UC San Diego researchers found a blood-based biomarker can predict a woman’s risk of developing dementia as many as 25 years before symptoms appear, according to a paper published Tuesday.
The study, published in JAMA Network Open, found higher levels of phosphorylated tau 217 (p-tau217) — a protein linked to the brain changes seen in Alzheimer’s disease — were “strongly associated with future mild cognitive impairment and dementia among older women who were cognitively healthy at baseline, meaning at the start of the study before any memory or thinking problems were detected,” a UCSD statement read.
“Our study suggests we may be able to identify women at elevated risk for dementia decades before symptoms emerge,” said Aladdin H. Shadyab, first author of the study and UCSD associate professor of public health and medicine. “That kind of long lead time opens the door to earlier prevention strategies and more targeted monitoring, rather than waiting until memory problems are already affecting daily life.”
Researchers used data from 2,766 participants in the Women’s Health Initiative Memory Study, a large national study that enrolled women ages 65 to 79 in the late 1990s and followed them for up to 25 years. All of those women were cognitively unimpaired when they entered the study, the UCSD statement read. Blood samples collected at the beginning of the survey were analyzed years later to measure p-tau217.
The correlation was clear: Those who had higher levels of p-tau217 in their blood at the start of the study were much more likely to develop dementia later in life.
However, the researchers also wrote the risk of cognitive impairment or dementia associated with higher levels of p-tau217 was not the same for everyone, partly depending on who had taken birth control, their race, and who had genetics predisposed to dementia.
“Blood-based biomarkers like p-tau217 are especially promising because they are far less invasive and potentially more accessible than brain imaging or spinal fluid tests,” said Linda K. McEvoy, senior author of the study, senior investigator at Kaiser Permanente Washington Health Research Institute and professor emeritus at UCSD’s Herbert Wertheim School of Public Health. “This is important for accelerating research into the factors that affect risk of dementia and for evaluating strategies that may reduce risk.”
In the report, the authors note additional studies are needed to determine how p-tau217 testing might be used in routine clinical care and whether early identification can meaningfully change outcomes.
“Ultimately, the goal is not just prediction, but using that knowledge to delay or prevent dementia altogether,” Shadyab said.
City News Service contributed to this article.
