Relationships between maximum temperature and heat-related illness across North Carolina, USA

A small area analysis of acute exposure to temperatures and mental health in North Carolina

Increasing evidence suggests that temperatures adversely impact mental and behavioral disorders (MBD). This study explores the effects of temperatures on mental health outcomes using over 5.9 million MBD-related emergency department (ED) visits across three geographical regions of North Carolina (i.e., Mountains, Piedmont, and Coast) from 2016 to 2019. A distributed lag non-linear model (DLNM) with a generalized linear model and quasi-Poisson distribution adjusted for humidity, long-term seasonal time trends, and day of the week examined the acute impact (i.e., 7-day) of temperature on daily MBD-related ED visits at zip code tabulation area (ZCTA) locations. Results were pooled at the region and state levels and reported in reference to the median temperature using a case-time series design for the analysis of small-area data. Stratified analyses were conducted for age, sex, and specific mental-health related ED visits (substance use, mood disorders, anxiety disorders). At the state level, we found significant positive associations between high temperatures (97.5th percentile) and an increase in relative risk (RR) for total MBDs (RR:1.04, 95% CI,1.03-1.05) and psychoactive substance use (RR:1.04, 95% CI, 1.02-1.06). Low air temperatures (2.5th percentile) only increased risk for the elderly (i.e., 65 and older) and predominantly white communities (RR: 1.03, CI: 1.03-1.05). During high temperatures (97.5th percentile), majority-white communities (RR:1.06, CI: 1.01-1.10) and low-income communities had the highest risk for MBDs (RR: 1.05, CI: 1.03-1.07). Our findings suggest there is a positive association between exposure to high temperatures and increased MBD-related ED visits, modified by patient age and place-based sociodemographic (ie., race and income) context.

A scoping review of the impact of extreme weather events on health outcomes and healthcare utilization in rural and remote areas

BACKGROUND

Extreme weather events affect health by directly and indirectly increasing illness burdens and changing healthcare usage patterns. These effects can be especially severe in rural and remote areas, exacerbating existing health disparities, and necessitating urgent mitigation or adaptation strategies. Despite increased research on health and climate change, studies focusing on rural and remote populations remain limited. This study aimed to review the relationships among extreme weather events, healthcare utilization, and health outcomes in rural and remote populations, identify research gaps, and inform policy development for adaptation and disaster management in these settings.

METHODS

A systematic scoping review was registered and conducted following the PRISMA-ScR guidelines. The search databases included PubMed, Web of Science, Scopus, the Cochrane Library, ProQuest, and the WHO IRIS. The included studies were primary research, focused on rural or remote areas, and investigated the effects of extreme weather events on either health outcomes or healthcare utilization. There were no methodological, date or language restrictions. We excluded protocols, reviews, letters, editorials, and commentaries. Two reviewers screened and extracted all data, other reviewers were invited to resolve conflicts. Findings are presented numerically or narratively as appropriate.

RESULTS

The review included 135 studies from 31 countries, with most from high-income countries. Extreme weather events exacerbate communicable and noncommunicable diseases, including cardiorespiratory, mental health, and malnutrition, and lead to secondary impacts such as mass migration and increased poverty. Healthcare utilization patterns changed during these events, with increased demand for emergency services but reduced access to routine care due to disrupted services and financial constraints.

CONCLUSIONS

The results highlighted the essential role of community and social support in rural and remote areas during extreme weather events and the importance of primary healthcare services in disaster management. Future research should focus on developing and implementing effective mitigation and adaptation programs tailored to the unique challenges faced by these populations.

Assessment of historical and projected changes in extreme temperatures of Balochistan, Pakistan using extreme value theory

The fundamental consequences of global warming include an upsurge in the intensity and frequency of temperature extremes. This study provides an insight into historical trends and projected changes in extreme temperatures on annual and seasonal scales across "Balochistan, Pakistan". Historical trends are analyzed through the Mann Kendal test, and extreme temperatures (Tmax and Tmin) are evaluated using generalized extreme value (GEV) distribution for historical period (1991-2020) from the observational data and the two projected periods as near-future (2041-2070) and far-future (2071-2100) using a six-member bias-corrected ensemble of regional climate models (RCMs) projections from the coordinate regional downscaling experiment (CORDEX) based on the worst emission scenario (RCP8.5). The evaluation of historical temperature trends suggests that Tmax generally increase on yearly scale and give mixed signals on seasonal scale (winter, spring, summer, and autumn); however, Tmin trends gave mixed signals at both yearly and seasonal scale. Compared to the historical period, the return levels are generally expected to be higher for Tmax and Tmin during the both projection periods in the order as far-future > near-future > historical on yearly and seasonal basis; however, the changes in Tmin are more evident. Station-averaged anomalies of + 1.9 °C and + 3.6 °C were estimated in 100-year return levels for yearly Tmax for near-future and far-future, respectively, while the anomalies in Tmin were found to be + 3.5 °C and + 4.8 °C which suggest the intensified heatwaves but milder colder extreme in future. The findings provide guidance on improved quantification of changing frequencies and severity in temperature extremes and the associated impacts.

