Possible adaptation measures for climate change in preventing heatstroke among older adults in Japan

Introduction

Heatstroke mortality is highest among older adults aged 65 years and older, and the risk is even doubled among those aged 75 years and older. The incidence of heatstroke is expected to increase in the future with elevated temperatures owing to climate change. In the context of a super-aged society, we examined possible adaptation measures in Japan that could prevent heatstroke among older people using an epidemiological survey combined with mathematical modeling.

Methods

To identify possible interventions, we conducted a cross-sectional survey, collecting information on heatstroke episodes from 2018 to 2019 among people aged 75 years and older. Responses were analyzed from 576 participants, and propensity score matching was used to adjust for measurable confounders and used to estimate the effect sizes associated with variables that constitute possible interventions. Subsequently, a weather-driven statistical model was used to predict heatstroke-related ambulance transports. We projected the incidence of heatstroke-related transports until the year 2100, with and without adaptation measures.

Results

The risk factor with the greatest odds ratio (OR) of heatstroke among older adults was living alone (OR 2.5, 95% confidence interval: 1.2-5.4). Other possible risk factors included an inability to drink water independently and the absence of air conditioning. Using three climate change scenarios, a more than 30% increase in the incidence of heatstroke-related ambulance transports was anticipated for representative concentration pathways (RCP) 4.5 and 8.5, as compared with a carbon-neutral scenario. Given 30% reduction in single living, a 15% reduction in the incidence of heatstroke is expected. Given 70% improvement in all three risk factors, a 40% reduction in the incidence can be expected.

Conclusion

Possible adaptation measures include providing support for older adults living alone, for those who have an inability to drink water and for those without air conditioning. To be comparable to carbon neutrality, future climate change under RCP 2.6 requires achieving a 30% relative reduction in all three identified risks at least from 2060; under RCP 4.5, a 70% reduction from 2050 at the latest is needed. In the case of RCP 8.5, the goal of heatstroke-related transports approaching RCP 1.9 cannot be achieved.

Amino acid solution mitigates hypothermia response and intestinal damage following exertional heat stroke in male mice

Increased gut permeability is implicated in the initiation and extent of the cytokine inflammatory response associated with exertional heat stroke (EHS). The primary objective of this study was to determine if a five amino acid oral rehydration solution (5AAS), specifically designed for the protection of the gastrointestinal lining, would prolong time to EHS, maintain gut function and dampen the systemic inflammatory response (SIR) measured during EHS recovery. Male C57/BL6J mice instrumented with radiotelemetry were gavaged with 150 μL of 5AAS or H2 O, and ≈12 h later were either exposed to an EHS protocol where mice exercised in a 37.5°C environmental chamber to a self-limiting maximum core temperature (Tc,max) or performed the exercise control (EXC) protocol (25°C). 5AAS pretreatment attenuated hypothermia depth and length (p < 0.005), which are indicators of EHS severity during recovery, without any effect on physical performance or thermoregulatory responses in the heat as determined by percent body weight lost (≈9%), max speed (≈6 m/min), distance (≈700 m), time to Tc,max (≈160 min), thermal area (≈550°C∙min), and Tc,max (42.2°C). EHS groups treated with 5AAS showed a significant decrease in gut transepithelial conductance, decreased paracellular permeability, increased villus height, increased electrolyte absorption and changes in tight junction protein expression pattern suggestive of improved barrier integrity (p < 0.05). No differences were witnessed between EHS groups in acute phase response markers of liver, circulating SIR markers, or indicators of organ damage during recovery. These results suggest that a 5AAS improves Tc regulation during EHS recovery through maintaining mucosal function and integrity.

