No nationally representative data on the prevalence or incidence of dementia. However, a smaller dementia prevalence study conducted in a rural, isiXhosa-speaking area in South Africa found no association with sex (De Jager et al., 2017). No representative data available to report on different ethnic groups (as study mentioned here did not have ethnic representativeness in sample).

References:

De Jager, C.A., Msemburi, W., Pepper, K., & Combrinck, M. (2017). Dementia Prevalence in a Rural Region of South Africa: A Cross-Sectional Community Study. Journal of Alzheimer’s Disease, 60(3), 1087–1096. https://doi.org/10.3233/JAD-170325