per million during 24 days following a 1 degrees C fall for 1 day, but no net excess deaths with SO(2) (mean 28.0 ppb) or CO (1.26 ppm). It suggested (P>0.05) some increase with smoke, perhaps acting as surrogate for PM(10), for which data were too scanty to analyze.     

Ischaemic heart disease mortality and weather temperature in Barcelona, Spain

Background: Association between ischaemic heart disease (IHD)mortality and extreme values of weather temperature has beenthe focus of many previous studies. To what extent moderatechanges in temperature also influence IHD mortality in milderregions, where either low temperatures or heat waves are exceptional,has been less Investigated. To further contribute to these issueswe have investigated the association between weather temperatureand IHD in Barcelona, Spain. Methods: A transfer function modelwas specified. The dependent variable was the daily time seriesof IHD while, weather temperature, relative humidity and airpollutants were the covariates. We also controlled for influenzaepidemics and annual seasonality. In order to relax the restrictiveassumptions (functional form and normality) imposed by the transferfunction, this was modelled non-parametrically. The influenceof unusual periods and outliers of weather temperature and humiditywas also assessed. Results: A non-linear relationship betweenweather temperature and IHD existed. Our results suggested atemperature threshold (estimated in 21.06°C) in the relationshipbetween IHD and weather temperature. The estimated value ofthe threshold was higher (23°C) for very humid days (relativehumidity above 85%). The risk of an IHD death increased approximately2.4% with every 1°C drop of temperature below 4.7°Cand approximately 4% with every 1°C rise above 25°C.Conclusion: Our findings corroborated that not only the thresholdbut also the magnitude of the association presents a differentrange depending on the latitude, and is wider for southern locations.We suggest that the effect of temperature could account forthe regional variations in IHD mortality.     

Effects of cold weather on mortality: results from 15 European cities within the PHEWE project

Weather-related health effects have attracted renewed interest because of the observed and predicted climate change. The authors studied the short-term effects of cold weather on mortality in 15 European cities. The effects of minimum apparent temperature on cause- and age-specific daily mortality were assessed for the cold season (October-March) by using data from 1990-2000. For city-specific analysis, the authors used Poisson regression and distributed lag models, controlling for potential confounders. Meta-regression models summarized the results and explored heterogeneity. A 1 degrees C decrease in temperature was associated with a 1.35% (95% confidence interval (CI): 1.16, 1.53) increase in the daily number of total natural deaths and a 1.72% (95% CI: 1.44, 2.01), 3.30% (95% CI: 2.61, 3.99), and 1.25% (95% CI: 0.77, 1.73) increase in cardiovascular, respiratory, and cerebrovascular deaths, respectively. The increase was greater for the older age groups. The cold effect was found to be greater in warmer (southern) cities and persisted up to 23 days, with no evidence of mortality displacement. Cold-related mortality is an important public health problem across Europe. It should not be underestimated by public health authorities because of the recent focus on heat-wave episodes.     

Modifiers of the temperature and mortality association in seven US cities

This paper examines effect modification of heat- and cold-related mortality in seven US cities in 1986-1993. City-specific Poisson regression analyses of daily noninjury mortality were fit with predictors of mean daily apparent temperature (a construct reflecting physiologic effects of temperature and humidity), time, barometric pressure, day of the week, and particulate matter less than 10 micro m in aerodynamic diameter. Percentage change in mortality was calculated at 29 degrees C apparent temperature (lag 0) and at -5 degrees C (mean of lags 1, 2, and 3) relative to 15 degrees C. Separate models were fit to death counts stratified by age, race, gender, education, and place of death. Effect estimates were combined across cities, treating city as a random effect. Deaths among Blacks compared with Whites, deaths among the less educated, and deaths outside a hospital were more strongly associated with hot and cold temperatures, but gender made no difference. Stronger cold associations were found for those less than age 65 years, but heat effects did not vary by age. The strongest effect modifier was place of death for heat, with out-of-hospital effects more than five times greater than in-hospital deaths, supporting the biologic plausibility of the associations. Place of death, race, and educational attainment indicate vulnerability to temperature-related mortality, reflecting inequities in health impacts related to climate change.     

