Variation in retinal microvascular parameters is associated with mild cognitive impairment and Alzheimer’s disease
Bibliographic record
Abstract
Abstract Background Alzheimer's disease (AD) is a neurodegenerative condition characterised by cognitive decline. Mild Cognitive Impairment (MCI) represents a transitional state between ageing normally and all forms of dementia, although those with MCI will not automatically convert to dementia. The retinal and cerebral microvasculature share similar embryological origins and physiological characteristics. Improved imaging technologies enable non‐invasive measurement of retinal microvascular parameters (RMPs). We investigated associations between RMPs and cognitive function in participants with AD and MCI. Method RMPs (arteriolar/venular diameter, fractal dimension, vessel tortuosity) were measured from optic disc centred fundus images and analysed using semi‐automated software. Thirty‐four MCI and thirty‐two AD participants were recruited for the study from the Belfast Health and Social Care Trust memory clinics. Nine MCI and thirteen AD participants were excluded as their retinal images were of insufficient quality for image analysis. Associations were assessed by logistic regression with comparison to an age and sex‐matched control group from the NICOLA study as the reference category. Models were adjusted for potential confounders including smoking, diabetes, hypertension, total cholesterol and Mini Mental State Exam (MMSE) score. P<0.05 was considered significant. Result Data were included for 126 participants with cognitive function measures and sufficient retinal images. Twenty‐five participants had a clinical diagnosis of MCI and nineteen AD. Eighty‐two age and gender‐matched controls with no previous history of cognitive impairment, and MMSE and Montreal Cognitive Assessment scores >26/30 were included. Decreased arteriolar fractal dimension (OR: 0.30; 95%CI: 0.10, 0.91; P=0.03) was significantly associated with AD in all models. Decreased venular fractal dimension and both arteriole and venular diameter were significantly associated with MCI in all models (P <0.05). No further associations were detected (P >0.05). Conclusion Our findings identified variation in RMPs in association with MCI and AD in an older population. Additionally, previous studies have reported associations between reduced fractal dimension with MCI and AD. We were able to replicate these associations in unadjusted analyses, and following adjustment for confounders. These non‐invasive retinal measures may help identify mechanistic pathways of microvascular complications early in the disease process in individuals at increased risk of MCI and AD.
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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 | 0.004 |
| 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 | 0.001 | 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".