Heat wave exposure and increased heat-related hospitalizations in young children in South Korea: A time-series study

BACKGROUND

Numerous studies have investigated the association between heat wave exposure increased heat-related hospitalizations in the general population. However, little is known about heat-related morbidity in young children who are more vulnerable than the general population. Therefore, we aimed to evaluate the association between hospitalization for heat-related illness in children and heat wave exposure in South Korea.

METHODS

We used the National Health Insurance Service (NHIS) database, which provides medical records from 2015 to 2019 in South Korea. We defined daily hospitalizations for heat-related illness of children younger than five years during the summer period (June to August). We considered the definition of heat waves considering the absolute temperature and percentile. A total of 12 different heat waves were used. A time-series analysis was used to investigate the association between heat wave exposure and heat-related hospitalization among children younger than five years. We used a two-stage design involving a meta-analysis after modeling by each region.

RESULTS

We included 16,879 daily heat-related hospitalizations among children younger than five years. Overall, heat wave exposure within two days was most related for heat-related hospitalizations in young children. The relative risk (RR) due to heat wave exposure within two days (lag2) (12 definitions: 70th to 90th percentile of maximum temperature) ranged from 1.038 (95% confidence interval (CI): 0.971, 1.110) to 1.083 (95% CI: 1.036, 1.133). We found that boys were more vulnerable to heat exposure than girls. In addition, we found that urban areas were more vulnerable to heat exposure than rural areas.

CONCLUSIONS

In our study, heat wave exposure during summer was found to be associated with an increased risk of hospitalization for heat-related illness among children younger than five years. Our findings suggest the need for summer heat wave management and prevention for children.

Short-term exposure to temperature and mental health in North Carolina: a distributed lag nonlinear analysis

Adverse mental health outcomes have been associated with high temperatures in studies worldwide. Few studies explore a broad range of mental health outcomes, and to our knowledge, none are specific to NC, USA. This ecological study explored the relationship between ambient temperature and mental health outcomes (suicide, self-harm and suicide ideation, anxiety and stress, mood disorders, and depression) in six urban counties across the state of NC, USA. We applied a quasi-Poisson generalized linear model combined with a distributed lag nonlinear model (DLNM) to examine the short-term effects of daily ambient temperature on emergency admissions for mental health conditions (2016 to 2018) and violent deaths (2004 to 2018). The results were predominately insignificant, with some key exceptions. The county with the greatest temperature range (Wake) displays higher levels of significance, while counties with the lowest temperature ranges (New Hanover and Pitt) are almost entirely insignificant. Self-harm and suicidal ideation peak in the warm months (July) and generally exhibit a protective effect at lower temperatures and shorter lag intervals. Whereas anxiety, depression, and major depressive disorders peak in the cooler months (May and September). Suicide is the only outcome that favored a 20-day lag period in the sensitivity analysis, although the association with temperature was insignificant. Our findings suggest additional research is needed across a suite of mental health outcomes to fully understand the effects of temperatures on mental health.

Estimating the Burden of Heat-Related Illness Morbidity Attributable to Anthropogenic Climate Change in North Carolina

Climate change is known to increase the frequency and intensity of hot days (daily maximum temperature ≥30°C), both globally and locally. Exposure to extreme heat is associated with numerous adverse human health outcomes. This study estimated the burden of heat-related illness (HRI) attributable to anthropogenic climate change in North Carolina physiographic divisions (Coastal and Piedmont) during the summer months from 2011 to 2016. Additionally, assuming intermediate and high greenhouse gas emission scenarios, future HRI morbidity burden attributable to climate change was estimated. The association between daily maximum temperature and the rate of HRI was evaluated using the Generalized Additive Model. The rate of HRI assuming natural simulations (i.e., absence of greenhouse gas emissions) and future greenhouse gas emission scenarios were predicted to estimate the HRI attributable to climate change. Over 4 years (2011, 2012, 2014, and 2015), we observed a significant decrease in the rate of HRI assuming natural simulations compared to the observed. About 3 out of 20 HRI visits are attributable to anthropogenic climate change in Coastal (13.40% [IQR: -34.90,95.52]) and Piedmont (16.39% [IQR: -35.18,148.26]) regions. During the future periods, the median rate of HRI was significantly higher (78.65%: Coastal and 65.85%: Piedmont), assuming a higher emission scenario than the intermediate emission scenario. We observed significant associations between anthropogenic climate change and adverse human health outcomes. Our findings indicate the need for evidence-based public health interventions to protect human health from climate-related exposures, like extreme heat, while minimizing greenhouse gas emissions.

