Established Alzheimer’s markers are also detected in blood samples from Nigeria and Tanzania. But other proteins in the blood differ from those seen in a comparable group in Canada. This is important if blood tests for Alzheimer’s are to be used globally.

Blood biomarkers may make it possible to detect changes seen in Alzheimer’s disease without advanced brain imaging or cerebrospinal fluid tests. At the same time, much of the research behind today’s biomarkers has been conducted in high-income countries and in people of European ancestry. Previous studies in African populations have mainly examined a smaller number of already established markers.

Need to work across different populations
Andrea Benedet, a researcher at Sahlgrenska Academy, University of Gothenburg, led the study together with Rufus Akinyemi at the University of Ibadan in Nigeria:

“As blood tests begin to be used to diagnose Alzheimer’s disease in different parts of the world, we need to know how well the markers work across different populations. Otherwise, we risk misdiagnosis because much of today’s knowledge is based on a limited part of the world’s population. People in different parts of the world may face different risk factors and environmental exposures and have different comorbidities,” says Andrea Benedet.

This is the largest biomarker study of Alzheimer’s disease conducted in Africa to date. The researchers analyzed blood samples from 949 people over age 50 in Nigeria and examined how a large number of proteins were associated with signs of amyloid changes and cognitive impairment.

The key findings were then tested in 196 older people in Tanzania and compared with detailed data from a Canadian study. The study is published in the journal Nature Communications.

Similarities and differences in the blood
Several established tau biomarkers showed similar patterns among people with and without likely amyloid pathology in the African and North American groups. The broader protein profile, however, showed some differences and was more similar between the Nigerian and Tanzanian groups than between the African and Canadian groups.
The researchers also found associations between levels of certain proteins and conditions including heart disease, a history of infectious disease, and high cholesterol. Such comorbidities may need to be taken into account when interpreting biomarkers and developing reference values for different parts of the world.

One methodological limitation is that amyloid pathology in the African groups could not be confirmed through brain imaging or cerebrospinal fluid tests. Instead, the researchers used blood p-tau217 and thresholds validated in non-Hispanic white populations, which are unlikely to be optimally suited to the African groups.

Article: Plasma proteomic profiles of Alzheimer’s disease and neurodegeneration in African cohorts; https://doi.org/10.1038/s41467-026-74971-4
Expert contact: Andrea Lessa Benedet, researcher, Sahlgrenska Academy at the University of Gothenburg, email andrea.benedet@gu.se.