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 subtypes 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 heterogeneous 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.

Objective

To examine the risk factors for mild cognitive impairment (MCI) in a longitudinal population study-the Cardiovascular Health Study Cognition Study.

Design

We examined the factors that in the period 1991 through 1994 predicted the development of MCI in all participants of the Cardiovascular Health Study Cognition Study. Further examination was conducted in the Pittsburgh, Pa, cohort (n = 927), where participants with MCI were classified as having either the MCI amnestic-type or the MCI multiple cognitive deficits-type.

Setting

Multicenter population study.

Patients

This study includes all participants of the Cardiovascular Health Study Cognition Study (n = 3608) who had a magnetic resonance imaging (MRI) scan of the brain between 1991 and 1994, and detailed neuropsychological, neurological, and medical evaluations to identify the presence of MCI or dementia in the period 1998 to 1999. The mean time between the closest clinical examination to the MRI and the diagnostic evaluation for cognitive disorders was 5.8 years for the Cardiovascular Health Study Cognition Study cohort and 6.0 years for the Pittsburgh cohort.

Main outcome measures

Risk factors for MCI at the time of the MRI were identified using logistic regression, controlling for age, race, educational level, baseline Modified Mini-Mental State Examination and Digit Symbol Test scores, measurements of depression, MRI findings (atrophy, ventricular volume, white matter lesions, and infarcts), the presence of the apolipoprotein E (APOE) epsilon4 allele, hypertension, diabetes mellitus, and heart disease.

Results

Mild cognitive impairment (n = 577) was associated with race (African American), low educational level, low Modified Mini-Mental State Examination and Digit Symbol Test scores, cortical atrophy, MRI-identified infarcts, and measurements of depression. The MCI amnestic-type was associated with MRI-identified infarcts, the presence of the APOE epsilon4 allele, and low Modified Mini-Mental State Examination scores. The MCI multiple cognitive deficits-type was associated with low Modified Mini-Mental State Examination and Digit Symbol Test scores.

Conclusions

The development of MCI is associated with measurements of cognition and depression, racial and constitutional factors, and cerebrovascular disease. Early cognitive deficits seem to be a common denominator for the 2 forms of MCI; the presence of cerebrovascular disease and the APOE epsilon4 allele is associated with the amnestic type of MCI.