Experimental investigation of the effects of personal protective equipment on thermal comfort in hot environments

Since the outbreak of COVID-19, wearing personal protective equipment (PPE) has become increasingly common, especially for healthcare workers performing nucleic acid sample collection. A field experiment and questionnaire survey were conducted in a semi-open transition space of a university building in Guangzhou, southern China. Thirty-two subjects wore PPE to simulate nucleic acid sample collection, during which thermal parameters were recorded and subjective questionnaires were completed. The relationship between thermal sensation and thermal index was analyzed to determine the neutral temperature and comfort temperature zones. Subjects had higher requirements for thermal environment parameters when wearing PPE than when not wearing PPE, and were found to have statistically significant differences in thermal perception when wearing and not wearing PPE. Wearing PPE significantly raised the subjects' thermal and humidity sensations and restricted their airflow. Wearing PPE resulted in thermal discomfort for the subjects and a high unacceptability rate for environmental thermal parameters. The subjects wore PPE for an acceptable duration of approximately 1.5 h. The neutral operative temperatures were significantly lower when wearing PPE than when not wearing PPE, and the deviation from the neutral temperature was 9.7 °C. The neutral operative temperature was 19.5 °C and the comfort temperature zone was 17.4-21.5 °C when subjects wore PPE, demonstrating that subjects who wore PPE preferred lower temperatures. These results suggest that people who wear PPE for work, especially outdoors, should receive more attention to ensure thermal comfort and safety.

Impact of extreme temperatures on emergency hospital admissions by age and socio-economic deprivation in England

Climate change poses an unprecedented challenge to population health and health systems' resilience, with increasing fluctuations in extreme temperatures through pressures on hospital capacity. While earlier studies have estimated morbidity attributable to hot or cold weather across cities, we provide the first large-scale, population-wide assessment of extreme temperatures on inequalities in excess emergency hospital admissions in England. We used the universe of emergency hospital admissions between 2001 and 2012 combined with meteorological data to exploit daily variation in temperature experienced by hospitals (N = 29,371,084). We used a distributed lag model with multiple fixed-effects, controlling for seasonal factors, to examine hospitalisation effects across temperature-sensitive diseases, and further heterogeneous impacts across age and deprivation. We identified larger hospitalisation impacts associated with extreme cold temperatures than with extreme hot temperatures. The less extreme temperatures produce admission patterns like their extreme counterparts, but at lower magnitudes. Results also showed an increase in admissions with extreme temperatures that were more prominent among older and socioeconomically-deprived populations - particularly across admissions for metabolic diseases and injuries.

Real-World Evidence for the Association between Heat-Related Illness and the Risk of Psychiatric Disorders in Taiwan

This study aimed to investigate the association between the heat-related illness (HRI) and the risk of developing psychiatric disorders. From 2000 to 2015, there were 3126 patients with newly diagnosed HRI selected from the National Health Insurance Research Database, along with 31,260 controls matched for gender and age. Fine and Gray’s analysis was used to compare the risk of psychiatric disorders during the 16 years of follow-up. Among the subjects, 523 of the HRI patients and 3619 of the control group (1774.18 vs. 1193.78 per 100,000 person-years) developed psychiatric disorders. Compared with non-HRI patients, the HRI ones had a 3.849-fold risk of being attacked by psychiatric disorders (95% CI: 3.632−4.369, p < 0.001) after adjusting for potential confounders. The sensitivity analysis revealed that the relationship between the HRI and the listed psychiatric disorders was determined by the exclusion of the first-year psychiatric events after the HRI. In spite of deleting the psychiatric diagnoses of the first five years, the HRI was still correlated with the development of psychiatric disorders with the exception of schizophreniform disorders, posttraumatic stress disorders, and acute stress disorder. Therefore, our findings concluded that the HRI could be a potential influence on the increased hazard of psychiatric disorders.

Comparison of health outcomes from heat-related injuries by National Weather Service reported heat wave days and non-heat wave days - Illinois, 2013-2019

It is predicted that heat waves will increase as climate changes. Related public health interventions have expanded over the past decades but are primarily targeted at health outcomes occurring during heat waves. However, heat adaptation is dynamic and adverse outcomes related to heat injuries occur with moderate increases in temperature throughout the summertime. We analyzed outpatient and inpatient heat related injuries from 2013 to 2019. National Weather Service event summaries were used to characterize reported heat wave days and weather data was linked to individual cases. Despite the higher rate of heat injury on heat wave days, only 12.7% of the 17,662 heat-related injuries diagnosed from 2013 to 2019 occurred during reported heat waves. In addition, the National Weather Service surveillance system monitoring heat related injuries only captured 2.1% of all heat related injuries and 30.6% of heat related deaths. As climate changes and warmer conditions become more common, public health response to moderate increases in temperature during summertime needs to be strengthened as do the surveillance systems used to monitor adverse heat related health events. Improved surveillance systems, long-term interventions and strategies addressing climate change may help mitigate adverse health outcomes attributable to heat related injuries over the summertime.

