Blood Test May Predict Women’s Dementia Risk 25 Years Early

A readily available blood test may offer a window into a woman’s future cognitive health, potentially predicting her risk of dementia up to 25 years before symptoms emerge. The test identifies elevated levels of phosphorylated tau 217 (p-tau217), a protein linked to the development of Alzheimer’s disease, the most common cause of dementia. Whereas currently used to diagnose Alzheimer’s in those already exhibiting symptoms, this research suggests its potential as a proactive risk assessment tool.

The findings, published in JAMA Network Open, stem from a study involving approximately 2,800 cognitively healthy women aged 65 to 79. Researchers followed these women for up to 25 years, during which time over 1,300 developed dementia or mild cognitive impairment – a condition often preceding dementia. Women with the highest levels of p-tau217 in their blood at the study’s outset were more than twice as likely to experience cognitive decline compared to those with the lowest levels.

Predictive Power Varies with Age and Genetic Factors

The study’s lead author, Aladdin Shadyab, PhD, MPH, an associate professor at the University of California in San Diego, emphasizes the potential for earlier intervention. “Our study suggests we may be able to identify women at elevated risk for dementia decades before symptoms emerge,” he says. “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.”

However, the predictive power of the blood test wasn’t uniform across the study population. Researchers found that higher p-tau217 levels were more strongly associated with cognitive decline in women over 70. The test proved more accurate in predicting dementia risk among women with a genetic predisposition to Alzheimer’s disease than in those without such a predisposition. This suggests that genetic factors may influence how p-tau217 levels correlate with future cognitive health.

Hormone Therapy and Cognitive Risk: A Nuanced Picture

Interestingly, the study also revealed a connection between hormone therapy and p-tau217 levels. Elevated protein levels were a stronger predictor of dementia risk in women who had used hormone therapy combining estrogen and progestin, compared to those who hadn’t. However, researchers caution against drawing definitive conclusions about a causal link. More research is needed to understand how hormone therapy might influence p-tau217 levels and, dementia risk.

JoAnn Manson, MD, MPH, DrPH, a professor at Harvard Medical School and chief of preventive medicine at Brigham and Women’s Hospital in Boston, clarifies the context of these findings. She points out that the increased risk of cognitive decline associated with hormone therapy in the study was observed in women who initiated hormone treatment after age 65. Mayo Clinic guidelines generally recommend starting hormone therapy before age 60 or within 10 years of the onset of menopause symptoms to minimize potential health risks.

Beyond Symptom Management: The Promise of Proactive Assessment

Currently, blood tests measuring p-tau217 are approved by the U.S. Food and Drug Administration (FDA) for diagnosing Alzheimer’s disease in individuals already experiencing symptoms. UC San Diego Today reports that this new research expands the potential application of the test to proactive risk assessment.

Dr. Shadyab highlights the advantages of blood-based biomarker tests over more invasive methods like spinal taps or brain scans. These tests are less invasive and potentially more accessible, making them suitable for wider-scale screening. While not yet approved or recommended for routine screening in symptom-free individuals, the study’s results are encouraging. GEN – Genetic Engineering and Biotechnology News notes this is one of the largest studies to demonstrate the predictive capability of p-tau217 blood levels.

What’s Next: Refining Risk Prediction and Exploring Interventions

The development of a reliable, proactive dementia risk assessment tool could revolutionize how we approach this devastating condition. However, several steps remain before such a test becomes widely available. Further research is needed to refine the accuracy of p-tau217 testing, particularly in diverse populations. Researchers also need to investigate the interplay between genetic factors, hormone therapy, and other lifestyle factors in influencing dementia risk.

the goal is not simply to predict who will develop dementia, but to identify individuals who might benefit from early interventions. These interventions could include lifestyle modifications, cognitive training, or, as research progresses, potential disease-modifying therapies. The long lead time offered by this blood test provides a crucial opportunity to explore and implement such strategies, potentially delaying or even preventing the onset of dementia.

Ongoing clinical trials are evaluating the effectiveness of various interventions aimed at preventing or slowing the progression of Alzheimer’s disease. Public health surveillance efforts continue to monitor dementia prevalence and identify risk factors, informing future prevention strategies. As our understanding of dementia evolves, so too will the tools and approaches we use to combat this growing global health challenge.