A prospective association between social isolation and cognitive performance among older adults in Europe: the role of loneliness and poor oral health

Objectives: The relationship between social isolation, loneliness, and tooth loss and cognition in older people is poorly understood. We examine how social isolation and cognitive performance are associated prospectively among older adults, as well as how tooth loss and loneliness are related to this association. Methods: Using data from 26,168 participants aged ≥50 from the Survey of Health, Ageing and Retirement in Europe (SHARE), we explored the association between social isolation, loneliness, tooth loss and cognition. We used bootstrapping with resampling strategies for testing a moderated mediating model. Results: Higher social isolation was associated with poorer cognitive performance (B = −0.20, 95% CI = −0.03, −0.01; R² =0.60), an association mediated by the respondent’s number of missing teeth (B = −0.001, 95% CI = −0.002, −0.001). Higher levels of social isolation were associated with a greater number of missing teeth, and a higher number of missing teeth was linked with poorer cognition. We also found that loneliness moderated the relationship between social isolation and both the number of missing teeth (B = −0.11, p = 0.047) and cognitive performance. Conclusion: In later life, social isolation and loneliness are associated with shoddy oral health and poor cognitive status. Clinicians and policymakers should be aware of both the association between social isolation and feelings of loneliness on dentition and oral health and their relationship to the cognitive status of older adults.