title: Apolipoprotein E ε4 is superior to apolipoprotein E ε2 in predicting cognitive scores over 30 months.
abstract: BACKGROUND
  The purpose of this study was to compare apolipoprotein E ε4 (Apo E ε4) and apolipoprotein E ε2 (Apo E ε2) as predictors of cognitive and functional trajectories over 30 months.
  
  
  METHODS
  This prospective cohort study included 287 community-dwelling memory clinic patients with dementia, mild cognitive impairment, or no cognitive impairment. The Addenbrooke Cognitive Examination, Mini-Mental State Examination, Montreal Cognitive Assessment, Delirium Index, and Nottingham Instrumental Activities of Daily Living tests were administered to each subject.
  
  
  RESULTS
  One hundred and nine subjects (40%) carried Apo E ε4 and 48 (16.7%) carried Apo E ε2. One hundred and nine ε4-positive subjects differed significantly from 178 ε4-negative subjects in 19/52 comparisons (36.5%), whereas 46 Apo E ε2-positive subjects had 0/52 significant differences from 239 ε2-negative subjects (P < 0.0001). The variables most affected by ε4 were the Delirium Index and Mini-Mental State Examination. Instrumental Activities of Daily Living score and residence were unrelated to Apo E ε4 or ε2.
  
  
  CONCLUSIONS
  Apo E ε4 positivity predicted four cognitive scores measured every 6 months over 30 months. Apo E ε2 scores predicted none of 52 comparisons.
authors.affiliation: Geriatric Medicine and Gerontology, University of Newcastle, Callaghan, NSW, Australia.
authors.forename: Paul
authors.initials: P
authors.lastname: Regal
authors.forename: Balakrishnan
authors.initials: B
authors.lastname: Nair
authors.forename: Eileen
authors.initials: E
authors.lastname: Hetherington
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D053329:Apolipoprotein E2 / Q000235:genetics*; D053327:Apolipoprotein E4 / Q000235:genetics*; D003072:Cognition Disorders / Q000175:diagnosis* / Q000235:genetics; D015331:Cohort Studies; D005260:Female; D005819:Genetic Markers; D006801:Humans; D008297:Male; D009483:Neuropsychological Tests; D009517:New South Wales; D011237:Predictive Value of Tests; D011446:Prospective Studies; D017678:Sex Distribution
chemical_list: D053329:Apolipoprotein E2; D053327:Apolipoprotein E4; D005819:Genetic Markers
keywords: apolipoprotein E genotype; dementia; mild cognitive impairment