Social frailty as a predictor of new onset dementia in older adults

Abstract

Social frailty, defined as the loss of essential social resources, has been linked to cognitive impairment. Yet, few studies have examined whether changes in social frailty influence dementia risk or transitions along the cognitive decline continuum. We included 13,207 community‐dwelling adults aged ≥ 65 from the National Health and Aging Trends Study (2011–2024), a nationally representative sample of US Medicare beneficiaries. Social frailty was measured using a 5‐item index (social frailty index [SFI]: 0–5) and treated as time varying in survey‐weighted Cox models estimating risk of probable dementia, mild cognitive impairment (MCI), and MCI‐to‐dementia transitions. Each 1‐point increase in SFI was associated with a 16% higher dementia risk (hazard ratio 1.16, 95% confidence interval 1.07–1.26) after adjustment. Compared to robust (0), prefrail (1) and frail (≥ 2) individuals had 29% and 75% higher risks, respectively. Similar patterns were observed for incident MCI, but not for MCI‐to‐dementia transition. Time‐varying social frailty was associated with incident dementia and MCI.