title: Vitamin B-12, apolipoprotein E genotype, and cognitive performance in community-living older adults: evidence of a gene-micronutrient interaction.
abstract: BACKGROUND
  The relation between vitamin B-12 and cognitive function in older adults is unclear. Limited evidence suggests that the relation is modulated by apolipoprotein E epsilon4. Hence, it is important to further examine this gene-nutrient interaction.
  
  
  OBJECTIVE
  The aim was to investigate the role of apolipoprotein E (APOE) epsilon4 as a genetic predisposing factor modulating the effect of vitamin B-12 on cognitive function.
  
  
  METHODS
  A battery of neuropsychological tests, including the Mini-Mental State Examination (MMSE) for global cognition, was administered at the baseline assessment to 539 Chinese adults aged > or =55 y. The MMSE was repeated at a median 18 mo (n = 376) and a median of 38 mo (n = 247) after baseline. The interaction of vitamin B-12 and APOE epsilon4 on cognitive function was examined in a linear mixed-effects model for MMSE and in a multiple linear regression model for neuropsychological test scores.
  
  
  RESULTS
  APOE epsilon4 was associated with a lower MMSE score. Vitamin B-12 (natural log transformed) was positively related to MMSE score, and this association was much stronger in APOE epsilon4 carriers than in APOE epsilon4 noncarriers (P for interaction = 0.016). Significant interactions between natural log-transformed vitamin B-12 and APOE epsilon4 were also found for the Digit Span Backward Longest Sequence (P for interaction = 0.013) and Rey Auditory Verbal Learning Test immediate recall (P for interaction = 0.005). Better performance in these 2 tests was associated with vitamin B-12 in APOE epsilon4 carriers but not in APOE epsilon4 noncarriers.
  
  
  CONCLUSIONS
  The association between vitamin B-12 and cognitive function was moderated by APOE epsilon4 status.
authors.affiliation: Gerontological Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, Singapore. pcmfl@nus.edu.sg
authors.forename: Lei
authors.initials: L
authors.lastname: Feng
authors.forename: Jialiang
authors.initials: J
authors.lastname: Li
authors.forename: Keng-Bee
authors.initials: KB
authors.lastname: Yap
authors.forename: Ee-Heok
authors.initials: EH
authors.lastname: Kua
authors.forename: Tze-Pin
authors.initials: TP
authors.lastname: Ng
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology* / Q000523:psychology*; D053327:Apolipoprotein E4 / Q000235:genetics*; D003071:Cognition / Q000502:physiology*; D003430:Cross-Sectional Studies; D005260:Female; D020022:Genetic Predisposition to Disease; D005820:Genetic Testing; D005838:Genotype; D015577:Geriatric Assessment; D006801:Humans; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D009752:Nutritional Status; D012846:Singapore; D014805:Vitamin B 12 / Q000097:blood*
chemical_list: D053327:Apolipoprotein E4; D014805:Vitamin B 12