An Advanced Internet of Things System for Heatstroke Prevention with a Noninvasive Dual-Heat-Flux Thermometer

Heatstroke is a concern during sudden heat waves. We designed and prototyped an Internet of Things system for heatstroke prevention, which integrates physiological information, including deep body temperature (DBT), based on the dual-heat-flux method. A dual-heat-flux thermometer developed to monitor DBT in real-time was also evaluated. Real-time readings from the thermometer are stored on a cloud platform and processed by a decision rule, which can alert the user to heatstroke. Although the validation of the system is ongoing, its feasibility is demonstrated in a preliminary experiment.

[Chinese foreign medical aid work should pay attention to heat stroke as a preventable disease under global warming context]

Within the global warming context, heat stroke heavily threatens human health as the most severe type of heat-related illnesses. Despite the urgent onset, severe condition and poor prognosis, heat stroke is entirely preventable and treatable. Most of the recipient countries of Chinese foreign medical aid work are concentrated in the tropical and subtropical regions. It is necessary to popularize the knowledge of heat stroke and improve the ability of diagnose and treatment among foreign medical aid members, which is critical to enhance the quality of medical service and provide better medical care for recipient countries and workers in Chinese-funded institutions. This article reviews the latest research progress in the epidemiology, pathophysiology, diagnosis, and treatment of heat stroke to provide scientific reference for actively implementing interventions and reducing morbidity and mortality.

Developing a geospatial measure of change in core temperature for migrating persons in the Mexico-U.S. border region

Although heat exposure is the leading cause of mortality for undocumented immigrants attempting to traverse the Mexico-U.S. border, there has been little work in quantifying risk. Therefore, our study aims to develop a methodology projecting increase in core temperature over time and space for migrants in Southern Arizona using spatial analysis and remote sensing in combination with the heat balance equation-adapting physiological formulae to a multi-step geospatial model using local climate conditions, terrain, and body specifics. We sought to quantitatively compare the results by demographic categories of age and sex and qualitatively compare them to known terrestrial conditions and prior studies of those conditions. We demonstrated a more detailed measure of risk for migrants than those used most recently: energy expenditure and terrain ruggedness. Our study not only gives a better understanding of the 'funnel effect' mechanisms, but also provides an opportunity for relief and rescue operations.

Diagnosis and Management of Heatstroke

Heatstroke is a life-threatening  and the most severe form of heat-related illnesses, characterized by body temperature >40ºC and central nervous system dysfunction. Heatstroke is classified into Non-Exertional Heatstroke (NEHS) and Exertional Heatstroke (EHS). The pathophysiology of heatstroke involves a combination of direct heat effects on the host, the systemic inflammatory and coagulopathic response. The diagnosis of heatstroke based on Bouchama's definition or Japan Association of Acute Medicine (JAAM) criteria. The basic principle of heatstroke management is early resuscitation and immediate cooling. Cold water immersion or convection evaporation method can be implemented based on the specific patient characteristic. Preventive strategies are early recognition by health workers, socialization to vulnerable groups and adequate acclimatization.

