Multiple long-term conditions, loneliness and social isolation: A scoping review of recent quantitative studies

Background: Multiple long -term conditions (MLTC), loneliness and social isolation are common in older adults. Recent studies have explored the association of MLTC with loneliness and social isolation. This scoping review aimed to map this current evidence and identify gaps in the literature. Methods: A scoping review was conducted following the PRISMA guidelines for scoping reviews. Ovid Medline, Embase, CINAHL, The Cochrane Library, PsycInfo, and Bielefeld Academic Search Engine were searched for studies published between January 2020 -April 2023. Quantitative studies, published in any language, that assessed the association of MLTC with loneliness and/or social isolation were included. Results: 1827 records were identified and screened. Of these, 17 met inclusion criteria. Most studies were crosssectional and based on older adults. Studies were conducted in Europe, the US, Canada, and low- and middleincome countries. Ten studies focused on the association between MLTC and loneliness, six assessed the association between MLTC and social isolation and one examined associations with both loneliness and social isolation. Most studies reported a significant cross-sectional association of MLTC with loneliness, but there was weaker evidence for a longitudinal association between MLTC and loneliness and an association between MLTC and social isolation. Studies were heterogenous in terms of measures and definitions of loneliness/social isolation and MLTC, confounders adjusted for, and analytical models used, making comparisons difficult. Conclusions: Further population -based longitudinal studies using consistent measures and methodological approaches are needed to improve understanding of the association of MLTC with both loneliness and social isolation.