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REVIEW ARTICLE

Social isolation and loneliness as modifiable risk factors for dementia: Evidence-based interventions and public health implications

Ongart Maneemai1* ,  Kunwara Maneemai2
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1 Department of Social and Administrative Pharmacy, School of Pharmaceutical Sciences, University of Phayao, Maung Phayao, Phayao, Thailand
2 Department of Nursing, Chiang Rai Prachanukroh Hospital, Maung Chiang Rai, Chiang Rai, Thailand
Advanced Neurology, 025220067 https://doi.org/10.36922/AN025220067
Received: 29 May 2025 | Revised: 3 July 2025 | Accepted: 16 July 2025 | Published online: 7 August 2025
© 2025 by the Author(s). This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution 4.0 International License ( https://creativecommons.org/licenses/by/4.0/ )
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Abstract

Social isolation and loneliness have emerged as significant and modifiable risk factors for dementia, especially in older adults. This narrative review synthesizes current evidence linking these social determinants with cognitive decline, drawing upon longitudinal studies, meta-analyses, and randomized controlled trials. Evidence indicates that social isolation and loneliness independently elevate the risk of developing dementia by 26% and 32%, respectively. These associations are mediated through multiple neurobiological pathways, including hypothalamic-pituitary-adrenal axis dysregulation, neuroinflammation, reduced cognitive reserve, and vascular and metabolic dysfunction. Beyond observational evidence, randomized trials provide causal support by demonstrating that targeted social interventions—particularly those involving group engagement and technology-enhanced connectivity—can slow cognitive decline and preserve functional independence. The Finnish Geriatric Intervention Study and other community-based trials offer proof-of-concept for integrating social support into multidomain dementia prevention strategies. This review also highlights heterogeneity in these associations, with differences observed across sex, education level, culture, and geographic settings. Such variability underscores the importance of tailored interventions that account for individual preferences and contextual barriers to social participation. Clinical implications include routine screening for social isolation and loneliness using validated tools such as the UCLA Loneliness Scale and the Lubben Social Network Scale, and implementation of risk-stratified intervention models within health-care systems. The findings reinforce the urgency of adopting social risk assessment in public health policy, particularly in the context of global population aging and the rise of solitary living. Future directions point to precision medicine approaches that integrate biomarkers and digital health technologies to personalize social interventions. Ultimately, addressing social isolation and loneliness offers a promising and actionable pathway to reduce dementia risk and promote cognitive health across the lifespan.

Keywords
Social isolation
Loneliness
Dementia prevention
Cognitive decline
Neuroinflammation
Public health interventions
Funding
None.
Conflict of interest
The authors declare they have no competing interests.
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