NEW research shows that dementia biomarkers can track cognitive decline and predict progression in people with subjective memory concerns, even before formal diagnosis is reached.
Why Dementia Biomarkers Matter in Subjective Cognitive Decline
People with subjective cognitive decline often report memory problems despite normal performance on clinical testing, placing them in a grey zone between ageing and early disease. Dementia biomarkers are increasingly seen as a way to clarify this uncertainty. Blood based testing is especially attractive because it is less invasive and easier to repeat than brain scans or spinal fluid sampling. Researchers have been searching for reliable markers that change over time in ways that mirror brain health. This approach could allow clinicians to identify people on a higher risk trajectory earlier, opening a window for monitoring, prevention, and future disease modifying therapies.
How Longitudinal Dementia Biomarkers Matched Cognitive Outcomes
The prospective cohort study followed 298 individuals with subjective cognitive decline evaluated at a memory clinic between January 1, 2005, and December 31, 2023. Mean [SD] age was 61.55 [8.08] years and 174 [58.4%] were male. Of these, 80 were amyloid positive and 218 amyloid negative. Mean [SD] follow up was 4.8 [2.6] years. Baseline levels of pTau 217, GFAP, and neurofilament light were higher in the amyloid positive group than the amyloid negative group with estimates [SE] amyloid β of 1.11 [0.11], 0.69 [0.13], and 0.36 [0.10], respectively with P < .001 for all. These dementia biomarkers also increased more steeply over time in amyloid positive participants. Steeper pTau 217 slope was linked to progression to mild cognitive impairment or dementia with a hazard ratio of 3.6 and 95% CI of 1.8 to 7.4 per 0.05 SD increase per year. Steeper GFAP and NfL slopes were also associated with progression. One in five participants initially negative for biomarkers became positive during follow up.
Implications For Clinical Practice and Future Monitoring
For clinicians, these findings support the use of longitudinal dementia biomarkers as practical tools for early risk stratification and disease monitoring. Repeated blood testing could help identify patients who warrant closer cognitive follow up, earlier lifestyle interventions, and future access to disease modifying treatments. As therapies targeting early Alzheimer pathology continue to emerge, the role of dementia biomarkers in guiding timely clinical decisions is likely to expand rapidly.
Reference
Trieu C et al. Longitudinal blood-based biomarkers and clinical progression in subjective cognitive decline. JAMA Netw Open. 2025;8(12):e2545862.
