Population attributable fraction of modifiable risk factors for dementia in the Democratic Republic of Congo: A community-based cross-sectional analysis.

Background: Estimates from high-income countries suggest that approximately 40% of dementia cases may be attributable to modifiable risk factors across the life course. However, most evidence informing these estimates originates from high-income settings, and population-level estimates from sub-Saharan Africa remain limited. We aimed to estimate population attributable fractions (PAFs) for modifiable dementia risk factors in the Democratic Republic of the Congo (DRC). Methods: We conducted a cross-sectional analysis of community-dwelling adults aged 65 years and older enrolled in the Findings: Combined modifiable risk factors were estimated to account for 37.3% (95% CI 14.3-55.6) of dementia cases in this sample. Poverty had the largest weighted PAF (18.4%, 95% CI 13.3-22.8), followed by low educational attainment (11.3%, 95% CI 7.3-15.3) and depression (5.8%, 95% CI 2.8-8.6). Additional contributors included traumatic events (5.4%), war exposure (2.1%), diabetes (1.3%), and hypertension (1.1%). A hypothetical 15% proportional reduction in these risk factors was estimated to reduce dementia prevalence by 6.4% (95% CI 2.1-10.8), corresponding to approximately 10 700 cases prevented in the DRC by 2025. Interpretation: Modifiable risk factors account for a substantial proportion of dementia burden in the DRC, with structural determinants such as poverty and education contributing the largest fractions. Dementia prevention strategies in low- and middle-income countries may therefore require broader public health approaches that address socioeconomic and structural determinants alongside conventional clinical risk factors. Funding: National Center for Advancing Translational Sciences of the National Institutes of Health (UL1TR002378).