Precooling, Exertional Heatstroke Risk Factors, and Postexercise Cooling Rates

BACKGROUND: Precooling (PC) before exercise may help prevent severe hyperthermia and exertional heatstroke (EHS). Before clinicians can advocate PC as an EHS prevention strategy, it must effectively mitigate factors associated with EHS development while not lessening the effectiveness of EHS treatment. Therefore, this study determined if PC affected rectal temperature (T_rec), body heat storage, heart rate (HR), ratings of perceived exertion (RPE), thermal sensation, sweat rate, and postexercise cold-water immersion (CWI) T_rec cooling rates.METHODS: In this randomized, crossover, counterbalanced study, 12 subjects (6 men, 6 women; age = 22 ± 2 yr; mass = 73.5 ± 7.9 kg; height = 171 ± 7 cm) underwent 15 min of CWI (10.0 ± 0.03°C) in an environmental chamber (38.6 ± 0.6°C; 36 ± 2% humidity). After a 10-min rest, they exercised to a T_rec of 39.5°C. Subsequently, they underwent CWI (9.99 ± 0.03°C) until T_rec reached 38°C. On control (CON) days, the same procedures occurred without the 15-min PC intervention. T_rec, HR, thermal sensation, and RPE were measured at various times before, during, and after exercise.RESULTS: PC lowered body heat storage and T_rec by 15.7 ± 15.0 W · m^-2 and 0.42 ± 0.40°C, respectively, before exercise. Subjects exercised significantly longer (PC = 66.7 ± 16.3 min, CON = 45.7 ± 9.5 min) and at lower T_rec (∼0.5 ± 0.5°C) and HR (∼10 ± 7 bpm) following PC. PC significantly lowered sweat rate (PC = 1.02 ± 0.31 L · h^-1, CON = 1.22 ± 0.39 L · h^-1), but did not affect RPE or CWI cooling rates (PC = 0.18 ± 0.14°C · min^-1; CON = 0.19 ± 0.05°C · min^-1). Thermal sensation significantly differed between conditions only at pre-exercise (PC = 3 ± 1, CON = 5 ± 0.5).DISCUSSION: PC delayed severe hyperthermia and mitigated dehydration without affecting thermal perception or cooling rates posthyperthermia. PC may help prevent dangerous hyperthermia in athletes.Wohlfert TM, Miller KC. Precooling, exertional heatstroke risk factors, and postexercise cooling rates. Aerosp Med Hum Perform. 2019; 90(1):12-17.

Top 10 Research Questions Related to Preventing Sudden Death in Sport and Physical Activity

Participation in organized sport and recreational activities presents an innate risk for serious morbidity and mortality. Although death during sport or physical activity has many causes, advancements in sports medicine and evidence-based standards of care have allowed clinicians to prevent, recognize, and treat potentially fatal injuries more effectively. With the continual progress of research and technology, current standards of care are evolving to enhance patient outcomes. In this article, we provided 10 key questions related to the leading causes and treatment of sudden death in sport and physical activity, where future research will support safer participation for athletes and recreational enthusiasts. The current evidence indicates that most deaths can be avoided when proper strategies are in place to prevent occurrence or provide optimal care.

Wearable deep body thermometers and their uses in continuous monitoring for daily healthcare

This paper introduces noninvasive deep body thermometers suitable for continuous deep body temperature (DBT) measurement. On the basis of their features, they were used in DBT monitoring for daily healthcare. A thermometer based on the dual-heat-flux method (T_DHFM), and an aural canal thermistor (ACT), were used in two studies of daily healthcare. The medical device CoreTemp by Terumo, based on the zero-heat-flux method, was also used for a DBT reference. The first study focused on preventing heat stroke in a high-temperature and high-humidity environment, while the other focused on the temperature monitoring of patients with spinal cord injuries. In the first study, CoreTemp and T_DHFM were used, whereas T_DHFM and ACT were used in the second study. Using the results from these two studies, we discuss the availability and performance of each thermometer and indicate the necessity of an appropriate method of measuring DBT.

Exertional Heat Stroke and American Football: What the Team Physician Needs to Know

Football is recognized as a leading contributor to sports injury secondary to the contact collision nature of the endeavor. While direct deaths from head and spine injury remain a significant contributor to the number of catastrophic injuries, indirect deaths (systemic failure) predominate. Exertional heat stroke has emerged as one of the leading indirect causes of death in high school and collegiate football. This review details for the team physician the unique challenge of exercising in the heat to the football player, and the prevention, diagnosis, management, and return-to-play issues pertinent to exertional heat illnesses.

[Heat stroke related to the use of topiramate. The importance of prevention]

Heat stroke is the most severe pathology related to heat. It is defined as an increase in core body temperature accompanied by signs of neurological dysfunction. In the absence of an early treatment, it has a very high mortality rate. Topiramate is a well known drug widely used in epilepsy treatment and migraine prevention. Oligohydrosis has been described amongst topiramate side effects, favouring the risk of hyperthermia and heatstroke. We present the case of a patient who developed heat stroke due to physical exercise while under topiramate treatment.

