Summary: New research indicates that Alzheimer’s-related changes can be detected in blood samples from people as young as their early 40s. A Finnish cohort study led by the University of Turku found elevated concentrations of several Alzheimer’s-associated blood biomarkers in middle-aged adults, with stronger signals among those whose mother had high biomarker levels and among individuals with impaired kidney function.
These results suggest blood-based testing could eventually enable earlier, more targeted prevention while pathology is still mild and potentially reversible. However, broader validation and standardized reference values are required to avoid misinterpretation and misdiagnosis before blood testing becomes routine in clinical practice.
Key Facts:
- Alzheimer’s-related blood biomarkers are detectable in some people aged 41–56.
- Higher parental—especially maternal—biomarker concentrations correlated with elevated levels in offspring.
- Markers of reduced kidney function were associated with adverse biomarker profiles in both generations.
- Blood biomarkers could become an affordable screening tool, pending further validation and standardization.
Source: University of Turku
A population study from Finland suggests Alzheimer’s-related brain changes may begin in middle age and can be reflected in blood biomarkers. If validated, blood tests could identify at-risk individuals earlier, improving the timing and targeting of preventive measures.
With global ageing, Alzheimer’s disease and other dementias are rising in prevalence. Pathological processes that lead to symptomatic cognitive decline often start many years, even decades, before memory or other functions decline noticeably. Detecting these changes earlier could be critical for effective prevention and intervention.
Researchers at the University of Turku measured several blood-based biomarkers associated with Alzheimer’s disease in a multigenerational Finnish cohort. They observed that biomarker concentrations tended to rise with age, and that certain familial and health factors were linked to higher levels already in middle age.
A notable result was the intergenerational association: elevated biomarker concentrations in a parent—most consistently in mothers—were associated with higher biomarker levels in their middle-aged children. The study also identified an association between impaired kidney function and higher concentrations of Alzheimer’s-related biomarkers across both generations.
Carriage of the APOE ε4 allele, a well-known genetic risk factor for Alzheimer’s disease, was associated with more adverse blood biomarker profiles in older adults, but this association was not yet apparent in the middle-aged group.
Blood tests could transform Alzheimer’s detection in the future
Recent advances in ultra-sensitive assays make it possible to detect Alzheimer’s-related proteins in blood. If validated and standardized, these assays could provide a low-cost, scalable approach to identify people at increased risk, prioritise them for confirmatory testing, and enrol them in prevention strategies while pathology is still limited.
“Currently, detecting beta-amyloid pathology requires PET imaging or cerebrospinal fluid analysis. New ultrasensitive blood assays now allow us to measure key Alzheimer’s biomarkers from blood samples,” says Suvi Rovio, Senior Researcher at the Research Centre of Applied and Preventive Cardiovascular Medicine at the University of Turku and lead author of the study.
However, blood-based diagnosis is not yet definitive. A key limitation is the absence of well-established reference values across diverse populations and ages, and an incomplete understanding of how other physiological conditions influence biomarker concentrations. Misinterpretation of blood biomarkers could therefore lead to false reassurance or unnecessary alarm.
“To reliably use blood-based biomarkers in routine clinical care, we need more research across different populations and age groups to develop standardized reference ranges,” Rovio adds.
This study analyzed blood samples from 2,051 participants: 1,237 middle-aged adults (41–56 years) and 814 of their parents (59–90 years). The findings extend biomarker research into midlife, offering new insight into when Alzheimer’s-associated changes begin to appear in peripheral blood.
“Most prior biomarker studies have focused on older adults. Our work reveals relevant biomarker patterns and risk associations that are already present in middle age,” says Marja Heiskanen, Senior Researcher at the same research centre.
The study is part of the national Cardiovascular Risk in Young Finns Study, coordinated by the Research Centre of Applied and Preventive Cardiovascular Medicine at the University of Turku. The results are published in Lancet Healthy Longevity.
About this Alzheimer’s disease research news
Author: Tuomas Koivula
Source: University of Turku
Contact: Tuomas Koivula – University of Turku
Image: The image is credited to Neuroscience News
Original Research: Open access.
“Factors related to blood-based biomarkers for neurodegenerative diseases and their intergenerational associations in the Young Finns Study: a cohort study” by Suvi Rovio et al. Lancet Healthy Longevity
Abstract
Factors related to blood-based biomarkers for neurodegenerative diseases and their intergenerational associations in the Young Finns Study: a cohort study
Background
Blood-based biomarkers (BBM) for neurodegenerative diseases are emerging as potentially cost-effective tools to support differential diagnosis of Alzheimer’s disease and other dementias. There is limited population-based data on what drives variation in BBM, and intergenerational associations have not been well characterised.
This study aimed to map BBM distributions in a population cohort, examine a wide range of potential explanatory factors in midlife and older age, and evaluate intergenerational associations of BBM within families.
Methods
Using the Quanterix Simoa HD-X analyser, researchers measured biomarkers reflecting amyloid-β and tau pathology—amyloid β42, amyloid β40, and phosphorylated tau (pTau)-217—alongside glial fibrillary acidic protein (GFAP) and neurofilament light chain (NfL). The cohort included 1,237 participants aged 41–56 and 814 parents aged 59–90 from the multigenerational Young Finns Study.
Standard statistical methods evaluated associations between BBM and age, sex, genetic factors (including APOE ε4), cardiometabolic markers, liver and kidney function, lifestyle factors, and intergenerational correlations.
Findings
Advancing age correlated with less favourable BBM profiles. Among examined factors, APOE ε4 carrier status in parents showed robust associations with adverse BBM (amyloid β42:40 ratio, pTau-217, GFAP). Elevated serum creatinine—an indicator of reduced kidney function—was linked to higher pTau-217, GFAP, and NfL in both generations.
Several metabolic factors related to glucose regulation and dyslipidaemia were associated with BBM, though many of these associations weakened after adjusting for BMI. Intergenerational correlations for BBM ranged from 0.20 to 0.33, most notably between mothers and offspring for pTau-217, GFAP, and NfL; no parent–offspring correlation was found for the amyloid β42:40 ratio.
Interpretation
The study identifies multiple factors that may influence blood-based neurodegeneration biomarkers, including parental transmission. To implement BBM reliably in clinical practice, it will be essential to distinguish factors directly reflecting amyloid and tau pathology from those that modify biomarker concentrations through other physiological pathways.
Funding
This research was funded by a range of national and international agencies and foundations, including the Research Council of Finland, the Social Insurance Institution of Finland, competitive state research financing of Finnish university hospitals, and several private foundations and EU research grants.