Diurnal temperature range and daily mortality in Shanghai, China

Although the relationship between temperature level and mortality outcomes has been well established, it is still unknown whether within-day variation in temperature, e.g. diurnal temperature range (DTR), is a risk factor for death independent of the corresponding temperature. Moreover, DTR is a meteorological indicator associated with global climate change which may be related to a variety of health outcomes. We hypothesized that large diurnal temperature change might be a source of additional environmental stress and therefore a risk factor for death. We used daily weather and mortality data from Shanghai, China to test this hypothesis. We conducted a time-series study to examine the association between DTR and mortality outcomes from 2001 to 2004. A semi-parametric generalized additive model (GAM) was used to assess the acute effect of DTR on mortality after controlling for covariates including time trend, day of the week (DOW), temperature, humidity, and outdoor air pollution. We found a strong association between DTR and daily mortality after adjustment for those potential confounders. A 1 degrees C increment of the 3-day moving average of DTR corresponded to a 1.37% (95% CI 1.08-1.65%) increase in total non-accidental mortality, a 1.86% (95% CI 1.40-2.32%) increase in cardiovascular mortality, and a 1.29% (95% CI 0.49-2.09%) increase in respiratory mortality. The effects of DTR on total non-accidental and cardiovascular mortality were significant on both "cold" (below 23 degrees C) and "warm" (at least 23 degrees C) days, although respiratory mortality was only significantly associated with DTR on "cold" days. This study suggests within-day variation in temperature may be a novel risk factor for death.     

The impact of heat waves and cold spells on mortality rates in the Dutch population

We conducted the study described in this paper to investigate the impact of ambient temperature on mortality in the Netherlands during 1979-1997, the impact of heat waves and cold spells on mortality in particular, and the possibility of any heat wave- or cold spell-induced forward displacement of mortality. We found a V-like relationship between mortality and temperature, with an optimum temperature value (e.g., average temperature with lowest mortality rate) of 16.5 degrees C for total mortality, cardiovascular mortality, respiratory mortality, and mortality among those [Greater and equal to] 65 year of age. For mortality due to malignant neoplasms and mortality in the youngest age group, the optimum temperatures were 15.5 degrees C and 14.5 degrees C, respectively. For temperatures above the optimum, mortality increased by 0.47, 1.86, 12.82, and 2.72% for malignant neoplasms, cardiovascular disease, respiratory diseases, and total mortality, respectively, for each degree Celsius increase above the optimum in the preceding month. For temperatures below the optimum, mortality increased 0.22, 1.69, 5.15, and 1.37%, respectively, for each degree Celsius decrease below the optimum in the preceding month. Mortality increased significantly during all of the heat waves studied, and the elderly were most effected by extreme heat. The heat waves led to increases in mortality due to all of the selected causes, especially respiratory mortality. Average total excess mortality during the heat waves studied was 12.1%, or 39.8 deaths/day. The average excess mortality during the cold spells was 12.8% or 46.6 deaths/day, which was mostly attributable to the increase in cardiovascular mortality and mortality among the elderly. The results concerning the forward displacement of deaths due to heat waves were not conclusive. We found no cold-induced forward displacement of deaths.     

The short-term influence of weather on daily mortality in congestive heart failure

The authors' purpose in this study was to determine whether changes in weather conditions were associated with daily mortality among people aged 65 years and older diagnosed as having congestive heart failure in Montreal, Canada, and who died in the urban area between 1984 and 1993. The authors used a time-stratified case-crossover design and adjusted the models for nitrogen dioxide and ozone. They found a strong nonlinear association with maximum temperature in the warmer months of the year, with a threshold at about 25 degrees C. The authors observed no associations after lag 3 days. In the cold period, they found that risks increased linearly with increasingly colder temperatures, but only after lag 2 days. The authors found no associations with relative humidity. For change in barometric pressure from the previous day, they found no associations in the cold period, but an increase in pressure from the previous day increased risk for lags 0 or 1 days. The authors found some differences between men and women.     

