Impact of meteorological factors on suicide risk: Insights from a generalized additive model analysis

This study investigates the effects of two specific meteorological factors, Physiologically Equivalent Temperature (PET) and Diurnal Temperature Range (DTR), on suicide risk in Ilam City, Iran, using Generalized Additive Model (GAM) analysis to quantify their relationship with suicide risk. Data on suicides from 2016 to 2022 were sourced from the Systematic Registration of Suicide Data (SRSD), alongside meteorological data (temperature, wind speed, humidity) obtained from the Ilam Meteorological Organization. PET was calculated utilizing Rayman Software, and DTR was defined as the difference between daily maximum and minimum temperatures. GAM was employed to model the relationships and assess lag effects. Over the six-year study period, 3112 suicides were recorded in Ilam City (mean: 1.42/day). Analysis revealed a linear exposure-response relationship for both PET and DTR on the same day (lag 0). The most notable finding was a consistent, cumulative increase in suicide risk associated with rising Diurnal Temperature Range (DTR). For each 1 °C increase in DTR, the risk escalated over successive lag periods, reaching a 3.24% increase (95% CI: 1.19, 5.33) over a 21-day period (lag 021). This study demonstrates that temperature variability, measured by DTR, significantly associates with suicide risk in Ilam City, Iran. These results highlight the importance of incorporating meteorological data into suicide prevention strategies and early-warning systems. Future research should explore the underlying mechanisms of this relationship across different populations and climates.