Fierce Heat and Players’ Health: Examining the View on Japan High School Baseball

A summer high school baseball tournament is held every mid-summer in Koshien Stadium. “Koshien Baseball” is very popular in Japan; however, it faces the problem of extremely high temperatures during games. Thus, high school players are threatened by harsh environmental conditions. For this reason, two Internet surveys were distributed to the same individuals. Then, their views regarding the Koshien tournament before and after the provision of information regarding environmental change in Japan were gathered. Using these data, this study examined how their views changed after being introduced to the information. Compared with their previous views, it was found that (1) respondents were more likely to agree that the management rules of the Koshien tournament should be altered to protect players’ health, and (2) the impact of providing information is greater for female respondents, young respondents, and highly educated respondents. This study provides evidence that the effect of information provision varies according to gender, age, and educational background. However, the mechanism causing this difference has not yet been analyzed. It would be valuable to consider this mechanism in future research.

Investigating age and regional effects on the relation between the incidence of heat-related ambulance transport and daily maximum temperature or WBGT

Background

Although age and regional climate are considered to have effects on the incidence ratio of heat-related illness, quantitative estimation of age or region on the effect of occurring temperature for heat stroke is limited.

Methods

By utilizing data on the number of daily heat-related ambulance transport (HAT) in each of three age groups (7–17, 18–64, 65 years old, or older) and 47 prefectures in Japan, and daily maximum temperature (DMT) or Wet Bulb Globe Temperature (DMW) of each prefecture for the summer season, the effects of age and region on heat-related illness were studied. Two-way ANOVA was used to analyze the significance of the effect of age and 10 regions in Japan on HAT. The population-weighted average of DMT or DMW measured at weather stations in each prefecture was used as DMT or DMW for each prefecture. DMT or DMW when HAT is one in 100,000 people (T₁ and W₁, respectively) was calculated for each age category and prefecture as an indicator of heat acclimatization. The relation between T₁ or W₁ and average DMT or DMW of each age category and prefecture were also analyzed.

Results

HAT of each age category and prefecture was plotted nearly on the exponential function of corresponding DMT or DMW. Average R² of the regression function in 47 prefectures in terms of DMW was 0.86, 0.93, and 0.94 for juveniles, adults, and elderly, respectively. The largest regional difference of W₁ in 47 prefectures was 4.5 and 4.8 °C for juveniles and adults, respectively between Hokkaido and Tokyo, 3.9 °C for elderly between Hokkaido and Okinawa. Estimated W₁ and average DMT or DMW during the summer season for 47 prefectures was linearly related. Regarding age difference, the regression line showed that W₁ of the prefecture for DMW at 30 °C of WBGT was 31.1 °C, 32.4 °C, and 29.8 °C for juveniles, adults, and elderly, respectively.

Conclusions

Age and regional differences affected the incidence of HAT. Thus, it is recommended that public prevention measures for heat-related disorders take into consideration age and regional variability.

Temperature-mortality relationship in North Carolina, USA: Regional and urban-rural differences

BACKGROUND

Health disparities exist between urban and rural populations, yet research on rural-urban disparities in temperature-mortality relationships is limited. As inequality in the United States increases, understanding urban-rural and regional differences in the temperature-mortality association is crucial.

OBJECTIVE

We examined regional and urban-rural differences of the temperature-mortality association in North Carolina (NC), USA, and investigated potential effect modifiers.

METHODS

We applied time-series models allowing nonlinear temperature-mortality associations for 17 years (2000-2016) to generate heat and cold county-specific estimates. We used second-stage analysis to quantify the overall effects. We also explored potential effect modifiers (e.g. social associations, greenness) using stratified analysis. The analysis considered relative effects (comparing risks at 99th to 90th temperature percentiles based on county-specific temperature distributions for heat, and 1st to 10th percentiles for cold) and absolute effects (comparing risks at specific temperatures).

RESULTS

We found null effects for heat-related mortality (relative effect: 1.001 (95% CI: 0.995-1.007)). Overall cold-mortality risk for relative effects was 1.019 (1.015-1.023). All three regions had statistically significant cold-related mortality risks for relative and absolute effects (relative effect: 1.019 (1.010-1.027) for Coastal Plains, 1.021 (1.015-1.027) for Piedmont, 1.014 (1.006-1.023) for Mountains). The heat mortality risk was not statistically significant, whereas the cold mortality risk was statistically significant, showing higher cold-mortality risks in urban areas than rural areas (relative effect for heat: 1.006 (0.997-1.016) for urban, 1.002 (0.988-1.017) for rural areas; relative effect for cold: 1.023 (1.017-1.030) for urban, 1.012 (1.001-1.023) for rural areas). Findings are suggestive of higher relative cold risks in counties with the less social association, higher population density, less green-space, higher PM_2.5, lower education level, higher residential segregation, higher income inequality, and higher income (e.g., Ratio of Relative Risks 1.72 (0.68, 4.35) comparing low to high education).

CONCLUSION

Results indicate cold-mortality risks in NC, with potential differences by regional, urban-rural areas, and community characteristics.

