1. 1) Holt-Lunstad, J., Smith, T. B. and Layton, J. B.: Social relationships and mortality risk: A meta-analytic review, PLoS Medicine, 7(7), e1000316, 2010.7. https://doi.org/10.1371/journal.pmed.1000316
2. 2) DiJulio, B., Hamel, L., Munana, C. and Brodie, M.: Loneliness and social isolation in the United States, the United Kingdom, and Japan: An international survey, KFF Report, pp.1-29, https://www.kff.org/other/report/loneliness-and-social-isolation-in-the-united-states-the-united-kingdom-and-japan-an-international-survey/, 2018(accessed 2022.2.28).
3. 3) Cabinet Secretariat: Rules on the Establishment of the Office of Loneliness and Isolation Prevention (in Japanese), 2021.2. 内閣官房: 孤独・孤立対策担当室の設置に関する規則, https://www.cas.go.jp/jp/seisaku/kodoku_koritsu_taisaku/pdf/setti_kisoku.pdf, 2021.2(accessed 2022.2.28).
4. 4) Council for the Promotion of Measures to Cope with Loneliness and Isolation : Priority Plan for Measures to Cope with Loneliness and Isolation(in Japanese), Cabinet Secretariat, 2021.12 孤独・孤立対策推進会議 : 孤独・孤立対策の重点計画,内閣官房 2021.12 https://www.cas.go.jp/jp/seisaku/juten_keikaku/pdf/jutenkeikaku.pdf (accessed 2022.2.28)
5. 5) Kotanaka, Y., Gocho, M., Yamashita, T., Yoshikawa, Y. and, Torigoe, S.: A review of research on the scarcity of human relationships: Focusing on social isolation, loneliness, and social networking, IPSS Discussion Paper Series, 2020-J01, pp1–50,2020.7(in japanese), 2020.7. 小田中悠, 牛膓政孝, 山下智弘, 吉川侑輝, 鳥越信吾：人間関係の希薄さに関する研究のレビュー: 社会孤立, 孤独, SNS に注目して. IPSS Discussion Paper Series, 2020-J01, pp1–50,2020.7.