Moving from prefabricated temporary housing to public reconstruction housing and social isolation after the Great East Japan Earthquake: a longitudinal study using propensity score matching

OBJECTIVES: After the Great East Japan Earthquake (GEJE) of 2011, many survivors have been forced to live in prefabricated temporary housing, which is uncomfortable and insufficiently durable for permanent living. Public reconstruction housing has been built to improve their living conditions; however, those moving have to rebuild personal relationships and adapt to a new environment. This study examined whether survivors moving to public reconstruction housing became more socially isolated than those remaining in prefabricated temporary housing. DESIGN, SETTING AND PARTICIPANTS: Self-report questionnaire data collected in 2015 (4 years after the GEJE) were used as the baseline for follow-up surveys in 2016 and 2017, as many survivors moved from prefabricated temporary housing to public reconstruction housing from 2015. We analysed longitudinal data from 393 survivors, distinguishing those who moved to public reconstruction housing during the 5th year after the disaster from those who remained in prefabricated temporary housing. Participants were assessed using the Lubben Social Network Scale-6 (LSNS-6) in all three surveys, with social isolation defined by a score of <12/30. To reduce the effect of selection bias, propensity score analysis was performed (178 of 393 participants were retained). We used a generalised estimated equation to evaluate the association between moving from prefabricated temporary housing to public reconstruction housing and changes in social isolation over 2 years. RESULTS: LSNS-6 scores of the reconstruction housing group were worse than those of the prefabricated housing group between 4 and 6 years after the GEJE (P=0.006). Over the same period, social isolation worsened in the reconstruction housing group but improved in the prefabricated housing group (P=0.002). CONCLUSIONS: Social isolation should be monitored while supporting survivors who moved to public reconstruction housing, and further longitudinal research is needed to clarify the risk of social isolation.