Weather-related subjective well-being in patients with coronary artery disease

One of the particularly vulnerable groups for adverse weather conditions is people with heart disease. Most of the studies analyzed the association between certain weather conditions and increased mortality, morbidity, hospital admissions, calls, or visits to the emergency department and used as statistical data. This study evaluated associations between daily weather conditions and daily weather-related well-being in patients with coronary artery disease (CAD). From June 2008 to October 2012, a total of 865 consecutive patients with CAD (mean age 60 years; 30% of women) were recruited from the cardiac rehabilitation program at the Hospital Palanga Clinic, Lithuania. To evaluate the well-being, all patients filled in Palanga self-assessment diary for weather sensitivity every day from 8 to 21 days (average 15 ± 3 days) about their well-being (psychological, cardiac, and physical symptoms) on the last day. The weather data was recorded in the database eight times every day with a 3-hour interval using the weather station "Vantage Pro2 Plus" which was located in the same Clinic. The daily averages of the eight time records for weather parameters were calculated and were linked to the same-day diary data. We found that the well-being of patients with CAD was associated with weather parameters; specifically, general well-being was better within the temperature range 9-15 °C and worse on both sides of this range. Worsened general well-being was also associated with higher relative humidity and lower atmospheric pressure. Weather parameters can explain from 3 to 8% of the variance of well-being in patients with CAD.

Geospatial indicators of exposure, sensitivity, and adaptive capacity to assess neighbourhood variation in vulnerability to climate change-related health hazards

BACKGROUND

Although the frequency and magnitude of climate change-related health hazards (CCRHHs) are likely to increase, the population vulnerabilities and corresponding health impacts are dependent on a community's exposures, pre-existing sensitivities, and adaptive capacities in response to a hazard's impact. To evaluate spatial variability in relative vulnerability, we: 1) identified climate change-related risk factors at the dissemination area level; 2) created actionable health vulnerability index scores to map community risks to extreme heat, flooding, wildfire smoke, and ground-level ozone; and 3) spatially evaluated vulnerability patterns and priority areas of action to address inequity.

METHODS

A systematic literature review was conducted to identify the determinants of health hazards among populations impacted by CCRHHs. Identified determinants were then grouped into categories of exposure, sensitivity, and adaptive capacity and aligned with available data. Data were aggregated to 4188 Census dissemination areas within two health authorities in British Columbia, Canada. A two-step principal component analysis (PCA) was then used to select and weight variables for each relative vulnerability score. In addition to an overall vulnerability score, exposure, adaptive capacity, and sensitivity sub-scores were computed for each hazard. Scores were then categorised into quintiles and mapped.

RESULTS

Two hundred eighty-one epidemiological papers met the study criteria and were used to identify 36 determinant indicators that were operationalized across all hazards. For each hazard, 3 to 5 principal components explaining 72 to 94% of the total variance were retained. Sensitivity was weighted much higher for extreme heat, wildfire smoke and ground-level ozone, and adaptive capacity was highly weighted for flooding vulnerability. There was overall varied contribution of adaptive capacity (16-49%) across all hazards. Distinct spatial patterns were observed - for example, although patterns varied by hazard, vulnerability was generally higher in more deprived and more outlying neighbourhoods of the study region.

CONCLUSIONS

The creation of hazard and category-specific vulnerability indices (exposure, adaptive capacity and sensitivity sub-scores) supports evidence-based approaches to prioritize public health responses to climate-related hazards and to reduce inequity by assessing relative differences in vulnerability along with absolute impacts. Future studies can build upon this methodology to further understand the spatial variation in vulnerability and to identify and prioritise actionable areas for adaptation.

Heat-Related Illnesses Transported by United States Emergency Medical Services

Background and objectives: Heat-related illness (HRI) can have significant morbidity and mortality consequences. Research has predominately focused on HRI in the emergency department, yet health care leading up to hospital arrival can impact patient outcomes. Therefore, the purpose of this study was to describe HRI in the prehospital setting. Materials and Methods: A descriptive epidemiological design was utilized using data from the National Emergency Medical Services (EMS) Information System for the 2017-2018 calendar years. Variables of interest in this study were: patient demographics (age, gender, race), US census division, urbanicity, dispatch timestamp, incident disposition, primary provider impression, and regional temperatures. Results: There were 34,814 HRIs reported. The majority of patients were white (n = 10,878, 55.6%), males (n = 21,818, 62.7%), and in the 25 to 64 age group (n = 18,489, 53.1%). Most HRIs occurred in the South Atlantic US census division (n = 11,732, 33.7%), during the summer (n = 23,873, 68.6%), and in urban areas (n = 27,541, 83.5%). The hottest regions were East South Central, West South Central, and South Atlantic, with peak summer temperatures in excess of 30.0 °C. In the spring and summer, most regions had near normal temperatures within 0.5 °C of the long-term mean. EMS dispatch was called for an HRI predominately between the hours of 11:00 a.m.-6:59 p.m. (n = 26,344, 75.7%), with the majority (27,601, 79.3%) of HRIs considered heat exhaustion and requiring the patient to be treated and transported (n = 24,531, 70.5%). Conclusions: All age groups experienced HRI but particularly those 25 to 64 years old. Targeted education to increase public awareness of HRI in this age group may be needed. Region temperature most likely explains why certain divisions of the US have higher HRI frequency. Afternoons in the summer are when EMS agencies should be prepared for HRI activations. EMS units in high HRI frequency US divisions may need to carry additional treatment interventions for all HRI types.

