Cumulative experience of loneliness and frailty progression: A prospective cohort study

OBJECTIVE: Loneliness undergoes changes over time, but its cumulative effect on frailty is unknown. We aimed to investigate the association between cumulative loneliness and frailty. METHODS: 3781 participants from English Longitudinal Study of Ageing (ELSA) waves 2 to 9 were involved. Cumulative loneliness was evaluated by Cumulative Loneliness Index-Sum (CLI-Sum); Cumulative Loneliness Index-AUC (CLI-AUC) and Time-Weighted Average Loneliness Index (TWA-LI). Thirty-items frailty index (FI) was used to assess frailty status. Multivariate linear mixed models and cox proportional hazards models were utilized. RESULTS: Participants in the highest quartile (Quartile 4) of cumulative loneliness exhibited worse frailty compared to Quartile 1: Quartile 4 groups showed faster annual increases in FI, the β (95%CI) were as follows: 0.28 (0.12-0.45) for CLI-Sum, 0.20 (0.04-0.37) for CLI-AUC, and 0.28 (0.12-0.44) for TWA-LI. In addition, Quartile 4 groups associated with higher frailty risk, the hazard ratios (95%CI) were as follows: 1.53 (1.24-1.89) for CLI-Sum; 1.65 (1.34-2.02) for CLI-AUC and 1.61 (1.31-1.99) for TWA-LI and all P trend <0.05. DISCUSSION: Cumulative loneliness can significantly accelerate the frailty progression. Our study emphasizes the significance of improving duration of loneliness.