Mortality in the elderly and ambient ozone concentration during the hot summer, 1994, in Belgium

Impact of environmental factors on heat-associated mortalities in an urban desert region

The troubling trend of rising heat-associated mortalities in an urban desert region (Maricopa County, AZ, USA) has motivated us to explore the extent to which environmental factors may contribute to increased heat-health risks. Summertime data from 2010 to 2019 were used to construct a suite of models for daily heat-associated mortalities. The best-performing full model included the following predictors, ordered from strongest to weakest influence: daily average air temperature, average of previous 5 days daily average air temperature, year, day of year, average of previous 5 days daily average dew point temperature, average of previous 5 days daily average PM_2.5, and daily average PM₁₀. This full model exhibited a 5.39% reduction in mean absolute error in daily heat-associated mortalities as compared to the best-performing model that included only air temperature as an environmental predictor. The extent to which issued and modeled excessive heat warnings (from both the temperature only and full models) corresponded with heat-associated mortalities was also examined. Model hindcasts for 2020 and 2021 showed that the models were able to capture the high number of heat-associated mortalities in 2020, but greatly undercounted the highest yet observed number of heat-associated mortalities in 2021. Results from this study lend insights into environmental factors corresponding to an increased number of heat-associated mortalities and can be used for informing strategies towards reducing heat-health risks. However, as the best-performing model was unable to fully capture the observed number of heat-associated mortalities, continued scrutiny of both environmental and non-environmental factors affecting these observations is needed.

Differences in the impact of heat waves according to urban and peri-urban factors in Madrid

Aside from climatic factors, the impact of heat waves on mortality depends on the demographic and socio-economic structure of the population as well as variables relating to local housing. Hence, this study's main aim was to ascertain whether there might be a differential impact of heat waves on daily mortality by area of residence. The study is a time-series analysis (2000-2009) of daily mortality and minimum and maximum daily temperatures (°C) in five geographical areas of the Madrid region. The impact of such waves on heat-related mortality due to natural causes (ICD-10: A00- R99), circulatory causes (ICD-10: I00-I99) and respiratory causes (ICD-10: J00-J99) was obtained by calculating the relative risk (RR) and attributable risk (AR), using GLM models with the Poisson link and controlling for trend, seasonalities and the autoregressive nature of the series. Furthermore, we also evaluated other external variables, such as the percentage of the population aged over 65 years and the percentage of old housing. No heat-related mortality threshold temperature with statistical significance was detected in the northern and eastern areas. While the threshold temperatures in the central and southern areas were very similar and close to the 90th percentile, the threshold in the western area corresponded to the 97th percentile. Attributable mortality proved to be highest in the central area with 85 heat wave-related deaths per annum. External factors found to influence the impact of heat on mortality in Madrid were the size of the population aged over 65 years and the age of residential housing. Demographic structure and the percentage of old housing play a key role in modulating the impact of heat waves. This study concludes that the areas in which heat acts earliest are those having a higher degree of population ageing.

Synergistic Effects of Ambient Temperature and Air Pollution on Health in Europe: Results from the PHASE Project

We studied the potential synergy between air pollution and meteorology and their impact on mortality in nine European cities with data from 2004 to 2010. We used daily series of Apparent Temperature (AT), measurements of particulate matter (PM₁₀), ozone (O₃), and nitrogen dioxide (NO₂) and total non-accidental, cardiovascular, and respiratory deaths. We applied Poisson regression for city-specific analysis and random effects meta-analysis to combine city-specific results, separately for the warm and cold seasons. In the warm season, the percentage increase in all deaths from natural causes per °C increase in AT tended to be greater during high ozone days, although this was only significant for all ages when all causes were considered. On low ozone days, the increase in the total daily number of deaths was 1.84% (95% CI 0.87, 2.82), whilst it was 2.20% (95% CI 1.28, 3.13) in the high ozone days per 1 °C increase in AT. Interaction with PM₁₀ was significant for cardiovascular (CVD) causes of death for all ages (2.24% on low PM₁₀ days (95% CI 1.01, 3.47) whilst it is 2.63% (95% CI 1.57, 3.71) on high PM₁₀ days) and for ages 75+. In days with heat waves, no consistent pattern of interaction was observed. For the cold period, no evidence for synergy was found. In conclusion, some evidence of interactive effects between hot temperature and the levels of ozone and PM₁₀ was found, but no consistent synergy could be identified during the cold season.

