Loneliness trajectories and long-term frailty in the english longitudinal study of ageing: The mediating role of depression

BACKGROUND: Although longitudinal studies have explored the relationship between loneliness and frailty, the long-term changes in these conditions have often been overlooked. The mechanism by which loneliness increases the risk of frailty remains unclear. This study aimed to explore the association between loneliness trajectories and frailty and the mediating role of depression. METHODS: The English Longitudinal Study of Ageing was used as the data source. Loneliness was measured using the revised University of California, Los Angeles Loneliness Scale and frailty was evaluated using the deficit accumulation frailty index. Group-based trajectory modeling (GBTM) was applied to analyze the loneliness and frailty trajectories. Ordinal logistic regression models were used to examine associations between loneliness trajectories and three-class frailty trajectories. Mediation analyses assessed depression to these associations. RESULTS: 4393 participants aged 62.38 (7.46) years were included in the study. Out of them, 57.5% were female and 98.6% were white. The GBTM identified five loneliness trajectories: long-term low (n = 1430, 32.55%), persistently decreasing (n = 677, 15.41%), persistently increasing (n = 878, 19.99%), long-term moderate (n = 1229, 27.98%), and long-term high loneliness (n = 179, 4.07%). Compared with the long-term low loneliness group, the full-adjusted ORs (95% CIs) for the persistently increasing, persistently decreasing, long-term moderate group, and the long-term high group were 1.454 (1.153-1.833), 1.707 (1.313-2.215), 2.162 (1.746-2.681), and 3.574 (2.426-5.260), respectively. Depression may play a potential mediating role in the association between loneliness and frailty. CONCLUSIONS: These findings suggest that alleviating loneliness is associated with a reduced risk of frailty among older adults.