Historical development of heat stroke prevention device in the military

Understanding of core body temperature, heat stress and heat stroke developed progressively over the centuries. Soldiers involved in military operations have a higher risk to develop heat stroke, and to not survive following the onset. This paper follows the evolving understanding of heat stroke and development of counter measures. At certain times in history, incomplete understanding of the causes of heat stroke led to the development of devices that did not lower the risk. As understanding improved, development of improved methods and devices became possible. In the present day, several designs for garments that can lower core body temperature or brain temperature have been developed, and would reduce the risk of heat stroke. These cooling devices include a vest and collar system. Further refinements of these designs to make them more practical would allow wider deployment.

Population at high-risk of indoor heatstroke: the usage of cooling appliances among urban elderlies in Japan

OBJECTIVES

Heatstroke due to a heat wave during the summer is one of the commonly known health impacts of climate change in Japan. The elderly are particularly at high-risk of developing indoor heatstroke with poor prognosis. This study aims to describe the population among elderlies at high-risk of indoor heatstroke by focusing on the usage of cooling appliances.

METHODS

We conducted a web-based household survey in eight urban areas during the winter season of 2011. Households with a person aged 65 and over were selected as samples from panel members of a research firm, and the oldest member of the household was queried about his/her usage of cooling appliances. The population at high-risk of indoor heatstroke is defined as the elderly staying in a room without cooling appliances, or not using the installed cooling appliances, or turning the cooling appliances on only when the room temperature is above 28 °C.

RESULTS

15.4 and 19.1 % of the elderlies living in urban areas of Japan are identified as at high-risk of indoor heatstroke during activity time and sleeping time, respectively, according to the definition of high-risk of indoor heatstroke in this study.

CONCLUSIONS

These figures are not negligible since the consequences of heatstroke are grave, but its risk can be eliminated by an appropriate usage of cooling appliances. The preventive interventions are needed to protect the elderlies at high-risk of heatstroke.

[Heat stroke and the elderly]

Recently, the heat stroke in the elderly who often remains at home during the day increases due to high temperatures in summer by urban heat island effect. We have examined how the elderly were influenced by the high summer temperatures. We explained the patients or the caregivers at home while showing the checklist of six items. In addition, we checked and interviewed time of visits, patients' room temperature, with or without air conditioning fan etc., and filled out their histories of summer heat. If some items of the checklist were not improved, we explained the care points again every time we visited. 10 people out of the 72 patients were identified as summer heat illness at home. We need to work together with medical cares and welfare services and the other organizations of each region.

[The Japanese government's efforts to prevent heat stroke]

In recent years, as one of the effects of global warming and heat island phenomenon, the risk of heat stroke in daily life is increasing. The worst heat wave in our history attacked in 2010, which killed more than 1,700 people. Therefore, the Japanese Government, including the Ministry of the Environment, has promoted the following measures: (1) Provision of information about prediction and observation of temperature and warning of hot weather (2) Awareness-raising of preventive measures appropriate to the heat stroke (3) Dissemination of information on the occurrence of heat stroke, e.g. the number of deaths, the number of persons taken to hospital by ambulance (4) Promotion of research and study on heat stroke

[Sports and heat stroke]

We described Characteristic of the heat stroke in the sports activity in Japan. It was common in teenage men, and 15 years old had a peak with a man, the woman. Most patients did not need specific treatment. Many happened from the end of July on the outdoors around 3:00 p.m. in mid-August. There are many in order of baseball, football, tennis, and a basketball. Running and cycling had high severity of illness. Probably, grasp of an environmental condition, suitable sportswear, suitable hydration, and condition management are the best things as preventive measures.

