Interventions Associated With Reduced Loneliness and Social Isolation in Older Adults: A Systematic Review and Meta-analysis.

Importance: Loneliness and social isolation are public health concerns faced by older adults due to physical, cognitive, and psychosocial changes that develop with aging. Loneliness and social isolation are associated with increased morbidity and mortality. Objective: To evaluate interventions, targeting older adults, associated with a reduction in loneliness and social isolation. Data Sources: OVID, CINAHL, CENTRAL, Embase, PsychINFO, Web of Science, and Scopus were searched from inception to March 2020. Study Selection: Peer-reviewed randomized clinical trials measuring loneliness and social isolation or support in adults aged 65 years or older. Only English language articles were included. Data Extraction and Synthesis: Two independent reviewers screened studies, extracted data, and assessed risk of bias. Random-effects models were performed to pool the overall effect size by intervention. Statistical heterogeneity was evaluated with the I2 statistic and by estimating prediction intervals. Data were analyzed from November 2021 to September 2022. Main Outcomes and Measures: Quantitative measures of loneliness, social isolation, or social support based on an effect size of standardized mean differences. Results: Seventy studies were included in the systematic review (8259 participants); 44 studies were included in the loneliness meta-analysis (33 in the community with 3535 participants; 11 in long-term care with 1057 participants), with participants' ages ranging from 55 to 100 years. Study sizes ranged from 8 to 741 participants. Interventions included animal therapy, psychotherapy or cognitive behavioral therapy, multicomponent, counseling, exercise, music therapy, occupational therapy, reminiscence therapy, social interventions, and technological interventions. Most interventions had a small effect size. Animal therapy in long-term care, when accounting for studies with no active controls, had the largest effect size on loneliness reduction (-1.86; 95% CI, -3.14 to -0.59; I2 = 86%) followed by technological interventions (videoconferencing) in long-term care (-1.40; 95% CI, -2.37 to -0.44; I2 = 70%). Conclusions and Relevance: In this study, animal therapy and technology in long-term care had large effect sizes, but also high heterogeneity, so the effect size's magnitude should be interpreted with caution. The small number of studies per intervention limits conclusions on sources of heterogeneity. Overall quality of evidence was very low. Future studies should consider measures of social isolation in long-term care and identify the contextual components that are associated with a reduction in loneliness.

Twenty-Seven Tamoxifen-Inducible iCre-Driver Mouse Strains for Eye and Brain, Including Seventeen Carrying a New Inducible-First Constitutive-Ready Allele.

To understand gene function, the cre/loxP conditional system is the most powerful available for temporal and spatial control of expression in mouse. However, the research community requires more cre recombinase expressing transgenic mouse strains (cre-drivers) that restrict expression to specific cell types. To address these problems, a high-throughput method for large-scale production that produces high-quality results is necessary. Further, endogenous promoters need to be chosen that drive cell type specific expression, or we need to further focus the expression by manipulating the promoter. Here we test the suitability of using knock-ins at the docking site 5' of Hprt for rapid development of numerous cre-driver strains focused on expression in adulthood, using an improved cre tamoxifen inducible allele (icre/ERT2), and testing a novel inducible-first, constitutive-ready allele (icre/f3/ERT2/f3). In addition, we test two types of promoters either to capture an endogenous expression pattern (MaxiPromoters), or to restrict expression further using minimal promoter element(s) designed for expression in restricted cell types (MiniPromoters). We provide new cre-driver mouse strains with applicability for brain and eye research. In addition, we demonstrate the feasibility and applicability of using the locus 5' of Hprt for the rapid generation of substantial numbers of cre-driver strains. We also provide a new inducible-first constitutive-ready allele to further speed cre-driver generation. Finally, all these strains are available to the research community through The Jackson Laboratory.