Heat Wave Period Research Articles

Neighborhood microclimates and vulnerability to heat stress

Human exposure to excessively warm weather, especially in cities, is an increasingly important public health problem. This study examined heat-related health inequalities within one city in order to understand the relationships between the microclimates of urban neighborhoods, population characteristics, thermal environments that regulate microclimates, and the resources people possess to cope with climatic conditions. A simulation model was used to estimate an outdoor human thermal comfort index (HTCI) as a function of local climate variables collected in 8 diverse city neighborhoods during the summer of 2003 in Phoenix, USA. HTCI is an indicator of heat stress, a condition that can cause illness and death. There were statistically significant differences in temperatures and HTCI between the neighborhoods during the entire summer, which increased during a heat wave period. Lower socioeconomic and ethnic minority groups were more likely to live in warmer neighborhoods with greater exposure to heat stress. High settlement density, sparse vegetation, and having no open space in the neighborhood were significantly correlated with higher temperatures and HTCI. People in warmer neighborhoods were more vulnerable to heat exposure because they had fewer social and material resources to cope with extreme heat. Urban heat island reduction policies should specifically target vulnerable residential areas and take into account equitable distribution and preservation of environmental resources.

Atmospheric aerosols during the 2003 heat wave in southeastern Spain I: Spectral optical depth

During the first half of August 2003 the Iberian Peninsula (IP) and a great part of Western Europe suffered a severe heat wave. This event was associated with a very robust and persistent high-pressure system over Western Europe that blocked the flow of rain-bearing low-pressure systems at 700 and 500 mb. Using sun-photometric data obtained during August 2003 we evidenced an exceptionally high turbidity event over Granada (37.16°N, 3.60°W, 680 m a.s.l.) in southeastern Spain from 1 to 15 August. Under heat wave conditions we found δ a(440 nm) in the range 0.12–0.70 with an average value of 0.35±0.10 whereas in the second half of the month δ a(440 nm) ranged between 0.04 and 0.30 with an average value of 0.15±0.06, with similar changes for other wavelengths. This long lasting turbidity event was also observed at other AERONET stations in the IP, El Arenosillo (37.11°N, 6.71°W, 17 m a.s.l.) and Évora (38.57°N, 7.91°W, 293 m a.s.l.), suggesting that this pronounced change in the atmospheric turbidity was not due to local causes. At a regional level the atmospheric aerosol is influenced by the synoptic situation and thus the special characteristics associated to the heat wave development can have strongly affected the regional atmospheric aerosol properties. The Ångström exponent, α, presented a rather large range of values, evidencing the high variety of aerosol particles that affected the area. Thus, during the heat wave α varied between 0.3 and 1.7 with an average value of 1.2±0.3 whereas after the heat wave it varied between 0.4 and 1.4 with an average value of 0.9±0.3. Considering the relationship between the Ångström exponent and the aerosol size distribution, it is evident that there was an increase in the contribution of fine particles during the heat wave period related to the typical summer conditions. This increase appears to be produced mainly by intense forest fires in southern Europe and by European-Mediterranean air masses influence. Trajectories ending at Granada (on 1–15 August) show that in all cases air masses overpass active forest fires in southern Europe, and that our study area was predominantly influenced by European-Mediterranean air masses. Also, in some cases air masses arrived from Africa. The occurrence of additional Saharan dust events after the heat wave highlighted changes in the features of these aerosol particles when combined with an important load of urban industrial particles and biomass burning aerosols. During dust events occurred in the heat wave period the average values of δ a(440 nm) and α ranged from 0.32 to 0.41 and from 0.8 to 1.0, respectively, while during those occurred after the heat wave event δ a(440 nm) and α ranged from 0.13 to 0.19 and from 0.4 to 0.5, respectively.

