Alzheimer's disease, genes, and environment: the value of international studies.
OBJECTIVE
To describe the construction of a disease model incorporating both genetic an environmental factors in the etiology of Alzheimer's disease (AD), using data generated from the Indianapolis-Ibadan dementia project (I-IDP).


METHODS
The I-IDP is a longitudinal comparative study of the prevalence and incidence o dementia in 2 communities: elderly African Americans living in Indianapolis, Indiana, an Yoruba living in Ibadan, Nigeria.


RESULTS
African Americans are more than twice as likely as Yoruba to develop AD. Possible explanations for this finding include genetic factors: the possession of the apolipoprotein E epsilon4 allele does not increase risk for AD among Yoruba but confers a sligh increase in AD risk for African Americans. As well, environmental factors may play a role: African Americans have a higher risk of vascular risk factors than do Yoruba.


CONCLUSIONS
International comparative studies, particularly those involving population from developing and developed countries, offer a unique opportunity for applying new in formation regarding population genetics to traditional AD risk factor research.
Hendrie
Hugh C
HC
Department of Psychiatry, Indiana University School of Medicine, Indiana University Center for Aging Research, Indianapolis 46202-2872, USA. hhendri@iupui.edu
Hall
Kathleen S
KS
Ogunniyi
Adesola
A
Gao
Sujuan
S
D000368:Aged; D000483:Alleles; D000544:Alzheimer Disease / Q000175:diagnosis / Q000453:epidemiology / Q000235:genetics*; D053327:Apolipoprotein E4; D001057:Apolipoproteins E / Q000235:genetics; D044383:Black People / Q000235:genetics* / Q000706:statistics & numerical data; D003431:Cross-Cultural Comparison; D003430:Cross-Sectional Studies; D015140:Dementia, Vascular / Q000175:diagnosis / Q000453:epidemiology / Q000235:genetics*; D014644:Genetic Variation / Q000235:genetics; D005828:Genetics, Population; D006801:Humans; D015994:Incidence; D007196:Indiana; D008019:Life Style; D008137:Longitudinal Studies; D009549:Nigeria; D010641:Phenotype; D012307:Risk Factors; D012931:Social Environment; D014505:Urban Population / Q000706:statistics & numerical data*; D001741:Black or African American
D053327:Apolipoprotein E4; D001057:Apolipoproteins E