Evidence on protective factors for dementia and cognitive impairment in older adults: an umbrella review.

Introduction: Dementia represents a global public health challenge, and no conclusive evidence exists on how to prevent its onset or at least reduce the risk. This umbrella review aims to identify interventions or exposures that can reduce the incidence of dementia or cognitive impairment.

Methods: A search of meta-analyses and systematic reviews published from 2018 to 2025 (January) was conducted across four databases. Articles assessing associations between interventions or exposures to protective factors and incidence of dementia or cognitive decline in non-demented older adults were selected.

Results: Out of 6,324 articles, 177 underwent full-text screening, and 17 were included. They showed that psychosocial factors (social engagement, purpose in life, life satisfaction, and cognitive reserve) and influenza vaccination protect against dementia. Evidence on antihypertensives is promising, while evidence on low-dose aspirin is promising yet inconclusive. No clear results emerged for both single- and multi-domain lifestyle interventions.

Conclusions: These results offer new insight on potential targets for dementia prevention, a global public health priority. In particular, favorable psychosocial factors and influenza vaccination, undervalued in the scientific debate on dementia prevention, emerged as promising and feasible targets for preventive initiatives. Future research should focus on fine-tuning interventions to promote brain health, exploring their underlying mechanisms, and developing targeted and personalized strategies for specific population subgroups.