Public Health

In 2024, the Lancet Commission on Dementia published another iteration of risk factors and observed that almost half of the burden of dementia is potentially preventable by tackling 14 modifiable risk factors. We performed a preliminary analysis of the risk factors in the African datasets of the ongoing Recruitment and Retention for Alzheimer's Disease Diversity Genetic Cohorts in the ADSP (READD-ADSP) study.

The READD-ADSP is an ongoing case-control study recruiting and evaluating 13,000 participants consisting of 5,000 Africans, 4,000 Black Americans, and 4,000 Hispanic/Latino individuals to elucidate the complete genetic background of AD for the development of global treatments and preventions. The African Dementia Consortium (AfDC) is coordinating ongoing recruitment in ten sub-Saharan African countries. Protocols were developed to ensure standardized data collection, phenotype harmonization, and culturally informed diagnostic algorithms. We present results of preliminary analysis exploring 12 of the Lancet Commission's 14 modifiable risk factors (excluding LDL-c and air pollution). A multivariable logistic regression analysis was used to assess the effect sizes of the dementia risk factors in the study population.

Data consisted of 1469 participants (626 cases and 843 controls; mean age 75.3 =/-9.5 yrs; 41.5% male). Mean age of the cases was 77.0±9.5years while that of controls was 74.1±9.2years (p <0.001). Older age, female sex, hypertension, hearing loss, depression, physical inactivity, low level of education, and social isolation were significantly more prevalent among cases compared to controls. However, self-reported Visual loss was more prevalent in the control population. Factors independently associated with dementia in this analysis include age (AOR 1.03: 1.02-1.04), hypertension (AOR=1.35; 1.06-1.72) alcohol use (AOR=0.34, 0.13-0.87), depression (AOR=2.60; 2.09-3.23) and self-reported visual impairment (AOR=0.62; 0.48-0.80). Age, sex, hypertension, and alcohol exhibit region-specific differences in magnitude and direction between East and West Africa, while depression and self-reported visual impairment show consistent effects. However, potential confounding remains a concern due to cross-regional variations in some factors.

Our findings highlight the unique contributions of multi-modal risk factors to dementia burden among Africans. As additional data are collected, further analyses will examine the interactive effects of region, ethnicity and other factors.