[Measures by local government--actions to take in dealing with heat stroke for firefighters]

This paper expresses educational viewpoints on preventing "heat stroke (hyperthermia)" for firefighters who are in charge of pre-hospital care such as "life saving and relieving the sick/wounded" considering how firefighters are liable to heat stroke and knowledge that is needed, based on example cases. It is essential to have knowledge and measures to prevent heat stroke considering its particularity not only to firefighters engaged in disaster relief activities but also to people with other occupation and sports.

Monitoring of the bed time body temperature and body weight to prevent the occurrence of heat stroke in the Royal Thai Army recruits, Lopburi Province, Thailand

OBJECTIVE

Heat stroke is still an important health problem in Thai army recruits. The authors aimed to evaluate a new method for preventing heat stroke in the newly army recruits during basic training in May-June 2006, by monitoring the bed time body temperature and body weight.

MATERIAL AND METHOD

One thousand one hundred and fifteen recruits from five army units in Lopburi Province, Thailand were enrolled in the present study. Standardized questionnaire was used for data collection including unit information, personal information, environmental information and daily activity information. Bed time body temperature and body weight were recorded daily. Anyone who had a body temperature > 37.8 degrees C or body weight lossing > 10% in 24 h had to stop training until these indicators were normal.

RESULTS

There was no incidence of heat stroke in these army units during this training period. There were 191 recruits who had a body temperature > 37.8 degrees C. The mean duration of the fever was 3.3 +/- 3.3 days. The incidence of fever was 21.4 per 100 persons-month. There were 30 recruits with the body weight lossing > 10%. The duration of body weight loss was one day. Analyzed by mixed model using STATA program, there was statistically significant difference of the body temperature (p < 0.001) but not the body weight (p = 0.644) among the period of time.

CONCLUSION

This monitoring of the bed time body temperature and body weight seems to be effective for the prevention of the occurrence of heat stroke because there was no case of heat stroke in the present study. However, further large-scale study with a control group should be performed.

National athletic trainers' association position statement: preventing sudden death in sports

OBJECTIVE

To present recommendations for the prevention and screening, recognition, and treatment of the most common conditions resulting in sudden death in organized sports.

BACKGROUND

Cardiac conditions, head injuries, neck injuries, exertional heat stroke, exertional sickling, asthma, and other factors (eg, lightning, diabetes) are the most common causes of death in athletes.

RECOMMENDATIONS

These guidelines are intended to provide relevant information on preventing sudden death in sports and to give specific recommendations for certified athletic trainers and others participating in athletic health care.

Local heat stroke prevention plans in Japan: characteristics and elements for public health adaptation to climate change

The adverse health effects from hot weather and heat waves represent significant public health risks in vulnerable areas worldwide. Rising temperatures due to climate change are aggravating these risks in a context of fast urbanization, population growth and societal ageing. However, environmental heat-related health effects are largely preventable through adequate preparedness and responses. Public health adaptation to climate change will often require the implementation of heat wave warning systems and targeted preventive activities at different levels. While several national governments have established such systems at the country level, municipalities do not generally play a major role in the prevention of heat disorders. This paper analyzes selected examples of locally operated heat-health prevention plans in Japan. The analysis of these plans highlights their strengths, but also the need of local institutions for assistance to make the transition towards an effective public health management of high temperatures and heat waves. It can also provide useful elements for municipal governments in vulnerable areas, both in planning their climate change and health adaptation activities or to better protect their communities against current health effects from heat.

When the heat is on

While most people would welcome a warm, sunny summer, the heat can prove life-threatening for some vulnerable groups.

Heat stroke: helping patients keep their cool

Heat stroke is a life-threatening illness that requires prompt diagnosis and treatment. Early vital sign assessment and history gathering are key to identifying this disorder.

