JAMA Study: Blood p‑tau217 Predicts Dementia Risk in Older Women Decades Before Symptoms
A new study in JAMA Network Open led by University of California San Diego researchers reports that levels of the blood biomarker phosphorylated tau 217 (p‑tau217) can strongly predict which older women will develop mild cognitive impairment or dementia as much as 25 years later. Investigators analyzed late‑1990s blood samples from 2,766 participants in the Women’s Health Initiative Memory Study, all women ages 65 to 79 without cognitive problems at baseline, and tracked them for up to a quarter‑century. Women with higher p‑tau217 at the start were much more likely to develop dementia, with particularly poor cognitive outcomes among those over 70 and carriers of the APOE ε4 Alzheimer’s risk gene, and the marker also appeared to be a stronger predictor in women assigned to estrogen‑progestin hormone therapy. The authors say blood‑based biomarkers like p‑tau217, while not yet ready for routine screening in symptom‑free people, could eventually allow far earlier identification of high‑risk patients and enable prevention trials, closer monitoring, and more targeted counseling long before memory loss emerges. Experts stress that such tests are less invasive and potentially more accessible than brain scans or spinal fluid analysis, underscoring how this line of research could reshape dementia detection and policy in an aging U.S. population.
📌 Key Facts
- Study analyzed blood from 2,766 women ages 65–79 in the Women’s Health Initiative Memory Study, collected in the late 1990s
- Participants were followed for up to 25 years to track development of mild cognitive impairment and dementia
- Higher baseline blood levels of phosphorylated tau 217 (p‑tau217) were strongly associated with later dementia, especially in women over 70 and APOE ε4 carriers
- p‑tau217 was a stronger predictor of dementia in women randomized to estrogen plus progestin hormone therapy than in those given placebo
- Researchers say blood‑based biomarkers like p‑tau217 could eventually permit dementia‑risk detection roughly two decades before symptoms, though such tests are not yet recommended for routine screening
📊 Relevant Data
Cumulative 25-year dementia risk at age 65 is 38% for African-Americans, 35% for American Indian/Alaska Natives, 32% for Latinos, 25% for Pacific Islanders, 30% for Whites, and 28% for Asian-Americans.
Inequalities in dementia incidence between six racial and ethnic groups over 14 years — Kaiser Permanente Division of Research
African Americans are more likely to carry the APOE ε4 allele compared to Whites, with ε4 allele prevalence higher among African Americans.
Associations between race, APOE genotype, cognition, and mortality among individuals with Alzheimer's disease in Georgia, 2000–2016 — Nature Scientific Reports
Menopausal hormone therapy was positively associated with development of all-cause dementia and Alzheimer's disease, even in women who received treatment at age 55 years or younger.
Menopausal hormone therapy and dementia: nationwide, nested case-control study — The BMJ
Genes associated with African ancestry appear to affect certain brain cells in ways that could increase the risk of Alzheimer's disease and stroke.
African ancestry genes may be linked to Black Americans' risk for Alzheimer's and stroke — NPR
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