Excess deaths during the August 2003 heat wave in Paris, France

During the August 2003 heat wave in France, almost 15,000 excess deaths were recorded. Paris was severely affected, with an excess death rate of 141%. This study had two aims: to identify individual factors associated with excess deaths during a heat wave in an urban environment and to describe the spatial distribution of deaths within the French capital. The study population included all people who died at home between August 1st and 20th, 2003 (N=961). We identified factors associated with excess deaths by comparing the sociodemographic characteristics of the study population with those of people who died at home during the same period in reference years (2000, 2001, 2002) (N=530). Spatial differences were analysed by calculating comparative mortality rates within Paris during August 2003. Mortality ratio was determined to demonstrate temporal variations in mortality between the heat wave period and reference years. The major factors associated with excess death were: age over 75 years (adjusted OR=1.44 (1.10-1.90), being female (adjusted OR=1.43 (1.11-1.83)), not being married (adjusted OR=1.63 (1.23-2.15)), particularly for men. Being a foreigner appeared to be a protective factor for women. Comparative mortality rates by neighbourhood showed a gradient in excess deaths from North-West to South-East. The mortality ratio was 5.44 (5.10-5.79), with very high rates of excess death in the South (12th, 13th, 14th and 15th "arrondissement"). The August 2003 heat wave in Paris was associated with both an exceptional increase in mortality rates and changes in the characteristics of those dying and spatial distribution of mortality. Understanding the effects of a heat wave on mortality can probably be improved by an analysis of risk at two levels: individual and contextual.

How emergency departments might alert for prehospital heat-related excess mortality?

IntroductionA major issue raised by the public health consequences of a heat wave is the difficulty of detecting its direct consequences on patient outcome, particularly because of the delay in obtaining definitive mortality results. Since emergency department (ED) activity reflects the global increase of patients' health problems during this period, the profile of patients referred to EDs might be a basis to detect an excess mortality in the catchment area. Our objective was to develop a real-time surveillance model based on ED data to detect excessive heat-related mortality as early as possible.MethodsA day-to-day composite indicator was built using simple and easily obtainable variables related to patients referred to the ED during the 2003 heat-wave period. The design involved a derivation and validation study based on a real-time surveillance system of two EDs at Cochin Hospital and Hôtel-Dieu Hospital, Paris, France. The participants were 99,976 adult patients registered from 1 May to 30 September during 2001, 2002 and 2003. Among these participants, 3,297, 3,580 and 3,851 patients were referred to the EDs from 3 August to 19 August for 2001, 2002 and 2003, respectively. Variables retained for the indicator were selected using the receiver operating characteristic curve methodology and polynomial regression.ResultsThe indicator was composed of only three variables: the percentage of patients older than 70 years, the percentage of patients with body temperature above 39°C, and the percentage of patients admitted to or who died in the ED. The curve of the indicator with time appropriately fitted the overall mortality that occurred in the region of interest.ConclusionA composite and simple index based on real-time surveillance was developed according to the profile of patients who visited the ED. It appeared suitable for determining the overall mortality in the corresponding region submitted to the 2003 heat wave. This index should help early warning of excessive mortality and monitoring the efficacy of public health interventions.

Were less disabled patients the most affected by 2003 heat wave in nursing homes in Paris, France?

To analyse the change of mortality rates (MRs) and their contributing medical factors among nursing home patients during the 2003 heat wave in France. A retrospective observational study was conduced in all nursing homes of the Assistance-Publique-Hôpitaux de Paris (AP-HP), the French largest public hospital group. All AP-HP nursing home patients (4,403) who were institutionalized in May, 2003, were concerned. The MRs of patients between three periods (before, during and after the August 2003 heat wave period) were compared according to their demographic characteristics, level of dependence and medical condition. The MR increased from 2.2 per cent persons month (ppm) (1.9-2.4) before heat wave up to 9.2 ppm (8.0-10.4) during heat wave and back to 2.4 ppm (2.2-2.7) after heat wave. MRs before heat wave were higher among highly dependent patients compared to those less dependent [mortality rate ratio (MRR) = 2.66 (1.69-4.21)]. This difference disappeared during the heat wave [MRR = 1.28 (0.91-1.81)] and appeared again after heat wave [MRR = 2.21 (1.52-3.23)]. The same pattern was observed for several medical conditions, such as severe malnutrition or swallowing disorders. These results suggest that medical care during heat wave has been directed towards more fragile patients, helping to limit deaths in this group. Less frail patients made the largest contribution to excess mortality during the heat wave. During extreme weather conditions, specific attention should be paid not only to frail persons, but to all the elderly community.

