Impact of heat waves on human morbidity and hospital admissions in a city of the western mediterranean area.

PURPOSE: The effect of heat waves on mortality is well known, but current evidence on morbidity is limited. Establishing the consequences of these events in terms of morbidity is important to ensure communities and health systems can adapt to them. METHODS: We thus collected data on total daily emergency hospital admissions, admissions to critical care units, emergency department admissions, and emergency admissions for specific diagnoses to Hospital Universitario de Son Espases from 1 January 2005 to 31 December 2021. A heat wave was defined as a period of ≥ 2 days with a maximum temperature ≥ 35 °C, including a 7 day lag effect (inclusive). We used a quasi-Poisson generalized linear model to estimate relative risks (RRs; 95%CI) for heat wave-related hospital admissions. RESULTS: Results showed statistically significant increases in total emergency admissions (RR 1.06; 95%CI 1 - 1.12), emergency department admissions (RR 1.12; 95%CI 1.07 - 1.18), and admissions for ischemic stroke (RR 1.26; 95%CI 1.02 - 1.54), acute kidney injury (RR 1.67; 95%CI 1.16 - 2.35), and heat stroke (RR 18.73, 95%CI 6.48 - 45.83) during heat waves. CONCLUSION: Heat waves increase hospitalization risk, primarily for thromboembolic and renal diseases and heat strokes.

Body mass index, but not sex, influences exertional heat stroke risk in young healthy men and women.

Exertional heat stroke (EHS) remains a persistent threat for individuals working or playing in the heat, including athletes and military and emergency service personnel. However, influence of biological sex and/or body mass index (BMI) on the risk of EHS remain poorly understood. The purpose of this study was to retrospectively assess the influence of sex and BMI on risk of EHS in the active-duty US Army. We analyzed data from 2016 to 2021, using a matched case-control approach, where each individual with a diagnosis of EHS was matched to five controls based on calendar time, unit ID, and job category, to capture control individuals who were matched to EHS events by location, time, and activity. We used a multivariate logistic regression model mutually adjusted for sex, BMI, and age to compare 745 (n = 61 F) individuals (26 ± 7 yr) with a diagnosed EHS to 4,290 (n = 384 F) case controls (25 ± 5 yr). Group average BMI were similar: 26.6 ± 3.1 (EHS) and 26.5 ± 3.6 kg/m2 (CON). BMI was significantly (P < 0.0001) associated with higher risk of EHS with a 3% increase in risk of EHS for every unit increase in BMI. Notably, sex was not associated with any difference in risk for EHS (P = 0.54). These data suggest that young healthy people with higher BMI have significantly higher risk of EHS, but, contrary to what some have proposed, this risk was not higher in young women.

Prediction of climate change impacts on heatstroke cases in Japan's 47 prefectures with the effect of long-term heat adaptation.

One of the negative consequences of increased air temperatures due to global warming is the associated increase in heat-related mortality and morbidity. Studies that focused on future predictions of heat-related morbidity do not consider the effect of long-term heat adaptation measures, nor do they use evidence-based methods. Therefore, this study aimed to predict the future heatstroke cases for all 47 prefectures of Japan, by considering long-term heat adaptation by translating current geographical differences in heat adaptation to future temporal heat adaptation. Predictions were conducted for age groups of 7-17, 18-64, and ≥65 years. The prediction period was set to a base period (1981-2000), mid-21st century (2031-2050), and the end of the 21st century (2081-2100). We found that the average heatstroke incidence (number of patients with heatstroke transported by ambulance per population) in Japan under five representative climate models and three greenhouse gas (GHG) emissions scenarios increased by 2.92- for 7-17 years, 3.66- for 18-64 years, and 3.26-fold for ≥65 years at the end of the 21st century without heat adaptation. The corresponding numbers were 1.57 for 7-17 years, 1.77 for 18-64 years, and 1.69 for ≥65 years with heat adaptation. Furthermore, the average number of patients with heatstroke transported by ambulance (NPHTA) under all climate models and GHG emissions scenarios increased by 1.02- for 7-17 years, 1.76- for 18-64 years, and 5.50-fold for ≥65 years at the end of 21st century without heat adaptation, where demographic changes were considered. The corresponding numbers were 0.55 for 7-17 years, 0.82 for 18-64 years, and 2.74 for ≥65 years with heat adaptation. The heatstroke incidence, as well as the NPHTA, substantially decreased when heat adaptation was considered. Our method could be applicable to other regions across the globe.

