Effect of age, ethnicity, and head injury on the association between APOE genotypes and Alzheimer's disease

Ann N Y Acad Sci. 1996 Dec 16;802:6-15. doi: 10.1111/j.1749-6632.1996.tb32593.x.


The association between apolipoprotein E (APOE)-epsilon 4 and Alzheimer's disease has been confirmed worldwide. We and others have observed a diminished association in the very old and among African-Americans compared to Caucasians and Hispanics in New York. In this review we describe a new method we developed to compare relative risks by APOE genotypes in an expanded cohort of cases and controls from three ethnic groups in a New York City community and discuss the association as between APOE epsilon 4 and Alzheimer's disease as modified by head injury. Compared to persons with APOE epsilon 3/epsilon 3 genotypes, relative risk (RR) for Alzheimer's disease associated with APOE epsilon 4 homozygosity was similar across ethnic groups (African-American RR = 3.3; 95% c.i. 1.6-6.8; Caucasian RR = 5.3; 1.6-16.0; Hispanic RR = 2.5; 1.1-5.8). The risk was also increased for APOE epsilon 4 heterozygous Caucasians (RR = 3.2; 1.8-5.8) and Hispanics (RR 1.5; 1.0-2.2) but not African-Americans (RR = 0.6; 0.4-0.9). Risk of AD was not significantly diminished for individuals in any group with APOE epsilon 2/epsilon 2 or -epsilon 2/epsilon 3 genotypes. A 10-fold increase in the risk of Alzheimer's disease was associated with both APOE epsilon 4 and a history of traumatic head injury, compared to a twofold increase in risk with APOE epsilon 4 alone. Head injury in the absence of an APOE epsilon 4 allele did not increase risk. These results imply that in Alzheimer's disease genotypic risk associated with APOE may be influenced by age, ethnicity, and certain environmental factors.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • African Americans
  • Age Factors
  • Aged
  • Alleles
  • Alzheimer Disease / etiology
  • Alzheimer Disease / genetics*
  • Apolipoprotein E4
  • Apolipoproteins E / genetics*
  • Craniocerebral Trauma / complications*
  • Ethnic Groups / genetics*
  • European Continental Ancestry Group
  • Female
  • Gene Frequency
  • Genotype
  • Hispanic Americans
  • Humans
  • Male
  • Risk Factors


  • Apolipoprotein E4
  • Apolipoproteins E