Motivation for Heat Adaption: How Perception and Exposure Affect Individual Behaviors During Hot Weather in Knoxville, Tennessee

Heat is the deadliest meteorological hazard; however, those exposed to heat often do not feel they are in danger of heat-health effects and do not take precautions to avoid heat exposure. Socioeconomic factors, such as the high cost of running air conditioning, might prevent people from taking adaption measures. We assessed via a mixed-methods survey how residents of urban Knoxville, Tennessee, (n = 86) describe and interpret their personal vulnerability during hot weather. Thematic analyses reveal that many respondents describe uncomfortably hot weather based on its consequences, such as health effects and the need to change normal behavior, which misaligns with traditional heat-communication measures using specific weather conditions. Only 55% of those who perceived excessive heat as dangerous cited health as a cause for concern. Respondents who have experienced health issues during hot weather were more likely to perceive heat as dangerous and take actions to reduce heat exposure. Social cohesion was not a chief concern for our respondents, even though it has been connected to reducing time-delayed heat-health effects. Results support using thematic analyses, an underutilized tool in climatology research, to improve understanding of public perception of atmospheric hazards. We recommend a multi-faceted approach to addressing heat vulnerability.

Influence of the spatial resolution of the exposure estimate in determining the association between heat waves and adverse health outcomes

BACKGROUND

Area-level estimates of temperature may lead to exposure misclassification in studies examining associations between heat waves and health outcomes. Our study compared the association between heat waves and preterm birth (PTB) or non-accidental death (NAD) using exposure metrics at varying levels of spatial resolution: ZIP codes, 12.5 km, and 1 km.

METHOD

Using geocoded residential addresses on birth (1990-2010) and death (1997-2010) records from Alabama, USA, we implemented a time-stratified case-crossover design to examine the association between heat waves and PTB or NAD. ZIP code- and 12.5 km heat wave indices (HIs) were derived using air temperatures from Phase 2 of the North American Land Data Assimilation System (NLDAS-2). We downscaled NLDAS-2 data, using land surface temperatures (LST) from the Moderate Resolution Imaging Spectroradiometer (MODIS) product, to estimate fine spatial resolution HIs (1 km).

RESULTS

The association between heat waves and PTB or NAD was significant and positive using ZIP code-, 12.5 km, and 1 km exposure metrics. Moreover, results show that these three-exposure metric analyses produced similar effect estimates. Urban heat islands were evident with the 1 km metric. When analyses were stratified by rurality, we found associations in urban areas were more positive than in rural areas.

CONCLUSIONS

Comparing results of models with a varying spatial resolution of the exposure metric allows for examination of potential bias associated with exposure misclassification.

The Effects of High-Temperature Weather on Human Sleep Quality and Appetite

High-temperature weather appears in high frequency, big strength, and long duration in the summer. It is therefore important to study the effects of high-temperature weather on sleep quality and appetite. Ten healthy college students were selected as subjects. The experiment conditions were divided by the daily maximum temperature into 28 °C, 32 °C, 36 °C, and 38 °C. The objective sleep quality was measured by an intelligent sleep monitoring belt, and the subjective sleep quality was measured by a questionnaire survey. The subjective appetites were assessed by a visual analog scale (VAS), and the objective appetites were assessed by the meal weight and the meal time. For sleep quality, the objective results indicated that the sleep quality at 32 °C was the best, followed by 28 °C, while the sleep quality at 36 °C and 38 °C was the worst. Significant effects were mainly reflected in sleep duration and shallow sleep. The subjective results showed that temperature had significant effects on sleep calmness, difficulty in falling asleep, sleep satisfaction, and sleep adequateness. For appetite, the VAS results indicated that high temperatures mainly led to a reduction of appetite at lunch time. The meal weights of lunch were larger than those of supper except for 28 °C, and the meal time of lunch and supper was longer than that of breakfast. The meal time of lunch was longer than that of supper except for 36 °C. This paper can provide a study method and reference data for the sleep quality and appetite of human in high-temperature weather.