Potential effect of heat adaptation on association between number of heatstroke patients transported by ambulance and wet bulb globe temperature in Japan.

This study analyzed the association between heatstroke incidence and daily maximum wet bulb globe temperature (WBGT) for all 47 prefectures in Japan by age group and severity using time-series analysis, controlling for confounders, such as seasonality and long-term trends. With the obtained association, the relative risk between the reference WBGT (defined as the value at which heatstroke starts to increase) and the daily maximum WBGT at 30 °C (RRwbgt30) of each prefecture were calculated. For the heatstroke data, the daily number of heatstroke patients transported by ambulance at the prefecture level, provided by the Fire and Disaster Management Agency, was utilized. The analysis was conducted for age groups of 7-17 y, 18-64 y, and ≥65 y, and for severity of Deceased, Severe, Moderate (combined as DSM), and Mild. The analysis period was set from May 1 to September 30, 2015-2019. Finally, the correlation between RRwbgt30 and the average daily maximum WBGT during the analysis period (aveWBGTms) of each prefecture was analyzed to examine the regionality of heatstroke incidence. The result showed that RRwbgt30 is negatively correlated with aveWBGTms for the age group 18-64 y and ≥65 y (except for the age group 7-17 y) and for severity. The natural logarithm of the RRwbgt30 of all 47 prefectures ranged from 2.0 to 8.2 for the age group 7-17 y, 1.1 to 4.0 for the age group 18-64 y, 1.8 to 6.0 for the age group ≥65 y, and 1.0 to 3.6 for DSM, and 0.9 to 4.0 for Mild. This regionality can be attributed to the effects of heat adaptation, where people in hotter regions are accustomed to implementing measures against hot environments and are more heat acclimatized than people in cooler regions.

Exertional heat stroke in sport and the military: epidemiology and mitigation.

NEW FINDINGS: What is the topic of this review? Exertional heat stroke epidemiology in sport and military settings, along with common risk factors and strategies and policies designed to mitigate its occurrence. What advances does it highlight? Individual susceptibility to exertional heat stroke risk is dependent on the interaction of intrinsic and extrinsic factors. Heat policies in sport should assess environmental conditions, as well as the characteristics of the athlete, clothing/equipment worn and activity level of the sport. Exertional heat stroke risk reduction in the military should account for factors specific to training and personnel. ABSTRACT: Exertional heat illness occurs along a continuum, developing from the relatively mild condition of muscle cramps, to heat exhaustion, and in some cases to the life-threatening condition of heat stroke. The development of exertional heat stroke (EHS) is associated with an increase in core temperature stemming from inadequate heat dissipation to offset the rate of metabolically generated heat. Susceptibility to EHS is linked to the interaction of several factors including environmental conditions, individual characteristics, health conditions, medication and drug use, behavioural responses, and sport/organisational requirements. Two settings in which EHS is commonly observed are competitive sport and the military. In sport, the exact prevalence of EHS is unclear due to inconsistent exertional heat illness terminology, diagnostic criteria and data reporting. In contrast, exertional heat illness surveillance in the military is facilitated by standardised case definitions, a requirement to report all heat illness cases and a centralised medical record repository. To mitigate EHS risk, several strategies can be implemented by athletes and military personnel, including heat acclimation, ensuring adequate hydration, cold-water immersion and mandated work-to-rest ratios. Organisations may also consider developing sport or military task-specific heat stress policies that account for the evaporative heat loss requirement of participants, relative to the evaporative capacity of the environment. This review examines the epidemiology of EHS along with the strategies and policies designed to reduce its occurrence in sport and military settings. We highlight the nuances of identifying individuals at risk of EHS and summarise the benefits and shortcomings of various mitigation strategies.