Heat and health in Antwerp under climate change: Projected impacts and implications for prevention

BACKGROUND

Excessive summer heat is a serious environmental health problem in several European cities. Heat-related mortality and morbidity is likely to increase under climate change scenarios without adequate prevention based on locally relevant evidence.

METHODS

We modelled the urban climate of Antwerp for the summer season during the period 1986-2015, and projected summer daily temperatures for two periods, one in the near (2026-2045) and one in the far future (2081-2100), under the Representative Concentration Pathway (RCP) 8.5. We then analysed the relationship between temperature and mortality, as well as with hospital admissions for the period 2009-2013, and estimated the projected mortality in the near future and far future periods under changing climate and population, assuming alternatively no acclimatization and acclimatization based on a constant threshold percentile temperature.

RESULTS

During the sample period 2009-2013 we observed an increase in daily mortality from a maximum daily temperature of 26°C, or the 89th percentile of the maximum daily temperature series. The annual average heat-related mortality in this period was 13.4 persons (95% CI: 3.8-23.4). No effect of heat was observed in the case of hospital admissions due to cardiorespiratory causes. Under a no acclimatization scenario, annual average heat-related mortality is multiplied by a factor of 1.7 in the near future (24.1deaths/year CI 95%: 6.78-41.94) and by a factor of 4.5 in the far future (60.38deaths/year CI 95%: 17.00-105.11). Under a heat acclimatization scenario, mortality does not increase significantly in the near or in the far future.

CONCLUSION

These results highlight the importance of a long-term perspective in the public health prevention of heat exposure, particularly in the context of a changing climate, and the calibration of existing prevention activities in light of locally relevant evidence.

Association between ambient ozone and health outcomes in Prague

PURPOSE

Though numerous studies investigating ambient ozone (O(3)) effects on human health were published, such a study for Central Europe is still lacking. We have investigated the association between ozone (O(3)) levels and hospital admissions and mortality due to cardiovascular and respiratory diseases for Prague inhabitants for summer months (April-September) over the 5-year period 2002-2006. Our hypothesis was that ambient O(3) levels in Prague resulted in adverse health outcomes and were associated with increased mortality and hospital admissions.

METHODS

The effect of O(3) on mortality and hospital admissions was investigated using the negative binomial regression after controlling for the influence of meteorological factors (air temperature and relative humidity) and calendar effects (seasonal patterns, long-term trends and day of week).

RESULTS

We found a statistically significant association between O(3) levels and daily mortality from respiratory diseases. Relative risk of 1.080 (95% CI: 1.031-1.132) was observed for mortality from respiratory diseases per 10 μg m(-3) increase in 1-day lagged daily mean O(3) concentration. No statistically significant association was detected between O(3) concentrations and daily mortality from all causes, daily mortality from cardiovascular diseases and hospital admissions for respiratory and cardiovascular diseases. The O(3) effects differed in men and women, nevertheless, the results were ambiguous with respect to used lag and O(3) metrics. No significant confounding effects of PM(10) on the investigated association were observed.

CONCLUSIONS

O(3) exposure in Prague, though lower as compared to many other cities in Europe, is high enough to cause adverse health effects.

Urban and rural mortality rates during heat waves in Berlin and Brandenburg, Germany

In large cities such as Berlin, human mortality rates increase during intense heat waves. Analysis of relevant data from north-eastern Germany revealed that, during the heat waves that occurred between 1990 and 2006, health risks were higher for older people in both rural and urban areas, but that, during the two main heat waves within that 17-year period of time, the highest mortality rates were from the city of Berlin, and in particular from its most densely built-up districts. Adaptation measures will need to be developed, particularly within urban areas, in order to cope with the expected future intensification of heat waves due to global climate change.

