Prevalence of Dementia and Cognitive Impairment in East Africa Region: A Scoping Review of Population-Based Studies and Call for Further Research

Background

Population-based research on the prevalence and determinants of dementia, Alzheimer's disease, and cognitive impairment is scarce in East Africa.

Objective

To provide an overview of community- and population-based studies among older adults on the prevalence of dementia and cognitive impairment in East Africa, and identify research gaps.

Methods

We carried out a literature search using three electronic databases (PubMed, Scopus, Google Scholar) using pertinent search terms.

Results

After screening 445 publications, we identified four publications on the population-based prevalence of dementia, and three on cognitive impairment. Prevalence rates varied from 6- 23% for dementia, and 7- 44% for cognitive impairment, among participants aged≥50-70 years. Old age and a lower education level were risk factors for dementia and cognitive impairment. Physical inactivity, lack of a ventilated kitchen, and history of central nervous system infections and chronic headache were associated with increased odds of dementia. Female sex, depression, having no spouse, increased lifetime alcohol consumption, low income, rural residence, and low family support were associated with increased odds of cognitive impairment. Potential misclassification and non-standardized data collection methods are research gaps that should be addressed in future studies.

Conclusions

Establishing collaborative networks and partnering with international research institutions may enhance the capacity for conducting population-based studies on dementia and cognitive impairment in East Africa. Longitudinal studies may provide valuable insights on incidence, as well as potential risk and protective factors of dementia and cognitive impairment, and may inform the development of targeted interventions including preventive strategies in the region.

Cognitive impairment and associated factors among mature and older adults living in the community of Gondar town, Ethiopia, 2020

Cognitive impairment and dementia are age-related major public health concerns in the elderly population. It is a major cause of disability, dependency, and poor quality of life. However, in Ethiopia, the magnitude of this cognitive impairment among the elderly community was not investigated. Hence, this study sought to determine the prevalence of cognitive impairment and associated factors among mature and older adults living in the community of Gondar town, Ethiopia, in 2020. A community-based cross-sectional study was conducted at Gondar town, from February 20 to April 30, 2020. Using a single-stage cluster sampling technique, 403 study participants were recruited. Data was collected by a pretested interviewer-administered structured questionnaire which consisting of sociodemographic variables, the Oslo Social Support Scale, and a Standardized Mini-mental State Examination (SMMSE) tool. Epi data version 3.0 was used to enter coded data and then exported into STATA 14 for analysis. Variables with a p-value < 0.25 in the bi-variable logistic regression were included in the multivariable regression. From multivariable logistic regression, variables having a p-value ≤ 0.05 were declared as statistically significant variables. In this study, a total of 403 study participants were involved, and 393 (97.5%) of them completed the survey. Among older participants screened for cognitive impairment, 43.8% was positive for cognitive impairment with a 95% CI (38.8-48.7%). The majority of the participants were (57.5%) male and (44.8%) aged over 60 years. After adjustment, the variables associated with cognitive impairment were age ≥ 75 years [odds ratio (OR) = 7.03, 95% CI 2.78-17.77] and between 61 and 74 years [OR = 3.18, 95% CI 1.81-5.59], and unable to read and write [OR = 5.05, 95% CI 2.04-12.50], low income level [OR = 2.60, 95% CI 1.26-5.20], being female [OR = 2.52, 95% CI 1.50-4.26], poor social support [OR = 2.50, 95% CI 1.30-4.81], and rural residence [OR = 2.39, 95% CI 1.26-4.51]. The prevalence of older participants who screened positively for cognitive impairment was high at Gondar town. The independent predictors of cognitive impairment among older individuals were older age, being unable to read and write, being female, low income, poor social support, and rural dwelling. Therefore, routine screening and social support, as well as free healthcare services for the mature and older community, are needed. Moreover, we strongly recommend the next researcher to use a diagnosis tool to estimate the actual prevalence of the problems among older people.

Dementia in Africa: Current evidence, knowledge gaps, and future directions

In tandem with the ever-increasing aging population in low and middle-income countries, the burden of dementia is rising on the African continent. Dementia prevalence varies from 2.3% to 20.0% and incidence rates are 13.3 per 1000 person-years with increasing mortality in parts of rapidly transforming Africa. Differences in nutrition, cardiovascular factors, comorbidities, infections, mortality, and detection likely contribute to lower incidence. Alzheimer's disease, vascular dementia, and human immunodeficiency virus/acquired immunodeficiency syndrome-associated neurocognitive disorders are the most common dementia subtypes. Comprehensive longitudinal studies with robust methodology and regional coverage would provide more reliable information. The apolipoprotein E (APOE) ε4 allele is most studied but has shown differential effects within African ancestry compared to Caucasian. More candidate gene and genome-wide association studies are needed to relate to dementia phenotypes. Validated culture-sensitive cognitive tools not influenced by education and language differences are critically needed for implementation across multidisciplinary groupings such as the proposed African Dementia Consortium.

Challenges and Assets of Older Adults in Sub-Saharan Africa: Perspectives of Gerontology Scholars

Life expectancy is increasing globally, with the biggest gains expected in sub-Saharan Africa. Using an online survey, we investigated the perspectives of gerontology scholars on the challenges of aging in sub-Saharan Africa as well as the assets of older adults. Respondents (n = 72) from 17 countries, primarily in Africa, and representing 16 disciplines, identified the top issues facing African older adults as: poverty, lack of trained geriatric professionals, food insecurity, disability/health issues, and long-term care. Older adults' unique strengths were noted as indigenous knowledge systems, being holders of cultural heritage, and their contributions to development. Respondents' biggest concerns about older adults in sub-Saharan Africa were the lack of government attention to aging issues (63%) and a lack of social services targeted to older adults' needs (57%). Government funding (77.8%) and international partnerships (38.9%) were noted as resources needed to support aging research in sub-Saharan Africa. The response or non-response of governments in sub-Saharan Africa will determine whether the growing number of older adults will increasingly experience unmet needs and whether their assets will be considered in development efforts. Establishing professional networks of gerontology scholars in the region will help to document the challenges faced by older adults, to plan for the coming demographic shift, and to empower older adults to thrive as valued community members.