Mild cognitive impairment and 10-year trajectories of disability in the Iowa Established Populations for Epidemiologic Studies of the Elderly cohort.
OBJECTIVE
To apply diagnostic criteria for mild cognitive impairment (MCI) to a geographically representative sample, to estimate the prevalence of MCI, and to estimate 10-year trajectories of incident disability for cognitively intact participants and subgroups with MCI.


METHODS
Prospective cohort; 10 years of follow-up.


METHODS
Community-based survey of noninstitutionalized population aged 65 and or older in two rural Iowa counties (Washington and Iowa).


METHODS
Iowa Established Populations for Epidemiologic Studies of the Elderly (aged > or = 65; N = 3,673; 61.3% female; 99.9% white).


METHODS
Age, sex, education, Short Portable Mental Status Questionnaire (SPMSQ), 20-item word recall, activities of daily living (ADLs), instrumental activities of daily living (IADLs), chronic medical conditions.


RESULTS
MCI was prevalent in 24.7% of participants at baseline. Most participants in the overall cohort remained stable or changed slowly (< or = 1 new limitations) over 10 years (63.1% for SPMSQ, 89.3% for word recall, and 61.7% for ADL disability). For MCI/no prevalent IADL disability (Stage 1 MCI), disability progression was similar to that in the cognitively intact subgroup (median = 0.08 vs 0.05 disabilities per year). For MCI plus prevalent IADL disability (Stage 2 MCI), the median rate of change was equivalent to that of the severely impaired (0.23 disabilities per year; interquartile range = 0.12-0.36).


CONCLUSIONS
Unlike participants with MCI who reported no IADL limitations, those with such limitations were more likely to develop ADL disability--a prerequisite for a diagnosis of dementia.
Purser
Jama L
JL
Division of Geriatrics, Department of Medicine, Duke University Medical Center, Durham, North Carolina 27710, USA. jlp@geri.duke.edu
Fillenbaum
Gerda G
GG
Pieper
Carl F
CF
Wallace
Robert B
RB
D000203:Activities of Daily Living / Q000145:classification; D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000453:epidemiology*; D000647:Amnesia / Q000453:epidemiology*; D003072:Cognition Disorders / Q000453:epidemiology*; D015331:Cohort Studies; D004185:Disability Evaluation; D018450:Disease Progression; D005260:Female; D005500:Follow-Up Studies; D006306:Health Surveys; D006801:Humans; D007484:Iowa; D008137:Longitudinal Studies; D008297:Male; D009483:Neuropsychological Tests / Q000706:statistics & numerical data; D011336:Probability; D011594:Psychometrics