Correlation of ambient inhalable bioaerosols with particulate matter and ozone: a two-year study

In this study, we have examined the relationships between the concentrations of ambient inhalable airborne fungi and pollen with PM10, PM2.5, ozone, organic carbon, selected trace metals (cadmium, copper, lead, and zinc), temperature, and relative humidity. The database was collected in Cincinnati, Ohio, USA, during two consecutive years. Measurements of all environmental variables were performed at the same site continuously 5 days a week except during winter months. The airborne concentrations of biological and non-biological pollutants ranged as follows: total fungi: 184-16 979 spores m(-3); total pollen: 0-6692 pollen m(-3); PM10: 6.70-65.38 microg m(-3); PM2.5: 5.04-45.02 microg m(-3); and ozone: 2.54-64.17 ppb. Higher levels of total inhalable fungi and particulate matter were found during fall and summer months. In contrast, total pollen concentration showed elevated levels in spring. Peak concentrations of ozone were observed during summer and beginning of fall. Our study concluded that several types of inhalable airborne fungi and pollen, particulate matter, and ozone could be positively correlated as a result of the atmospheric temperature influence.

[Epidemiology and heat waves: analysis of the 2003 episode in France]

Epidemiology and heat waves: analysis of the 2003 episode in France. The heat wave that struck France in 2003 has been accompanied with an estimated 15,000 excess deaths. This paper stresses the difficulties of the epidemiology of such an event. The relevant clinical and biological information is incomplete or even inaccessible and many of the deaths are due to multiple factors. The data presently available indicate that the deaths occurred in persons already vulnerable, and that the heat wave caused a five- to eight-month loss of lifetime for the affected individuals. There is a noteworthy similarity between the profiles of this exceptional summer mortality surge, and those of many past winters when similar or larger excess mortalities ave occurred without as yet eliciting much public attention.

Mortality and displaced mortality during heat waves in the Czech Republic

The aims of this study were to assess impacts of hot summer periods on mortality in the Czech Republic and to quantify the size of the short-term displacement effect which resulted in lower than expected mortality after heat waves. The analysis covered the period 1982-2000 when several extraordinarily hot summers occurred in central Europe. Daily total all-cause mortality and mortality due to cardiovascular diseases (CVD) in the entire population of the Czech Republic (approximately 10 million inhabitants) were examined. The daily death counts were standardized to account for the long-term decline in mortality and the seasonal and weekly cycles. Heat-related mortality is better expressed if 1-day lag after temperature is considered compared to the unlagged relationship. With the 1-day lag, both excess total mortality and excess CVD mortality were positive during all 17 heat waves, and in 14 (12) heat waves the increase in total (CVD) mortality was statistically significant ( P=0.05). The mean relative rise in total mortality during heat waves was 13%. The response was greater in females than males and similar regardless of whether total or CVD mortality was used. The largest relative increases, exceeding 20% in both total and CVD mortality, were associated with heat waves which occurred in early summer (the first half of July 1984 and June 1994). The mortality displacement effect played an important role since mortality tended to be lower than expected after hot periods. The mean net mortality change due to heat waves was estimated to be about a 1% increase in the number of deaths. The large relative increases during some heat waves were particularly noteworthy since the study (in contrast to most analyses of the heat stress/mortality relationship) was not restricted to an urban area and/or an elderly population.

The rate and risk of heat-related illness in hospital emergency departments during the 1995 Chicago heat disaster

OBJECTIVES

To conduct an Emergency Department (ED)-based treated prevalence study of heat morbidity and to estimate the rate and risk of heat morbid events for all Chicago MSA EDs (N = 95; 2.7 million visits per year).

METHODS

ED patient log data were compiled from 13 randomly selected hospitals located throughout the Chicago MSA during the 2 weeks of the 1995 heat disaster and from the same 2-week period in 1994 (controls). Measurements included: age, sex, date, and time of ED service, up to three ICD-9 diagnoses, and disposition.

RESULTS

Heat morbidity for Chicago MSA hospital EDs was calculated at 4,224 (95% CI = 2964-5488) cases. ED heat morbidity increased significantly 5 days prior to the first heat-related death. In 1995, there was an increase in the estimated relative risk for the city = 3.85 and suburbs = 1.89 over the control year of 1994.

CONCLUSIONS

Real time ED-based computer automated databanks should be constructed to improve public health response to infectious or noninfectious outbreaks. Rapid area-wide M&M tabulations can be used for advancing the effectiveness of community-based prevention programs, and anticipating hospital ED resource allocation.