In-person interventions to reduce social isolation and loneliness: An evidence and gap map
Authors: Welch Vivian Andrea , Ghogomu Elizabeth , Dowling Sierra , Barbeau Victoria , Al-Zubaidi Ali AA , Beveridge Ella , Bondok Mostafa , Desai Payaam , Doyle Rebecca , Huang Jimmy , Hussain Tarannum , Jearvis Alyssa , Jahel Fatima , Madani Leen , Choo Wan Yuen , Yunus Raudah M , Mohd Tengku Amatullah Madeehah T , Wadhwani Arpana , Ameer Abdulah Al , Ibrahim Rayan , Allam Sarah , Haitas Niobe , Bomze Sivan , Dahrouge Simone , Garcia Edward , Holt-Lunstad Julianne , Lasgaard Mathias , Lim Michelle H , Mulligan Kate , Salzwedel Douglas M , Qualter Pamela , Hébert Paul C , Mikton Christopher 
Published: July 2023

Background There is a growing body of research indicating that social isolation and loneliness can occur in all age groups, and they have been shown to be linked to increased mortality and poorer health outcomes. Hence the need for research on interventions aiming to alleviate social isolation and loneliness. Objectives To map available evidence on the effects of in-person interventions aimed at mitigating social isolation and/or loneliness across all age groups and settings.Search methods The following databases were searched from inception up to February 2022 with no language restrictions: Ovid MEDLINE, Embase, EBM Reviews – Cochrane Central Register of Controlled Trials, APA PsycInfo via Ovid, CINAHL via EBSCO, EBSCO (all databases except CINAHL), Global Index Medicus, ProQuest (all databases), ProQuest ERIC, Web of Science, Korean Citation Index, Russian Science Citation Index, and SciELO Citation Index via Clarivate, and Elsevier Scopus.Selection criteria Titles, abstracts and full texts of potentially eligible articles identified were screened independently by two reviewers for inclusion following the outlined eligibility criteria. Data collection and analysis We developed and pilot tested a data extraction code set in Eppi-Reviewer. Data was individually extracted and coded. Main results A total of 513 articles were included in this evidence and gap map (421 primary studies and 92 systematic reviews) which assessed the effectiveness of in-person interventions on the reduction of social isolation and loneliness. Most (68%) of the reviews were classified as critically low quality, while less than 5% were classified as high or moderate quality. The evidence is unevenly distributed with most reviews looking at interpersonal delivery and community-based delivery interventions, especially interventions for changing cognition led by a health professional and group activities, respectively. Loneliness, wellbeing, and depression/anxiety were the most assessed outcomes. Most research was conducted in high-income countries, concentrated in the United States, United Kingdom, and Australia, with none from low-income countries. Major gaps were identified in societal level and community-based delivery interventions that address policies and community structures, respectively. Less than 5% of included reviews assessed process indicators or implementation outcomes. Similar trends of findings were found in primary studies. All age groups were represented although more reviews and primary studies focused on older adults ≥ 60 years (60%) than young people ≤ 24 years (34%). Two thirds described how at-risk populations were identified and even fewer assessed differences in effect across PROGRESS-Plus factors for populations experiencing inequities.Authors’ conclusions There is growing evidence that social isolation and loneliness are public health concerns. This evidence and gap map shows the available evidence, at the time of the search, on the effectiveness of in-person interventions at reducing social isolation and loneliness across all ages and settings. Despite a large body of research, with much of it published in more recent years, it is unevenly distributed. Most of the systematic reviews are of critically low quality indicating the need for high quality research. This map can guide funders and researchers to consider the areas in which the evidence is lacking and to address these gaps as future research priorities.