P‐162: Homocysteine levels and cognitive scores in a cohort of normal older adults at baseline: Longitudinal analysis
Bibliographic record
Abstract
Large epidemiological studies have shown that elevated homocysteine (tHcy) is a risk factor for dementia, but the longitudinal impact of changing tHcy levels is unclear. We have investigated the longitudinal relation between tHcy levels, and cognitive scores in a cohort of volunteer older adults with normal cognitive function at baseline. Cohort study of 279 older adults (65 years and older) living independently in the community and cognitively normal at baseline, followed every 2–2.5 years for up to 7.5 years. Demographic, medical and dietary information was collected at all visits. The battery of cognitive tests included: Mini-Mental State Exam (MMSE), Stroop Neuropsychological Screening Inventory (Stroop) (a test of focused attention), Mattis Dementia Rating Scale (DRS) and California Verbal Learning Test (CVLT). Biochemical determinations included tHcy and methylmalonic acid (MMA) by mass spectrometry gas-chromatography, cobalamin (Cbl) and total folate. Analysis included Spearman correlations, Mann-Whitney, T-test, and Mixed models to examine the relationship within subjects over time, between tHcy and cognitive scores, before and after adjusting for: age at baseline, time since baseline and years of education. The Mixed model accounted for the dependence induced by the repeated measures per subject. From the 279 older adults there were a total of 689 observations. Calculations were conducted including all 689 observations and excluding outliers (tHcy >25mcM). Age at baseline and years since baseline were negatively related to all cognitive scores in all models (p<.01). Years of education were positively related to cognitive scores. Including all observations and after adjusting for age at baseline, time since baseline and years of education, only the Stroop scores maintain a negative significant relationship with tHcy levels (p=.048). This relationship became insignificant (p>.15) after removal of observations with very high tHcy levels. Conclusion: This longitudinal analysis suggests that the relationship between tHcy and cognitive scores is driven by high tHcy (>25 mcM, normal <13.9 mcM) and is restricted to focused attention (Stroop). It appears that levels of tHcy lower than 25mcM do not affect cognitive scores.
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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 | 0.003 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 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".