Blood-based biomarkers show promise for early Alzheimer’s detection

A population study from Finland suggests that early signs of Alzheimer’s disease may be detectable in the brain as early as middle age. The findings open up possibilities for earlier intervention using blood-based biomarkers - potentially allowing preventive treatments to be targeted before cognitive symptoms arise.

As rates of dementia rise with ageing populations, research has increasingly focused on identifying the preclinical stages of Alzheimer’s. Disease processes can begin decades before the first signs of memory loss, yet detection methods such as PET imaging or cerebrospinal fluid analysis remain invasive and costly.

Now, a team at the University of Turku’s Research Centre of Applied and Preventive Cardiovascular Medicine has found that even middle-aged individuals (aged 41–56) can carry elevated levels of blood biomarkers associated with Alzheimer’s disease. These levels increased with age and were also found to correlate with concentrations in older parents (aged 59–90) - particularly mothers. The study [1] involved over 2,000 participants from the ongoing national Cardiovascular Risk in Young Finns Study.

Researchers also found that kidney disease may influence biomarker levels in midlife. The APOE ε4 gene - a known genetic risk factor for Alzheimer’s - was linked to higher biomarker levels in older age, though not significantly in the younger cohort.

“These ultrasensitive measurement technologies allow us to detect Alzheimer’s-related brain pathology through a simple blood test,” said Senior Researcher Suvi Rovio, who led the study. “However, blood-based diagnostics still lack clear reference values and remain vulnerable to confounding factors, which can increase the risk of misdiagnosis.”

The team emphasises that more research is needed across diverse populations and age groups to standardise biomarker thresholds and confirm their clinical utility.

“Until now, most studies have focused on older individuals,” added Senior Researcher Marja Heiskanen. “Our findings give us new insight into how Alzheimer’s-related changes may start emerging decades earlier.”

More information online

1.    Factors related to blood-based biomarkers for neurodegenerative diseases and their intergenerational associations in the Young Finns Study: a cohort study published in The Lancet Healthy Longevity