How well do social frailty indices predict incident dementia in older adults?

Few studies have examined the association between social frailty and dementia. We aim to assess if social frailty indices predict dementia and evaluate causality.

Data from 851 community-dwelling participants aged 70 years and older without dementia from the Sydney Memory and Ageing Study were used. Social frailty was assessed using five published indices that incorporated a range of psychosocial factors. Incident dementia was assessed by consensus diagnosis using biennial neuropsychological tests over a 12-year period.

Based on Cox regression, social frailty was predictive of an increased risk of incident dementia using three different indices. After adjusting for a range of confounders, including physical and psychological frailty, evidence of a causal association was found using one of the indices (socially frail vs nonfrail hazard ratio [HR] 1.47, 95% confidence interval [CI] 1.05-2.07). Low financial and family satisfaction, infrequent social contacts, and limited participation in social activities and volunteering were associated with an increased risk of dementia, with low financial satisfaction an independent predictor.

Well-designed social frailty indices are an effective way to help identify older adults at increased risk of dementia. Replication of these findings in other cohorts is necessary to validate a screening tool for social frailty. Screening for social frailty using brief measures in primary care is a key next step, alongside social prescribing programs for those at risk of social frailty and cognitive decline.