Social disconnection and suicide mortality among Japanese older adults: A seven-year follow-up study

Few prospective studies have examined the association between social disconnection and late-life suicide. Therefore, we conducted a large-scale prospective study of older adults in Japan to examine differences in suicide mortality according to specific aspects of social disconnectedness.

We conducted a nationwide baseline survey of functionally independent older adults (age ≥65 years) from 12 municipalities in Japan from 2010 to 2011. We followed the participants (n = 46,144) for cause of death through December 2017 using vital statistics. Social disconnection was assessed based on the indicators of eating alone, a lack of instrumental/emotional support, no participation in community activities, and no contact with friends. We adopted Cox regression models with multiple imputation for missing values and calculated the population-attributable fraction (PAF).

A total of 55 suicide deaths were recorded during an average follow-up of 7 years. Older adults with social disconnection had a marginally increased risk of suicide. The hazard ratio for eating alone vs. eating together was 2.81 (95% confidence interval [CI]: 1.47-5.37). The direction of these associations and point estimations did not largely change after controlling for depressive symptoms, an evident risk factor for suicidal behavior. The PAF indicated that eating alone was attributable to around 1800 (29%) of the suicide deaths among older adults annually in Japan.

Avoidance of not only depressive symptoms, but also social disconnection including eating alone, is useful in suicide prevention among older adults.