Plasma and cerebrospinal fluid (CSF) biomarkers of dementia have impacted the field significantly in recent years. Biomarkers now allow for increasingly accurate classification of patients in terms of amyloid status (e.g. pTau217), neuroinflammation (e.g. GFAP), and neurodegeneration (e.g. NfL), aiding in diagnosis and prognosis. Dementia, however, is a heterogeneous condition, and specific endophenotypes exist beyond these general classifications. Proteomic profiling of patients may allow for a better understanding of disease subtypes and reveal therapeutic targets. Brazil has the world’s largest recently admixed population, with remarkable genetic diversity, but it remains severely understudied in dementia research. Here we report on the first affinity proteomics dataset from a Brazilian dementia cohort. This study contributes proteomic data from an understudied population and may provide insights into the molecular dynamics between brain amyloidosis and cognitive decline.