# Influence of housing damage caused by the Great East Japan Earthquake on the association between new social isolation and depressive symptoms during the COVID-19 pandemic: findings from the Tohoku Medical Megabank Community-Based Cohort Study

## TL;DR

This study found that new social isolation during the pandemic was linked to higher depressive symptoms, but past disaster experience did not change this link.

## Contribution

The study examines how past disaster experience affects the link between social isolation and depression during the pandemic.

## Key findings

- New social isolation during the pandemic was associated with higher depressive symptoms in both men and women.
- Past disaster experience, such as housing damage from the GEJE, did not influence this association.
- Preventing social isolation is crucial for reducing depression during major pandemics.

## Abstract

It is unclear whether past disaster experience, specifically housing damage caused by the Great East Japan Earthquake (GEJE), influenced the association between social isolation and depressive symptoms during the coronavirus disease 2019 (COVID-19) pandemic. Therefore, we aimed to examine the association between new social isolation and depressive symptoms during the COVID-19 pandemic and whether this association was influenced by past disaster experience.

We analyzed the longitudinal data of 8,647 individuals, excluding those who reported social isolation before COVID-19. The presence of social isolation and depressive symptoms were defined using the Lubben Social Network Scale-6 (LSNS-6) score < 12 and the Center for Epidemiological Studies-Depressive Scale (CES-D) score ≥ 16, respectively. Pre-COVID-19 survey was conducted between June 2017 and February 2020, and COVID-19 survey was conducted between November 2020 and March 2021. Participants were categorized into “not socially isolated” and “newly socially isolated” groups. Logistic regression analyses were performed to calculate the multivariable-adjusted odds ratio (AOR) with 95% confidence interval (CI) for depressive symptoms, comparing both groups.

Participants who were newly socially isolated during the COVID-19 pandemic had a significantly higher prevalence of depressive symptoms than those who were not socially isolated in both men and women (men: AOR 1.53 [CI: 1.15–2.02]; women: AOR 1.96 [CI: 1.64–2.34]). However, past disaster experience did not affect this association in both men and women.

To reduce depressive symptoms during a major infectious disease pandemic such as the COVID-19 pandemic, it is important to adopt a public health perspective to prevent social isolation.

The online version contains supplementary material available at 10.1186/s12889-025-25996-9.