title: Serum folate and B12 levels in association with cognitive impairment among seniors: results from the VELESTINO study in Greece and meta-analysis.
abstract: OBJECTIVE
  To summarize existing evidence on the effect of serum folate and vitamin B12 levels on cognitive impairment among elders via a meta-analysis, also including unpublished data from a cross-sectional study of seniors ( > 65 years) residing in Velestino, Greece.
  
  
  METHODS
  Serum measurements and Mini-Mental State Examination (MMSE) assessments were available for 593 Velestinians. In addition, 12 studies availing data on folate blood levels (N = 9,747) and 9 on B12 (N = 8,122) were identified following a search algorithm; pooled effect estimates were derived.
  
  
  RESULTS
  Cognitive impairment (MMSE < 24) among Velestenians was associated with lower education level in both genders; decreased social activity, depressive symptoms and low folate levels in males; older age in females. Meta-analyses showed an adverse effect of low-folate levels on cognition (OR: 1.66, 95% CI: 1.40-1.96); B12 was nonsignificantly associated (OR: 1.11, 95% CI: 0.88-1.40).
  
  
  CONCLUSIONS
  Low folate levels are associated with cognitive impairment of seniors; underlying pathophysiological mechanisms should be further explored.
authors.affiliation: Department of Hygiene, Epidemiology and Medical Statistics, Athens University Medical School, Athens, Greece.
authors.forename: Theodoros
authors.initials: T
authors.lastname: Michelakos
authors.forename: Antonis A
authors.initials: AA
authors.lastname: Kousoulis
authors.forename: Konstantinos
authors.initials: K
authors.lastname: Katsiardanis
authors.forename: Nick
authors.initials: N
authors.lastname: Dessypris
authors.forename: Anastasia
authors.initials: A
authors.lastname: Anastasiou
authors.forename: Kalliopi-Penelopi
authors.initials: KP
authors.lastname: Katsiardani
authors.forename: Prodromos
authors.initials: P
authors.lastname: Kanavidis
authors.forename: Christodoulos
authors.initials: C
authors.lastname: Stefanadis
authors.forename: Fotios C
authors.initials: FC
authors.lastname: Papadopoulos
authors.forename: Eleni Th
authors.initials: ET
authors.lastname: Petridou
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D003072:Cognition Disorders / Q000097:blood*; D003430:Cross-Sectional Studies; D005260:Female; D005492:Folic Acid / Q000097:blood*; D006115:Greece; D006801:Humans; D008297:Male; D012307:Risk Factors; D012959:Socioeconomic Factors; D014805:Vitamin B 12 / Q000097:blood*
chemical_list: D005492:Folic Acid; D014805:Vitamin B 12
keywords: B12; aged; cognitive impairment; folate; meta-analysis