THE IMPACT OF SUMMER 2003 HEAT WAVE ON MORTALITY AMONG ELDERLY PEOPLE IN THE ITALIAN CITY OF GENOA

ISEE-357 Introduction: During Summer 2003 much of Europe was affected by heat waves. Nationwide seasonal temperatures were the warmest on record in many countries such as France, Portugal and Italy, where an excess of mortality accompanied this unprecedented heat wave. According to the results of the Italian National Rapid Survey, carried out by the authors on behalf of the Italian Ministry of Health, Genoa was one of the cities where individuals 75 years of age or more experienced a dramatic increase in mortality. The aim of this paper is to analyse excess mortality, to investigate whether it has been a mortality displacement, to estimate the lag time between the onset of extreme climate conditions and the death, as well as to study the specific causes of death. Methods: Persons aged 75 years or more, resident and dead in Genoa during the heat wave period (16 July – 31 August 2003) were studied. Excess mortality was calculated comparing the number of deaths observed on a given day with the corresponding average value for the period 1998–2002. The relationship between mortality and climate was investigated comparing daily distributions of deaths with Humidex values.To detect the prominent causes of death during the heat wave, and to analyse all the underlying causes of death, the original death certificates of the elderly dead in the same summer period of 2003 and 2002 were examined. Results: During the examined period, 968 deaths were observed among the elderly in Genoa, compared with 633 expected on the basis of a five-years time series (SMR = 1.53, 95% C.I. 1.43–1.63). This was a significant excess mortality which was not a mortality displacement: during the months following summer (September to December) 2003 the mortality observed was not significantly different from the mortality expected on the basis of the above mentioned five-years period (SMR 1.03, 95% C.I. 0.99–1.07). The correlation between daily mortality and Humidex values was high (R2=0.501) and the lag time between the onset of extreme climate conditions and the death corresponded to a very short period (1–2 days). The prominent causes of death resulted to be cerebrovascular disesases, severe respiratory diseases, severe renal diseases, dementia; also pathologic conditions and symptoms, such as hypovolemia, hyperpyrexia, decubitus ulcers, wasting syndrome were frequent causes of death. Discussion: The relationship between mortality on one side and discomfort climatic conditions, as well as the short lag time on the other hand, give a clear Public Health message: preventive, social and health care actions have to be administered to elderly and frail people, in order to avoid excess deaths during heat waves. Particular care must be taken to the elderly affected by severe chronic diseases, in particular to those confined to bed.

HEAT-RELATED DEATHS DURING 1994 HEAT WAVE IN SEOUL

ISEE-292 Aim: The objective of this study is to assess the impact on mortality of the heat wave and to examine differences with respect to cause, gender, age at death during the 1994 heat wave in Seoul. A key contribution of this study is that we characterize the population at risk for heat wave. Methods: Daily meteorological data were obtained from Korea Meteorological Administration and daily counts of deaths were extracted from mortality information of Korea National Statistical Office, for the period of 1993-1995. All cause of mortality was classified ICD-10 code. For statistical analysis of data, we calculated excess deaths for heat wave periods, and compared it to number of deaths for the same period before and after 1994 by cause, age and gender. Results: An estimated 888 excess deaths were observed during this heat wave period, compared with deaths for the same period before and after 1994. The majority of excess deaths were due to endocrine, nutritional and metabolic disease (43.0%), diseases of the circulatory system (30.5%) and diseases of the respiratory system (43.8%). Mortality for all causes increased up to 75.3% in the age group over 65 years, for the heat wave period. Also the effect was more noticeable in women compared to men. Discussion: This study found that the summer heat wave was associated with increased mortality in Seoul. This result suggests the necessity of the more comprehensive research, for the prevention of extreme heat wave mortality and heat wave warning system in Seoul.

