Trajectories of cognitive decline before and after new-onset loneliness: The English Longitudinal Study of Ageing

BACKGROUND: The trajectories of cognitive decline before and after new-onset loneliness remain largely unknown. This study aims to explore the change trajectory of cognitive function before and after the onset of loneliness in individuals compared with those who were non-loneliness. METHODS: Participants were included without loneliness at baseline and with at least two recorded cognitive measures from the English Longitudinal Study of Ageing (ELSA) database. Propensity score matching (PSM) was used to balance the confounding factors between groups. A linear mixed-effects model was used to analyze the trend of cognitive function changes over time before and after loneliness. RESULTS: Before the onset of loneliness, there was no significant difference in the slope of cognitive decline between the two groups (the loneliness group vs. the non-loneliness group). After the onset of loneliness, the rate of global cognitive decline of the loneliness group was significantly faster than the non-loneliness group (β: -0.010 standard deviation/year, 95% confidence interval: -0.015 to -0.005). CONCLUSIONS: Incident loneliness is associated with accelerated cognitive decline after, but not before, the event. The onset of loneliness marks a critical inflection point, associated with a subsequent acceleration in cognitive decline. The identification of new-onset loneliness can be an indication to initiate more intensive cognitive monitoring.