The prevalence of cognitive impairment with no dementia in older people: the Seoul study.

OBJECTIVE

This study aimed to estimate prevalence of cognitive impairment with no dementia (CIND) in older people. It was conducted in an urban area of Korea, Seoul, and employed a two-stage design for case identification.

METHODS

Overall 643 persons aged 65 years and older participated and 217 persons sampled from the three levels of performance of MMSE underwent a second stage clinical evaluation. CIND was diagnosed when the global Clinical Dementia Rating (CDR) index was 0.5 and the Diagnostic and Statistical Manual of Mental Disorders, 4th edition diagnostic features of dementia were not satisfied. CIND cases without any apparent causes were classified as CIND of unidentified cause (CIND(uc)).

RESULTS

CIND prevalence ranged from 26.3% in persons aged 65-69 to 46.5% in persons aged 85 years and older. The age-standardized prevalence for overall CIND was 31.9% and for CIND(uc) 19.2%. The prevalences of CIND for the three severity grade were 15.8%, 9.7%, and 6.2% for CDR sum of boxes scores of 0.5, 1-1.5, and >or=2, respectively.

CONCLUSIONS

The prevalence of CIND in community-residing elderly is probably higher than previously reported. The results of this study are useful for assessments of present and future demands for healthcare services.