Suicide and Ambient Temperature: A Multi-Country Multi-City Study

Area of Science:

• Environmental epidemiology
• Public health
• Climate change impacts

Background:

• Previous studies suggest a link between higher ambient temperature and increased suicide risk.
• A comprehensive multi-country analysis of temperature's role in suicide risk, considering heat variations, was lacking.

Purpose of the Study:

• To investigate the short-term relationship between ambient temperature and suicide risk across diverse global locations.
• To explore the nonlinear nature and geographical variations of the temperature-suicide association.

Main Methods:

• Utilized daily time-series data from 341 locations in 12 countries.
• Employed a two-stage meta-analysis: location-specific case-crossover analyses followed by multivariate meta-regression.
• Examined lag-cumulative nonlinear associations to understand temperature-suicide links.

Main Results:

• A total of 1,320,148 suicides were analyzed.
• Ambient temperature elevation was linked to increased suicide risk, exhibiting an inverted J-shaped curve peaking at 27°C (RR=1.33).
• Nonlinear associations were more evident in Northeast Asia, with higher risk temperatures compared to Western countries and South Africa.

Conclusions:

• The risk of suicide generally rises with increasing ambient temperature, but the extent and linearity vary significantly across countries.
• The temperature-suicide association requires cautious interpretation, necessitating further research into modifying factors.
• Findings highlight the need for public health strategies addressing temperature-related suicide risks.