The data is available in Brazil for people aged 25 years and over through the PNAD 2017 (National Household Sample Survey) and shows that 59% of the population have completed primary education in Brazil. However, if we consider the proportion of people that have the primary education as their most advanced level of education, this proportion drops to 8.5% among people aged 25 years and older. There are 12.4% of women and 13.6% of men who completed primary education as their most advanced level of education (PNAD, 2017).  As mentioned previously, a systematic review conducted in 2011 showed that the prevalence of dementia increased with age and was inversely related to the socioeconomic status and number of years of education (Fagundes et al., 2011).

References:

Fagundes, S. D., Silva, M. T., Thees, M. F. R. S., & Pereira, M. G. (2011). Prevalence of dementia among elderly Brazilians: A systematic review. Sao Paulo Medical Journal, 129(1), 46–50. https://doi.org/10.1590/S1516-31802011000100009

PNAD. (2017). PNAD Contínua: Edição 2017. https://agenciadenoticias.ibge.gov.br/media/com_mediaibge/arquivos/05dc6273be644304b520efd585434917.pdf