Clinical Spectrum of Pediatric Heat Illness and Heatstroke in a North American Desert Climate.

ABSTRACT: The spectrum of historical features and clinical presentations of heat illness and heatstroke in the pediatric population has received limited focus in the emergency medicine literature. The majority of published cases involve children trapped in closed spaces and adolescent athletes undergoing high-intensity training regimens in geographical regions with moderately high ambient temperatures and high humidity. There has been less research on the potential impact of extreme temperatures and radiant heat that are the hallmarks of the US southwest region. We performed a retrospective review of pediatric heat illness at our facility located in a North American desert climate.

[Investigation on occupational injury of sanitation workers in Shenzhen City].

Objective: To understand the occurrence of occupational injuries among sanitation workers in Shenzhen, and provide a scientific basis for the prevention of occupational injuries among sanitation workers. Methods: From May to November 2020, a cluster sampling method was used to select some street sanitation workers in Shenzhen to conduct a questionnaire survey. A total of 2200 questionnaires were recovered, of which 2167 were valid (98.5% effective recovery rate) . The socio-demographic data, length of service, type of work and occurrence of occupational injuries of sanitation workers were collected, and the distribution characteristics of occupational injuries and their relationship with factors such as type of work were analyzed. Results: Among the 2167 sanitation workers, 240 (11.1%) had experienced occupational injuries. The most common occupational injuries among sanitation workers were sharp injury, heat stroke and motor vehicle traffic accident, with the incidence rates of 6.1% (133/2167) , 2.4% (53/2167) and 1.7% (36/2167) respectively. There were statistically significant differences in the distribution of occupational injuries among sanitation workers with different lengths of work and types of work (P<0.05) . The incidence of occupational injury among sanitation workers with more than 5 years of service was significantly higher than that of workers with less than 5 years of service (P<0.05) . The incidence of sharp injury among garbage sorting and transportation personnel was higher (7.9%, 21/265) , the incidence of heat stroke among manual cleaners was higher (3.1%, 42/1366) , and the incidence of motor vehicle traffic accident among mechanized cleaners was higher (5.4%, 10/184) . Conclusion: There are many cases of occupational injuries among sanitation workers in Shenzhen. Targeted measures should be taken to prevent the occurrence of different types of work and different types of occupational injuries, and to improve the occupational health level of sanitation workers.

Context-aware heatstroke relief station placement and route optimization for large outdoor events.

BACKGROUND: Heatstroke is becoming an increasingly serious threat to outdoor activities, especially, at the time of large events organized during summer, including the Olympic Games or various types of happenings in amusement parks like Disneyland or other popular venues. The risk of heatstroke is naturally affected by a high temperature, but it is also dependent on various other contextual factors such as the presence of shaded areas along traveling routes or the distribution of relief stations. The purpose of the study is to develop a method to reduce the heatstroke risk of pedestrians for large outdoor events by optimizing relief station placement, volume scheduling and route. RESULTS: Our experiments conducted on the planned site of the Tokyo Olympics and simulated during the two weeks of the Olympics schedule indicate that planning routes and setting relief stations with our proposed optimization model could effectively reduce heatstroke risk. Besides, the results show that supply volume scheduling optimization can further reduce the risk of heatstroke. The route with the shortest length may not be the route with the least risk, relief station and physical environment need to be considered and the proposed method can balance these factors. CONCLUSIONS: This study proposed a novel emergency service problem that can be applied in large outdoor event scenarios with multiple walking flows. To solve the problem, an effective method is developed and evaluates the heatstroke risk in outdoor space by utilizing context-aware indicators which are determined by large and heterogeneous data including facilities, road networks and street view images. We propose a Mixed Integer Nonlinear Programming model for optimizing routes of pedestrians, determining the location of relief stations and the supply volume in each relief station. The proposed method can help organizers better prepare for the event and pedestrians participate in the event more safely.

Inpatient burden and mortality of heatstroke in the United States.

