APOE ε4 and the risk for Alzheimer disease and cognitive decline in African Americans and Yoruba

Hugh Hendrie, Jill Murrell, Olusegun Baiyewu, Kathleen A. Lane, Christianna Purnell, Adesola Ogunniyi, Frederick Unverzagt, Kathleen Hall, Christopher Callahan, Andrew Saykin, Oye Gureje, Ann Hake, Tatiana Foroud, Sujuan Gao

Research output: Contribution to journalArticle

18 Citations (Scopus)

Abstract

Background: There is little information on the association of the APOEe4 allele and AD risk in African populations. In previous analyses from the Indianapolis-Ibadan dementia project, we have reported that APOE ε4 increased the risk for Alzheimer's disease (AD) in African Americans but not in Yoruba. This study represents a replication of this earlier work using enriched cohorts and extending the analysis to include cognitive decline. Methods: In this longitudinal study of two community dwelling cohorts of elderly Yoruba and African Americans, APOE genotyping was conducted from blood samples taken on or before 2001 (1,871 African Americans & 2,200 Yoruba). Mean follow up time was 8.5 years for African Americans and 8.8 years for Yoruba. The effects of heterozygosity or homozygosity of ε4 and of the possession of e4 on time to incident AD and on cognitive decline were determined using Cox's proportional hazards regression and mixed effects models. Results: After adjusting for covariates, one or two copies of the APOE ε4 allele were significant risk factors for incident AD (p < 0.0001) and cognitive decline in the African-American population (p < 0001). In the Yoruba, only homozygosity for APOE ε4 was a significant risk factor for AD (p = 0.0002) but not for cognitive decline (p = 0.2346), however, possession of an e4 allele was significant for both incident AD (p = 0.0489) and cognitive decline (p = 0.0425). Conclusions: In this large longitudinal comparative study, APOE ε4 had a significant, but weaker, effect on incident AD and on cognitive decline in Yoruba than in African Americans. The reasons for these differences remain unclear.

Original languageEnglish
Pages (from-to)977-985
Number of pages9
JournalInternational Psychogeriatrics
Volume26
Issue number6
DOIs
StatePublished - 2014

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African Americans
Alzheimer Disease
Alleles
Longitudinal Studies
Independent Living
Cognitive Dysfunction
Alzheimer disease type 4
Population
Dementia
Cohort Studies

Keywords

  • African Americans
  • Alzheimer disease
  • APOE ε4
  • cognitive impairment
  • Yoruba

ASJC Scopus subject areas

  • Geriatrics and Gerontology
  • Psychiatry and Mental health
  • Gerontology
  • Clinical Psychology
  • Medicine(all)

Cite this

APOE ε4 and the risk for Alzheimer disease and cognitive decline in African Americans and Yoruba. / Hendrie, Hugh; Murrell, Jill; Baiyewu, Olusegun; Lane, Kathleen A.; Purnell, Christianna; Ogunniyi, Adesola; Unverzagt, Frederick; Hall, Kathleen; Callahan, Christopher; Saykin, Andrew; Gureje, Oye; Hake, Ann; Foroud, Tatiana; Gao, Sujuan.

In: International Psychogeriatrics, Vol. 26, No. 6, 2014, p. 977-985.

Research output: Contribution to journalArticle

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AU - Murrell, Jill

AU - Baiyewu, Olusegun

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AU - Purnell, Christianna

AU - Ogunniyi, Adesola

AU - Unverzagt, Frederick

AU - Hall, Kathleen

AU - Callahan, Christopher

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AU - Foroud, Tatiana

AU - Gao, Sujuan

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