Knowledge and perception of dementia risk and protective factors: a systematic review and meta-analysis

BACKGROUND: Optimal dementia risk reduction strategies benefit from sufficient public knowledge of risk factors and risk perception, but current public awareness is uncertain. METHODS: In a systematic literature review on public knowledge and perception of dementia risk factors, we searched relevant databases for original research articles until 2024. When possible, we pooled study results using random effects meta-analysis, and explored sources of heterogeneity through meta-regression. Qualitative studies and studies about risk perception were analysed using narrative synthesis. FINDINGS: Of 4996 articles screened, 155 were eligible for inclusion. Of these, 125 reported on knowledge of risk factors and 50 on risk perception, jointly providing data from 164,644 participants in 41 countries across 6 continents. Recognition of the 28 queried risk and protective factors was moderate, somewhat higher for lifestyle factors (medians: 38.5-71.5%) than for cardiovascular (9.9-66.9%) and environmental (25.4-44.4%) factors, but with large heterogeneity across queried factors. With the exception of physical activity (71.5%, IQR:46.9-88.3%), social isolation (66.6% [23.7-84.0%]) and traumatic brain injury (65.0% [18.0-76.7%]), recognition of all established modifiable risk factors for dementia from prespecified lists was below 50%, lowest for education (19.5% [7.8-54.9%]), air pollution (25.4% [16.3-41.0%]), and obesity (30.4% [27.0-43.0%]). Recall of risk factors (7 studies) was markedly lower than recognition. Meta-regression analyses showed no consistent differences by year of publication, or by participants' age, gender, and educational attainment. Among 23 qualitative studies, limited knowledge emerged particularly regarding dementia-specific risk factors like hearing loss. Perceived risk was measured inconsistently across studies, but was generally moderate to high, along with notable worry about dementia in a large part of the older population. CONCLUSIONS: Knowledge of dementia risk and protective factors in the general population remains limited. These findings call for population-level interventions, including educational campaigns, to enhance preventive strategies.