Ambient Temperature and Suicide Risk in Thailand: Evidence from Chiang Mai and Bangkok Provinces

Suicide is a critical public health issue with rates varying across regions and demographic groups. Recent evidence suggests that ambient temperature may influence suicide risk. This study examines the association between temperature and suicide in Thailand's tropical climate, focusing on Chiang Mai and Bangkok provinces, and quantifies the attributable burden. Daily suicide and meteorological data from 2002 to 2021 were analyzed using a time-stratified case-crossover approach with a distributed lag nonlinear model, adjusted for relative humidity. Province-specific estimates were pooled through a multivariate meta-regression model. The study found a positive, mostly linear association between temperature and suicide risk, with a relative risk (RR) of 1.70 (95% CI: 1.35, 2.15) across the temperature range. Approximately 24.61% of suicides were attributable to temperature, with 12.05% due to hot temperatures above the 66th percentile. The pooled attributable fractions were higher in the 0-64 age group compared to those aged ≥65, while differences between sexes were not statistically significant. This study highlights the significant association between higher ambient temperatures and increased suicide risks in Thailand, emphasizing the need to integrate climate considerations into mental health and suicide prevention policies. Further research across diverse climatic zones is essential for understanding climate influences on mental health globally.