Impact of Heat Waves on Mortality—Rome, Italy, June-August 2003

During June-August 2003, record high temperatures were reported across Europe; Italy was one of the countries most affected. To assess the impact of the summer 2003 heat waves on mortality, the Rome Local Health Authority analyzed temperature and daily mortality data for June-August 2003. This report summarizes the results of that analysis, which indicated that an estimated 1,094 excess deaths occurred during three major heat wave periods in 2003, an increase of 23% compared with the average annual number of deaths during 1995-2002. Improvements have been made in warning systems and prevention programs that target persons at high risk to reduce excess mortality during future heat waves.

Changes in the Frequency of Extreme Warm-Season Surface Dewpoints in Northeastern Illinois: Implications for Cooling-System Design and Operation

Warm-season (1 May‐30 September) hourly dewpoint data were examined for temporal changes at two weather stations in northeastern Illinois during a 42-yr period (1959‐2000). This area has dense population (greater than 8 million), and shifts to more or less atmospheric moisture have major implications on cooling demands. The 42-yr period was analyzed as two separate arbitrarily chosen equally sized periods, the early (1959‐79) and the later (1980‐2000) periods. Analyses of data from Chicago’s O’Hare International Airport and the Greater Rockford Airport showed a statistically significant increase in the number of hours with dewpoints greater than or equal to 248C (an important cooling-plant threshold) in the latter period. Examination of heat-wave periods indicated that later (especially 1995 and after) heat waves contained many more extreme dewpoint values. These increases in extreme dewpoint characteristics in northeastern Illinois affect the operation of, and suggest shifts in design criteria for, air-conditioning systems and affect summer peak electrical loads.

Heat Waves in the South Moravian Region During the Period 1961-1995

Heat waves (periods of extremely hot summer weather) in the region of south Moravia are in the focus of this study. The introduced definition consists of three requirements imposed on the period that is considered a heat wave: at least three days with T MAX ≥30.0°C must be observed; the mean T MAX over the whole period is at least 30.0°C; and T MAX must not drop below 25.0°C. To compare the severity of the individual heat waves, various characteristics (duration, number of tropical days, peak temperature, cumulative temperature excess, precipitation amount) are examined. The heat wave index HWI is defined to express the severity of heat waves in the most comprehensive way.

Excess hospital admissions during the July 1995 heat wave in Chicago

Introduction: This study describes medical conditions treated in all 47 non-VA hospitals in Cook County, IL during the 1995 heat wave. We characterize the underlying diseases of the susceptible population, with the goal of tailoring prevention efforts. Methods: Primary and secondary discharge diagnoses made during the heat wave and comparison periods were obtained from computerized inpatient hospital discharge data to determine reasons for hospitalization, and comorbid conditions, respectively. Results: During the week of the heat wave, there were 1072 (11%) more hospital admissions than average for comparison weeks and 838 (35%) more than expected among patients aged 65 years and older. The majority of this excess (59%) were treatments for dehydration, heat stroke, and heat exhaustion; with the exception of acute renal failure no other primary discharge diagnoses were significantly elevated. In contrast, analysis of comorbid conditions revealed 23% ( p = 0.019) excess admissions of underlying cardiovascular diseases, 30% ( p = 0.033) of diabetes, 52% ( p = 0.011) of renal diseases, and 20% ( p = 0.027) of nervous system disorders. Patient admissions for emphysema ( p = 0.007) and epilepsy ( p = 0.009) were also significantly elevated during the heat wave week. Conclusions: The majority of excess hospital admissions were due to dehydration, heat stroke, and heat exhaustion, among people with underlying medical conditions. Short-term public health interventions to reduce heat-related morbidity should be directed toward these individuals to assure access to air conditioning and adequate fluid intake. Long-term prevention efforts should aim to improve the general health condition of people at risk through, among other things, regular physician-approved exercise.

