Folate and B12 serum levels in association with depression in the aged: a systematic review and meta-analysis

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 (OR_folate:1.23, 95%CI:1.07–1.43, OR_B12:1.20, 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 (OR_females:1.37, 95%CI:0.90–2.07; OR_males: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.

Keywords:

• folate
• vitamin B12
• depression
• meta-analysis
• gender
• geriatric

Acknowledgement

The authors would like to thank Dr. Prodromos Kavavidis and Dr Katerina Vyllioti from the University of Athens for their contributions to the systematic review and archiving processes. Dr Konstantinos Katsiardanis, Dr Kalliopi-Penelopi Katsiardani, and Dr Anastasia Anastasiou are also acknowledged for their contribution to the collection of data in the Michelakos et al., 2013 study. The authors are also especially thankful to Dr Robert D Lindeman for providing original data related to his publication.

Disclosure statement

No potential conflict of interest was reported by the authors.