title: Serum folate, vitamin B-12 and cognitive function in middle and older age: The HAPIEE study.
abstract: BACKGROUND
  Nutrient status of B vitamins, particularly folate and vitamin B-12, may be related to cognitive ageing but epidemiological evidence remains inconclusive.
  
  
  OBJECTIVE
  The aim of this study was to estimate the association of serum folate and vitamin B-12 concentrations with cognitive function in middle-aged and older adults from three Central and Eastern European populations.
  
  
  METHODS
  Men and women aged 45-69 at baseline participating in the Health, Alcohol and Psychosocial factors in Eastern Europe (HAPIEE) study were recruited in Krakow (Poland), Kaunas (Lithuania) and six urban centres in the Czech Republic. Tests of immediate and delayed recall, verbal fluency and letter search were administered at baseline and repeated in 2006-2008. Serum concentrations of biomarkers at baseline were measured in a sub-sample of participants. Associations of vitamin quartiles with baseline (n=4166) and follow-up (n=2739) cognitive domain-specific z-scores were estimated using multiple linear regression.
  
  
  RESULTS
  After adjusting for confounders, folate was positively associated with letter search and vitamin B-12 with word recall in cross-sectional analyses. In prospective analyses, participants in the highest quartile of folate had higher verbal fluency (p<0.01) and immediate recall (p<0.05) scores compared to those in the bottom quartile. In addition, participants in the highest quartile of vitamin B-12 had significantly higher verbal fluency scores (β=0.12; 95% CI=0.02, 0.21).
  
  
  CONCLUSIONS
  Folate and vitamin B-12 were positively associated with performance in some but not all cognitive domains in older Central and Eastern Europeans. These findings do not lend unequivocal support to potential importance of folate and vitamin B-12 status for cognitive function in older age. Long-term longitudinal studies and randomised trials are required before drawing conclusions on the role of these vitamins in cognitive decline.
authors.affiliation: Department of Epidemiology & Public Health, UCL, 1-19 Torrington Place, London WC1E 7HB, UK. Electronic address: pia.horvat.10@ucl.ac.uk.
authors.forename: Pia
authors.initials: P
authors.lastname: Horvat
authors.affiliation: Department of Education, University of Oxford, 15 Norham Gardens, Oxford OX2 6PY, UK.
authors.forename: Julian
authors.initials: J
authors.lastname: Gardiner
authors.affiliation: National Institute of Public Health, Srobarova 48, 10042 Prague, Czech Republic.
authors.forename: Ruzena
authors.initials: R
authors.lastname: Kubinova
authors.affiliation: Department of Epidemiology and Population Studies, Jagellonian University Collegium Medicum, Grzegorzecka 20, 31-531 Krakow, Poland.
authors.forename: Andrzej
authors.initials: A
authors.lastname: Pajak
authors.affiliation: Department of Population Studies, Institute of Cardiology, Lithuanian University of Health Sciences, Kaunas LT-50161, Lithuania.
authors.forename: Abdonas
authors.initials: A
authors.lastname: Tamosiunas
authors.affiliation: Division of Clinical Epidemiology and Aging Research, German Cancer Research Center, Im Neuenheimer Feld 581, 69120 Heidelberg, Germany.
authors.forename: Ben
authors.initials: B
authors.lastname: Schöttker
authors.affiliation: Department of Epidemiology & Public Health, UCL, 1-19 Torrington Place, London WC1E 7HB, UK.
authors.forename: Hynek
authors.initials: H
authors.lastname: Pikhart
authors.affiliation: Department of Epidemiology & Public Health, UCL, 1-19 Torrington Place, London WC1E 7HB, UK.
authors.forename: Anne
authors.initials: A
authors.lastname: Peasey
authors.affiliation: Center for Health Protection, National Institute for Public Health and the Environment, PO Box 1, 3720 BA, Bilthoven, The Netherlands.
authors.forename: Eugene
authors.initials: E
authors.lastname: Jansen
authors.affiliation: Department of Epidemiology & Public Health, UCL, 1-19 Torrington Place, London WC1E 7HB, UK.
authors.forename: Martin
authors.initials: M
authors.lastname: Bobak
mesh_terms: D000367:Age Factors; D000368:Aged; D000375:Aging / Q000097:blood* / Q000523:psychology*; D015415:Biomarkers / Q000097:blood; D003071:Cognition; D003430:Cross-Sectional Studies; D005060:Europe; D005260:Female; D005492:Folic Acid / Q000097:blood*; D015577:Geriatric Assessment; D006801:Humans; D016014:Linear Models; D008297:Male; D008570:Memory, Short-Term; D008875:Middle Aged; D009483:Neuropsychological Tests; D015596:Nutrition Assessment; D009752:Nutritional Status; D011446:Prospective Studies; D014705:Verbal Behavior; D014805:Vitamin B 12 / Q000097:blood*
chemical_list: D015415:Biomarkers; D005492:Folic Acid; D014805:Vitamin B 12
keywords: Ageing; Biomarkers; Cognitive function; Eastern Europe; Folate; Vitamin B-12