title: Folate and B12 serum levels in association with depression in the aged: a systematic review and meta-analysis.
abstract: To systematically review and meta-analyse existing evidence on the association between folate/B12, and depression among the aged people.
  
  
  
  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.
  
  
  
  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).
  
  
  
  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.
authors.affiliation: a Department of Hygiene , Epidemiology and Medical Statistics, Athens University Medical School , Athens , Greece.
authors.forename: Eleni Th
authors.initials: ET
authors.lastname: Petridou
authors.affiliation: a Department of Hygiene , Epidemiology and Medical Statistics, Athens University Medical School , Athens , Greece.
authors.forename: Antonis A
authors.initials: AA
authors.lastname: Kousoulis
authors.affiliation: a Department of Hygiene , Epidemiology and Medical Statistics, Athens University Medical School , Athens , Greece.
authors.forename: Theodoros
authors.initials: T
authors.lastname: Michelakos
authors.affiliation: a Department of Hygiene , Epidemiology and Medical Statistics, Athens University Medical School , Athens , Greece.
authors.forename: Paraskevi
authors.initials: P
authors.lastname: Papathoma
authors.affiliation: a Department of Hygiene , Epidemiology and Medical Statistics, Athens University Medical School , Athens , Greece.
authors.forename: Nick
authors.initials: N
authors.lastname: Dessypris
authors.affiliation: b Department of Neuroscience , Psychiatry, Uppsala University Hospital, Uppsala University , Uppsala , Sweden.
authors.forename: Fotios C
authors.initials: FC
authors.lastname: Papadopoulos
authors.affiliation: c First Department of Cardiology , Athens University Medical School, Hippokration Hospital , Athens , Greece.
authors.forename: Christodoulos
authors.initials: C
authors.lastname: Stefanadis
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D003866:Depressive Disorder; D005260:Female; D005492:Folic Acid / Q000097:blood*; D006801:Humans; D008297:Male
chemical_list: D005492:Folic Acid
keywords: depression; folate; gender; geriatric; meta-analysis; vitamin B12