BACKGROUND: This study aimed to assess inpatient prevalence, characteristics, outcomes, and resource utilisation of hospitalisation for heatstroke in the United States. Additionally, this study aimed to explore factors associated with in-hospital mortalities of heatstroke. METHODS: The 2003-2014 National Inpatient Sample database was used to identify hospitalised patients with a principal diagnosis of heatstroke. The inpatient prevalence, clinical characteristics, in-hospital treatments, outcomes, length of hospital stay, and hospitalisation cost were studied. Multivariable logistic regression was performed to identify independent factors associated with in-hospital mortality. RESULTS: A total of 3372 patients were primarily admitted for heatstroke, accounting for an overall inpatient prevalence of heatstroke amongst hospitalised patients of 36.3 cases per 1 000 000 admissions in the United States with an increasing trend during the study period (P < .001). Age 40-59 was the most prevalent age group. During the hospital stay, 20% required mechanical ventilation, and 2% received renal replacement therapy. Rhabdomyolysis was the most common complication. Renal failure was the most common end-organ failure, followed by neurological, respiratory, metabolic, hematologic, circulatory, and liver systems. The in-hospital mortality rate of heatstroke hospitalisation was 5% with a decreasing trend during the study period (P < .001). The presence of end-organ failure was associated with increased in-hospital mortality, whereas more recent years of hospitalisation was associated with decreased in-hospital mortality. The median length of hospital stay was 2 days. The median hospitalisation cost was $17 372. CONCLUSION: The inpatient prevalence of heatstroke in the United States increased, while the in-hospital mortality of heatstroke decreased.

Exertional heat illnesses in marching band artists: a case series.

Marching band (MB) artists frequently spend many hours engaged in outdoor physical activity. Anecdotal evidence and small studies have indicated that MB artists do experience heat-related health problems. Yet, unlike athletes, military personnel, or workers, there is very little research on heat-related hazards among this unique population. Here, we seek to understand the incidence and circumstances under which exertional heat illnesses (EHIs) occur among MB artists over a 31-year period (1990-2020) across the USA. Using an on-line news dataset, we identified 34 separate events and at least 393 total EHIs. Heat syncope (~ 55%) and heat exhaustion (~ 44%) comprised the majority of EHIs, although a small number of exertional heat stroke cases were also reported. EHIs were reported in all types of MB activities with ~ 32% during rehearsal, ~ 29% during parades, ~ 21% during competition, and ~ 15% during a performance. Also, the vast majority of events occurred with high school (~ 88%) marching bands. Finally, EHIs overwhelmingly occurred when the weather was unusually hot by local conditions. In light of these findings, we emphasize the need for MB specific heat polices that incorporate weather-based activity modification, acclimatization, education about EHIs, and access to on-site medical professionals.

Heat stroke-related deaths in India: An analysis of natural causes of deaths, associated with the regional heatwave.

Soaring temperatures cause deaths in large numbers in various parts of India. The number of deaths vary with region and are influenced by the demographics and socioeconomic characteristics of the region. This study tried to estimate the number of deaths associated with exposure to heat in the different states of India. Secondary data was used, which was collected from the website data.gov.in, an Open Government Data (OGD) Platform of the Indian government. Descriptive statistics were applied using Microsoft Excel-10. It was found that there 3014 men died from heat-related causes in 2001-05, which increased to 5157 in the period 2011-15. For women the number of deaths in the corresponding periods were 849 and 1254 respectively. Deaths caused by heatwaves were found to be higher than those resulting from avalanches, exposure to cold, cyclone, tornado, starvation due to natural calamity, earthquake, epidemic, flood, landslide, torrential rain and forest fire. The study revealed that there are regional variations in the number deaths due to heatstroke. From the perspective of disaster preparedness, it is important to note that deaths from heat strokes occur every year. With rising temperatures, the numbers are likely to increase. The findings of the study highlight this concern. Therefore, there is a need for targeted region-specific interventions for reducing the number of deaths due to heatwaves.

The efficacy of antibiotics in reducing morbidity and mortality from heatstroke - A systematic review.

