한국 수도권 지역 열대야 현상의 온도 기준과 사망 위험

Abstract

The effects of extreme climate events associated with global warming on health have become a major public health concern. Previous studies on the mortality risk of high night-time temperatures, called “hot nights”, demonstrated that the current hot-night warning system in South Korea may not be sufficient because the warning system does not report the risks of night-time temperatures lower than 25°C (the current cut-off point for hot nights) and the threshold points were heterogeneous among subpopulations. Therefore, this study aimed to investigate the mortality risk of hot nights using various cut-off points and subpopulation analysis to suggest effective health risk-based warning systems.BR We collected time-series data on daily mortality and minimum temperature for 66 districts (si-gun-gu) in the capital area (Seoul, Gyeonggi, and Incheon) of South Korea during the summer period (Jun. ~ Sep.) from 2011 to 2017. Cut-off point temperatures were set from 20°C to 25°C, and the days with a daily minimum temperature above the cut-off point were defined as hot nights. Through two-stage time-series analysis with a distributed lag model, the association between hot nights and mortality was estimated for each district. We then calculated the pooled risk estimates using a meta-regression model.BR In the capital areas as a whole, positive mortality risk was detected around at 22°C, and the risk was highest at 25°C. In general, across all cut-off temperatures, Seoul showed higher risk compared to Gyeonggi and Incheon, and the cut-off value at which the risk was significant was the lowest (22°C). In addition, risk disparities between subpopulations (sex, age, education status, and marital status) were prominent at the highest cut-off point (25°C).BR In conclusion, this study provides evidence for health-risk-based hot night warning systems, which should be expanded to lower night-time temperatures and should account for regions and subpopulations.