P1‐110: Vitamin D insufficiency and seasonal decrease: Effects on cognition
Bibliographic record
Abstract
Vitamin D3 deficiency has been associated with dementia. Supplementation increases acetlylcholine levels, hippocampal neuronal densities and enhances neuroprotection. However, few prospective human studies have assessed D3 levels and cognition. It was hypothesized that a significant proportion of northern British Columbians would have insufficient levels (<75 nmol/L) that would impact cognitive functioning. Healthy adults >20 yrs participated in the 1st (July-Oct 2010) and 2nd Phase (Nov 2010-March 2011) of the D-COG pilot study. Cognitive testing consisted of the Symbol Digit Modalities Test, phonemic fluency, Digit Span (DS) and CANTAB battery. Different versions were utilized in a counter-balanced fashion. Blood D3 levels were analyzed via mass spectrometry. 1st Phase: 32 participants, 72% female, 52 ± 16 yrs, 14 ± 3 yrs of education. Nearly half (46%) were D3 insufficient and these participants performed worse on Backward Digit Span (BDS): mean 5.8 ± 2 vs 7.9 ± 2, t(30) = 2.5, P = .018. In multivariate analyses, sufficiency status was an independent predictor of BDS, R = 0.41, P = .01. Partial correlation correcting for age and education revealed a negative relationship between D3 levels and delayed verbal memory (r = -.44, P = .026).2nd Phase: 22 participants, 19 with useable data. The majority (63%) were D3 insufficient, half of whom had been sufficient in the 1st Phase. D3 levels decreased 17 nmol/L on average (median 15). Those with insufficient levels performed worse on spatial working memory (SWM): mean 29.3 ± 8 versus 36.1 ± 6, t(17) = 1.96, P = .05 but better on delayed verbal memory (mean 33.8 ± 4 versus 29.4 ± 2.5, P = .01) and nonverbal pattern memory(mean 89.6 ± 9.5 versus 67.9 ± 19, P = .004).Those with larger drops in levels (≥ 15nmol/L) showed a decline/less improvement from the 1st to 2nd Phase: DS-forward (P <.008), SWM (P <.07), and Stockings of Cambridge (P <.008), tests of working memory/executive functioning. A significant proportion of northern British Columbians are D3 insufficient. Larger seasonal declines were associated with comparatively worse working memory. In the cross-sectional analyses, insufficiency was associated with inferior working memory but superior verbal and nonverbal (pattern) memory. Optimal D3 levels for cognition are not known and may vary by cognitive domain. What effects D3 supplementation has on different cognitive domains is not known but is currently being tested in our randomized-controlled pilot study.
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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 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.001 | 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) | 0.005 | 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".