A potential for granulocyte-colony stimulating factor for use as a prophylactic agent for heatstroke in rats

Heatstroke is a form of excessive hyperthermia associated with a systemic inflammatory response that leads to multi-organ dysfunction in which central nervous system disorders predominate. Herein we determined to ascertain whether heat-induced multi-organ dysfunction in rats could be attenuated by granulocyte-colony stimulating factor (G-CSF) preconditioning. Anesthetized rats were divided into 2 major groups and given vehicle solution (isotonic saline, 0.3 ml, subcutaneously) or G-CSF (50-200 μg/kg body weight in 0.3 ml normal saline, subcutaneously) daily and consecutively for 5 days before the start of thermal experiments. They were exposed to an ambient temperature of 43°C for 68 min to induce heatstroke. G-CSF preconditioning significantly prolonged the survival time in heatstroke rats in a dose-related way (82-98 min vs 127-243 min). The non-preconditioning heatstroke animals showed hyperthermia, arterial hypotension, increased serum levels of systemic inflammatory response molecules, increased hypothalamic apoptotic cell numbers as well as neuronal damage scores, and increased serum levels of renal and hepatic dysfunction indicators. These heatstroke syndromes could be significantly reduced by G-CSF preconditioning. Thus our results revealed a potential for G-CSF used as a prophylactic agent for heatstroke in rats.

[Heat stroke in the workplace: description of a case with fatal outcome]

BACKGROUND

Heat exposure represents an occupational risk factor in various work settings. Adverse effects may range from mild symptoms, like muscular cramps, to life threatening conditions, like heat stroke. Data on the occurrence of work-related adverse effects of heat exposure in Italy are lacking.

OBJECTIVES

To highlight the risk of heat stroke in a common working activity.

METHODS

The case of a fatal heat stroke in a 19-year-old worker, in apparently good health, employed in maintenance of open park spaces is presented. After working 7 hours outdoors on a sunny day he was found unconscious. He was immediately taken to the local Emergency Department, where he arrived in hyperthermic and comatose conditions, and died due to multiple organ failure after 36 hours. After excluding other main causes of hyperthermia, heatstroke was identified as the initial cause of death.

RESULTS

The case presented describes the possible extreme consequences of an underestimation of the risk related to occupational heat exposure, even in young and apparently healthy workers. Heat-related adverse effects may occur in a number of common activities, not necessarily involving heavy workload or extreme temperatures. Different methods, including simplified methods, are available for heat stress risk evaluation. The main preventive measures include adequate acclimatization, periodic interruption of exposure, sufficient fluid intake, adequate clothing and appropriate Personal Protective Equipment. Adequate training and workers' health surveillance are also essential.

CONCLUSIONS

Heat exposure may be a significant occupational risk, potentially inducing life-threatening conditions, in a number of common activities but is frequently underestimated. An example of undervaluation of the risk and of the possible consequences, are presented and discussed in this case report.

Singapore Armed Forces Medical Corps-Ministry of Health clinical practice guidelines: management of heat injury

The Singapore Armed Forces (SAF) Medical Corps and the Ministry of Health (MOH) have published clinical practice guidelines on Management of Heat Injury to provide doctors and patients in Singapore with evidence-based guidance on the prevention and clinical management of exertional heat injuries. This article reproduces the introduction and executive summary (with recommendations from the guidelines) from the SAF Medical Corps-MOH clinical practice guidelines on Management of Heat Injury, for the information of readers of the Singapore Medical Journal. Chapters and page numbers mentioned in the reproduced extract refer to the full text of the guidelines, which are available from the Ministry of Health website: http://www.moh.gov.sg/mohcorp/publications.aspx?id=25178. The recommendations should be used with reference to the full text of the guidelines. Following this article are multiple choice questions based on the full text of the guidelines.

