title: n-3 Fatty acid erythrocyte membrane content, APOE varepsilon4, and cognitive variation: an observational follow-up study in late adulthood.
abstract: BACKGROUND
  Evidence for an inverse relation between dietary intake of n-3 polyunsaturated fatty acids (PUFAs) and age-related cognitive decline is inconsistent. This inconsistency may arise because the relation is present only in the absence of the apolipoprotein E epsilon4 (APOE epsilon4) allele.
  
  
  OBJECTIVE
  We aimed to determine the contribution of erythrocyte n-3 PUFA content to cognitive aging in the presence or absence of the APOE epsilon4 allele.
  
  
  METHODS
  We followed up 120 volunteers, born in 1936, at approximate ages of 64, 66, and 68 y. Their intelligence quotient at 11 y old was available. At first follow-up, we determined APOE genotype and measured the PUFA composition of erythrocyte membranes. Six cognitive tests were administered at all follow-ups. We related cognitive performance at approximately 64 y old and cognitive changes from approximately 64 to approximately 68 y old to erythrocyte n-3 PUFA composition on recruitment and to APOE epsilon4 allele status.
  
  
  RESULTS
  Total n-3 PUFA and docosohexaenoic acid concentrations were associated with benefits for cognition at approximately 64 y old and from approximately 64 to approximately 68 y old. After adjustment for sex, APOE epsilon4 status, and intelligence quotient at 11 y old, the effects associated with total n-3 PUFA remained significant. Cognitive benefits were associated with higher erythrocyte n-3 PUFA content but were significant only in the absence of the APOE epsilon4 allele.
  
  
  CONCLUSIONS
  These data are evidence of a gene x environment interaction for cognitive aging. They are relevant to the analysis of trials of n-3 PUFA supplements in cognitive aging and dementia prevention, and they support heterogeneity in cognitive aging and, possibly, in Alzheimer disease.
authors.affiliation: Department of Environmental and Occupational Medicine, University of Aberdeen, Aberdeen, United Kingdom. l.j.whalley@abdn.ac.uk
authors.forename: Lawrence J
authors.initials: LJ
authors.lastname: Whalley
authors.forename: Ian J
authors.initials: IJ
authors.lastname: Deary
authors.forename: John M
authors.initials: JM
authors.lastname: Starr
authors.forename: Klaus W
authors.initials: KW
authors.lastname: Wahle
authors.forename: Kellie A
authors.initials: KA
authors.lastname: Rance
authors.forename: Victoria J
authors.initials: VJ
authors.lastname: Bourne
authors.forename: Helen C
authors.initials: HC
authors.lastname: Fox
mesh_terms: D000368:Aged; D000375:Aging / Q000378:metabolism*; D053327:Apolipoprotein E4 / Q000378:metabolism*; D003071:Cognition; D004910:Erythrocyte Membrane / Q000378:metabolism*; D015525:Fatty Acids, Omega-3 / Q000378:metabolism*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged
chemical_list: D053327:Apolipoprotein E4; D015525:Fatty Acids, Omega-3