Association between neurodegenerative plasma biomarkers and geriatric depression in older adults with and without clinical dementia in Kinshasa, Democratic Republic of the Congo

Abstract

Introduction: Previous Western studies have shown an association between neurodegenerative plasma biomarkers and geriatric depression. However, few studies have examined this relationship in sub-Saharan African countries. This article examines this association in older adults with or without clinical dementia in Kinshasa, Democratic Republic of Congo. Methods: This cross-sectional study included eighty-one people aged 65 years and older assessed for dementia using the Community Dementia Screening Instrument (CSID) and the Alzheimer's Disease Questionnaire. Depression and cognitive impairment were assessed using the Geriatric Depression Scale and the African Neuropsychological Battery (ANB), respectively. Plasma biomarkers measured included β-amyloid (Aβ) 40/42, phosphorylated tau 181 (p-tau), neurofilament light chain (NfL), glial fibrillar acid protein (GFAP), interleukins (IL-1β, IL-10), and tumor necrosis factor-α (TNF-α). Logistic regression models were used to estimate the likelihood that these biomarkers are associated with depression, adjusting for sex, age, and education level. Results: The mean age of the participants was 72.9 years. Of those suspected of suffering from Alzheimer's disease (AD), 80% had geriatric depression. High blood pressure was common in participants with suspected AD (60%). People with dementia had significantly lower cognitive scores on all ANB tests than those without dementia. GFAP and NfL were significantly associated with higher odds of geriatric depression, with odds ratios of 1.98 (1.17-3.67; p = 0.02) and 1.76 (1.06-3.20; p = 0.04), respectively. Other biomarkers were not associated with depression. Conclusion: This study suggests a potential role of nonspecific biomarkers of AD, neurodegeneration, and astrocytic glial activation in geriatric depression in older adults in sub-Saharan Africa.