A thermoresponsive microfluidic system integrating a shape memory polymer-modified textile and a paper-based colorimetric sensor for the detection of glucose in human sweat

Textile-based microfluidic analytical devices have demonstrated significant potentials in biomolecular detection; however, to date, they have not been integrated with a shape memory polymer to prepare a thermoresponsive device for human sweat analysis. Herein, a thermoresponsive textile/paper-based microfluidic analysis system was constructed by combining biocompatible polyurethane (PU), cotton fabric and a paper-based colorimetric sensor. The coating of PU endowed the textile with temperature-dependent shape memory capability and patterned the channels to guide the liquid transport. A paper-based colorimetric sensor was prepared via a layer-by-layer deposition method and coupled with a smartphone for the quantitative analysis of glucose concentration. The as-prepared thermoresponsive textile/paper-based microfluidic analysis system had the dynamic range of 50–600 μM and the detection limit of 13.49 μM. After being fixed in the inner collar of a shirt, the system demonstrated great capabilities for the thermal-triggered sweat transport and in situ detection of glucose in human sweat under a high-temperature condition (59 °C). This study not only provides a low-cost and easy-to-wear sweat analysis tool for the health monitoring of people working at high temperatures, but also expands the applications of shape memory polymers and textile-based microfluidic devices in point-of-care testing.

A thermoresponsive textile/paper-based microfluidic system was fabricated by integrating a shape memory polymer, fabric and a paper-based sensor for human sweat glucose analysis.

A new look at weather-related health impacts through functional regression

A major challenge of climate change adaptation is to assess the effect of changing weather on human health. In spite of an increasing literature on the weather-related health subject, many aspect of the relationship are not known, limiting the predictive power of epidemiologic models. The present paper proposes new models to improve the performances of the currently used ones. The proposed models are based on functional data analysis (FDA), a statistical framework dealing with continuous curves instead of scalar time series. The models are applied to the temperature-related cardiovascular mortality issue in Montreal. By making use of the whole information available, the proposed models improve the prediction of cardiovascular mortality according to temperature. In addition, results shed new lights on the relationship by quantifying physiological adaptation effects. These results, not found with classical model, illustrate the potential of FDA approaches.

Adolescents in crisis: A geographic exploration of help-seeking behavior using data from Crisis Text Line

Nearly 3 out of 4 all lifelong mental disorders occur by the age of twenty-four. Remote crisis support holds great potential in filling a critical gap in complementing and expanding access to mental health services for acute episodes of mental distress in adolescents and young adults; yet little is understood about the individual factors that influence help-seeking behavior in this group. Recent evidence suggests technology-based mental health services have high acceptability among youth and may be used to treat anxiety and depression. The objective of this study was to examine county-level help-seeking behavior among adolescents and young adults using Crisis Text Line (CTL). CTL is a free, text-based crisis counseling service that has been available nationally since 2013. Spatial error regression was used to (1) identify the individual-level factors that correlate with help-seeking behavior for depression, anxiety, and suicidal thoughts and (2) to explore the geographic trends in text-based help-seeking behavior between adolescents and young adults across the rural-urban continuum. Increased rates of text-based help-seeking occurred in counties with higher mean household incomes, higher divorce rates, and lower residential stability. Rurality was the strongest predictor for low rates of help-seeking, and this finding is particularly concerning in light of elevated rates of suicide among rural counties. Rural communities, particularly those with low support-seeking behavior and comparatively high suicide rates, should be the target of future research and outreach.

Heatwave and infants' hospital admissions under different heatwave definitions

OBJECTIVES

Data on the health impacts of heatwaves in infants are limited, and this study aimed to examine how heatwaves affect hospital admissions in infants.

METHODS

A quasi-Poisson generalized additive model was used to assess the effects of heatwaves on hospital admissions in infants from 1st January 2005 to 31st December 2015 in Brisbane, Australia, using a series of heatwave definitions after controlling for possible confounders. A case-only analysis was conducted to examine the possible modification effects of personal and community characteristics on the heatwaves effects on infants' hospital admissions.

RESULTS

There was no significant increase in infants' hospital admissions when heatwave intensity was defined as mean temperature ≥90^th percentile or ≥95th percentile of the mean temperature across the study period. When heatwave intensity increased to ≥97th percentile, infants' hospital admissions increased significantly (RR: 1.05, 95% CI: 1.01, 1.10), and this increase raised with the increase of heatwave duration. No modification effect of gender, indigenous status, or Socio-Economic Indexes for Areas (SEIFA) level on heatwave effect was observed.

CONCLUSIONS

Infants in Brisbane were sensitive to intense heatwaves, and future heat early warning system based on a local evidence-based heatwave definition is needed to protect infants from heatwave impacts. Community-based heatwave adaptation programs aiming at raising the awareness of the adverse health impacts of intense heatwaves among infants' caregivers may relieve the postnatal health care demand in infants.

