Loneliness in Japan during the COVID-19 pandemic: Prevalence, correlates and association with mental health.

Loneliness, which is increasingly recognised as an important public health problem, may have increased during the COVID-19 pandemic in the wake of social distancing measures. This study examined loneliness in Japan during the ongoing pandemic and its association with mental health. Cross-sectional online survey data that were collected at monthly intervals from April to December 2020 were analysed. Loneliness was assessed with the Three-Item Loneliness Scale. Information was also obtained on depressive (PHQ-9) and anxiety (GAD-7) symptoms. Logistic regression analysis was used to examine associations. For the combined sample (N = 9000), 41.1% of the respondents were categorised as lonely when using ≥ 6 as a cutoff score, and 16.5% when the cutoff was ≥ 7. The prevalence of loneliness changed little across the period. Younger age, male sex and socioeconomic disadvantage (low income, deteriorating financial situation, unemployment) were associated with loneliness. In fully adjusted analyses, loneliness was linked to depressive (odds ratio [OR]: 5.78, 95% confidence interval [CI]: 5.08-6.57) and anxiety symptoms (OR: 5.34, 95% CI: 4.53-6.29). Loneliness is prevalent in Japan during the COVID-19 pandemic and associated with socioeconomic disadvantage and poorer mental health. A focus on loneliness as a public health issue in Japan is now warranted.