Canine tactical field care. Part two--Massive hemorrhage control and physiologic stabilization of the volume depleted, shock-affected, or heatstroke-affected canine

Military and law enforcement agencies have seen a dramatic increase in the utilization of military working dogs (MWDs) and working canine officers, respectively both at home and in foreign deployments. Due to the fact that professional veterinary care is often distant from internal disaster or foreign deployment sites, the military medic, police tactical medic, or other first-response medical care providers may be charged with providing emergency or even basic, non-emergency veterinary care to working canines. The medical principles involved in treating canines are essentially the same as those for treating humans; however, the human healthcare provider needs basic information on canine anatomy and physiology, and common emergency conditions, in order to provide good basic veterinary care until a higher level of veterinary care can be obtained. This article represents the second in a series designed to provide condensed, basic veterinary information on the medical care of working canines, including police canines, federal agency employed working canines, and search-and-rescue dogs, in addition to the MWD, to those who are normally charged with tactical or first responder medical care of human patients. This article focuses on diagnosing and treating some of the more common high-mortality conditions affecting canines in the field including massive hemorrhage, volume-depletion, shock, and heatstroke.

Role of endotoxin and cytokines in the systemic inflammatory response to heat injury

Environmental heat exposure represents one of the most deadly natural hazards in the United States. Heat stroke is a life-threatening illness that affects all segments of society with few effective treatment strategies to mitigate the long-term debilitating consequences of this syndrome. Although the etiologies of heat stroke are not fully understood, the long-term sequelae are thought to be due to a systemic inflammatory response syndrome (SIRS) that ensues following heat-induced tissue injury. Endotoxin and cytokines have been implicated as key mediators of the heat-induced SIRS, based almost exclusively on correlative data that show high circulating concentrations of these substances in heat stroke patients and animal models. However, endotoxin and cytokine neutralization studies have not consistently supported this hypothesis indicating that the mechanisms of heat stroke morbidity / mortality remain poorly understood. This review discusses the current understanding of the role of endotoxin and cytokines in heat-induced SIRS. Insight is provided into genetic conditions that may predispose to heat stroke and potential therapeutic strategies that may be efficacious against the adverse consequences of this debilitating illness.

Summer heat and mortality in New York City: how hot is too hot?

BACKGROUND

To assess the public health risk of heat waves and to set criteria for alerts for -excessive heat, various meteorologic metrics and models are used in different jurisdictions, generally without systematic comparisons of alternatives. We report such an analysis for New York City that compared maximum heat index with alternative metrics in models to predict daily variation in warm-season natural-cause mortality from 1997 through 2006.

MATERIALS AND METHODS

We used Poisson time-series generalized linear models and generalized additive models to estimate weather-mortality relationships using various metrics, lag and averaging times, and functional forms and compared model fit.

RESULTS

A model that included cubic functions of maximum heat index on the same and each of the previous 3 days provided the best fit, better than models using maximum, minimum, or average temperature, or spatial synoptic classification (SSC) of weather type. We found that goodness of fit and maximum heat index-mortality functions were similar using parametric and nonparametric models. Same-day maximum heat index was linearly related to mortality risk across its range. The slopes at lags of 1, 2, and 3 days were flat across moderate values but increased sharply between maximum heat index of 95 degrees F and 100 degrees F (35-38 degrees C). SSC or other meteorologic variables added to the maximum heat index model moderately improved goodness of fit, with slightly attenuated maximum heat index-mortality functions.

CONCLUSIONS

In New York City, maximum heat index performed similarly to alternative and more complex metrics in estimating mortality risk during hot weather. The linear relationship supports issuing heat alerts in New York City when the heat index is forecast to exceed approximately 95-100 degrees F. Periodic city-specific analyses using recent data are recommended to evaluate public health risks from extreme heat.

[Prevention of non infectious health problems in expatriates and humanitarian workers]

Frequently, expatriates and humanitarian workers change their lifestyle during expatriation and take more risks. Exposure to sun and heat, alcohol abuse, unprotected sexual relationships, stress, accidents and security incidents are the main non infectious health risks. It is important to prevent them, as the consequences are more serious abroad. Their prevention lies on the responsibility of every individual to adapt their behaviour and lifestyle to the environment, as well as on institutional guidelines concerning risky behaviour.

