P3‐136: How does higher bmi preserve cognition among older adults? a 12‐month exploratory neuroimaging study
Bibliographic record
Abstract
Obesity and dementia are both increasing in prevalence worldwide. While obesity are associated with key vascular risk factors (e.g., hypertension, diabetes) for dementia, the relationship between body fat and cognitive function in older adults remain equivocal. In fact, there is evidence body fat may be neural-protective for older adults. Neuroimaging studies of otherwise healthy adults demonstrate that increased body mass index (BMI) is associated with global and regional brain atrophy, as well as altered functional connectivity. However, few studies to date have investigated neural mechanisms of obesity-induced cognitive changes in older adults. In a 12-month prospective study, we aimed to examine: 1) the impact of BMI on functional brain connectivity; and 2) the role of functional brain connectivity in the association between BMI and cognitive function. A 12-month prospective fMRI study with 66 seniors aged 70 to 80 years; 24 normal weight (with BMI≤18.50), 26 overweight (with BMI between 18.5 and 29.99), and 15 obese (with BMI ≥ 30.00). Participants performed a finger tapping task during fMRI scanning. Clinical measures of executive functions were assessed at baseline and 12 months. After adjusting for baseline performance measure, comorbidity, gender, and age, obese individuals showed decreased task-related connectivity in the default mode network (DMN; p<0.006), which was significantly correlated with Digit Span Test performance (i.e. working memory) at 12 months (p<0.02) and BMI (p<0.001). Supporting evidence that report older individuals with higher BMI had less observable amyloid deposition within the DMN, we found elevated BMI indirectly lead to lower task-state DMN connectivity, which, in turn, lead to better performance on Digit Span Test. This suggests DMN connectivity mediates and suppresses the effect of BMI on cognitive function, and may be involved in compensatory processes in older adults. Bonferroni-Corrected Task-State Group Contrast Map Highlighted areas show regions where Normal > Obese in DMN functional connectivity (p<0.006) during finger tapping. Direct and Indirect Effects of the Proposed Mediation Model
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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) | 0.001 | 0.001 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| 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".