Prevalence and Risk of Dementia Among Adults Who Have Experienced Homelessness, a Meta‐Analysis

Background Understanding the prevalence and risk of dementia in homeless adults has important implications for ensuring appropriate resources are directed towards dementia prevention and healthy aging. We aimed to estimate the: (1) prevalence and (2) risk of dementia among homeless adults, and (3) risk of homelessness in adults experiencing dementia. Methods A systematic search was completed in MEDLINE, PsycINFO, Embase, CINAHL, Cochrane Central, Social Works Abstracts, and the gray literature from inception to September 26, 2024. Studies investigating the prevalence of dementia among individuals experiencing homelessness aged 18 years or older were included. Title, abstract, and full text screening, extraction, and risk of bias assessments were completed in duplicate. Random effects meta‐analysis using generalized linear mixed models was used to estimate the prevalence of dementia. For the risk and incidence of dementia, we meta‐analyzed the risk and hazards of dementia comparing homeless to housed individuals. Results A total of 1585 citations were retrieved, with 102 studies undergoing full‐text review. Thirty‐six studies were included in the final review (504,766 individuals experiencing homelessness, with the following weighted by sample size: mean age 63.08, female percentage 10.64). The prevalence of dementia was 6.81% (95% CI: 4.49, 10.19%, I 2 = 99.7%). Among those who experienced homelessness compared to housed individuals, the risk ratio for dementia was 1.03 (95% CI: 0.52, 2.03, I 2 = 99.7%), and the incidence (hazard ratio) for dementia was 1.54 (0.52, 4.50, I 2 = 98.0%). One study showed that a younger age was associated with homelessness among adults with dementia. Conclusions This systematic review and meta‐analysis suggests that homeless individuals have a dementia prevalence higher than population‐based studies of housed adults of a similar age, where the estimated prevalence is under 3%. Research on models of care aimed at reducing homelessness in those experiencing dementia is needed. Trial Registration PROSPERO: CRD42024595047