Examining the Benefits of Greenness on Reducing Suicide Mortality Rate: A Global Ecological Study

Abstract

ObjectiveThis study applied an ecological-based analysis aimed to evaluate on a global scale the association between greenness exposure and suicide mortality.MethodsSuicide mortality data provided by the Institute for Health Metrics and Evaluation and the Normalized Difference Vegetation Index (NDVI) were employed. The generalized additive mixed model was applied to evaluate with an adjustment of covariates the association between greenness and suicide mortality. Sensitivity tests and positive-negative controls also were used to examine less overt insights. Subgroup analyses were then conducted to investigate the effects of greenness on suicide mortality among various conditions.ResultsThe main finding of this study indicates a negative association between greenness exposure and suicide mortality, as greenness significantly decreases the risk of suicide mortality per interquartile unit increment of NDVI (relative risk = 0.69, 95%CI: 0.59–0.81). Further, sensitivity analyses confirmed the robustness of the findings. Subgroup analyses also showed a significant negative association between greenness and suicide mortality for various stratified factors, such as sex, various income levels, urbanization levels, etc.ConclusionsGreenness exposure may contribute to a reduction in suicide mortality. It is recommended that policymakers and communities increase environmental greenness in order to mitigate the global health burden of suicide.

The association between nation-level social and economic indices and suicide rates: A pilot study

“…This result remained significant in the partial correlation and linear regression analyses, suggesting that it is unlikely to be due to chance. Recent research has highlighted the associations between environmental factors and suicide risk: for example, air pollution is associated with suicide (Casas et al, 2017;Heo et al, 2021), while exposure to green spaces may exert a protective effect (Helbich et al, 2018;Jiang et al, 2021;Asri et al, 2022;Mendoza et al, 2023). There is also some evidence that rising temperatures, which may reflect anthropogenic climate change, are associated with a short-term increase in suicide rates (Heo et al, 2021;Casas et al, 2022).…”