TY - JOUR
T1 - Spatial and temporal variation in emergency transport during periods of extreme heat in Japan
T2 - A nationwide study
AU - Onozuka, Daisuke
AU - Hagihara, Akihito
N1 - Funding Information:
This work was supported by Japan Society for the Promotion of Science (JSPS) KAKENHI Grant Number 15K08714 . The funder had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. We thank Dr. Manabu Hasegawa and Dr. Takashi Nagata for their assistance in helping us acquire data from the Fire and Disaster Management Agency of the Ministry of Internal Affairs and Communications, Japan.
Publisher Copyright:
© 2015 Elsevier B.V.
PY - 2016/2/15
Y1 - 2016/2/15
N2 - Background: Several studies have reported the burden of climate change on extreme heat-related mortality or morbidity. However, few studies have investigated the spatial and temporal variation in emergency transport during periods of extreme heat on a national scale. Methods: Daily emergency ambulance dispatch data from 2007 to 2010 were acquired from all 47 prefectures of Japan. The temporal variability in the relationship between heat and morbidity in each prefecture was estimated using Poisson regression combined with a distributed lag non-linear model and adjusted for time trends. The spatial variability in the heat-morbidity relationships between prefectures was estimated using a multivariate meta-analysis. Results: A total of 5,289,660 emergency transports were reported during the summer months (June through September) within the study period. The overall cumulative relative risk (RR) at the 99th percentile vs. the minimum morbidity percentile was 1.292 (95% CI: 1.251-1.333) for all causes, 1.039 (95% CI: 0.989-1.091) for cardiovascular diseases, and 1.287 (95% CI: 1.210-1.368) for respiratory diseases. Temporal variation in the estimated effects indicated a non-linear relationship, and there were differences in the temporal variations between heat and all-cause and cause-specific morbidity. Spatial variation between prefectures was observed for all causes (Cochran Q test, p<0.001; I2=45.8%); however, there was no significant spatial heterogeneity for cardiovascular (Cochran Q test, p=0.054; I2=15.1%) and respiratory (Cochran Q test, p=0.681; I2=1.0%) diseases. Conclusions: Our nationwide study demonstrated differences in the spatial and temporal variations in the relative risk for all-cause and cause-specific emergency transport during periods of extreme heat in Japan between 2007 and 2010. Our results suggest that public health strategies aimed at controlling heat-related morbidity should be tailored according to region-specific weather conditions.
AB - Background: Several studies have reported the burden of climate change on extreme heat-related mortality or morbidity. However, few studies have investigated the spatial and temporal variation in emergency transport during periods of extreme heat on a national scale. Methods: Daily emergency ambulance dispatch data from 2007 to 2010 were acquired from all 47 prefectures of Japan. The temporal variability in the relationship between heat and morbidity in each prefecture was estimated using Poisson regression combined with a distributed lag non-linear model and adjusted for time trends. The spatial variability in the heat-morbidity relationships between prefectures was estimated using a multivariate meta-analysis. Results: A total of 5,289,660 emergency transports were reported during the summer months (June through September) within the study period. The overall cumulative relative risk (RR) at the 99th percentile vs. the minimum morbidity percentile was 1.292 (95% CI: 1.251-1.333) for all causes, 1.039 (95% CI: 0.989-1.091) for cardiovascular diseases, and 1.287 (95% CI: 1.210-1.368) for respiratory diseases. Temporal variation in the estimated effects indicated a non-linear relationship, and there were differences in the temporal variations between heat and all-cause and cause-specific morbidity. Spatial variation between prefectures was observed for all causes (Cochran Q test, p<0.001; I2=45.8%); however, there was no significant spatial heterogeneity for cardiovascular (Cochran Q test, p=0.054; I2=15.1%) and respiratory (Cochran Q test, p=0.681; I2=1.0%) diseases. Conclusions: Our nationwide study demonstrated differences in the spatial and temporal variations in the relative risk for all-cause and cause-specific emergency transport during periods of extreme heat in Japan between 2007 and 2010. Our results suggest that public health strategies aimed at controlling heat-related morbidity should be tailored according to region-specific weather conditions.
UR - http://www.scopus.com/inward/record.url?scp=84949595364&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84949595364&partnerID=8YFLogxK
U2 - 10.1016/j.scitotenv.2015.11.098
DO - 10.1016/j.scitotenv.2015.11.098
M3 - Article
C2 - 26657368
AN - SCOPUS:84949595364
SN - 0048-9697
VL - 544
SP - 220
EP - 229
JO - Science of the Total Environment
JF - Science of the Total Environment
ER -
