Mild cognitive impairment associated with higher serum 25-hydroxyvitamin D levels in a middle aged population living at a moderately high latitude in New Zealand
Bibliographic record
Abstract
Objective: The association between serum 25-hydroxyvitamin D (s25OHD) concentrations and cognitive function has been investigated in only a few studies of middle aged adults (40-60 years); with inconsistent results found. The main objective of this Canterbury-based study was to examine the association between s25OHD levels and mild cognitive impairment (MCI) in participants in their early fifties, while adjusting for a number of confounders. The secondary objective was to assess if this association would differ when stratified by gender.\nDesign: Cross-sectional study participants, 366 adults aged 49-53 years living within the Canterbury District Health Board region from the Canterbury Health, Aging and Life Course study, were divided into two cognitive function groups: MCI and normal cognitive function (NCF). A score of <26 on the Montreal Cognitive Assessment test was defined as MCI and NCF was defined as a score ≥26 out of 30. Logistic regression was used to investigate the relationship between the cognitive function groups (outcome variable) and two s25OHD groups: insufficient s25OHD (≤50 nanomoles per litre (nmol/L)) and sufficient s25OHD (>50 nmol/L). Age, gender, education, ethnicity, annual household income, body mass index, depression, season of blood draw, alcohol intake, current smoking status, serum intact parathyroid hormone, serum creatinine, general health, vitamin D food intake, calcium food intake, vitamin D supplement use and chronic diseases were considered as potential confounders.\nResults: In the univariate and multivariate logistic regression with cognitive function as the binary outcome variable (MCI (n=89) and NCF (n=277)) and vitamin D as a continuous predictor variable, the results did not reach statistical significance (crude odds ratio (OR) 1 (0.99, 1.01) p=0.306, adjusted OR 0.99 (0.98, 1.00) p=0.084). However, an inverse association between s25OHD levels and cognitive function were observed in the univariate and multivariate logistic regression with vitamin D as a categorical variable. Compared to those with MCI, participants with NCF belonged more often to the insufficient s25OHD group (≤50 nmol/L, n=124) than the sufficient s25OHD group (>50 nmol/L, (n=242)) (crude OR 0.52 (0.30, 0.89) p=0.020, adjusted OR 0.44 (0.24, 0.79) p=0.008). In the analyses stratified by gender, the effect observed was similar, however, the association reached statistical significance only for female participants (adjusted OR 0.43 (0.18, 0.94) p=0.041) and not for male participants (adjusted OR 0.48 (0.18, 1.19) p=0.127). Further adjusted for vitamin D supplement use and season, did not change the effect size, however was just statistically significant, for female participants (adjusted OR 0.43 (0.17, 0.99) p=0.053).\nConclusions: Those with MCI belonged more often to the s25OHD group >50 nmol/L than the s25OHD group ≤50 nmol/L in a middle aged community-dwelling cohort, mostly for women, and appeared to be due to vitamin D supplement use. However, causality cannot be concluded due to the cross-sectional design of this study.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.003 | 0.002 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.000 | 0.002 |
| Insufficient payload (model declined to judge) | 0.000 | 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 teacher head, 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".