Contextual effects on male suicide mortality in Japan: changes over the past 20 years
METHODS: Bayesian estimates of male suicide rates for 354 health districts in 1983-1987, 1988-1992, 1993-1997, 1998-2002, and 2003-2007 were obtained from the Center for Suicide Prevention at the National Center of Neurology and Psychiatry. Eligible 352 health districts, belonging to 47 prefectures, grouped into 10 regions that probably share similar characteristics. A three-level random intercept model was used to examine variations in male suicide rates across 47 prefectures (level2) and 10 regions (level3) with adjustment for population density and average household income.
RESULTS: Significant prefecture-level variations were found in all the periods. Significant region-level variations were found in the periods after the sharp increase in suicides in 1998. Variance partition coefficients for the prefecture and region levels were 26% and 0%, respectively in 1983-1987, 31% and 0%, respectively in 1988-1992, 33% and 0%, respectively in 1993-1997, 22% and 22%, respectively in 1998-2002, and 19% and 30%, respectively in 2003-2007. Significantly negative contextual effects were detected continuously in Aomori, Akita, Niigata, and Fukuoka prefectures. Aomori and Akita prefectures showed a risk for the middle-aged and elderly, Niigata prefecture showed a risk for the elderly, and Fukuoka prefecture showed a risk for the middle-aged. Significantly positive contextual effects were detected continuously or intermittently in Miyagi and Tokushima prefectures.
CONCLUSIONS: The geographical variations in male suicide mortality in Japan may be due in part to the local socio-cultural context. Further studies are needed to identify underlying contextual factors that may increase or decrease the risk of suicide.
This work was supported by was supported by JSPS KAKENHI Grant Number 25460815.