Social determinants of health and health inequalities in Alzheimer's Disease in the United Kingdom: A Systematic Review of the Evidence between 2018 and 2024

Background: Alzheimer's disease (AD) accounts for 60–70% of dementia cases worldwide and remains a leading cause of death in England and Wales (Leahy et al., 2023; WHO, 2021). Its prevalence, progression and management are shaped not only by biological ageing but also by health inequalities and the social determinants of health (SDoH), yet the mechanisms linking these factors to AD outcomes in the UK remain fragmented across the literature. 
Aim: This systematic review synthesises evidence on how health inequalities and SDoH influence AD prevalence, progression and management in the UK. 
Methods: Following PRISMA 2020 guidance (Page et al., 2021), a systematic literature search was conducted across ProQuest Central, PubMed, Medline and APA PsycINFO (supplemented by Web of Science, Scopus, ScienceDirect and Embase) for studies published between January 2018 and January 2024. Thirteen studies (quantitative n=8, qualitative n=4, mixed-methods n=1) met the eligibility criteria and were appraised using the Mixed Methods Appraisal Tool. 
Results: Four themes emerged: (1) demographic, socioeconomic and geographic health inequalities in AD; (2) SDoH – including economic stability, education, healthcare access and social context – as drivers of AD prevalence; (3) the influence of health inequalities on disease progression, institutionalisation and mortality; and (4) the role of health promotion in dementia-risk reduction. Deprivation, social isolation, loneliness and unequal access to healthcare consistently predicted poorer AD outcomes across demographic groups, including older adults, women, and socioeconomically disadvantaged populations. 
Conclusion: Health inequalities and SDoH interact across individual, interpersonal, community and societal levels to shape AD outcomes in the UK. 
Recommendations: Policy and practice should prioritise equitable healthcare access, health literacy, social-support infrastructure, and multidisciplinary, Theory-of-Change-informed strategies to reduce AD-related health disparities.