Which age-related factors moderate the relationship between loneliness and depression in older adults, and what is their effect? A systematic review and narrative synthesis

Objective: To review and synthesise available evidence on ageing-related factors that influence the strength or direction of the relationship between loneliness and depression in older adults.Methods: Systematic review: Four databases (MEDLINE, PsychINFO, Embase, CINAHL) were searched from 2013-2023, using search terms related to ageing, loneliness, depression, factors linked to ageing and moderation analysis.Results: Database searches yielded 8165 individual articles; eight were selected for full text screening and five studies met the inclusion criteria. The moderating factors examined in the included studies were categorised into 3 broad topics: psychological constructs, social network characteristics and health behaviour.Conclusion: More work is needed to confirm these findings and to determine which aspects may be most relevant and effective to pursue as potential intervention mechanisms. This should be done in collaboration with older adults with lived experience of loneliness and depression; with input from health care practitioners and third sector organisations with a focus on ageing and mental health.