A time series study on the effects of cold temperature on road traffic injuries in Seoul, Korea.
OBJECTIVE
Although traffic accidents are associated with weather, the influence of temperature on injuries from traffic accidents has not been evaluated sufficiently. The objective of this study was to evaluate the effect of temperature, especially cold temperatures, on injuries from traffic accidents in Seoul, Korea. We also explored the relationship of temperature with different types of traffic accident.


METHODS
The daily frequencies of injuries from traffic accidents in Seoul were summarized from the integrated database established by the Korea Road Traffic Authority. Weather data included temperature, barometric pressure, rainfall, snow, and fog from May 2007 to December 2011. The qualitative relationship between daily mean temperature and injuries from traffic accidents was evaluated using a generalized additive model with Poisson distribution. Further analysis was performed using piecewise linear regression if graph the showed non-linearity with threshold.


RESULTS
The incidence of injuries was 216 per 100,000 person-months in Seoul. The effect of temperature on injuries from traffic accidents was minimal during spring and summer. However, injuries showed a more striking relationship with temperature in winter than in other seasons. In winter, the number of injuries increased as the temperature decreased to <0°C. The injuries increased by 2.1% per 1°C decrease under the threshold of the daily average temperature -5.7°C, which is 10-fold greater than the effect of temperature above the threshold. Some groups were more susceptible to injuries, such as young and male drivers, according to the types of traffic accident when the temperature decreased to below the freezing temperature.


CONCLUSIONS
The incidence of injuries increased sharply when the temperature decreased below freezing temperature in winter. Temperature can be effectively used to inform high risk of road traffic injuries, thus helping to prevent road traffic injuries.
Department of Social and Preventive Medicine, Inha University School of Medicine, Republic of Korea; Department of Preventive Medicine, School of Medicine, Ewha Womans University, 071, Anyangcheon-ro, Yangcheon-ku, Seoul 158-710, Republic of Korea.
Won-Kyung
WK
Lee
Department of Preventive Medicine, School of Medicine, Ewha Womans University, 071, Anyangcheon-ro, Yangcheon-ku, Seoul 158-710, Republic of Korea.
Hye-Ah
HA
Lee
Department of Social and Preventive Medicine, Inha University School of Medicine, Republic of Korea.
Seung-sik
SS
Hwang
Department of Epidemiology and Biostatistics, Seoul National University, Seoul, Republic of Korea.
Ho
H
Kim
Institute of Health and Environment, Seoul National University, Seoul, Republic of Korea.
Youn-Hee
YH
Lim
Department of Preventive Medicine, School of Medicine, Seoul National University, Seoul, Republic of Korea.
Yun-Chul
YC
Hong
Department of Preventive Medicine, School of Medicine, Ewha Womans University, 071, Anyangcheon-ro, Yangcheon-ku, Seoul 158-710, Republic of Korea.
Eun-Hee
EH
Ha
Department of Preventive Medicine, School of Medicine, Ewha Womans University, 071, Anyangcheon-ro, Yangcheon-ku, Seoul 158-710, Republic of Korea. Electronic address: hpark@ewha.ac.kr.
Hyesook
H
Park
D000063:Accidents, Traffic / Q000706:statistics & numerical data*; D000328:Adult; D000368:Aged; D005260:Female; D005615:Freezing; D006801:Humans; D008297:Male; D008875:Middle Aged; D056910:Republic of Korea
Injuries; Temperature; Traffic accidents; Weather