Five elderly patients with cerebral infarction seen during a heat wave

Five elderly patients (> or = 65 y) with cerebral infarction induced by dehydration during a heat wave were described to clarify the relationship between dehydration and stroke in the aged. When the daily maximum temperature exceeded 30 degrees C every day for two weeks, 6 patients with acute stroke came to our hospital. Five of them were patients with cerebral infarction aged 73-89 (the elderly group) and one was a 52-year-old woman with putaminal hemorrhage. As control groups, patients with ischemic stroke during the period 4 weeks before and after, but excluding the heat wave period, which consisted of an elderly control group (n = 7) and a young control group (n = 5), were also studied retrospectively with regard to clinical findings and neuroimaging. The incidence of cerebral infarction in the elderly group was higher in the heat wave period among all three groups. Atherothrombotic, lacunar, and cardioembolic infarctions were seen in 1, 2 and 2 cases, respectively. The onset in the elderly group was characteristic as all occurred before noon and were related to exercise. Physical examination at arrival revealed decreased skin turgor and dry tongue. A high BUN/creatinine ratio (> or = 25) and elevated fibrinogen (> 400 mg/dl) was frequently noted, although high hematocrit (> or = 45) was not seen. According to clinical findings, dehydration was diagnosed and they were infused with fluid, resulting in the improvement of skin turgor and tongue moisture. These findings indicated that dehydration due to excess perspiration due to the heat wave induced cerebral infarction in the elderly. It suggests that water intake on awakening in summer is important to prevent dehydration and ischemic stroke because elderly people are especially susceptible to those conditions in the morning.

Letter: Treatment of Wilson's disease.

<h3>Abstract</h3> <h3>Introduction</h3> It is well established that heatwaves increase demand for emergency transport in metropolitan areas, however little is known about the impact of heat events on demand for prehospital retrieval services in rural and remote areas, or how heatwaves are defined in this context. <h3>Inclusion criteria</h3> Papers were eligible for inclusion if they reported on the impact of a heat event on the activity of a prehospital and retrieval service in a rural or remote area. <h3>Methods</h3> A search of PubMed, Cochrane, Science Direct, CINAHL and Google Scholar databases was undertaken on 18 August 2020, using search terms related to emergency medical transport, extreme heat and rural or remote. Data relevant to the impact of heat on retrieval service activity was extracted, as well as definitions of extreme heat. <h3>Results</h3> Two papers were identified, both from Australia. Both found that heat events increased the number of road ambulance call-outs. Both studies used the Excess Heat Factor to define heatwave periods of interest. <h3>Conclusions</h3> This review found almost no primary literature on demand for prehospital retrieval services in rural and remote areas, and no data specifically related to aeromedical transport. The research did recognise the disproportionate impact of heat-related increase in service demand on rural and regional health services. With the effects of climate change already being felt, there is an urgent need for more research and action in this area.

A Case study of a heat wave during July 1966

A heat wave started affecting the southeastern and central parts of India due to a "break" in the southwest monsoon over the country during the first part of July 1966. The heat wave abated when the monsoon revided during the second week of July. Some stations recorded maximum temperatures which surpassed the previous highest maximum temperatures for July. This study deals with the synoptic situation, rainfall distribution and wind circulation over the country during the period of the heat wave. The thermal structure of the lower troposphere during the period of the heat wave has also been studied. It has been concluded that the heat wave was the result of a large defect in rainfall due to the prolonged “break” and the circulation pattern prevailing in the lower tropospheric levels over the central parts of the country during the heat wave period was more or less similar to that to May.