Daily mortality in relation to weather and air pollution in Christchurch, New Zealand

OBJECTIVE: To investigate the relationship between the daily number of deaths, weather and ambient air pollution. METHOD: An ecological study. We assembled daily data for the city of Christchurch, New Zealand (population 300,000) from June 1988 to December 1993. We used Poisson regression models, controlling for season using a parametric method. RESULTS: Above the third quartile (20.5 degrees C) of maximum temperature, an increase of 1 degree C was associated with a 1% (95% CI: 0.4 to 2.1%) increase in all-cause mortality and a 3% (0.1 to 6.0%) increase in respiratory mortality. An increase in PM10 of 10 micrograms/m3 was associated (after a lag of one day) with a 1% (0.5 to 2.2%) increase in all-cause mortality and a 4% (1.5 to 5.9%) increase in respiratory mortality. We found no evidence of interaction between the effects of temperature and particulate air pollution. CONCLUSIONS: High temperatures and particulate air pollution are independently associated with increased daily mortality in Christchurch. The fact that these results are consistent with those of similar studies in other countries strengthens the argument that the associations are likely to be causal. IMPLICATIONS: These findings contribute to evidence of health consequences of fuel combustion, both in the short term (from local air pollution) and in the long term (from the global climatic effects of increased atmospheric CO2).     

A case-crossover analysis of air pollution and mortality in Philadelphia.

This study reassessed Schwartz and Dockery's analysis of daily mortality from nonexternal causes among residents of Philadelphia, Pennsylvania, over 8 years, from 1973 to 1980 [American Review of Respiratory Disease 145:600-604 (1992)]. A Poisson regression analysis using the same model found that a 100-microg/m(3) increment in the 48-hr mean concentration of total suspended particulates (TSP) was associated with increased all-cause mortality [rate ratio = 1.069; 95% confidence interval (CI), 1.043-1.096) after adjustment for quadratic trend, season, year, previous day's mean temperature, dew point, winter temperature, and indicators of hot (temperature > 80 degrees F) and humid days (dew point > 66 degrees F). Critics suggested that time-varying factors such as season and day of week were not sufficiently controlled in this analysis and subsequent studies in other locations. We used a conditional logistic regression analysis with a case-crossover design to reanalyze the data, with air pollution in the prior and subsequent weeks to the day of death serving as referent periods. The case-crossover approach controls for season and day of week by design rather than modeling. We found that a 100-microg/m(3) increment in the 48-hr mean level of TSP was associated with increased all-cause mortality [odds ratio (OR) = 1.056; CI, 1.027-1.086) after adjustment for the same weather variables as above. Similar associations were observed for deaths in individuals over 65 years of age (OR = 1.074; CI, 1. 037-1.111) and for deaths due to cardiovascular disease (OR = 1.063; CI, 1.021-1.107). The current case-crossover analysis confirms the general conclusion of the previous Poisson regression analysis of an association of TSP with daily mortality in Philadelphia, Pennsylvania.     

