Associations between Homelessness and Alzheimer's Disease and Related Dementia: A Systematic Review.

The homeless population in the United States is rapidly aging, with a parallel increase in Alzheimer's disease and related dementia (ADRD). During an evolving pandemic that jeopardizes employment and housing, assessing the relationship between ADRD and homelessness is critical since the latter is potentially intervenable. The objective of this study is to review the literature and determine whether there is an association between homelessness and dementia risk. A systematic review of existing studies was conducted through PubMED, SCOPUS, and EMBASE among others. Of the 228 results found, nine met inclusion criteria. Homeless studies mainly centered on veteran populations (n = 6/9). There is a complex relationship suggesting homelessness as a risk for and consequence of ADRD but also co-occurrence with psychiatric disorders, substance abuse, and traumatic injuries. Future studies should employ enumeration surveys with modular longitudinal tracking and measure social determinants of health, discrimination, chronic stress, and mood disorders.