Prevalence and classification of mild cognitive impairment in the cardiovascular health study cognition study part 1

Objective: To examine the prevalence of mild cognitive impairment (MCI) and its diagnostic classification in the Cardiovascular Health Study (CHS) Cognition Study. Design: The CHS Cognition Study is an ancillary study of the CHS that was conducted to determine the presence of MCI and dementia in the CHS cohort. Setting: Multicenter population study. Patients: We examined 3608 participants in the CHS who had undergone detailed neurological, neuropsychological, neuroradiological, and psychiatric testing to identify dementia and MCI. Main Outcome Measures: The prevalence of MCI was determined for the whole cohort, and specific sub-types of MCI were examined in detail only at the Pittsburgh, Pa, center (n=927). Mild cognitive impairment was classified as either MCI amnestic-type or MCI multiple cognitive deficits-type. Results: The overall prevalence of MCI was 19% (465 of 2470 participants) prevalence increased with age from 19% in participants younger than 75 years to 29% in those older than 85 years. The overall prevalence of MCI at the Pittsburgh center was 22% (130 of 599 participants); prevalence of the MCI amnesic-type was 6% and of the MCI multiple cognitive deficits-type was 16%. Conclusions: Twenty-two percent of the participants aged 75 years or older had MCI. Mild cognitive impairment is a heterogenous syndrome, where the MCI amnestic-type is less frequent than the MCI multiple cognitive deficits-type. Most of the participants with MCI had comorbid conditions that may affect their cognitive functions.