The association between loneliness, cognition, and dementia among Unites States older adults.

BackgroundThe "loneliness epidemic" is a major public health concern, and its effects can be especially adverse in older adults.ObjectiveThe current study used longitudinal data to investigate the associations between loneliness, cognitive function and decline, and dementia risk.MethodsData were derived from older adults (n = 5730 at the baseline) who participated in the 2008-2018 Health and Retirement Study (HRS). We fit cross-lagged panel as well as linear and logistic regression models, accounting for the complex design of HRS, to assess the bi- and uni-directional relationship between loneliness and cognitive function/decline/dementia risk, sequentially adjusting for social determinants of health, health conditions, and functional limitations. We tested for modifications by race/ethnicity.ResultsWe found low support for a bidirectional association between loneliness and cognitive function. Instead, higher levels of loneliness were linked to more pronounced cognitive decline as well as a higher risk of dementia prevalence and incidence, irrespective of race/ethnicity. Education partially attenuated the relationship, and overall functional limitations further reduced the associations.ConclusionsFindings suggest that education and overall functional limitations can play an important role through several pathways, such as increasing social engagement, facilitating social support and cognitive stimulation, and thus reducing the impact of loneliness on cognitive decline and dementia risk.