FRIDAY, March 13, 2026 (HealthDay News) -- Plasma phosphorylated tau 217 (p-tau217) is associated with incident mild cognitive impairment (MCI) and dementia up to 25 years later in cognitively unimpaired older women, according to a study published online March 10 in JAMA Network Open.
Aladdin H. Shadyab, Ph.D., from the University of California San Diego in La Jolla, and colleagues examined the association of baseline plasma p-tau217 with incident MCI and dementia in a cohort of women recruited into the Women's Health Initiative Memory Study. Participants were randomly assigned to receive estrogen alone versus placebo or estrogen plus progestin versus placebo and were assessed for up to 25 years. The analysis included women aged 65 to 79 years who were cognitively unimpaired at baseline.
The researchers found that 1,311 of the 2,766 participants developed the combined end point of MCI or dementia (849 and 752, respectively). There was an association seen for 1-standard deviation increase in log2-transformed p-tau217 with incident MCI or dementia and with each individual outcome (hazard ratios, 2.43 for incident MCI or dementia, 1.94 for MCI, and 3.17 for dementia). For women randomly assigned to estrogen plus progestin versus placebo, associations of p-tau217 with dementia were larger in magnitude (hazard ratios, 4.18 versus 3.07), while no significant variation was seen for estrogen alone versus placebo. For women older than 70 years, APOE ε4 carriers, and White versus Black women, p-tau217 associations with MCI or dementia were larger in magnitude.
"Our results support the value of plasma p-tau217 as an easily measured biomarker for future MCI or dementia that may have a variety of uses in both research and clinical practice among diverse populations," the authors write.
One author disclosed ties to the biopharmaceutical industry; a second author received residual class settlement funds from April Krueger versus Wyeth Inc.