Association between increase in temperature due to climate change and depressive symptoms in Korea

Studies on the long-term effects of rising temperature by climate change on mental health are limited. This study investigates the influence of temperature rise on the prevalence rate of depressive symptoms according to district type and age group in Korea.

This cross-sectional study included 219,187 Korea Community Health Survey 2021 participants. Yearly average temperature and yearly average temperature difference are the main exposures of this study. Temperature difference was calculated by subtracting the historical average temperature in 1961-1990 (climate normal) from the yearly average temperature. The main outcomes are moderate depressive symptoms measured by Patient Health Questionnaire-9. Multilevel analyses were conducted to estimate the association between temperature factors and depressive symptoms.

7491 (3.4 %) participants reported moderate depressive symptoms, and 99,653 (69.9 %) participants lived in an urban district. The odds of depressive symptoms increased with 1 °C increase in temperature difference for all participants, adult participants aged 19-40, and participants who lived in same metropolitan area for 20 years or more (aOR = 1.13, CI: 1.04-1.24, aOR = 1.14, CI: 1.02-1.24, and aOR = 1.15 CI: 1.04-1.27). The association between temperature difference and depressive symptoms was consistent among urban districts participants.

Due to the study's cross-sectional nature, the temporal association between regional and individual factors and depressive symptoms could not be assessed. Limited number of weather stations, especially among less populated in-land areas, may limit the accuracy of this study.

The increase in temperature compared with historical average is associated with increased likelihood of depressive symptoms, especially for the adults aged 19-40 years old. More study on the long-term impact of climate change on mental health is needed to determine effective responses to climate change.