Impact of Maximum Air Temperature on Ambulance Transports Owing to Heat Stroke During Spring and Summer in Tottori Prefecture, Japan: A Time-stratified Case-crossover Analysis

Fujitani, Y; Otani, Shinji; Majbauddin, Abir; Amano, Hiroki; Masumoto, Toshio; Kurozawa, Youichi

doi:10.33160/yam.2019.03.007

Cited by 11 publications

(14 citation statements)

References 20 publications

(31 reference statements)

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“…We only used the air temperature as a meteorological indicator in the case-crossover analysis and did not include relative humidity. Our previous study did not find an association with heat stroke transport [12] and we also found no association with heat stroke severity in the present study. One of the reasons is that the relative humidity in the target area remained extremely high in July and August.…”

Section: Discussioncontrasting

confidence: 80%

“…transports for heat strokes and were able to quantify the risk by temperature [12]. However, to date, most studies have focused on the maximum temperature.…”

Section: Study Design and Sitesmentioning

confidence: 99%

“…A number of studies have been conducted on the relationship between maximum temperatures and heat strokes, reporting a strong correlation [ 6 , 7 , 8 , 9 , 10 , 11 ]. We previously noted a strong correlation between maximum temperatures and the number of emergency transports for heat strokes and were able to quantify the risk by temperature [ 12 ]. However, to date, most studies have focused on the maximum temperature.…”

Section: Introductionmentioning

confidence: 99%

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The Effect of Minimum and Maximum Air Temperatures in the Summer on Heat Stroke in Japan: A Time-Stratified Case-Crossover Study

Otani

Ishizu

Masumoto

et al. 2021

IJERPH

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An increase in the global surface temperature and changes in urban morphologies are associated with increased heat stress especially in urban areas. This can be one of the contributing factors underlying an increase in heat strokes. We examined the impact of summer minimum air temperatures, which often represent nighttime temperatures, as well as a maximum temperature on a heat stroke. We collected data from the records of daily ambulance transports for heat strokes and meteorological data for July and August of 2017–2019 in the Tottori Prefecture, Japan. A time-stratified case-crossover design was used to determine the association of maximum/minimum air temperatures and the incidence of heat strokes. We used a logistic regression to identify factors associated with the severity of heat strokes. A total of 1108 cases were identified with 373 (33.7%) calls originating in the home (of these, 59.8% were the age of ≥ 75). A total of 65.8% of cases under the age of 18 were related to exercise. Days with a minimum temperature ≥ 25 °C had an odds ratio (95% confidence interval) of 3.77 (2.19, 6.51) for the incidence of an exercise-related heat stroke (reference: days with a minimum temperature < 23 °C). The odds ratio for a heat stroke occurring at home or for calls for an ambulance to the home was 6.75 (4.47, 10.20). The severity of the heat stroke was associated with older age but not with air temperature. Minimum and maximum air temperatures may be associated with the incidence of heat strokes and in particular the former with non-exertional heat strokes.

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Section: Discussioncontrasting

confidence: 80%

“…transports for heat strokes and were able to quantify the risk by temperature [12]. However, to date, most studies have focused on the maximum temperature.…”

Section: Study Design and Sitesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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The Effect of Minimum and Maximum Air Temperatures in the Summer on Heat Stroke in Japan: A Time-Stratified Case-Crossover Study

Otani

Ishizu

Masumoto

et al. 2021

IJERPH

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“…The proportion of elderly people among all heat stroke patients has been high in Tottori Prefecture [3]. The current study found that this trend was amplified in 2020.…”

Section: Discussionmentioning

confidence: 51%

Elevated Heat Stroke Risk in Older Adults Indirectly Caused by COVID-19 Restrictions in a Provincial Prefecture of Japan

Otani

Ishizu

Masumoto

et al. 2021

The 3rd International Electronic Conference on Environmental Research and Public Health—Public Health Issues in the C

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Emergency transport data from Tottori Prefecture, Japan were used to evaluate the indirect impact of coronavirus disease 2019 (COVID-19) restrictions on heat stroke. There were 426 cases of emergency transport owing to heat stroke in summer 2020 compared with 1,465 cases combined for the summers of 2017-2019. The mean age of cases in 2020 was 66.2 years-significantly higher than in previous years (57.4-60.0 years). In 2020, 47.7% of cases were older than 75 (previously, 35.6%-44.2%), and 36.9% were transported from their residence, (previously, 26.6%-29.3%). Thus, COVID-19 measures, such as "stay at home" requests, may have increased the risk of heat stroke in older adults.

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“…The maximum temperature on the day when heatstroke occurred (case period) was compared to the maximum temperature on another day when heatstroke did not occur (reference period). The reference period was selected on the same day of the week, in the same year and month as the case period, using the time strati cation method, referring to examples from previous studies [23,37]. The analysis was performed using R version 1.3.1093.…”

Section: ( )mentioning

confidence: 99%

Comparative evaluation of accuracy of the multiple methods of heatstroke risk model including time-stratified case-crossover analysis

Nemoto

Hirabayashi²,

Sato

et al. 2022

Preprint

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Background High temperatures in urban areas owing to climate change and urban heat islands have led to an increase in the number of heatstroke patients. To prevent heatstroke, accurate heatstroke patient prediction model should be used to predict and alert people to their risk. However, most previous models have not tested sufficient training data, although susceptibility to heatstroke is likely to be dependent on year-wise trends and is susceptible to training data. We investigated an accurate heatstroke risk model that is robust to the training data. By examining the factors affecting the accuracy and trade-off between the quantity and quality of adding old data to training data, the method of selecting training data for constructing an accurate model was also investigated. Method We compared the accuracies of three methods: multiple regression analysis (MR), generalized additive model (GAM), and time-stratified case-crossover analysis (TC). The training data for all combinations from 2012 were tested. By comparing the errors of each method, we identified the error influencing factors in the training data. Results The TC errors were the smallest (p < 0.005) and much less sensitive to the training data than others. Best accuracy odds ratios were 1.41–1.44. The error was significantly larger when the number of extremely hot days differed between the training and test data in MR and GAM (p < 0.01, p < 0.05). All three methods tended to increase accuracy up to a certain point and decrease from the middle of the year when adding past years retroactively from the most recent year in training data. Conclusions By using the odds ratios produced by TC with low sensitivity to training data, we can develop highly accurate heatstroke risk model that are robust to training data, which has not been possible with previous models. If data are to be included continuously, a model constructed from three or four years of data from the latest one is the most accurate.

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Impact of Maximum Air Temperature on Ambulance Transports Owing to Heat Stroke During Spring and Summer in Tottori Prefecture, Japan: A Time-stratified Case-crossover Analysis

Cited by 11 publications

References 20 publications

The Effect of Minimum and Maximum Air Temperatures in the Summer on Heat Stroke in Japan: A Time-Stratified Case-Crossover Study

The Effect of Minimum and Maximum Air Temperatures in the Summer on Heat Stroke in Japan: A Time-Stratified Case-Crossover Study

Elevated Heat Stroke Risk in Older Adults Indirectly Caused by COVID-19 Restrictions in a Provincial Prefecture of Japan

Comparative evaluation of accuracy of the multiple methods of heatstroke risk model including time-stratified case-crossover analysis

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