Modifying Effect of Heat Waves on the Relationship between Temperature and Mortality

Area of Science:

• Environmental Health
• Epidemiology
• Biostatistics

Background:

• Temporal trends of heat-related mortality studies often overlook heat waves.
• Heat waves are known to impact mortality and modify temperature-mortality relationships.
• Understanding these effects is crucial for public health interventions.

Purpose of the Study:

• To analyze temporal trends of heat-related mortality in Seoul and Busan.
• To evaluate the modifying effect of heat waves on temperature-related mortality.
• To compare these effects in an inland versus a coastal city.

Main Methods:

• Utilized a generalized additive model with Poisson distribution.
• Analyzed non-accidental deaths in Seoul and Busan from 1991-2012.
• Stratified analysis by heat wave occurrence and time periods.

Main Results:

• Seoul showed a significant increase in mortality risk during heat waves (15.9% per 1°C), unlike non-heat wave periods (0.31%).
• Busan exhibited a linear temperature-mortality relationship with no significant difference between heat wave and non-heat wave years.
• Heat wave modifying effects on mortality differed notably between the inland and coastal cities.

Conclusions:

• Heat waves substantially modify temperature-mortality relationships, particularly in inland areas.
• Failure to account for heat waves can lead to misinterpretation of temperature-mortality trends.
• Findings highlight the heterogeneous impact of heat waves on mortality in different urban environments.