Occupational heat illness in Washington State, 1995-2005

BACKGROUND

Little information exists describing the incidence of heat-related illness (HRI) among non-military working populations. An analysis of HRI cases utilizing workers' compensation data has not been previously reported.

METHODS

We used both ICD-9 and ANSI Z16.2 codes with subsequent medical record review to identify accepted Washington State Fund workers' compensation claims for HRI over the 11-year time period from 1995-2005.

RESULTS

There were 480 Washington workers' compensation claims for HRI during the 11-year study period. NAICS industries with the highest workers' compensation HRI average annual claims incidence rate were Fire Protection 80.8/100,000 FTE, Roofing Construction 59.0/100,000 FTE, and Highway, Bridge and Street Construction 44.8/100,000 FTE. HRI claims were associated with high outdoor ambient temperatures. Medical risk factors for HRI were present in some cases.

CONCLUSIONS

HRI cases occur in employed populations. HRI rates vary by industry and are comparable to those previously published for the mining industry.

[Prophylactic effect of quinacrine against experimental heatstroke]

The present study is to assess the prophylactic effect of quinacrine (QA) , an anti-malarial drug, against heatstroke in rats. Conscious rats were orally given equal volume normal saline or QA (dissolved in normal saline and final dosage for rats was 4.5, 9.0 and 18 mg x kg(-1)). An hour later rats were put into a warm water circulated hot chamber (41.0 +/- 0.5) degrees C. Rectal temperature (core temperature, T(co)) of rats in hot chamber was continuously monitored by a thermocouple. T(co) and survival time of rats showed that QA pre-treatment postponed the hyperthermia, and increased the survival time of rats in hot chamber. Primary striatum neurons' culture from new born rats was maintained with D-MEM and 10% FBS. After immuno-cytochemistry identification with antibodies against neural specific proteins, culture received 20 micromol x L(-1) QA only for 1 h and followed by 43.0 degrees C heat treatment for another hour, or 20 micromol x L(-1) QA for 1 h followed by 43.0 degrees C heat treatment for another hour. Control culture received heat treatment only. Cultures were labeled with the fluorescent indicator DPH and the relative membrane fluidity of neurons was measured with the help of fluorescent polarized spectrophotometer. [3H] Arachidonic acid (AA) labeled membrane of E. Coli cells was used as substrate to determine cPLA2 activity of neurons. Gas chromatography and mass spectrum were also employed to detect on the level of fatty acids level in rat striatum neurons. Results from cells indicated that inhibition of cPLA2, reduction the release of active fatty acids such as AA, and possibly, stabilization of the cell membrane which was disturbed by hot treatment, may contribute to the mechanism underlying heat protection and heatstroke preventive effects of quinacrine.

August 2003 Heat Wave in France: Risk Factors for Death of Elderly People Living at Home

The August 2003 heat wave in France resulted in many thousands of excess deaths particularly of elderly people. Individual and environmental risk factors for death among the community-dwelling elderly were identified. We conducted a case-control survey and defined cases as people aged 65 years and older who lived at home and died from August 8 through August 13 from causes other than accident, suicide, or surgical complications. Controls were matched with cases for age, sex, and residential area. Interviewers used questionnaires to collect data. Satellite pictures provided profiles of the heat island characteristics around the homes. Lack of mobility was a major risk factor along with some pre-existing medical conditions. Housing characteristics associated with death were lack of thermal insulation and sleeping on the top floor, right under the roof. The temperature around the building was a major risk factor. Behaviour such as dressing lightly and use of cooling techniques and devices were protective factors. These findings suggest people with pre-existing medical conditions were likely to be vulnerable during heat waves and need information on how to adjust daily routines to heat waves. In the long term, building insulation and urban planning must be adapted to provide protection from possible heat waves.