Suicide and Ambient Temperature in East Asian Countries: A Time-Stratified Case-Crossover Analysis

Abstract

BackgroundA limited number of studies suggest that ambient temperature contributes to suicide; these studies typically focus on a single nation and use temporally and spatially aggregated data.ObjectiveWe evaluated the association between ambient temperature and suicide in multiple cities in three East Asian countries.MethodsA time-stratified case-crossover method was used to explore the relationship between temperature and suicide, adjusting for potential time-varying confounders and time-invariant individual characteristics. Sex- and age-specific associations of temperature with suicide were estimated, as were interactions between temperature and these variables. A random-effects meta-analysis was used to estimate country-specific pooled associations of temperature with suicide.ResultsAn increase in temperature corresponding to half of the city-specific standard deviation was positively associated with suicide in most cities, although average suicide rates varied substantially. Pooled country-level effect estimates were 7.8% (95% CI: 5.0, 10.8%) for a 2.3°C increase in ambient temperature in Taiwan, 6.8% (95% CI: 5.4, 8.2%) for a 4.7°C increase in Korea, and 4.5% (95% CI: 3.3, 5.7%) for a 4.2°C increase in Japan. The association between temperature and suicide was significant even after adjusting for sunshine duration; the association between sunshine and suicide was not significant. The associations were greater among men than women in 12 of the 15 cities although not significantly so. There was little evidence of a consistent pattern of associations with age. In general, associations were strongest with temperature on the same day or the previous day, with little evidence of associations with temperature over longer lags (up to 5 days).ConclusionsWe estimated consistent positive associations between suicide and elevated ambient temperature in three East Asian countries, regardless of country, sex, and age.CitationKim Y, Kim H, Honda Y, Guo YL, Chen BY, Woo JM, Ebi KL. 2016. Suicide and ambient temperature in East Asian countries: a time-stratified case-crossover analysis. Environ Health Perspect 124:75–80; http://dx.doi.org/10.1289/ehp.1409392

Increasing ambient temperature reduces emotional well-being

“…Our results support the existence of a psychological link between heat exposure and mental health that could be a contributing factor behind the association between heat exposure 14 and suicide mortality (Kim et al, 2016;Maes et al, 1994;Page et al, 2007;Qi et al, 2015). Furthermore, our results are consistent with, and provide evidence of, mechanisms mediating the effect of temperature on economic activity and interpersonal aggression.…”

“…Previous studies have focused on suicide mortality and indicate that heat exposure is associated with increased suicide rates (Basagaña et al, 2011;Kim et al, 2016;Maes, De Meyer, Thompson, Peeters, & Cosyns, 1994;Page, Hajat, & Kovats, 2007;Qi, Hu, Page, & Tong, 2015). One study has found an impact of heat exposure on hospital admissions for mental and behavioral disorders (Hansen et al, 2008).…”

Ambient Temperature and Mortality Due to External Causes: A Systematic Review

“…The results of studies that have addressed death due to one or more external causes separately, are consistent with these results. For example, several studies have examined the effect of temperature on death due to suicide and have shown that high temperatures are associated with an increase in suicides [32] [33] [34].…”

Climate change and adolescents in South Africa: The role of youth activism and the health sector in safeguarding adolescents’ health and education

“…Together, these direct and indirect impacts pose mental health risks for ado lescents, including post-traumatic stress disorder, depression, anxiety, sleep disorders and even suicide. [21][22][23] Heat exposure can also increase irritability, aggression and violence, [24] a major concern given the rates of physical and sexual violence in schools in SA, both pupil-onpupil and between teacher and pupil. Extreme weather events such as storms, droughts and wildfires have been strongly linked with mental health conditions in adolescents, which commonly persist into adulthood.…”