Inactivity is associated with worse cognition and neurodegeneration in aging adults
Bibliographic record
Abstract
Abstract Background Greater physical activity is known to be beneficial for healthier brain aging outcomes. However, less is known about how inactivity might influence the aging brain. Inactivity is highly prevalent in older adulthood and may be an important modifiable risk factor. We examined how inactivity relates to cognitive performance and structural imaging variables in community‐dwelling older adults, particularly among individuals at genetic risk for sporadic AD (i.e., apolipoprotein E (APOE)‐e4 carriers). Method Vanderbilt Memory and Aging Project (n = 265, 74±8 years, 37% female) participants completed at least 7 days of wrist actigraphy, neuropsychological assessment, and 3T brain MRI. Actigraphy data was processed using the GGIR package. Linear regression analyses related average daily minutes spent in inactivity during wake periods to cognition and brain structure adjusting for age, sex, race/ethnicity, education, Framingham Stroke Risk Profile score, APOE‐e4 status, cognitive status, actigraphy wear time, and intracranial volume (for MRI outcomes). Models were repeated testing interactions with APOE‐e4 status. Result The total sample was inactive for 14±2 hours/day. More minutes of inactivity related to worse episodic memory performance (β = ‐0.001, p = 0.03), a smaller AD‐signature composite of cortical thickness (β = ‐0.0002, p = 0.008), and lower occipital lobe grey matter volume (β = ‐10.01, p = 0.01). Inactivity time interacted with APOE‐e4 status on naming (β = ‐0.01, p = 0.01) and visuospatial performances (β = ‐0.02, p = 0.04); total grey matter volume (β = ‐201.40, p<0.001); and frontal (β = ‐96.24, p = 0.001), temporal (β = ‐27.13, p = 0.03), and parietal lobe volumes (β = ‐54.72, p<0.001). In stratified models, more minutes of inactivity related to worse neuropsychological performance and smaller brain volumes among APOE‐e4 carriers. All stratified models in non‐carriers were null (p‐values>0.12). Conclusion Among community‐dwelling older adults, more time spent inactive each day related to worse episodic memory performance and lower cortical thickness in regions susceptible to AD‐related neurodegeneration. Results were stronger among APOE‐e4 carriers. This study supports the importance of not just increasing physical activity but also reducing the time spent inactive each day, particularly among aging adults at genetic risk for AD. Funding: IIRG‐08‐88733, P20‐AG068082, R01‐AG034962, K24‐AG046373
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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 | 0.000 | 0.001 |
| 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 | 0.001 |
| 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".