Severe hyperthermia, for example, classical heatstroke or exertional heatstroke from heatwaves or exercise respectively, or from drug ingestion or other non-infective pyrogens, is associated with a high mortality and morbidity, which may be chronic or permanent. Abolition of lipopolysaccharide, from gram-negative intestinal bacteria translocating into the systemic circulation via an intestinal wall rendered permeable from the hyperthermia, reduces the adverse effects, suggesting that antibiotics against the intestinal bacteria may have a similar effect. A systematic review searching Embase, MEDLINE and PubMed from the earliest date available until 2019 was conducted, according to PRISMA guidelines. Two papers were found which fit the criteria. In one, non-absorbable oral antibiotics were administered prior to the onset of heat stress, which reduced the cardiovascular dysfunction and rise in endotoxaemia, but animals succumbed at a lower temperature. In the second, non-absorbable oral antibiotics, in combination with a laxative and enema, given prior to the onset of heat stress, improved mortality; antibiotics administered after the heat stress did not, but the antibiotics used may have limited action against intestinal bacteria. Only two papers were found; both suggest an improvement in organ dysfunction or mortality after an episode of heat stress. No papers were found that investigate the sole use of antibiotics effective against intestinal bacteria given after the onset of heat stress, although biological plausibility suggest they warrant further research.

Patient-related factors associated with severe heat-related illnesses in Karachi: A hospital perspective.

In 2015, Karachi saw its first ever epidemic of severe heatrelated illnesses that resulted in an extraordinary number of hospital admissions, especially in the intensive care, for fatal heat stroke within-hospital mortality of 3.7%.We conducted this study to elucidate the patient-related factors that lead to an increase in hospital admissions with heat-related illnesses in a tertiary care hospital. It was a descriptive case series conducted in the department of medicine at the Aga Khan University in June 2015. A total of 134 patients were admitted with heat-related illnesses of which 76(56.7%) were males. The mean age of the patients was 66 ±14.5 years. Heatstroke was present in 86 (64.2%) patients, followed by heat exhaustion in 48 (35.8%) and in-hospital mortality from heat-related illnesses was 5(3.7%). Hypertension (OR 2(95 % CI 1.0, 3.6) and insufficient sleep or food or water intake (OR 1.7(95 % CI 0.8, 3.8) was associated with severe heat-related illnesses. The effects remained even after adjusting for type and area of residence.

Incidence of Recurrent Exertional Heat Stroke in a Warm-Weather Road Race.

Background and Objectives: Exertional heat stroke (EHS) survivors may be more susceptible to subsequent EHS; however, the occurrence of survivors with subsequent EHS episodes is limited. Therefore, the purpose of this study was to evaluate the incidence of participants with repeated EHS (EHS-2+) cases in a warm-weather road race across participation years compared to those who experienced 1 EHS (EHS-1). Materials and Methods: A retrospective observational case series design was utilized. Medical record data from 17-years at the Falmouth Road Race between 2003-2019 were examined for EHS cases. Incidence of EHS-2+ cases per race and average EHS cases per EHS-2+ participant were calculated (mean ± SD) and descriptive factors (rectal temperature (TRE), finish time (FT), Wet Bulb Globe Temperature (WBGT), age, race year) for each EHS was collected. Results: A total of 333 EHS patients from 174,853 finishers were identified. Sixteen EHS-2+ participants (11 males, 5 females, age = 39 ± 16 year) accounted for 11% of the total EHS cases (n = 37/333). EHS-2+ participants had an average of 2.3 EHS cases per person (range = 2-4) and had an incidence rate of 2.6 EHS per 10 races. EHS-2+ participants finished 93 races following initial EHS, with 72 of the races (77%) completed without EHS incident. Initial EHS TRE was not statistically different than subsequent EHS initial TRE (+0.3 ± 0.9 °C, p > 0.050). Initial EHS-2+ participant FT was not statistically different than subsequent EHS FT (-4.2 ± 7.0 min, p > 0.050). The years between first and second EHS was 3.6 ± 3.5 year (Mode: 1, Range: 1-12). Relative risk ratios revealed that EHS patients were at a significantly elevated risk for subsequent EHS episodes 2 years following their initial EHS (relative risk ratio = 3.32, p = 0.050); however, the risk from 3-5 years post initial EHS was not statistically elevated, though the relative risk ratio values remained above 1.26. Conclusions: These results demonstrate that 11% of all EHS cases at the Falmouth Road Race are EHS-2+ cases and that future risk for a second EHS episode at this race is most likely to occur within the first 2 years following the initial EHS incident. After this initial 2-year period, risk for another EHS episode is not significantly elevated. Future research should examine factors to explain individuals who are susceptible to multiple EHS cases, incidence at other races and corresponding prevention strategies both before and after initial EHS.

