Prevalence rates for dementia and Alzheimer's disease in African Americans: 1992 versus 2001.
BACKGROUND
This study compares age-specific and overall prevalence rates for dementia and Alzheimer's disease (AD) in two nonoverlapping, population-based cohorts of elderly African Americans in Indianapolis in 2001 and 1992.


METHODS
We used a two-stage design. The first stage involves the Community Screening Interview for Dementia (CSI-D). The CSI-D scores are grouped into good, intermediate, and poor performance before selection for clinical assessment. Diagnoses were performed using standard criteria in a consensus diagnosis conference; clinicians were blind to performance groups. In 1992, interviewers visited randomly sampled addresses to enroll self-identified African Americans aged > or =65 years. Of 2582 eligible, 2212 enrolled (9.6% refused, and 4.7% were too sick). In 2001, Medicare rolls were used for African Americans aged >70 years. Of 4260 eligible, 1892 (44%) enrolled, 1999 (47%) refused, and the remainder did not participate for other reasons.


RESULTS
The overall age-adjusted prevalence rate for dementia at age > or =70 years in 2001 was 7.45% (95 confidence interval [CI], 4.27-10.64), and in the 1992 cohort, this prevalence rate was 6.75% (95% CI, 5.77-7.74). The overall age-adjusted prevalence rate at age > or =70 years for AD in the 2001 cohort was 6.77% (95% CI, 3.65-9.90), and for the 1992 cohort, it was 5.47% (95% CI, 4.51-6.42). Rates for dementia and AD were not significantly different in the two cohorts (dementia, P = .3534; AD, P = .2649).


CONCLUSIONS
We found no differences in the prevalence rates of dementia and AD between 1992 and 2001, despite significant differences in medical history and medical treatment within these population-based cohorts of African American elderly.
Hall
Kathleen S
KS
Department of Psychiatry, Indiana University School of Medicine, Indianapolis, IN, USA. khall@iupui.edu
Gao
Sujuan
S
Baiyewu
Olusegun
O
Lane
Kathleen A
KA
Gureje
Oye
O
Shen
Jianzhao
J
Ogunniyi
Adesola
A
Murrell
Jill R
JR
Unverzagt
Frederick W
FW
Dickens
Jeanne
J
Smith-Gamble
Valerie
V
Hendrie
Hugh C
HC
D001741:Black or African American / Q000235:genetics / Q000706:statistics & numerical data*; D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000175:diagnosis / Q000453:epidemiology* / Q000208:ethnology / Q000235:genetics; D003072:Cognition Disorders / Q000453:epidemiology* / Q000208:ethnology / Q000235:genetics; D015331:Cohort Studies; D016001:Confidence Intervals; D003704:Dementia / Q000175:diagnosis / Q000453:epidemiology* / Q000208:ethnology / Q000235:genetics; D039721:Diagnostic and Statistical Manual of Mental Disorders; D005260:Female; D005838:Genotype; D006801:Humans; D007196:Indiana / Q000453:epidemiology; D038801:International Classification of Diseases; D008297:Male; D008403:Mass Screening; D009483:Neuropsychological Tests; D015995:Prevalence; D011569:Psychiatric Status Rating Scales; D012307:Risk Factors; D011795:Surveys and Questionnaires