Table 2.

Summary of the tools or scales used in each study.

Variable	Tools or Scale	No. of Items	Study
Meaning in Life
Whole construct	Meaning in Life Questionnaire (MLQ)	10	McGee et al., 2017 [41] Aftab et al., 2019 [42]
Sense of coherence	Orientation to Life Questionnaire (OLQ)	13	Bartrés-Faz et al., 2018 [26] Macià et al., 2021 [43] Sutin et al., 2020 [23]
Purpose in life	Purpose in life subscale of Ryff’s Well-Being Scale (PiL)	6	Bartrés-Faz et al., 2018 [26] Macià et al., 2021 [43]
		7	Sutin et al., 2018 [44] Lewis et al., 2021 [45] Kim et al., 2019 [22]
		6 and 7	Sutin et al., 2021 [21]
	PiL scale from Ryff and Keyes’ Psychological Wellbeing Scale	10	Wingo et al., 2020 [46] Boyle et al., 2021 [47]
Engagement with life	Engaged Living Scale (ELS)	16	Bartrés-Faz et al., 2018 [26] Macià et al., 2021 [43]
Psychosocial Factors
Resilience	Brief Resilience Coping Scale (BRCS)	4	Meléndez et al., 2018 [48]
	Connor–Davidson Resilience Scale (CD-RISC)	25	Eyre et al., 2017 [49]
Stress	Perceived Stress Scale (PSS)	4	Turner et al., 2017 [50] Feeney et al., 2018 [51]
		10	Elkana et al., 2020 [52]
		14	Katz et al., 2016 [53] Jiang et al., 2017 [54]
Loneliness	UCLA Loneliness Scale	3	Lara et al., 2019 [55] Jang et al., 2021 [56]
		11	Lee et al., 2021 [57]
		20	Kwon et al., 2017 [58] Gené-Badia et al., 2020 [59]
	De Jong Gierveld Loneliness Scale	6	Burholt et al., 2017 [60] Fung et al., 2019 [61] Evans et al., 2019 [62]
Social isolation	Lubben Social Network Scale (LSNS)	6	Burholt et al., 2017 [60] Evans et al., 2019 [62] Li et al., 2019 [63] Gené-Badia et al., 2020 [59] Jang et al., 2021 [56] Foong et al., 2021 [64]
		12	Siette et al., 2020 [65]
	Shankar Index	5	Lara et al., 2019 [55]

The tests or scales shown in bold were selected for use in the DeCo-B.