A new study published in JAMA Network Open reports that a blood biomarker, plasma phosphorylated tau 217 (p-tau217), may help identify postmenopausal women at higher risk of developing mild cognitive impairment or dementia years before symptoms appear. The findings were released on Mar. 11 and are based on data from the Women’s Health Initiative Memory Study (WHIMS), which followed cognitively healthy women aged 65 to 79 for more than two decades.
The research is significant because it suggests that a simple blood test could provide an accessible and minimally invasive way to detect Alzheimer’s disease-related changes long before clinical symptoms arise. Early detection is important for timely intervention and planning.
Researchers measured baseline plasma p-tau217 levels in over 2,700 WHIMS participants using the ALZpath Simoa pTau217 assay. Over a median follow-up of 14.1 years, they found that higher levels of p-tau217 were linked with increased risk of developing mild cognitive impairment or probable dementia. The association was strongest for dementia outcomes compared to mild cognitive impairment alone.
The study also examined whether hormone therapy exposure affected these associations. While no significant difference was observed between those randomized to estrogen alone versus placebo, participants assigned to estrogen plus progestin showed a larger association between elevated p-tau217 and dementia risk compared to placebo. However, this interaction was not significant for mild cognitive impairment or the combined endpoint.
Differences emerged across racial groups and genetic backgrounds as well. Associations between p-tau217 and cognitive decline were larger among White participants than Black individuals, and stronger among carriers of the APOE ε4 gene variant—known to increase Alzheimer’s risk—compared with non-carriers. Age also played a role: people aged over 70 had greater associations between high p-tau217 levels and dementia outcomes than younger participants.
The authors caution that some subgroup analyses were exploratory and involved multiple comparisons, so results should be interpreted carefully. They note that factors such as hormone therapy exposure, age, race, and APOE ε4 status may influence how strongly plasma p-tau217 predicts future cognitive decline. Further studies are needed to confirm these findings.
