Risk factors and Alzheimer's disease: a comparative study of two communities.
OBJECTIVE
To determine the association between demographic, lifestyle and medical history factors to Alzheimer's disease (AD), we studied samples of two community dwelling populations with significantly different prevalence rates of AD in Indianapolis, USA (6.24%) and Ibadan, Nigeria (1.4%).


METHODS
The samples were drawn from African-American community dwelling residents 65 years of age and over in Indianapolis, and Yoruba community-dwelling residents 65 years of age and over in Ibadan. A two-stage epidemiological design was used in which diagnosis of AD was by National Institute of Neurological and Communicative Disorders and Stroke and the Alzheimer's Disease and Related Disorders Association criteria.


RESULTS
In Indianapolis, age (odds ratio [OR] = 1.16; 95% confidence interval [CI] = 1.11-1.21), family history of dementia (OR = 5.40; 95% CI = 1.99-14.62), low education (0-6 years, OR = 3.49; 95% CI = 1.06-11.48) and rural residence (OR = 2.49; 95% CI = 1.05-5.88) were associated with a higher risk of AD. In Ibadan, age (OR = 1.15; 95% CI = 1.12-1.18) and female gender (OR = 13.9; 95% CI = 3.85-50.28) were associated with a higher risk of AD.


CONCLUSIONS
The remarkably similar odds ratios between age and AD between sites suggest that biological processes associated with ageing are essential elements in the development of AD but that genetic and environmental risk factors may alter age-specific rates. In our longitudinal study, we intend to investigate in more depth the interaction between these ageing, genetic and environmental factors.
Hall
K
K
Department of Psychiatry, Indiana University School of Medicine, Indianapolis, USA.
Gureje
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O
Gao
S
S
Ogunniyi
A
A
Hui
S L
SL
Baiyewu
O
O
Unverzagt
F W
FW
Oluwole
S
S
Hendrie
H C
HC
D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000208:ethnology* / Q000209:etiology; D015897:Comorbidity; D003431:Cross-Cultural Comparison; D005260:Female; D006306:Health Surveys; D006801:Humans; D007196:Indiana / Q000453:epidemiology; D008019:Life Style; D008297:Male; D009549:Nigeria / Q000453:epidemiology; D012189:Retrospective Studies; D012307:Risk Factors; D012959:Socioeconomic Factors; D013223:Statistics as Topic