Variation in Clinical Presentations and Outcomes of Heat Stroke Victims in the Mass-Casualty Setting.

BACKGROUND: Immigrants crossing the Southern U.S. border are particularly susceptible to heat illness. We review 3 patients from a heat-related mass-casualty incident with variations in heat stroke presentation, course, and outcome. CASE REPORT: On July 23, 2017, emergency medical services responded to a trafficking-related mass-casualty incident in San Antonio, Texas, involving 39 migrants found inside an abandoned tractor trailer without air conditioning who had been trafficked from Laredo, Texas. Three victims exhibiting heat stroke symptoms were taken to the ED of a large academic teaching hospital. Patient 1 was a 42-year-old man who presented with seizing, vomiting, and a core temperature of 38.8°C (101.8°F). His 54-day hospital course was notable for 2 cardiac arrests, disseminated intravascular coagulation, prolonged lactic acidosis, and residual kidney disease. Patient 2 was a 32-year-old man who presented to the emergency department intubated in the field with a core temperature of 40.7°C (105.3°F). His 60-day hospital course was notable for disseminated intravascular coagulation, severely elevated troponin, prolonged lactic acidosis, and stroke. Patient 3 was a 20-year-old man who presented with seizing and decorticate posturing, with a core temperature of 40.5°C (104.9°F). His 6-day hospital course was notable for rapid clinical improvement and full recovery. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: Emergency physicians will encounter heat stroke victims. Our patients were exposed to an identical environment, and while each patient was otherwise healthy and differed significantly only in age, they exhibited a diversity of heat stroke presentations and sequelae. Treatment prioritizes cooling, but rapid deterioration requires intensive treatment of multiorgan failure.

Causes of nonfatal occupational injury in the private sector in Tunisia.

The absence of studies that investigate the causes and risk factors of nonfatal occupational injury in Tunisia inhibits the development of effective preventive strategies. The objective of this study was to identify the causes and risk factors of nonfatal occupational injury in the private sector in Tunisia. We used retrospective data derived from the occupational injury reporting forms submitted to the Caisse Nationale d'Assurance Maladie. A sample of 42,293 workers in the private sector for 2014 contains information on sociodemographic variables. Multivariable Poisson regression was used to investigate the association of cause-specific injury with demographic variables. The leading causes of nonfatal occupational injury were "falls" (employee fall and falling objects; 36%) and "struck by objects" (23%). Male employees were at higher risk of "exposure to extreme temperatures" (PR = 12 [7-45]), "asphyxia and poisoning" (PR = 4 [2.4-12]), "transport and handling" (PR = 2.4 [1.9-5]), "falling objects" (PR = 2.3 [1.4-3.7]), and "employee fall" (PR = 1.2 [1.1-1.5]). Although, rural areas were at higher risk to "asphyxia and poisoning" (PR = 3.6 [1.1-11.4]), "transport and handling" (PR = 2.5 [1.3-5.4]), and "burns" (PR = 1.3 [1.1-3]). It is important that effective interventions be developed to minimize the impact of falls and "struck by objects." The most vulnerable categories to occupational injury are less educated men, rural residents aged between 15 years and 24 years, and elderly employees (55 years and over). Thus, our findings can contribute to the planning of prevention intervention programs that should expand to the most vulnerable categories.

