Blood-Based Biomarkers Could Detect Alzheimer's as Early as Middle Age

As the global population ages, Alzheimer's disease and other dementing diseases are becoming more prevalent. The disease processes leading to Alzheimer's symptoms can begin years or even decades before cognitive decline becomes apparent. Detecting the disease at its early stages is challenging, and the current methods for identifying Alzheimer's, such as imaging studies or cerebrospinal fluid sampling, are invasive and costly. Furthermore, the identification of biomarkers associated with Alzheimer’s is not well-established in younger populations. Now, a Finnish population study has shown that signs related to Alzheimer’s disease may already be found in the brain in middle age. In the future, blood-based biomarkers associated with Alzheimer's could allow earlier detection of the disease. This would allow preventive treatment to be targeted at the right individuals while the disease is still at the mild stage.

The study conducted at the University of Turku in Finland (Turku, Finland investigated blood-based biomarkers as a method for detecting Alzheimer’s risk. The study involved middle-aged participants (ages 41–56) and their parents (ages 59–90), totaling 2,051 individuals. The researchers measured the levels of biomarkers in the blood to understand how these levels may be associated with Alzheimer’s, particularly in middle-aged individuals. The study found that high levels of certain blood-based biomarkers associated with Alzheimer’s were already present in middle-aged individuals, with concentrations increasing with age. A key finding was the association between high biomarker levels in parents, especially mothers, and higher biomarker levels in their middle-aged offspring.

These findings, published in Lancet Healthy Longevity, demonstrates that blood-based biomarkers could be a promising tool for detecting Alzheimer's at earlier stages. Although the blood sample method is not yet definitive for diagnosing Alzheimer's, the study shows potential for identifying individuals at risk using this non-invasive approach. It was also found that kidney disease may be linked to higher biomarker levels in middle age, while the APOE ε4 gene, which increases Alzheimer's risk, was associated with higher biomarker levels in older age but not in middle age. The findings suggest that blood-based biomarkers could become a cost-effective and less invasive diagnostic method in the future, but more research is needed to standardize reference values and account for confounding factors.

“Until now, brain biomarkers associated with Alzheimer's disease have mainly been studied in older individuals. Our study provides new insights into biomarker levels and associated factors starting from middle age," said Marja Heiskanen, Senior Researcher at the University of Turku.