title: IQ, educational attainment, memory and plasma lipids: associations with apolipoprotein E genotype in 5995 children.
abstract: BACKGROUND
  Apolipoprotein E (APOE) genotype (ε2/ε3/ε4: rs429358 ε4 allele; rs7412 ε2 allele) is strongly associated with both lipid levels and Alzheimer's disease. Although there is also evidence of milder cognitive impairment in later life in carriers of the APOE ε4 allele, there have been few studies investigating the impact of APOE genotype on cognitive function in children.
  
  
  METHODS
  We determined APOE genotype in 5995 children from the Avon Longitudinal Study of Parents and Children and investigated associations between APOE genotype and plasma lipids (at age 9), IQ (at age 8), memory (at ages 8 and 10), and performance in school attainment tests (at ages 7, 11, and 14).
  
  
  RESULTS
  Observed genotype group counts were consistent with Hardy-Weinberg equilibrium (χ(2)p value = .84). There were strong relationships between APOE genotype and low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, and triglycerides, which follow the same patterns as in adults. There was no strong evidence to suggest that APOE genotype was associated with IQ (all p values ≥ .46), memory function (p ≥ .35), or school attainment test results (p ≥ .28).
  
  
  CONCLUSIONS
  Although APOE genotype does have strong associations with lipid levels in childhood, there does not seem to be meaningful effects on cognitive performance, suggesting that any detrimental effects of the ε4 allele on cognitive function are not important until later life.
authors.affiliation: MRC Centre for Causal Analyses in Translational Epidemiology, School of Social and Community Medicine, University of Bristol, Bristol, UK. amy.taylor@bristol.ac.uk
authors.forename: Amy E
authors.initials: AE
authors.lastname: Taylor
authors.forename: Philip A I
authors.initials: PA
authors.lastname: Guthrie
authors.forename: George Davey
authors.initials: GD
authors.lastname: Smith
authors.forename: Jean
authors.initials: J
authors.lastname: Golding
authors.forename: Naveed
authors.initials: N
authors.lastname: Sattar
authors.forename: Aroon D
authors.initials: AD
authors.lastname: Hingorani
authors.forename: John E
authors.initials: JE
authors.lastname: Deanfield
authors.forename: Ian N M
authors.initials: IN
authors.lastname: Day
mesh_terms: D001057:Apolipoproteins E / Q000235:genetics*; D002648:Child; D002784:Cholesterol / Q000097:blood / Q000235:genetics; D003071:Cognition / Q000502:physiology; D004493:Education; D004522:Educational Status; D005260:Female; D005787:Gene Frequency; D006801:Humans; D007360:Intelligence / Q000235:genetics*; D008055:Lipids / Q000097:blood* / Q000235:genetics*; D008074:Lipoproteins / Q000097:blood / Q000235:genetics; D008297:Male; D008568:Memory / Q000502:physiology*; D009483:Neuropsychological Tests; D011247:Pregnancy; D011795:Surveys and Questionnaires
chemical_list: D001057:Apolipoproteins E; D008055:Lipids; D008074:Lipoproteins; C030104:lipoprotein cholesterol; D002784:Cholesterol