Impact of hot temperatures on death in London: a time series approach

STUDY OBJECTIVE: This study investigated the relation between heat and mortality in London to determine the temperature threshold at which death rates increase and to quantify the effect of extreme temperatures on mortality. DESIGN: Daily data on all cause mortality and temperature were obtained for a 21 year period and the relation between them investigated both graphically and by using non-parametric time series methods of analysis. SETTING: Greater London. PARTICIPANTS: Daily mortality counts in Greater London between January 1976 and December 1996. MAIN RESULTS: A plot of the basic mortality-temperature relation suggested that a rise in heat related deaths began at about 19 degrees C. Average temperatures above the 97th centile value of 21.5 degrees C (excluding those days from a 15 day "heatwave" period in 1976) resulted in an increase in deaths of 3.34% (95% CI 2.47% to 4.23%) for every one degree increase in average temperature above this value. It was found that the 1976 heatwave resulted in a particularly large number of deaths in comparison with other hot periods. CONCLUSIONS: These results suggest that heat related deaths in London may begin at relatively low temperatures. Hot days occurring in the early part of any year may have a larger effect than those occurring later on; and analysis of separate heatwave periods suggest that episodes of long duration and of highest temperature have the largest mortality effect.     

Cardiovascular mortality attributable to high blood cholesterol in New Zealand

OBJECTIVE: To estimate mortality attributable to higher-than-optimal blood cholesterol in New Zealand in 1997, and the mortality burden that could be potentially avoided in 2011 if modest reductions in mean population blood cholesterol concentrations were achieved. DESIGN: Comparative risk assessment methodology was used to estimate the attributable and avoidable mortality due to higher-than-optimal total blood cholesterol (> 3.8 mmol/L). Disease outcomes assessed were deaths from ischaemic heart disease (IHD) and ischaemic stroke. RESULTS: Overall, higher-than-optimal blood cholesterol contributed to 4,721 deaths in New Zealand in 1997 (17% of all deaths). This included 4,096 IHD deaths (64%) and 625 ischaemic stroke deaths (38%). Modest reductions in mean population blood cholesterol concentrations (e.g. 0.1 mmol/L) could potentially prevent 300 deaths (261 IHD and 39 ischaemic stroke) each year from 2011. CONCLUSIONS: Higher-than-optimal blood cholesterol concentrations are a leading cause of mortality in New Zealand. Modest reductions in blood cholesterol levels could have a major impact on population health within a decade.     

High summer temperatures and mortality in the Czech Republic 1982-2000

The heat-stress-related mortality, which is among main impacts of periods of high summer temperature on society, was reported in many European countries, but analyses focusing on central European population have been rare. Results of the analysis for the period of 1982-2000 in the Czech Republic indicate that heat stress leads to a considerably increased all-causes mortality and mortality due to cardiovascular diseases. Periods with the highest deviations of the daily number of deaths from a baseline (in all-year data) are influenza epidemics and heat waves; the distribution of days with the highest excess mortality in a year is clearly bimodal, showing a main peak in winter and a secondary one in summer. Summer days with a considerably increased mortality are almost entirely days with a positive temperature deviation from the seasonal course. Deviations of mortality from the baseline exceed 100 deaths daily (more than 30% relative increase) in heat wave peaks, and the excess total mortality during the severe 1994 heat waves was +456 deaths (+10.3%) for June 17 to 30, and 8 deaths (+12.3%) for July 24 to August 8. The relative increase in mortality due to cardiovascular diseases was even more pronounced. The mortality displacement effect played an important role, since it was estimated to account for as much as 52% of the total number of victims for the June 1994 heat wave and 48% for the July-August heat wave. People who would die soon without oppressive weather conditions make about half of the total number of deaths, which is a larger value compared to what other studies reported. The increased mortality is observed at maximum (average, minimum) daily temperatures higher than 25 degrees C (18 degrees C, 14 degrees C) and their anomalies from mean seasonal courses larger than 3 degrees C. The same values hold for both the total and cardiovascular mortality. The mortality response at high temperatures is more pronounced in females than males. Correlations between mortality and temperature variables (including heat index) are positive and statistically significant (P = 0.01), stronger for deviations of meteorological variables from seasonal courses than for raw values, in females than males, and for heat index than for any temperature variable and summer simmer index. The unlagged correlations are stronger than correlations with lags 1-3 days; positive values of correlation coefficients hold for lags 0 to 3 days only while at lags of 4 to 25 days, the link is negative (mostly statistically significant) which demonstrates the mortality displacement effect and its time extent.     

