Individual and neighborhood socioeconomic inequality and the risk of dementia: A 14‐year follow‐up study

INTRODUCTION: Socioeconomic inequality is a non-negligible risk factor for dementia. However, complex associations of individual socioeconomic status (ISES) and neighborhood socioeconomic status (NSES) with dementia risk have not been determined. METHODS: In 327,641 adults aged 40-69 years from the UK Biobank, we estimated the separate, interactive, and joint associations of ISES and NSES with the risk of dementia and explored the role of inflammatory markers and metabolites. RESULTS: Low ISES and low NSES were associated with higher risks of all-cause dementia and its subtypes. A stronger association between ISES and dementia was observed in those with low NSES. The subpopulation with disadvantages in both ISES and NSES showed the highest risk of dementia. Inflammatory markers (e.g., lymphocyte percentage) and metabolites (e.g., valine) mediated the associations of socioeconomic status (SES) profiles with all-cause dementia. DISCUSSION: These findings underscore the importance of eliminating socioeconomic inequality at both individual and neighborhood levels for preventing dementia. HIGHLIGHTS: Disadvantages in both individual socioeconomic status (ISES) and neighborhood socioeconomic status (NSES) are associated with higher risks of dementia. There are significant interactions between ISES and NSES on dementia risk. The low SES subpopulation with disadvantages in both ISES and NSES has the highest risk of dementia. Inflammatory markers and metabolites partially mediate the associations of socioeconomic status (SES) profiles with all-cause dementia. Narrowing socioeconomic inequality at both the individual and neighborhood levels may help prevent dementia.