title: Regional differences in effects of APOE ε4 on cognitive impairment in non-demented subjects.
abstract: BACKGROUND
  The APOE ε4 allele is a risk factor for Alzheimer's disease (AD). APOE ε4 is common in non-demented subjects with cognitive impairment. In both healthy people and people with AD, its prevalence has a north-south gradient across Europe. In the present study, we investigated whether the relation between the APOE ε4 allele and cognitive impairment varied across Northern, Middle and Southern Europe. We also investigated whether a north-south gradient existed in subjects with subjective cognitive impairment (SCI), amnestic mild cognitive impairment (MCI) and non-amnestic MCI.
  
  
  METHODS
  Data from 16 centers across Europe were analyzed.
  
  
  RESULTS
  A north-south gradient in APOE ε4 prevalence existed in the total sample (62.7% for APOE ε4 carriers in the northern region, 42.1% in the middle region, and 31.5% in the southern region) and in subjects with SCI and amnestic MCI separately. Only in Middle Europe was the APOE ε4 allele significantly associated with poor performance on tests of delayed recall and learning, as well as with the amnestic subtype of MCI.
  
  
  CONCLUSIONS
  The APOE ε4 allele frequencies in subjects with SCI and amnestic MCI have a north-south gradient. The relation between the APOE ε4 allele and cognition is region dependent.
authors.affiliation: Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Stockholm, Sweden.
authors.forename: J
authors.initials: J
authors.lastname: Norberg
authors.forename: C
authors.initials: C
authors.lastname: Graff
authors.forename: O
authors.initials: O
authors.lastname: Almkvist
authors.forename: M
authors.initials: M
authors.lastname: Ewers
authors.forename: G B
authors.initials: GB
authors.lastname: Frisoni
authors.forename: L
authors.initials: L
authors.lastname: Frölich
authors.forename: H
authors.initials: H
authors.lastname: Hampel
authors.forename: R W
authors.initials: RW
authors.lastname: Jones
authors.forename: P G
authors.initials: PG
authors.lastname: Kehoe
authors.forename: H
authors.initials: H
authors.lastname: Lenoir
authors.forename: L
authors.initials: L
authors.lastname: Minthon
authors.forename: F
authors.initials: F
authors.lastname: Nobili
authors.forename: M
authors.initials: M
authors.lastname: Olde Rikkert
authors.forename: A-S
authors.initials: AS
authors.lastname: Rigaud
authors.forename: P
authors.initials: P
authors.lastname: Scheltens
authors.forename: H
authors.initials: H
authors.lastname: Soininen
authors.forename: L
authors.initials: L
authors.lastname: Spiru
authors.forename: M
authors.initials: M
authors.lastname: Tsolaki
authors.forename: L-O
authors.initials: LO
authors.lastname: Wahlund
authors.forename: B
authors.initials: B
authors.lastname: Vellas
authors.forename: G
authors.initials: G
authors.lastname: Wilcock
authors.forename: L S
authors.initials: LS
authors.lastname: Elias-Sonnenschein
authors.forename: F R J
authors.initials: FR
authors.lastname: Verhey
authors.forename: P J
authors.initials: PJ
authors.lastname: Visser
mesh_terms: D001057:Apolipoproteins E / Q000235:genetics*; D003071:Cognition; D003072:Cognition Disorders / Q000453:epidemiology / Q000235:genetics*; D003704:Dementia / Q000145:classification / Q000453:epidemiology / Q000235:genetics*; D005060:Europe / Q000453:epidemiology; D005787:Gene Frequency; D006801:Humans; D012016:Reference Values; D019371:Topography, Medical
chemical_list: D001057:Apolipoproteins E