Ten-year risk of dementia in subjects with mild cognitive impairment.
OBJECTIVE
To investigate the 10-year risk of dementia in subjects with mild cognitive impairment (MCI) ages 40 to 85 years.


METHODS
We selected subjects from a memory clinic if they met one of the following definitions of MCI: cognitive complaints (n = 181), aging-associated cognitive decline (AACD) (n = 163), mild functional impairment (n = 86), or amnestic MCI (n = 64). Subjects were reassessed after 2, 5, and 10 years. The risk of dementia was calculated with Kaplan-Meier statistics. Analyses were conducted in the entire sample and in subgroups of subjects aged 40 to 54 years, 55 to 69 years, and 70 to 85 years.


RESULTS
The 10-year risk of dementia was 0.27 (95% CI 0.20 to 0.34) in subjects with cognitive complaints, 0.28 (95% CI 0.21 to 0.35) in subjects with AACD, 0.44 (95% CI 0.32 to 0.56) in subjects with mild functional impairment, and 0.48 (95% CI 0.35 to 0.61) in subjects with amnestic MCI. Ninety-one percent of the demented subjects had probable AD. The risk of dementia increased with increasing age for all MCI definitions (p < 0.001). Depending on the MCI definition used, the risk for dementia ranged from 0 to 0.06 in subjects aged 40 to 54 years, from 0.37 to 0.52 in subjects aged 55 to 69 years, and from 0.77 to 1.0 in subjects aged 70 to 85 years.


CONCLUSIONS
The majority of subjects with MCI do not progress to dementia at the long term. Age strongly influences the dementia risk. MCI often represents the predementia stage of a neurodegenerative disorder in elderly subjects but rarely in younger subjects.
Visser
Pieter Jelle
PJ
Department of Psychiatry and Neuropsychology, University of Maastricht, Maastricht, The Netherlands. pj.visser@np.unimaas.nl
Kester
Arnold
A
Jolles
Jellemer
J
Verhey
Frans
F
D017677:Age Distribution; D000367:Age Factors; D003072:Cognition Disorders / Q000175:diagnosis / Q000453:epidemiology*; D015897:Comorbidity; D003704:Dementia / Q000175:diagnosis / Q000453:epidemiology*; D018450:Disease Progression; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D018570:Risk Assessment / Q000379:methods*; D012307:Risk Factors; D012720:Severity of Illness Index