Longitudinal trajectories of region-level suicide mortality in Tokyo, Japan, 2011 to 2021

Abstract

Background: Suicide mortality in Japan has declined over a period of more than 10 years, however, differences in longitudinal trajectories at a regional level are not well characterized. Objective was to clarify the longitudinal suicide mortality trajectories at the regional level in Tokyo from 2011 to 2021 by considering spatial smoothing, before and during the COVID-19 pandemic. Methods: This longitudinal cross-sectional analysis used fifty-four regions in Tokyo, Japan. Suicide mortality trends used data from the Cabinet Office of the Japanese government from 2011 to 2021. Regional social and environmental characteristics were used as 10 covariates. Empirical Bayes estimates for the standardized mortality ratio were obtained. A conditional autoregressive (CAR) model was applied to capture the spatial correlation for a crude and adjusted with 10 covariates using OpenBUGS. Spatial clusters were also identified by FlexScan, SaTScan, and Tango’s test. Results: Longitudinal trajectories for both males and females were similar to a decreasing trend in all Japan until 2019. In 2020, the beginning of the COVID-19 pandemic, the age-specific suicide deaths were the highest among those in their 20s. However, those were the highest among males in their 50s in 2021. The results of the CAR models adjusted for 10 covariates detected several regions as having higher suicide rates, but those regions were somewhat varied. Conclusion: During the COVID-19 pandemic, both sexes in their 20s and males in their 50s showed a tendency toward an increase in suicides. The detected regions by spatial epidemiology varied with sex.