Folate and B12 serum levels in association with depression in the aged: a systematic review and meta-analysis
Bibliographic record
Abstract
OBJECTIVES: To systematically review and meta-analyse existing evidence on the association between folate/B12, and depression among the aged people. METHODS: Following PRISMA/STROBE guidelines, the Medline abstracts were retrieved using an algorithm comprising relevant MeSH terms. Publications on the association of folate/B12 serum measurements with depression were abstracted independently by two reviewers and included in both gender and gender-specific meta-analyses, following recarculations of published data as appropriate. The Newcastle-Ottawa scale was used to evaluate the quality of included studies. RESULTS: Both gender data were contributed by 11 folate-related (7949 individuals) and 9 B12-related studies (6308 individuals), whereas gender-specific data by 4 folate-related (3409 individuals) and 3 B12-related studies (1934 individuals). A statistically significant overall association between both exposures of interest (low folate and B12 levels) and depression was observed (ORfolate:1.23, 95%CI:1.07-1.43, ORB12:1.20, 95%CI:1.02-1.42). Gender-specific estimates pointed to a statistically significant positive association between low B12 levels and depression only among women (OR:1.33, 95%CI:1.02-1.74); the gender specific associations of low folate levels with depression were, however, non-significant and of counter-direction (ORfemales:1.37, 95%CI:0.90-2.07; ORmales:0.84, 95%CI:0.57-1.25). CONCLUSION: Low folate and B12 serum levels seem to be associated with depression in the aged. The gender-specific analyses are confined to a positive association of low B12 with depression among older women and call for further research in this direction.
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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 | 0.016 | 0.042 |
| Meta-epidemiology (narrow) | 0.003 | 0.002 |
| Meta-epidemiology (broad) | 0.021 | 0.034 |
| Bibliometrics | 0.010 | 0.009 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.004 | 0.002 |
| Open science | 0.002 | 0.002 |
| Research integrity | 0.003 | 0.001 |
| Insufficient payload (model declined to judge) | 0.004 | 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".