Advancements in Early Detection of Dementia
Diagnostic tests are improving in their ability to detect the earliest signs of dementia. Recent research indicates that a simple blood test might identify individuals at risk up to 25 years before symptoms manifest.
Having a warning is essential when it comes to conditions like dementia. It allows for better preparation in terms of preventive treatments, support, and care, while also enabling researchers to understand the underlying biological mechanisms.
This latest study, conducted by a team from various U.S. institutions, analyzed blood samples from 2,766 women aged 65 to 79. All participants were cognitively healthy at the time of testing in the 1990s, and their cognitive functions were tracked for up to 25 years.
The focus of the research was a specific protein in the blood known as plasma phosphorylated tau 217 (p-tau217). Elevated levels of this protein in the blood have been associated with tau tangles in the brain, a hallmark of Alzheimer’s and other types of dementia.
Neuroscientist Linda McEvoy from the Kaiser Permanente Washington Health Research Institute remarked that “blood-based biomarkers like p-tau217 are particularly promising, as they are less invasive and could be more accessible than traditional brain imaging or spinal fluid tests.”
This research highlights a strong correlation between high levels of p-tau217 and an increased risk of developing mild cognitive impairment (MCI) and dementia. While these levels don’t absolutely predict an onset of dementia, p-tau217 seems to be a valuable biomarker.
Notably, this test isn’t entirely new and has been applied in several prior studies. However, what makes this particular research significant is the extended follow-up period and the analysis based on race and hormone usage among participants.
The results regarding hormone therapy were somewhat mixed. Elevated p-tau217 levels were clear indicators of dementia in women who had used estrogen and progestin, but this wasn’t the case for estrogen alone. Additionally, there wasn’t a straightforward connection between p-tau217 levels and hormone usage for MCI.
When looking at race, the associations between dementia risk and high p-tau217 levels were consistent for both White and Black women, yet no link was found for MCI in Black women. Researchers speculate that this could result from misdiagnosis or varied underlying factors in dementia among different racial groups.
They noted potential demographic differences and other characteristics that weren’t fully accounted for could also play a role, along with the smaller sample size of Black women in the study.
Interestingly, the link between p-tau217 and dementia was stronger in women over 70 and among those with the APOE ε4 gene, known for its association with Alzheimer’s.
While the p-tau217 blood test isn’t ready for widespread screening just yet—more studies are needed—the findings contribute to our understanding of how Alzheimer’s and dementia may develop and be potentially preventable.
Neurologist Masud Husain from the University of Oxford, who wasn’t involved in the study, commented that “these results reinforce the idea that testing p-tau217 in blood could be essential for screening individuals most at risk of dementia years before any diagnosis.”
It’s important to note that high p-tau217 levels don’t guarantee dementia will occur, even if tau-related brain changes may already be underway. Understanding the reasons behind this could be an intriguing direction for future research.
Aladdin Shadyab, an epidemiologist from the University of California, San Diego, suggested that this study shows we might be able to identify women at an elevated risk of dementia decades before symptoms emerge. This kind of advance could pave the way for earlier preventive measures and tailored monitoring, moving beyond reactive approaches once memory issues start impacting daily life.
The research findings were published in JAMA Network Open.
