- Plasma level of total tau showed a graded association with Alzheimer's disease (AD) risk, with a predictive capability at least as good as that of cerebrospinal fluid (CSF) level of total tau.
Why this matters
- Attractiveness of blood-based biomarkers for dementia and its subtypes.
- As plasma total tau level increased, so did adjusted risk for AD dementia (HR per standard deviation, 1.35; 95% CI, 1.10-1.67).
- Adding plasma total tau to model including age and sex improved stratification for AD dementia risk (net reclassification improvement, 0.382; 95% CI, 0.030-0.716).
- In replication cohort, plasma and CSF total tau levels weakly correlated (Spearman correlation coefficient, 0.16; P=.07).
- But they similarly predicted adjusted AD dementia risk:
- Log plasma total tau: HR, 2.33 (95% CI, 1.00-5.48).
- Log CSF total tau: HR, 2.14 (95% CI, 1.33-3.44).
- Dual prospective cohort study:
- Base cohort: 1453 dementia-free participants in US Framingham Heart Study aged ≥65 years (median, 6-year follow-up).
- Replication cohort: 367 participants in French multicenter Memento study of people with mild cognitive impairment or subjective cognitive complaints (median, 4-year follow-up).
- Main outcome: dementia, AD dementia.
- Funding: National Institute on Aging; others.
- Participants mainly white.
- Subtypes largely based on clinical diagnosis.