title: Dementia incidence declined in African-Americans but not in Yoruba.
abstract: BACKGROUND
  To compare dementia incidence of African-American and Yoruba cohorts aged ≥70 years enrolled in 1992 and 2001.
  
  
  METHODS
  African-Americans residing in Indianapolis and Yoruba in Ibadan, Nigeria without dementia were enrolled in 1992 and 2001 and evaluated every 2-3 years until 2009. The cohorts consist of 1440 African-Americans, 1774 Yoruba in 1992 and 1835 African-Americans and 1895 Yoruba in the 2001 cohorts aged ≥70 years.
  
  
  RESULTS
  In African-Americans, dementia and Alzheimer's disease (AD) incidence rates were significantly lower in 2001 than 1992 for all age groups except the oldest group. The overall standardized annual dementia incidence rates were 3.6% (95% confidence interval [CI], 3.2%-4.1%) in the 1992 cohort and 1.4% (95% CI, 1.2%-1.7%) in the 2001 cohort. There was no significant difference in dementia or AD incidence between the Yoruba cohorts.
  
  
  CONCLUSIONS
  Future research is needed to explore the reasons for the differential changes in incidence rates in these two populations.
authors.affiliation: Department of Biostatistics, Indiana University School of Medicine, Indianapolis, IN, USA. Electronic address: sgao@iu.edu.
authors.forename: Sujuan
authors.initials: S
authors.lastname: Gao
authors.affiliation: Department of Medicine, College of Medicine, University of Ibadan, Ibadan, Nigeria.
authors.forename: Adesola
authors.initials: A
authors.lastname: Ogunniyi
authors.affiliation: Department of Psychiatry, Indiana University School of Medicine, Indianapolis, IN, USA.
authors.forename: Kathleen S
authors.initials: KS
authors.lastname: Hall
authors.affiliation: Department of Psychiatry, College of Medicine, University of Ibadan, Ibadan, Nigeria.
authors.forename: Olusegun
authors.initials: O
authors.lastname: Baiyewu
authors.affiliation: Department of Psychiatry, Indiana University School of Medicine, Indianapolis, IN, USA.
authors.forename: Frederick W
authors.initials: FW
authors.lastname: Unverzagt
authors.affiliation: Department of Biostatistics, Indiana University School of Medicine, Indianapolis, IN, USA.
authors.forename: Kathleen A
authors.initials: KA
authors.lastname: Lane
authors.affiliation: Department of Pathology and Laboratory Medicine, Indiana University School of Medicine, Indianapolis, IN, USA.
authors.forename: Jill R
authors.initials: JR
authors.lastname: Murrell
authors.affiliation: Department of Psychiatry, College of Medicine, University of Ibadan, Ibadan, Nigeria.
authors.forename: Oye
authors.initials: O
authors.lastname: Gureje
authors.affiliation: Department of Neurology, Indiana University School of Medicine, Indianapolis, IN, USA.
authors.forename: Ann M
authors.initials: AM
authors.lastname: Hake
authors.affiliation: Department of Psychiatry, Indiana University School of Medicine, Indianapolis, IN, USA; Indiana University Center for Aging Research, Indianapolis, IN, USA; Regenstrief Institute, Inc., Indianapolis, IN, USA.
authors.forename: Hugh C
authors.initials: HC
authors.lastname: Hendrie
mesh_terms: D001741:Black or African American; D017677:Age Distribution; D000368:Aged; D000369:Aged, 80 and over; D015331:Cohort Studies; D003704:Dementia / Q000453:epidemiology* / Q000208:ethnology*; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D009549:Nigeria / Q000453:epidemiology; D011569:Psychiatric Status Rating Scales; D014481:United States / Q000453:epidemiology
keywords: African-Americans; Alzheimer's disease; Dementia; Incidence; Nigerians