Loneliness is associated with risk of cognitive impairment in the Survey of Health, Ageing and Retirement in Europe

Objectives: To test whether loneliness is associated with risk of cognitive impairment up to 11 years later in a European sample of middle-aged and older adults. The study examines whether this association is independent of measures of social isolation, depression and other risk factors for cognitive impairment and dementia.Methods: Participants (N = 14,114) from the Survey of Health, Ageing and Retirement in Europe (SHARE) answered a single item on loneliness at baseline and were assessed for cognitive impairment every two-to-three years for 11 years. Participants who scored at least 1.5 standard deviations below the age-graded mean on both a memory recall task and verbal fluency task were classified as impaired. A 3-item measure of loneliness was available for a sample of respondents followed up to 4 years.Results: Feeling lonely was associated with increased risk of incident cognitive impairment (HR = 1.31, 95%CI = 1.19-1.44), after accounting for age, sex, education, and SHARE country strata. The association was robust but reduced in magnitude when controlling for clinical and behavioral risk factors, health-related activity limitations, social isolation, social disengagement and depressive symptoms. The association was not moderated by socio-demographic factors and was also apparent when using the 3-item loneliness scale instead of the single-item measure.Conclusions: These findings expand the extant literature on loneliness and risk of cognitive impairment in older adulthood. Loneliness is one modifiable factor that can be intervened on prior to the development of severe impairment or dementia.