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. 2011 Jan-Mar;25(1):4-10.
doi: 10.1097/WAD.0b013e3181f1c8b1.

Incidence and risk factors for cognitive impairment no dementia and mild cognitive impairment in African Americans

Frederick W Unverzagt  1 , Adesola Ogunniyi, Vanessa Taler, Sujuan Gao, Kathleen A Lane, Olusegun Baiyewu, Oye Gureje, Valerie Smith-Gamble, Ann Hake, Hugh C Hendrie, Kathleen S Hall
Affiliations

Incidence and risk factors for cognitive impairment no dementia and mild cognitive impairment in African Americans

Frederick W Unverzagt et al. Alzheimer Dis Assoc Disord. 2011 Jan-Mar.

Abstract

The aim of this study was to estimate the age-specific incidence of cognitive impairment, no dementia and mild cognitive impairment (CIND/MCI) in a large, community-based sample of older African Americans in Indianapolis, IN. A longitudinal, prospective, 2-stage design was used with follow-up assessments 2 and 5 years after the baseline. A total of 1668 participants completed the 2-year follow-up and a total of 1255 participants completed the 5-year follow-up. The person-years method was used to calculate incidence rates. The age-standardized, annual incidence of CIND/MCI was 4.95% (CI=3.39-6.52) and the subtype of medically unexplained memory loss (single-domain and multidomain amnestic MCI) was 3.67% (CI 2.75-4.48). Rates increased with age (3.43% for participants aged 65 to 74 y, 6.44% from age 75 to 84 y, and 9.62% from age 85+ y), history of head injury [OR 2.37 (CI 1.31-4.29)], and history of depression [OR 2.22 (CI 1.16-4.25)] while increased years of schooling was protective [OR 0.91 (CI 0.85-0.97)]. Rates did not vary substantially by sex. Almost 1 in 20 elderly community-dwelling African Americans, and almost 1 in 10 of the oldest-old (85+ y) developed CIND/MCI each year in this cohort. Risk factors of age and education suggest exposures or mechanisms at both ends of the life span may be important variables in onset of CIND/MCI.

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Figures

Figure 1
Figure 1
Study Design and Participant Flow (* denotes total number of subjects who provided follow-up information).
Figure 2
Figure 2
Comparison of age-specific and age-standardized incidence rates of CIND/MCI and dementia in this cohort.
See this image and copyright information in PMC

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