Risk factors for incident Alzheimer's disease in African Americans and Yoruba.
BACKGROUND
The incidence rate of Alzheimer's disease (AD) was found to be 2 times lower in Yoruba than in African Americans. This study was aimed at identifying the factors associated with increased risk of incident AD in the two communities.


METHODS
A two-stage design with initial screening using the CSI'D followed by neuropsychological test battery, relations' interview and physician assessment in a sub-sample.NINCDS-ADRDA criteria were met for AD. The risk factor variables assessed included demographic, lifestyle, medical and family history items.


RESULTS
In the Yoruba, AD was associated with age (OR = 1.07) and female gender (OR = 2.93). In African Americans, age (OR = 1.09) and rural living (OR = 2.08) were the significant risk factors, while alcohol was protective (OR = 0.49).


CONCLUSIONS
Age was a significant risk factor for AD at both sites. The higher risk of incident AD in the Yoruba female, and in African Americans who resided in rural areas in childhood were similar with the prevalence cases. Alcohol emerged a protective factor in African Americans. More studies are required, including biological measurements, to adequately explain the differences in rates.
Ogunniyi
A
A
Departments of Medicine and Psychiatry, University College Hospital, Ibadan, Nigeria.
Hall
K S
KS
Gureje
O
O
Baiyewu
O
O
Gao
S
S
Unverzagt
F W
FW
Smith-Gamble
V
V
Evans
R E
RE
Dickens
J
J
Musick
B S
BS
Hendrie
H C
HC
D001741:Black or African American / Q000706:statistics & numerical data; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000453:epidemiology*; D015331:Cohort Studies; D005260:Female; D006801:Humans; D007196:Indiana / Q000453:epidemiology; D008019:Life Style; D008137:Longitudinal Studies; D008297:Male; D009549:Nigeria / Q000453:epidemiology; D012307:Risk Factors; D012737:Sex Factors; D012959:Socioeconomic Factors