Association between cognitive social capital and all-cause mortality in Great East Japan Earthquake survivors: a prospective cohort study.

OBJECTIVES: Cognitive social capital (SC), such as attitude, trust, or norms, may help improve resilience among survivors, thus improving their health. However, the association between cognitive SC and the risk of all-cause mortality among survivors after the natural disaster has never been investigated. The purpose of the present study is to investigate the association between cognitive SC and the risk of all-cause mortality among survivors of the Great East Japan Earthquake (GEJE). STUDY DESIGN: Prospective cohort study. METHODS: We conducted a health survey on 1654 residents aged ≥18 years who lived in two areas affected by the GEJE. One year after the GEJE, between June and August 2012, cognitive SC (helping each other, trust, greeting, and solving problems together) was assessed using a self-administrated questionnaire. We divided the subjects into two groups based on response to questionnaire: "high" or "low." We obtained information on death and emigration from the Residential Registration Record and followed up on the participants from June 2012 to November 2020. The Cox proportional hazards regression analysis was used for estimating the multivariate-adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) for the risk of all-cause mortality according to each cognitive SC indicator. RESULTS: During the 8.5 years of follow-up, 213 subjects died (12.9%). For greeting, compared with subjects who were "high," subjects who were "low" were significantly associated with the risk of all-cause mortality (HR: 2.92, 95% CI: 1.19-7.17). No statistically significant association was observed for helping each other, trust, and solving problems together. CONCLUSION: Our findings suggest that perception of greeting may be associated with the risk of all-cause mortality in survivors after natural disasters.