Heatwaves and hospitalizations due to hyperthermia in defined climate regions in the conterminous USA.

Heatwaves are one of the deadliest natural disasters that occur annually with thousands of people seeking medical attention. The spatio-temporal synchronization between peaks in disease manifestation and high temperature provides important insights into the seasonal timing of the heatwave and the response it may cause with respect to emergence, severity, and duration. The objectives of this study are to examine the association between hospitalizations due to heat stroke in older adults and heat in the United States (US) and explore synchronization with respect to heatwave sequence, time of arrival, and regional climate. Three large data sets were utilized: daily hospitalization records of the US elderly between 1991 and 2006, annual demographic summaries on Medicare beneficiaries maintained by the Centers for Medicare and Medicaid Services (CMS), and nationwide daily meteorological observations. We modeled seasonal fluctuations in health outcomes, such as the timing and intensity of the seasonal peak in hospitalizations using refined harmonic GLM for eight climatically similar regions. During the 16-year study period, there were 40,019 heat-related hospitalizations (HRH) in the conterminous  US. The rates of HRH varied substantially across eight climatic regions: with the highest rate of 7.05 cases per million residents observed in areas with temperate arid summers and winters (TaTa) and the lowest rate of 0.67-in areas with cold moderately dry summers and arid winters (CdCa), where summer temperatures are about  18.3 °C and 12.1 °C, respectively. We detected 400 heatwaves defined as any day when the night time temperature is above its 90th percentile for the current and previous nights. The first seasonal heatwave in a season resulted in 4274 hospitalizations over 342 heatwave-days: 34.3% of 12,442 hospitalizations occurred in 26% of 1308 heatwave-days. The relative risks of increased HRH associated with the first and second heatwaves were 10.4 (95%CI: 8.5; 12.3) and 11.4 (95%CI: 9.6; 13.3), respectively, indicating the disproportional effects of early heatwave arrivals. The seasonal spike in heat stroke hospitalizations in regions with relatively similar annual temperatures, e.g. in areas with temperate moderately dry summers and winters (TdTa: 12.8 °C) and (TaTa: 11.1 °C) ranged between 4.5 (95%CI: 3.3; 5.5) and 11.0 (95%CI: 8.2; 14.9) cases per million residents, respectively, indicating substantial regional differences. The differences in heat-related hospitalizations and response to heatwaves are substantial among older adults residing in different climate regions of the conterminous US. The disproportionally high response to the early seasonal heatwave deserves special attention, especially in the context of prevention and decision support frameworks.

Exertional heat illness incidence and on-site medical team preparedness in warm weather.

To investigate the influence of estimated wet bulb globe temperature (WBGT) and the International Institute of Race Medicine (IIRM) activity modification guidelines on the incidence of exertional heat stroke (EHS) and heat exhaustion (HEx) and the ability of an on-site medical team to treat those afflicted. Medical records of EHS and HEx patients over a 17-year period from the New Balance Falmouth Road Race were examined. Climatologic data from nearby weather stations were obtained to calculate WBGT with the Australian Bureau of Meteorology (WBGTA) and Liljegren (WBGTL) models. Incidence rate (IR) of EHS, HEx, and combined total of EHS and HEx (COM) were calculated, and linear regression analyses were performed to assess the relationship between IR and WBGTA or WBGTL. One-way ANOVA was performed to compare differences in EHS, HEx, and COM incidence to four alert levels in the IIRM guidelines. Incidence of EHS, HEx, and COM was 2.12, 0.98, and 3.10 cases per 1000 finishers. WBGTA explained 48, 4, and 46% of the variance in EHS, HEx, and COM IR; WBGTL explained 63, 13, and 69% of the variance in EHS, HEx, and COM IR. Main effect of WBGTA and WBGTL on the alert levels were observed in EHS and COM IR (p < 0.05). The cumulative number of EHS patients treated did not exceed the number of cold water immersion tubs available to treat them. EHS IR increased as WBGT and IIRM alert level increased, indicating the need for appropriate risk mitigation strategies and on-site medical treatment.