Predictive role of loneliness on 10-year all-cause mortality among mid-to later-life adults in the United States: findings from the Health and Retirement Study.

BACKGROUND: Loneliness is increasingly recognized as a critical factor influencing health outcomes. Previous studies have reported associations between loneliness and increased mortality risk across chronic medical conditions. However, findings remain inconsistent, particularly regarding the predictive role of loneliness on all-cause mortality within mid- to late-life populations.

METHODS: This prospective cohort study utilized 2010 to 2020 data from the Health and Retirement Study (HRS) to investigate the impact of loneliness on all-cause mortality among U.S. adults aged 50 years and older. Loneliness was assessed using the 11-item University of California, Los Angeles Loneliness Scale (UCLA-11), and total scores were grouped into quintiles. Cox proportional hazards models were employed to estimate hazard ratios (HRs) for all-cause mortality, adjusting for sociodemographic and health-related covariates. Subgroup and sensitivity analyses were performed to assess interactions and the robustness of findings.

RESULTS: A total of 6807 participants were included in this study, with 1561 deaths recorded over a mean follow-up of 7.8 years. Higher baseline loneliness levels (i.e., UCLA-11 total score of ≥15) were associated with increased all-cause mortality across chronic disease groups, with significant HRs for Quintiles 3 to 5 compared to Quintile 1. The loneliness symptom "[not] a lot in common with friends" was significantly associated with all-cause mortality in the diabetes subgroup (adjusted HR: 1.14, 95% CI:1.00-1.30; P = 0.05). Subgroup analyses indicated the association between baseline loneliness scores and all-cause mortality among participants with heart conditions was more pronounced among women (adjusted HR, 1.55; 95% CI:1.22-1.97), compared to men (adjusted HR, 1.04; 95% CI: 0.83-1.31), p for interaction = 0.02.

CONCLUSION: Loneliness is a significant predictor of all-cause mortality among middle-aged and older U.S. adults with chronic medical conditions, especially among women with heart conditions. Findings highlight the importance of assessment and tailored interventions to address loneliness in clinical settings, particularly for vulnerable mid- to late-life subgroups. Future research should focus on refining screening and intervention strategies to mitigate loneliness-related mortality risks.