Citation

Kim Y, Kim H, Honda Y, Guo YL, Chen BY, Woo JM, Ebi KL. Environ. Health Perspect. 2015; 124(1): 75-80.

Affiliation

Department of Pediatric Infectious Diseases, Institute of Tropical Medicine, Nagasaki University, Nagasaki, Japan.

Copyright

(Copyright © 2015, National Institute of Environmental Health Sciences)

DOI

10.1289/ehp.1409392

PMID

26069051

Abstract

OBJECTIVES: A limited literature base suggests that ambient temperature contributes to suicide, with studies typically focused on a single nation using temporal and spatial aggregated data. We evaluated an association between ambient temperature and suicide in multiple cities in three East Asian countries.

METHODS: A 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. Gender- 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.

RESULTS: An 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 2.3ºC increase in ambient temperature in Taiwan, 6.8% (95% CI: 5.4, 8.2%) for a 4.7ºC increase in Korea, and 4.5% (95% CI: 3.3, 5.7%) for a 4.2ºC 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 significant. 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).

CONCLUSIONS: We estimated consistent positive associations between suicide and higher ambient temperature in three East Asian countries, regardless of country, gender, and age.

Language: en