Vulnerability to temperature-related mortality in Seoul, Korea

Abstract

Studies indicate that the mortality effects of temperature may vary by population and region, although little is known about the vulnerability of subgroups to these risks in Korea. This study examined the relationship between temperature and cause-specific mortality for Seoul, Korea, for the period 2000-7, including whether some subgroups are particularly vulnerable with respect to sex, age, education and place of death. The authors applied time-series models allowing nonlinear relationships for heat- and cold-related mortality, and generated exposure-response curves. Both high and low ambient temperatures were associated with increased risk for daily mortality. Mortality risk was 10.2% (95% confidence interval 7.43, 13.0%) higher at the 90th percentile of daily mean temperatures (25 °C) compared to the 50th percentile (15 °C). Mortality risk was 12.2% (3.69, 21.3%) comparing the 10th (-1 °C) and 50th percentiles of temperature. Cardiovascular deaths showed a higher risk to cold, whereas respiratory deaths showed a higher risk to heat effect, although the differences were not statistically significant. Susceptible populations were identified such as females, the elderly, those with no education, and deaths occurring outside of a hospital for heat- and cold-related total mortality. Our findings provide supportive evidence of a temperature-mortality relationship in Korea and indicate that some subpopulations are particularly vulnerable.

Figure 1

Relationship between temperature and risk of mortality, comparing various temperature levels with a reference temperature of 15 °C for (A) total, (B) male and (C) female. (Note: lag 0 day for heat effect; lag 0–25 days for cold effect. The shaded portions of the curves represent 95% confidence intervals. The bars represent the ranges of the curves measured as heat effects (dark yellow: 99th–90th percentile; light yellow: 90th–50th percentile) and cold effects (dark gray: 1st–10th percentile; light gray: 10th–50th percentile).)