Extreme temperatures and mortality: assessing effect modification by personal characteristics and specific cause of death in a multi-city case-only analysis

BACKGROUND: Extremes of temperature are associated with short-term increases in daily mortality. OBJECTIVES: We set out to identify subpopulations and mortality causes with increased susceptibility to temperature extremes. METHODS: We conducted a case-only analysis using daily mortality and hourly weather data from 50 U.S. cities for the period 1989-2000, covering a total of 7,789,655 deaths. We used distributions of daily minimum and maximum temperature in each city to define extremely hot days (>/= 99 th percentile) and extremely cold days (相似文献   

Air pollution and cause-specific mortality in Milan, Italy, 1980-1989.

In several studies, investigators have reported associations among air pollution, weather, and daily deaths, usually from all causes. In the current study, we focused on the difference in lag time between exposure to total suspended particulates or extreme weather and cause-specific mortality in an effort to understand the potential underlying mechanism. We used a robust Poisson regression in a generalized additive model to investigate the association between air pollution and daily mortality. We used a loess smooth function to model season, weather, and humidity; indicator variables for hot days were also used. To examine the relationship in a currently meaningful range, we excluded all days with a total suspended particulate concentration higher than 200 microg/m3. We found a significant association on the concurrent day, both for respiratory infection deaths (11% increase/100 microg/m3 increase in total suspended particulate; 95% confidence interval = 5, 17) and for heart-failure deaths (7% increase; 95% confidence interval = 3, 11). The associations with myocardial infarction (i.e., 10% increase; 95% confidence interval = 3, 18) and chronic obstructive pulmonary disease (12% increase, 95% confidence interval = 6, 17) were found for the means of 3 and 4 d prior to death. We observed an effect of cold weather at lag 1 for respiratory infections and an effect of hot weather at lag 0 for heart failure and myocardial infarctions. The association for all causes and cause-specific deaths was almost identical to that noted previously in Philadelphia, Pennsylvania. Smoothed functions of total suspended particulates suggested a higher slope at lower concentrations, and this finding may account for differences noted between European and U.S. studies. Given that both the dependence between weather and daily mortality and the lag between exposure and death varies by cause of death, analyses by specific causes of death would be very useful in the future.     

Seasonal variation in mortality in Scotland

BACKGROUND: Seasonal patterns in mortality have been recognized for many years. This study assesses seasonal variation in mortality in Scotland between 1981 and 1993 and considers its association with socioeconomic status and outdoor temperature. METHODS: Lagged Poisson regression analysis of numbers of deaths and average weekly temperature with adjustment for serial autocorrelation and influenza epidemics. RESULTS: There was significant seasonal variation in weekly death rates with a difference of about 30% between a summer trough and a winter peak. This variation was principally attributable to respiratory disease, cerebrovascular disease and coronary artery disease. Seasonal variation in mortality fell from around 38% in 1981-1983 to around 26% in 1991-1993. There was no clear evidence of a relationship between socioeconomic status and seasonal mortality, however the extent of the fall in seasonal variation was greater in deprived areas than in affluent areas. Overall, a 1 degree C decrease in mean temperature was associated with a 1% increase in deaths one week later. The lag in this relationship varied by cause of death and underlying temperature. CONCLUSIONS: Seasonal variations in mortality and the relationship between temperature and mortality are a significant public health problem in Scotland. It is likely that the strength of this relationship is a result of the population being unable to protect themselves adequately from the effects of temperature rather than the effects of temperature itself.     

