Age-Period-Cohort Analysis of Suicide Mortality in Japan: A 40-Year Nationwide and Prefectural-Level Study.

INTRODUCTION

Suicide remains a major public health concern in Japan. Age-period-cohort analysis can differentiate the effects of age, date, and birthyear on an outcome. This study used an age-period-cohort analysis to analyze suicide mortality in all of Japan and in the 47 prefectures.

METHODS

Suicide mortality data from 1980 to 2021 were from the Global Burden of Disease database. Trends in the crude and age-standardized mortality rate were analyzed using Joinpoint regression. Age-period-cohort analysis was conducted using a Poisson model.

RESULTS

The suicide rate was consistently greater in men than in women. Analysis of different age groups indicated the highest rate was in men aged >80 years, although it decreased in this group over time. The suicide rate increased in the group aged 15 to 19 years, particularly in cohorts born after 1972. A strong period effect occurred from the late 1990s to early 2000s, particularly among working-age men in their 50s and 60s. There were some disparities among prefectures, in that Akita had the highest rate and Tokyo had the lowest.

CONCLUSIONS

We identified key age-period-cohort effects of suicide in Japan. Economic downturns and generational differences affected suicide risk, and adolescents and middle-aged men had high risk.