Genetic and environmental risk factors for dementia in African adults: A systematic review

Dementia, a leading cause of global mortality, disproportionately impacts sub-Saharan Africans due to complex genetic and environmental interactions. This systematic review evaluated dementia risk factors among sub-Saharan Africans, identifying significant genetic and environmental influences using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The ATP-binding cassette subfamily A member 7 (ABCA7) gene, linked to dementia in African Americans, and unique genetic variants like those in A-kinase anchor protein 9 (AKAP9) and cytidine deaminase (CDA) genes, emerge as potential contributors. Conversely, apolipoprotein E (APOE) ε4 shows lesser impact in older sub-Saharan Africans. Environmental findings highlight that exposure to air pollution, including nitrogen dioxide and particulate matter increases the likelihood of dementia. These findings highlight the role of genetic and environmental diversity in shaping dementia risk profiles. Strategies such as training health-care professionals, enhancing funding for research, combating stigma through awareness campaigns, and fostering global collaborations are vital to ensure African representation in dementia studies. These efforts aim to improve the knowledge of dementia tailored to sub-Saharan Africa's needs. HIGHLIGHTS: The ATP-binding cassette subfamily A member 7 (ABCA7) gene is strongly associated with dementia risk, particularly in African American populations. Apolipoprotein E (APOE) ε4, a well-established risk factor for Alzheimer's disease in Western populations, has a lesser impact in older sub-Saharan Africans, suggesting unique genetic-environment interactions. Exposure to air pollutants, such as nitrogen dioxide and particulate matter, significantly increases dementia risk. The development of dementia in sub-Saharan Africans is influenced by complex interactions between genetic predispositions and environmental exposures, emphasizing the need for tailored prevention strategies.