Mortality and temperature in Sofia and London

STUDY OBJECTIVE: Heat and cold have been associated with increased mortality, independently of seasonal trends, but details are little known. This study explores associations between mortality and temperature in two European capitals-Sofia and London-using four years of daily deaths, air pollution, and weather data. DESIGN: Generalised additive models were used to permit non-linear modelling of confounders such as season and humidity, and to show the shape of mortality-temperature relations-using both two day and two week average temperatures separately. Models with linear terms for heat and cold were used to estimate lags of effect, linear effects, and attributable fractions. PARTICIPANTS: 44701 all age all cause deaths in Sofia (1996-1999) and 256464 in London (1993-1996). Main results: In London, for each degree of extreme cold (below the 10th centile of the two week mean temperature), mortality increased by 4.2% (95% CI 3.4 to 5.1), and in Sofia by 1.8% (0.6 to 3.9). For each degree rise above the 95th centile of the two day mean, mortality increased by 1.9% (1.4 to 2.4) in London, and 3.5% (2.2 to 4.8) in Sofia. Cold effects appeared after lags of around three days and lasted-particularly in London-at least two weeks. Main heat effects occurred more promptly. There were inverse associations at later lags for heat and cold in Sofia. CONCLUSIONS: Average temperatures over short periods do not adequately model cold, and may be inadequate for heat if they ignore harvesting effects. Cold temperatures in London, particularly, seem to harm the general population and the effects are not concentrated among persons close to death.     

Hypothermia-related deaths--Philadelphia, 2001, and United States, 1999

Hypothermia is defined as the unintentional lowering of the deep body (core) temperature below 95.0 degrees F (35.0 degrees C). Hypothermia can be mild (90.0 degrees F-<95.0 degrees F [32.2 degrees C-<35.0 degrees C]), moderate (82.5 degrees F-<90.0 degrees F [28.0 degrees C-<32.2 degrees C]), or severe (<82.5 degrees F [<28.0 degrees C]). Common risk factors for hypothermia include exposure to cold while under the influence of alcohol or drugs, altered mental status, and immersion in cold water. During 1979-1998, approximately 700 persons (range: 420-1,024) died annually in the United States from hypothermia; approximately half of these deaths were attributed to extremely cold weather. This report presents three cases of hypothermia-related deaths in Philadelphia during 2001 as examples of risk factors for hypothermia and summarizes information about hypothermia-related deaths in the United States during 1999. Hypothermia deaths are preventable; by avoiding hypothermia, persons also can prevent other adverse health effects of cold weather.     

The impact of temperature on mortality in Tianjin, China: a case-crossover design with a distributed lag nonlinear model

Background: Although interest in assessing the impacts of temperature on mortality has increased, few studies have used a case-crossover design to examine nonlinear and distributed lag effects of temperature on mortality. Additionally, little evidence is available on the temperature–mortality relationship in China or on what temperature measure is the best predictor of mortality.Objectives: Our objectives were to use a distributed lag nonlinear model (DLNM) as a part of case-crossover design to examine the nonlinear and distributed lag effects of temperature on mortality in Tianjin, China and to explore which temperature measure is the best predictor of mortality.Methods: We applied the DLNM to a case-crossover design to assess the nonlinear and delayed effects of temperatures (maximum, mean, and minimum) on deaths (nonaccidental, cardiopulmonary, cardiovascular, and respiratory).Results: A U-shaped relationship was found consistently between temperature and mortality. Cold effects (i.e., significantly increased mortality associated with low temperatures) were delayed by 3 days and persisted for 10 days. Hot effects (i.e., significantly increased mortality associated with high temperatures) were acute and lasted for 3 days and were followed by mortality displacement for nonaccidental, cardiopulmonary, and cardiovascular deaths. Mean temperature was a better predictor of mortality (based on model fit) than maximum or minimum temperature.Conclusions: In Tianjin, extreme cold and hot temperatures increased the risk of mortality. The effects of cold last longer than the effects of heat. Combining the DLNM and the case-crossover design allows the case-crossover design to flexibly estimate the nonlinear and delayed effects of temperature (or air pollution) while controlling for season.     

