Established Alzheimer's blood markers turned up as expected in samples collected in Nigeria and Tanzania, but a broader look at blood proteins found meaningful differences compared with a similar group in Canada. The study was led by Andrea Benedet, a researcher at Sahlgrenska Academy, University of Gothenburg, together with Rufus Akinyemi at the University of Ibadan in Nigeria.
The finding lands at a practical moment. Blood biomarkers are attractive because they can flag Alzheimer's-related changes without PET imaging or a spinal tap, which makes them plausible tools for settings where advanced scanners and specialist labs are scarce. But nearly all the research underpinning today's biomarkers has come from high-income countries and people of European ancestry, and the handful of earlier studies in African populations looked only at a small set of already established markers.
That imbalance is the problem Benedet and Akinyemi are pointing to. As Benedet put it, if blood tests are rolled out for diagnosis in different parts of the world without knowing how the markers behave in those populations, misdiagnosis becomes a real risk. Different regions bring different risk factors, environmental exposures and co-existing illnesses, and blood chemistry reflects all of that, not just brain pathology.
The reassuring half of the result is that the core Alzheimer's markers held up across continents. The cautionary half is that the surrounding protein landscape did not, which suggests reference ranges and interpretation thresholds worked out in North America and Europe cannot simply be copied elsewhere. Validating these tests in the populations that will actually use them is the obvious next step.