0156 The Association of Living Alone with Depression and Insomnia Among Rural Adults: A Social Support Perspective

Abstract Introduction More than a quarter of Americans now live alone, a strong risk factor for depression and insomnia. Social support—encompassing emotional, instrumental, and informational assistance—represents a mechanistic pathway through which living arrangements may influence sleep and mental health. Does social support mediate the relationship between living alone and the comorbidity of depression and insomnia among adults in rural Appalachia? Our primary model examined the association between living alone and a composite depression-insomnia outcome, with social support as a mediator. Supporting models evaluated the associations between living alone and insomnia with serial mediation through social support and depression, and between living alone and depression with serial mediation through social support and insomnia. Methods Participants in the REST-KY study were recruited from 12 counties in Eastern Kentucky in the Central Appalachian region of the United States. All counties are sparsely resourced, rural, and economically distressed. The final analytic sample comprised 252 participants. Eligible participants completed well-validated scales measuring sleep, mental health, and social support. An insomnia-depression comorbidity index was constructed by Principal Component Analysis. The primary analysis utilized a causal mediation approach (5,000 simulations) using the mediation package. Supporting analyses utilized a serial mediation approach using the lavaan package. Analyses were conducted in R. Results Among these participants, 52 (20.6%) reported living alone. Individuals living alone were more likely to be unmarried and had significantly lower household incomes. Participants living alone had significantly lower social support scores compared to those not living alone (p < 0.001) and were significantly more likely to experience mild to severe depressive symptoms (p = 0.008). In causal mediation models, social support accounted for 47.9% of the total effect between living alone and depression/insomnia comorbidity (Average Causal Mediated Effect [95% Confidence Interval]: 0.21 [0.08, 0.37]). While the total effect was significant (p=0.028), the direct effect was not (p=0.24). Conclusion Living status is associated with lesser social support, greater depressive symptoms, and greater insomnia severity. These results suggest that the relationship between living alone and insomnia severity operates substantially through the pathway of reduced social support. Interventions focused on living arrangements or social relationships may improve depressive symptoms or insomnia severity. Support (if any) R01MD016236