Cohort profile: A community-based prospective cohort study of Alzheimer's disease and related dementias in the Democratic Republic of Congo

INTRODUCTION: The Étude du Vieillissement Cognitif et de Démence en République Démocratique du Congo (Study of Cognitive Aging and Dementia in the Democratic Republic of Congo, EVCD-RDC) was launched in 2024 to characterize cultural, biological, and environmental risk factors of cognitive aging and dementia in Kinshasa. METHODS: The study is enrolling 800 adults aged ≥65 years across four diagnostic groups (cognitively unimpaired, mild cognitive impairment, Alzheimer's disease [AD], and other dementias). Recruitment occurs through community and clinical settings. Assessments include neuropsychological testing, neurological examination, social determinants, biospecimen collection, and air pollution exposure, with follow-up every two years. RESULTS: To date, 506 participants have been enrolled (mean age: 73.4 years; 59.3% women). Dementia cases had greater prevalence of hypertension and other comorbidities, more neuropsychiatric symptoms, higher rates of smoking and alcohol use, lower body weight, reduced educational attainment and resilience, and increased exposure to air pollution, war, traumatic experiences, and poverty. The internal consistency of cognitive measures ranged from 0.44 to 0.91. DISCUSSION: EVCD-RDC establishes the first large-scale dementia cohort in French-speaking Sub-Saharan Africa, providing critical infrastructure and insights into risk factors for Alzheimer's disease and related dementias.