The effects of age and sex on plasma p‐tau181 concentrations in Alzheimer’s Disease
Bibliographic record
Abstract
Abstract Background Quantifying levels of phosphorylated tau in plasma is a highly promising and specific marker for Alzheimer’s disease (AD), but limited data are available on the effect of age on plasma p‐tau181 concentrations in specific clinical groups and especially control subjects. Similarly, the effect of sex on concentration of plasma ptau‐181 levels are unclear. Method A total of 343 samples of EDTA plasma from patients examined at the UBC Hospital Alzheimer Clinic between 2008 – 2018 included. The patients had been referred with complaint of cognitive impairment and were assessed for dementia and they sorted into four diagnostic groups: Non‐Cognitive Impairment (NCI), non‐ AD neurodegenerative diseases, possible AD, and probable AD, according to US National Institute on Aging (NIA) and the Alzheimer’s Association (AA) criteria diagnosis. The concentrations of their plasma p‐tau181 was measured by a homebrew ADX assay on SIMOA HD‐X platform. We analysed the effect of age and sex on the concentrations of plasma p‐tau181 among and within clinically defined groups. We also assessed p‐tau181 levels in a separate group of healthy individuals (n=60). Result There was no significant sex difference in p‐tau181 levels across and between the diagnostic categories (p=0.426). We also confirmed there was not any correlation between age and p‐tau181 levels in healthy controls. Moreover, we did not find any correlation between the age and plasma concentrations of p‐tau181 within each diagnostic group separately. Further with two model linear regression, age was not found to be a significant contributor of plasma p‐tau181 variations (F (3, 429) = 109.04, B=.16, t= 1.42, p<0.16). Interestingly, there was a correlation between average of plasma p‐tau181 with age among the spectrum from NCI to AD. Conclusion We did not detect any sex difference in plasma p‐tau181 levels. Our findings about the age‐effect of plasma p‐tau181 levels especially within and among diagnostic groups might be described by the intricate dynamics, and kinetics of p‐tau181 in brain and plasma and it needs to investigate with larger healthy control population and multicenter clinical studies.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".