The potential benefits of location-specific biometeorological indexes

It is becoming popular to use biometeorological indexes to study the effects of weather on human health. Most of the biometeorological indexes were developed decades ago and only applicable to certain locations because of different climate types. Merely using standard biometeorological indexes to replace typical weather factors in biometeorological studies of different locations may not be an ideal research direction. This research is aimed at assessing the difference of statistical power between using standard biometeorological indexes and typical weather factors on describing the effects of extreme weather conditions on daily ambulance demands in Hong Kong. Results showed that net effective temperature and apparent temperature did not perform better than typical weather factors in describing daily ambulance demands in this study. The maximum adj-R ² improvement was only 0.08, whereas the maximum adj-R ² deterioration was 0.07. In this study, biometeorological indexes did not perform better than typical weather factors, possibly due to the differences of built environments and lifestyles in different locations and eras. Regarding built environments, the original parameters for calculating the index values may not be applicable to Hong Kong as buildings in Hong Kong are extremely dense and most are equipped with air conditioners. Regarding lifestyles, the parameters, which were set decades ago, may be outdated and not suitable to modern lifestyles as using hand-held electrical fans on the street to help reduce heat stress are popular. Hence, it is ideal to have tailor-made updated location-specific biometeorological indexes to study the effects of weather on human health.

Hospitalizations for heat-stress illness varies between rural and urban areas: an analysis of Illinois data, 1987-2014

BACKGROUND

The disease burden due to heat-stress illness (HSI), which can result in significant morbidity and mortality, is expected to increase as the climate continues to warm. In the United States (U.S.) much of what is known about HSI epidemiology is from analyses of urban heat waves. There is limited research addressing whether HSI hospitalization risk varies between urban and rural areas, nor is much known about additional diagnoses of patients hospitalized for HSI.

METHODS

Hospitalizations in Illinois for HSI (ICD-9-CM codes 992.x or E900) in the months of May through September from 1987 to 2014 (n = 8667) were examined. Age-adjusted mean monthly hospitalization rates were calculated for each county using U.S. Census population data. Counties were categorized into five urban-rural strata using Rural Urban Continuum Codes (RUCC) (RUCC1, most urbanized to RUCC5, thinly populated). Average maximum monthly temperature (°C) was calculated for each county using daily data. Multi-level linear regression models were used, with county as the fixed effect and temperature as random effect, to model monthly hospitalization rates, adjusting for the percent of county population below the poverty line, percent of population that is Non-Hispanic Black, and percent of the population that is Hispanic. All analyses were stratified by county RUCC. Additional diagnoses of patients hospitalized for HSI and charges for hospitalization were summarized.

RESULTS

Highest rates of HSI hospitalizations were seen in the most rural, thinly populated stratum (mean annual summer hospitalization rate of 1.16 hospitalizations per 100,000 population in the thinly populated strata vs. 0.45 per 100,000 in the metropolitan urban strata). A one-degree Celsius increase in maximum monthly average temperature was associated with a 0.34 increase in HSI hospitalization rate per 100,000 population in the thinly populated counties compared with 0.02 per 100,000 in highly urbanized counties. The most common additional diagnoses of patients hospitalized with HSI were dehydration, electrolyte abnormalities, and acute renal disorders. Total and mean hospital charges for HSI cases were $167.7 million and $20,500 (in 2014 US dollars).

CONCLUSION

Elevated temperatures appear to have different impacts on HSI hospitalization rates as function of urbanization. The most rural and the most urbanized counties of Illinois had the largest increases in monthly hospitalization rates for HSI per unit increase in the average monthly maximum temperature. This suggests that vulnerability of communities to heat is complex and strategies to reduce HSI may need to be tailored to the degree of urbanization of a county.

Study on the association between ambient temperature and mortality using spatially resolved exposure data

There are many studies that have posited an association between extreme temperature and increased mortality. However, most studies use temperature at a single station per city as the reference point to analyze deaths. This leads to exposure misclassification and usually the exclusion of exurban, small town, and rural populations. In addition, few studies control for confounding by PM_2.5, which is expected to induce upward bias. The high-resolution temperature and PM_2.5 data at a resolution of 1km² were derived from satellite images and other land use sources. To capture the nonlinear association of temperature with mortality we fit a piecewise linear spline function for temperature, with a change in slope at -1°C and 28°C, the temperature threshold at which mortality in Georgia, North Carolina, and South Carolina increases due to cold and heat, respectively. We conducted stratified analyses by age group, sex, race, education, and urban vs nonurban, as well as sensitivity analyses of different temperature threshold and covariate sets. We found a 0.19% (95% CI=-0.98, 1.34%) increase in mortality for each 1°C decrease in temperature below -1°C and a 2.05% (95% CI=0.87, 3.24%) increase in mortality for each 1°C increase in temperature above 28°C, a 79.8% larger effect size for heat compared to the station-based metric. The effect estimates relying on the monitoring stations were 0.09% (95% CI=-0.79, 0.95%) and 1.14% (95% CI=0.08, 1.57%) for the equivalent temperature changes. The estimates were not confounded by PM_2.5. Children under 15 years of age had the largest percentage increase per 1°C increase in temperature (8.19%, 95% CI=-0.38 to 17.49%) followed by Blacks (4.35%, 95% CI=2.22 to 6.53%). Higher education was a protective factor for the effect of extreme temperature on mortality. There was a suggestion that people in less urban areas were more susceptible to extreme temperature. The relationship between temperature and mortality was stronger when using exposure data with more spatial variability than using exposure data based on existing monitors alone.