The effect of temperature on mortality in Stockholm 1998--2003: a study of lag structures and heatwave effects

AIMS: To describe seasonal patterns of natural mortality in Stockholm as well as the temperature-mortality relationship and the lag structure for effects of high and low temperatures; to describe the impact of high temperatures on cardiovascular and respiratory mortality, and the general effect of high temperatures in different age groups; and to investigate whether there is any indication of an additional heatwave or cold spell effect. METHODS: Generalized additive Poisson regression models were fitted to mortality and temperature data from Stockholm from the period 1998-2003, controlling for influenza, season, time trends, week day, and holidays. RESULTS: The mortality in Stockholm followed a seasonal pattern, with a peak in the winter season. The ;;optimal temperature' was around 11-12 degrees C. Above this temperature, the cumulative general relative risk (RR) corresponded to a 1.4% (95% confidence interval (CI)=0.8-2.0) increase per degrees C, and below this temperature the cumulative RR corresponded to a 0.7% (95% CI=0.5-0.9) decrease per degrees C. Age-specific RRS were estimated above the threshold for age <65 years, age 65-74 years, and age >74 years, with estimated increases of 0.5% (not significant), 1.5% (not significant) and 1.6% (95% CI=0.9-2.3) per degrees C, respectively. The RRs for cardiovascular and respiratory causes were studied above the breakpoint, and estimated to be 1.1% (95% CI=0.3-2.0) and 4.3% (95% CI=2.2-6.5) per degrees C, respectively. The lag structures from moving averages and polynomial distributed lag models coincided with a rather direct effect during summer (lag 0 and 1) and a more prolonged effect during winter, covering about a week. The inclusion of an indicator of heatwaves added an increase in daily mortality of 3.1-7.7%, depending on the threshold. CONCLUSIONS: These results show that the predicted increase in heat events must also be taken seriously in Scandinavia, whatever the extent of the decreasing cold related mortality. The relative risks associated with heat and heatwaves seem stronger than the cold effects and thus a larger public health threat, since northern populations have not yet adapted to heat as have been done over a long time for the cold periods. The pressure on the healthcare sector will probably increase in the warm season, periodically it may become even greater than the pressure due to cold weather, which will be a new phenomenon for the healthcare sector to cope with. We need to be prepared for these kind of events by developing adaptation and education strategies to handle the consequences that a warmer climate will have for public health and the healthcare sector.     

Hypothermia and mortality and morbidity. An epidemiological analysis.

STUDY OBJECTIVE--The aim was to identify socioeconomic variables associated with deaths and hospital admissions due to hypothermia and to quantify the risk due to ambient outside temperature. DESIGN--The study was a survey of deaths and hospital admissions due to hypothermia (ICD 991.6), for the period 1979-85 inclusive, identified from death certificates and Hospital Inpatient Enquiry (HIPE) data. SETTING--The study included all deaths and hospital admissions due to hypothermia (1979-85) in the 26 counties of the Republic of Ireland, population 3.5 million. SUBJECTS--All deaths coded during the study period as being due to hypothermia and all persons admitted to hospital during the study period for whom hypothermia was recorded as a discharge diagnosis in HIPE data. MEASUREMENTS AND MAIN RESULTS--Demographic data and date of death/diagnosis were obtained from both data sets. Complete national temperature records were obtained from the meteorological service and a temperature was assigned to each case representing ambient outside temperature at which hypothermia developed. Risk of hypothermia at a given temperature was obtained by dividing the number of cases at that temperature by the appropriate person-years of exposure of the entire national population. Incidence of and mortality from hypothermia doubled with each 5 degrees C and 4 degrees C fall in temperature respectively; the majority of deaths and hospital admissions occurred between October and March. Incidence and mortality increased with age and men had 30% higher case fatality than women. Single men had four times the incidence and 6.5 times the mortality, and single women had double the incidence and four times the mortality of married men and women respectively. Low population density was also an important risk marker. CONCLUSIONS--The risk of hypothermia due to ambient outside temperature has been quantified and a high risk group was identified. A combination of statutory support measures and good neighbourliness could prevent illness and deaths from hypothermia.