| Outline of Annual Research Achievements |
The multi-country multi-city database for this project has been updated with location-specific daily time series of suicide mortality and weather factors in 494 locations across 26 countries from 4 to 45 years (please see the list* below).
We have developed epidemiological methodologies for the effects of season on suicide mortality and the short-term spatiotemporal temperature-suicide associations. We observed a consistent seasonal pattern of suicide mortality in 10 countries, with a peak in spring and a trough in winter. We also observed a spatially heterogeneous pattern of the temperature-suicide association but its unclear temporal changes in Japan. Furthermore, we projected the excess temperature-related suicide mortality in Japan under climate change scenarios until the 2090s. Although the progress of this project was slightly delayed, we will examine the spatial heterogeneity of the temperature-suicide association and the temporal changes for both seasonality of suicide and the association with temperature based on the updated multi-country database.
*List of the 26 countries: Australia, Brazil, Canada, Chile, China, Costa Rica, Czech Republic, Estonia, Ecuador, Finland, Germany, Guatemala, Italy, Japan, Mexico, Paraguay, Philippines, Romania, South Africa, South Korea, Spain, Switzerland, Taiwan, UK, USA, and Vietnam
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| Current Status of Research Progress |
Current Status of Research Progress
3: Progress in research has been slightly delayed.
Reason
As of the end of FY2021, we have updated the location-specific daily time series multi-country multi-city data for suicide mortality and weather factors from 4 to 45 years in 494 locations in 26 countries. We have developed the epidemiological methodologies, i.e., a two-stage time-stratified case-crossover analysis, for the effects of season on suicide mortality and the short-term spatiotemporal temperature-suicide associations. We observed a consistent seasonal pattern of suicide mortality in 10 countries, with a peak in spring and a trough in winter. The seasonality of suicide was larger for colder areas and older populations in general but weak for areas with higher unemployment rates. Also, we observed that the suicide risks associated with higher temperature were larger for rural prefectures and colder and drier regions in Japan across 47 prefectures spanning from 1972 to 2015, although the temporal changes in the associations were unclear. Furthermore, we projected the excess temperature-related suicide mortality in Japan under climate change scenarios until the 2090s.
The progress of this project was slightly delayed by the data quality issues and the need for more refined analytical methods to proceed further with the spatial heterogeneity and temporal changes in the temperature-suicide associations embracing the 26 multi-countries.
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| Strategy for Future Research Activity |
In the final year of this project, we will finalize the examination of the spatial heterogeneity of the temperature-suicide association and the temporal changes for both seasonality of suicide and the association with temperature, using the updated multi-country multi-city database. We will select countries where the time-series data was long enough to produce the time-varying effect estimates when investigating the temporal changes. Also, a subset of the multi-country database, including overlapping years, should be used to make the results of the spatial heterogeneity comparable as much as possible.
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| Causes of Carryover |
The progress of this project was slightly delayed by the data quality issues, the need for more refined analytical methods, and the COVID-19 pandemic and the consequent travel limit. The rest of the budget will be used n FY2022 mainly for research meetings with international collaborators.
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