title: Risk-reducing effect of education in Alzheimer's disease.
abstract: OBJECTIVE
  To estimate the effect of education on the risk of Alzheimer's disease (AD).
  
  
  METHODS
  373 patients diagnosed with AD and 559 healthy control individuals without first degree relatives with known dementia, were included in a case-control study (2003-2006). All individuals were genotyped for APOE alleles. Odds ratio (OR) for developing AD was calculated by binary logistic regression, with the number of APOE epsilon 4 alleles and educational level as covariates. Analyses were carried out separately for men and women and for different age groups.
  
  
  RESULTS
  Carriers of one APOE epsilon 4 allele had OR of 4.2, and carriers of two APOE epsilon 4 alleles OR of 12.4 for developing AD. When adjusted for the number of APOE epsilon 4 alleles, OR for developing AD was significantly reduced in participants with 8-9 years of education compared to those with only 6-7 years, and was reduced further for those with 10-18 years of education. These findings were obtained for all the age groups studied and for both men and women.
  
  
  CONCLUSIONS
  Education had a consistently protective effect on the risk of developing clinical AD in a dose-dependent manner in both men and women, and in all age groups, also when adjusting for the number of APOE epsilon 4 alleles. Male gender was protective, probably at least in part because of a higher educational level.
authors.affiliation: Department of Neuroscience, Norwegian University of Science and Technology, Trondheim, Norway. sigrid.b.sando@ntnu.no
authors.forename: Sigrid Botne
authors.initials: SB
authors.lastname: Sando
authors.forename: Stacey
authors.initials: S
authors.lastname: Melquist
authors.forename: Ashley
authors.initials: A
authors.lastname: Cannon
authors.forename: Michael
authors.initials: M
authors.lastname: Hutton
authors.forename: Olav
authors.initials: O
authors.lastname: Sletvold
authors.forename: Ingvild
authors.initials: I
authors.lastname: Saltvedt
authors.forename: Linda R
authors.initials: LR
authors.lastname: White
authors.forename: Stian
authors.initials: S
authors.lastname: Lydersen
authors.forename: Jan
authors.initials: J
authors.lastname: Aasly
mesh_terms: D017668:Age of Onset; D000368:Aged; D000369:Aged, 80 and over; D000483:Alleles; D000544:Alzheimer Disease / Q000235:genetics* / Q000517:prevention & control*; D053327:Apolipoprotein E4 / Q000235:genetics*; D016022:Case-Control Studies; D004522:Educational Status; D005260:Female; D005787:Gene Frequency; D020022:Genetic Predisposition to Disease / Q000235:genetics; D006801:Humans; D016015:Logistic Models; D008297:Male; D016017:Odds Ratio; D018570:Risk Assessment; D017678:Sex Distribution
chemical_list: D053327:Apolipoprotein E4